 Okay, Harun Dheesh Who are all there? Okay, Nikhil Talitha Tapas Nikhil. Good afternoon Nikhil, Dheesh Atmesh. Hi, Atmesh. Okay, so we'll start Today we are going to start metallurgy and Today only we'll finish this particular chapter. So first of all in this chapter you see there is Like again, it's a theoretical chapter There are a few Processes we have that generally you should you know know in board also they ask a Few theoretical things from this chapter for board exam also it is a bit important for J It is not that much important if you have a little bit of idea of electrode potential what metal can replace the other metal or not depending on its electrode potential then High stress, high iron Then you can actually do those kind of questions Okay, but you see this metallurgy obviously in this chapter We are going to discuss about the extraction of metals, right? How do we extract metal from its ore? right So this chapter is actually Like classified or we're going to study this chapter into two different part One the first part we have is the extraction of metals extraction of metals From It's ore from it's ores and Alloy we'll see about alloy Okay, so this is nothing this in this part. There is not much thing only our one particular Alloy are made up of what all elements? Okay the composition and all sometimes they ask not in J But need they ask, okay? Extraction of metals you see first of all there are two terms we have in this and that is mineral and ores right two terms two different terms we have here that is minerals or ores Right, so first of all you write down the definition of minerals These are the Definition of minerals you write down. These are the compounds of Metals compounds of metals which are which are Naturally available which are Naturally available in the Earth's crust Earth's crust and can be obtained and Can be obtained Okay, these are the compounds of metals which are which are naturally available in the earth's crust and can be obtained by Mining okay, what are these things ores? Right, so these are the minerals you see the definition of this these are the minerals from which a metal can be extracted Metal can be extracted Economically and conveniently Conveniently okay, so ores are the minerals Right, but all minerals are not ores. Minerals are actually all those compounds of Any metals which is available in the earth's crust right? like if I take the example of Iron-Pyrite FES2 Right FES2 is a mineral Okay Example here I'll write down for mineral FES2 you write down FES2 is a Mineral it's not an ore Why it is not an ore because it contains iron into this but we don't use this particular Mineral for the extraction of iron Right for extraction of iron. We don't use FES2. That's why iron-Pyrite which is FES2 is not an ore, but it is a Mineral understood so here you see So from this particular thing we can say that all ores This point also you write down the last one here all ores are minerals all ores are minerals all minerals are not ores are Not ores vice versa is not true We only consider those minerals as an ore from which we can extract the metal economically and conveniently Right iron-Pyrite if you use this particular compound to extract iron you will get iron, but that is That process is not cost effective Okay, you have to put a lot of money and it requires a lot of time also. That's why we don't use all those Elements or compounds available in the earth crust for the preparation or extraction of any metals, right? These are the diff these are difference of minerals and ores we have okay ores are the compounds from which the metal Can be extracted right? That's the only thing minerals are all those compounds of metals Okay, all those are minerals now. There is one more term that we have that is gang, right on GAN GUE right these are the impurities these are The impurities present in the ore obviously when the formation or extraction of Metals we are doing with We're doing from a compound and that compound contains many other elements also apart from the metals which we have to extract Right so apart from that particular metal all other elements which is present in the ore that we consider as impurities and those impurities We call it as gang right GAN GUE now, of course if I have one ore right and from this ore you have to extract the metal Right, so what are the different different processes we can have processes when I say it may be physical Processes also it may be chemical by chemical reactions also, right? So for any extraction for any kind of extraction we have a set of you know a set of Process we have to follow But that particular process is not necessary that it will be same for all kind of metal Okay, remember all these processes that we have we use this process We have different different for one particular thing. We have different different kinds of processes those process We use according to the nature or the properties of metals or ores that we are using Correct, so depending on the properties of metals or ores we use different different processes again one thing that we whenever Whenever we do this extraction you must keep this in mind that the the process must be cost effective It's not like you are putting lax of money for extraction of one particular small amount of metal Okay, so everything is involved into this what time you are putting in for the extraction What is the manpower you are putting in what is the money you are putting in in the extraction if all these Like if all these things are too much like you're putting so much of time You're putting so much of money for extraction of one metals and then after using that matters the no the revenue that you Generate that must be balanced right the the money you are putting in and the money you are getting after the no Making product from that particular metal so depending all these you know Things will have different different processes and according to the properties will use those process for Different different methods so we cannot say for every metal. This is the process We have to follow maybe for iron iron. We have different different set of processes Maybe for aluminium. We have different processes. Maybe for copper. We have different processes, right? So first of all what we do we'll see some examples of some general name of compounds Like that also they ask some time in the exam obviously not in JEE but in others exam like you know bit sad and Karnataka CET comet K and all they ask this kind of question. So first of all, we'll see some you know some Common names of compounds. Okay, and then we'll see the extraction processes general extraction processes We'll see right. So what we are going to do today General extraction processes. We'll see like suppose if I tell you any metal if you have to extract first of all the ores that you are getting right that ores you have to grind or pulverize, okay Grinding means what because whenever you get the Ores from the earth crust it is a big lump actually, okay? It's a big lump. So this you have to grind into small pieces, right? That we call it as grinding the Dissociation of this into small pieces and when you finally divide this into very fine particles that process is pulverizing Okay, so this lump will dissociate into the small pieces and then we'll do the concentration of ore So first step is what I'll write down all this thing. I'm just giving you a brief No idea of this thing grinding and pulverizing then we'll do concentration of ore Concentration of ore means what we have to remove all those All those impurities into that okay removing impurities. We call it as ore dressing also Or concentration of ore also now in this we have three four different types of method possible Right, like we can have hand-picking hand-picking means what if you can easily dig sting the The metal and the impurities you can hand-pick those impurities that we call it as hand-picking, right? Again, we have depending on the nature of the minerals and ores that is we have magnetic separation process, right? we have Hydraulic processes which we call it as gravity separation or Lavigation also and then after this when we do the concentration will have for will have this thing Calcination of ores right that is a reduction of concentrated ores when we do Calcination or roasting then after that we have reduction of the roasted calcinated ores, right? So basically, this is the general processes we have and in all these steps We may have two three different types of process and those process will use according to again the nature of metals and impurities so first of all will See and after this will have one Important thing here that is Ellingham diagram, which is important for both point of view also that also will discuss Okay, after all these will see one or two metals extraction What are the different processes involves? What are the reaction we have into this? So if that will be same for all kind of metals, right? When you understand the general thing you can go through any book you will understand, right? So we'll see one or two examples into that. Okay, and then we'll see what can be done after that Okay, anyways some examples of ores you write down first This you have to few in this is important that I'll tell you examples of ores first one is ZnO zinc oxide We also call it as ginside this name sometimes they ask in State-level exams not in J. Okay, this is ginside FE203 We call it as hematite. You must have heard this name also hematite third one E304 FE304 we call it as magnetite fourth one MnO2 pyrolycite pyrolycite mineral also We call it as SNO2 Caceterite CAA double SE TERIT Caceterite and we also call it as tin stone 6th one L2O3 dot 3H2O This we call it as bauxite next one is Galena or PBS PBS is what? Galena 8th one HGS HGS We call it as cinnabar and these two names they have asked in the exam Galena and cinnabar Fools gold fools gold also they have asked in neat exam fools gold This is FeS2 and pyrite common name is fools gold Argentite Argentite is AG2S Argentite next one ZNS ZNS is zinc blend BLEND Cu FeS2 We call it as copper pyrite or we also call it as Chalco pyrite copper pyrite or Chalco pyrite few more compounds and the common name that you should know is KNO3 you must have done this in S-Block also KNO3 is Indian salt peter chili salt peter next one AGCL AGCL is horned silver this question they have asked horned silver AGCL is important NA3ALF6 NA3ALF6 is cryolite CAF2 CAF2 is Florspar KCL is selvine FeCO3 is FeCO3 is Ciderite and the last one ZNCO3 is Calamine so these are a few common names I have given you in this Important one we have is this AGCL CAF2 FeCO3 ZNCO3 here we have ZNS PBS Fools gold That is it this 5, 8, 6, 7 examples that we have is a bit important Okay, we have seen these kind of questions in a different state level exams obviously not in JEE and few questions They have asked in NEET exam also Okay now Okay, write it down. We'll see then extraction of metals Okay Now you see write down extraction of metals from its ore is there any kind of Pooja today here in Karnataka Yes Right on the extraction of metals the extraction of metals from its ore involves The extraction of metals from its ore involves four different processes involves four different processes The name of the processes are The first one is grinding verizing of ore We'll see this Sometimes in the board they ask the definition of this also. What is grinding? What is pulverizing like this? Okay second step is concentration of concentration of ore Concentration of ore and iron it is it means it does not mean the concentration is that concentration of solute and solvent that we write Concentration of ore means what if this we also call it as ore dressing right, so we used to remove Impurities here or gang into this process. Okay, and the ore that we get up to this process because it is concentrate Okay third one third step Is the reduction of reduction of concentrated ore concentrated ore into Crude metal or that we get from in the second process that we call this concentrate or Concentrated or so reduction of concentrated ore into crude metal fourth process is this Okay, and then the metal that we get here crude metal. We have to do the refining of that crude metal. So last step is Defining of crude metal Okay, so one by one we'll see these methods. What is this method definition and all so in this the first method you write down Definition you must remember. Okay. The first method here you write down that is grinding and pulverizing Amog is there Aditya is there Snigda is there. So you use a stress RN. Okay. Where is Amog? Aditya any Information you have Okay, they're fine. Okay, write down this grinding write down ores Optane from the earth crust Right on into this ores obtained from the earth crust usually have big lumps or you write down ores obtained from the earth crust are Are usually occur right now like this ores Obtained crust usually occur in the form of in the form of big lumps big lumps right on these lumps are broken or Cursed into small pieces these lumps these lumps are broken or crossed into small pieces small pieces by jaw crushers or grinders jaw crushers or Grinders these are the machines basically that we use. Okay grinding machine that we call this grinders also in jaw crushers Also one kind on same kind of machine, right? so usually By jaw crushers or grinders this process is known as grinding next line write down here When you have this lump, right? When and if you do the grinding of it This will dissociate into the small pieces like this and get the small pieces of This lump right now when you do the pulverizing of it after this the small pieces That you write down here The small pieces Obtained are reduced to fine powder The small pieces obtained are reduced to fine powder Fine powder this process is known as pulverization Okay pulverization so after pulverization or when we pulverize this will get a small fine pieces of these of these elements, right? So this process we call it as pulverization or pulverizing of Ores, right? So for grinding we use Here we are using jaw crushers jaw crushers or grinders For pulverizing we use ball mill Okay, it is not important But we use ball mail or stamp mill also you can use this Basically it is a kind of Device or machine we have that we use to reduce the size of the particles. That is it. Okay name of these machine You don't have to memorize basically. So this is the first step We'll get the fine powder here of the, you know, lump or ores that we get from the earth crust Right. Okay. Now is that fine now the next step is what the concentration of ore Or ore dressing the next step you write down The second step second process is the concentration of ore Concentration of ore Which we also call it as ore dressing, right? Right down into this right on the process of removing The process of removal of gang you write down the process of removal of gang Which is the impurities basically the process of removal of gang From the ore the process of removal of gang from the ore is known as concentration of ore or dressing of ore Or benification benifaction process B E N E F A C T I O N Benifaction process usually we don't use this term, but since it is there. I'm giving you this. Okay So concentration of ore ore dressing Benifaction or these are same thing Right right on in this the concentrated or We get into this step The concentrated or we get in this step is known as concentrate The concentrated or we get in this step is known as concentrate Okay Concentrated or concentrate now like I said just now I've given you that what we do in this concentration of ore. What is the? Thing we are going to do into this step the thing is what we have to remove the impurities, right? Removal of impurity is nothing but concentration of ore for this removal process We can also use three four different different methods like I said in the beginning Depending upon the nature of minerals the nature of ores, right? Depending on that we have different different process involves to get concentrate or For the process of concentration of ore, right? The first thing which is the easiest one we have in this a write down into this under this point and the this second step the first method for the concentration of ore is Handpicking, okay, just to write down handpicking In this also you can understand with the name only if you can easily Distinct the mineral and or then we can handpick those minerals and remove those impurities right minerals are generally When I say minerals in this it means you're not talking about ores. We're talking about all other elements which is present in That sample, okay apart from the ore material that you have, okay write down into this when the impurities present Handpicking just one line you write down when the impurities present are distinct from the ore when the impurities present are distinct from the ore So that they can be easily differentiated by our eyes so that They can be easily differentiated By our eyes Then we can handpick those impurities. That's what the handpicking We can handpick those impurities. So under concentration of old first is this which is generally not very useful Okay, second one is what second one is gravity separation gravity Separation method and we also call it as Lavigation Lavigation is the other term we use for this process Okay, right on to this See like the name suggests gravity separation, okay So this particular method we use when the Specific gravity of metal and gang is different right right down this process we use This process we use when the specific gravity of metallic ore when the specific gravity of metallic ore and Gang particles are different Gang particles is different story Metallic ores and gang particle is different This is used only for heavier ores only for heavier Ores like SN o2 you say For SN o2, which is casseterite. Okay. This is CA double SE T e r i T e casseterite or hematite, which is Fe 2 O 3 Fe 2 O 3 H A E M E T I T E for these oh for these ores we can use this particular Method now you see in this what happens. I'll just draw a diagram in the next slide You see see we have an arrangement like this here. We have a table like this Okay, and in this table there is a you know system we have Funnel kind of thing is there and here We have an arrangement of flow of water from this we Produce water here Right and from this funnel we used to put the Or right which is crossed actually the crossed or which this crossed or we get in the first step grinding and you know Pulverizing that we have right so when I put it here and here there is an arrangement like this and In this we have a raffles raffles means there's a net kind of thing is there which can You know hold the impurities you see here. There is a Net kind of thing here. It is arranged And just giving you a brief idea of this not the exact and diagram we have here Right, so this is we call it as raffles Okay, and then here we have a beaker where this Okay, now you see what happens here. This is the water. We are putting in there's a flow of water which is going like this Okay, and crust or is going over here since there's a difference in the specific gravity So the mineral that you have here or the ore particles that you have okay that will Stuck here into this raffles, which is nothing but a you know net Kind of arrangement is there which can hold the ore particles here and all those gang That will settle down here with this water and flows from this side and get down into this Beaker, okay. This is nothing but here Here we have the mixture which contains gang impurities plus water H2 Right and what we do when we flow this water. This is a table. We have okay, and we This table we have an arrangement so then we can continuously shake this table so that there will be settling of this or This gang material here and that will come Through this with this water into the speaker. Okay, so what happened into this just to write down the continuous vibration of Table the continuous vibration table results Results lighter particles particles moves heavier particles and heavier particles are left behind behind in the Barrier barrier means that laugh raffles that we have here in this net it will be stuck and these impurities Will go down with the help of water, but this is a table We have which is which we used to shake continuously for this process to Possible, right? So this we use like I said, there are different different processes This we use when there's a difference in specific gravity of the impurities and Impurities and ore that we have. Okay, so this is the second process that we use for the concentration of ores Magnetic separation the third one we have and this one you must have Have the idea of it what we when we use this magnetic separation method. Okay, so write down this magnetic separation So what we do in magnetic separation right down it is used for Magnetic and non magnetic impurities It is used for magnetic and Non magnetic impurities This method is useful This method is useful for the separation of for the separation of Chromite for the separation of chromite ore chromite ore is this fe cr2o4 from the man from the separation of chromite ore from from Silicius impurities. Silicius means the impurities of contains silica Silicius impurities where like I said this is the magnetic thing and This one is non magnetic So what happens in this the arrangement that we have here? We have a we have two roller here I'll try to and these rollers these rollers contains One magnetic Like there's a magnetic belt we have here like this and again we have a funnel here From which we used to put the crust ore into this here. We'll have the Crust ore So all these crust ore Just a second. See these are the crust ore we have That we are putting in and this crust ore contains The impurities where we have Magnetic nature, right? So those magnetic particles the magnetic particles that we have that will be in contact with this belt For a longer time and that will come down over here because of the magnetic nature and non magnetic particles Will separate here only and that will fall on over here, right? So this is what here that you get here that will be the magnetic impurities and This one here that you get that will be concentrated or Concentrated or it may be a reverse also, right? If the Concentrate if the ore is has the magnetic property then here will get concentrated or and the impurities if it is non Magnetic then here will be the Non-magnetic impurities, okay, so this is very simple and easy to understand, right? Understood, so this we call it as magnetic separation. This is what this is the roller we have Which is connected with the motor and it moves this is the belt this roller is actually it is Magnetic Okay, so this is the another third method of method for the Concentration of ore now the next one in this the next one here We have two more methods into this next one is Froth flotation process Froth flotation process third one right on in this Just write down quickly because we have a lot of theory into this chapter Okay, write down the method is based. It is based on We double T. I. N. G. waiting characteristics characteristics of ore and Gang G. A. N. G. U. E. waiting characteristics of when ore and gang by oil Water whether this ore or gang get wet with get to get sped with oil or water or not Okay, this method is Used for write down in short you write down used for The concentration of sulphide ores, okay, this you must remember sulphide ores For example, we have galena pbs We can have copper pyrite C u f e s 2 Or we can have zinc blend also ZNS for all these three Different ores we can use this particular method Okay, right on in this process in this process a suspension of a suspension of finely powdered ore and water is made We'll make a suspension of finally powder powdered ore and water finally powdered ore and water Depending upon the nature of ore depending upon the nature of ore We use we use various additives various additives such as various additives such as frotters froth stabilizers frotters froth Stabilizers right on this F R O T H E R S frotters froth stabilizers collectors C O double le C T O R S collectors See what are frotters? Frotters froth stabilizers and collectors see frotters are frotters are frotters These are the compound such as pine oil Example is pine oil which we use for which helps in the formation of froth. Okay Because froth see actually the overall process of this is what When the froth forms this contains the impurities. Okay, so when you will have this the whole setup is like this we have a system like this and There we have a pedal kind of thing here And this we can rotate right this is fixed here and this is this is keeps this this keeps on rotating like this Okay, so when this moves and here we have the solution here we have the Or particle we have here so and this continue when you agitates this particular You know mixture here then it forms froth and that that froth contains the in various impurities with it And which is there in the upper layer above here the front that forms Okay, so which you can with the and those froth can be easily skimmed off, right? On its own and from that you can easily remove the particles there, right? That is what the process we have here So depending on the nature of the over whether the formation of if the formation of froth is difficult Then we add frotters into it. What are frotters frotters are an example of this is pine oil Pine oil we use which helps in the formation of froth. Okay, so these are frotters Froth stabilizers are what because frotters are can be easily skimmed off So we should use some froth stabilizers also into this so example of this you write on froth stabilizers Which stabilizes the froth, right? That is we have Cressol Cressol is an example of froth stabilizers. You must remember this froth stabilizers. Aniline is also another example Aniline Cressols are the froth stabilizers, right? Collectors are what? Collectors you write down the examples of collectors It is ethyl xanthate This example they have asked once xanthate ethyl xanthate potassium ethyl xanthate potassium ethyl xanthate xanthate What this collector do actually this enhancing the non-vetability of the mineral particles it enhances the non-vetability of mineral particles There's a few examples that you notice two three lines you write down on rotating the paddle on rotating the paddle The formation of froth takes place the formation of froth takes place Which carries mineral particle with it which carries mineral particles with it mineral particles with it the froth being lighter The froth being lighter Floats on the surface being lighter Floats on the surface and is skimmed off which we can dry for recovery of mineral particles Okay Now the next last process for concentration of course we have here that is leaching L-E-A C-H-I-N-G Leaching we also call it as hydro metallurgy leaching or Hydro metallurgy Write down into this leaching depends upon difference in chemical properties of ore and gang leaching depends on The difference in chemical properties of the ore and gang it involves it involves the treatment of Powdered ore it involves treatment of powdered ore with suitable reagent powdered ore with suitable reagent This reagent actually it can be anything so when you write down suitable reagent in bracket You write down acid base or other chemicals acid base or other chemicals Okay, so basically whenever you have any ore right and If the mineral and ore is like their chemical properties are different then we use this process. Okay, we can use various chemical reagent for this process to take place like for example, you see if you have bauxite Okay, so just you write down two examples. I'll give you this is important leaching of bauxite or in this way I don't examples leaching of bauxite Bauxite or This process we call it as bear's process. Remember that bear's process now in this what happens this bauxite or which is L2O3 Solid it is allowed to react to it. I'll just write down the reaction. Okay I'm not giving you theory the line of all these L2O3 alumina solid reacts with the aqueous Sorry, the solution of a sodium the hydroxide sodium hydroxide we have it is aqueous solution of this and Obviously, we have some amount of water here present and this reaction takes place. It forms sodium meta-aluminate which is 2 Na Al OH Whole 4 aqueous this we call it as sodium meta-aluminate Now this solution is Cooled and it's pH is adjusted Right. So what happens this and a al OH and a al OH whole 4 Right, it's pH decreases a bit, right? By dilution or neutralization pH of the solution Decreases a bit by dilution or neutralization, right? And we allow CO2 to pass through. So what happens is Na Al H? Al OH whole 4 minus in This the neutralization takes place or upon dilution pH decreases CO2 passes through then this dissociate in the form of Al OH whole thrice solid Plus OH minus hydroxide and goes off Right now this al OH was al OH whole thrice. I'll write down here the last reaction When you heat this Right, this is solid When you heat this around 1473 or 1500 Kelvin, right then this dissociates into Alumina that is Al 2 O 3 solid Plus H2O plus H2O. This is the concentrated ore we have here Alumina like this the concentration is done of alumina. So basically in this chemical reaction, we use the chemical properties of various compounds ores minerals and then according to that we'll use some suitable reagent to purify the ore that we have here Right, so this is these are the four processes we use for the concentration of ores write down this Next is the third step is Reduction of concentrated ore the third one is reduction of Concentrated ore now reduction of concentrated ore that we get in the second step That is what we call it as it Concentrated ore reduction of that We have to do in the third step for this. I'll directly come to the you know the important point here for this We use generally two different Processes one is cancellation and Other one is roasting So first of all you write down calcination of this. Okay. What is calcination? definition of calcination you write down it is the process in which The definitions are important. Okay, so you must remember It is a process in which the ore is heated strongly. The ore is Heated strongly In absence or limited supply of air in absence or limited supply of air and supply of air at a Temperature at a temperature or does not melt Below the melting point we use a temperature where the melting is not taking place for the ore that we have to take care of So limited supply of air if you have then it is calcination and other one like I said that is roasting Which is when we have excess of that is the only difference. Okay, so you see here the reaction The examples I like don't in this what happens the volatile component Goes off when you heat this strongly the volatile component Like you see CO2 SO2 H2O Goes off. This is what happens into this. You see when you have this hydroxide of iron When you heat this in this H2O goes out We'll get oxides of iron and H2O goes out three Moles of this if you have CACO3 When you heat this CACO3 it forms CAO and CO2 Goes off. So this is what the cancellation is now the next Method in this only we have that is Roasting O A S T I N G Right B. This actually in this process The ores are heated strongly in this process. The ores are heated strongly In presence of air in presence of air a temperature a temperature Below its melting point So in this usually what happens? Ores Converts into its oxide for example, you see if you have Hg s and when you heat this with oxygen It forms Hg O Plus SO2 to SO2 Get the oxides of acid if you have ZNS it forms to ZnO Plus 2s o2 again sometimes sulfide also we use into this PBS plus 3 or 2 it forms what? PBO Plus 2s o2 right sometimes what happens in soluble sulfide or Also converted into corresponding sulfate. Okay, which is soluble, which is water soluble So this is see you as plus 202 gives you see you SO4 so this is insoluble sulfide over and this is water soluble This is how this process takes place if you have any sulfide or it converts into its oxide. Okay, sometimes the sulfide also behave as in you know reducing agent here the example is this and here It sometimes convert into its sulfates which is which is water soluble. Okay, so like this the roasting process takes place Oh, you see the third reaction this Sulfides are behaving as a reducing agent You see oxygen is getting reduced in all these reaction. You see oxygen is in zero oxidation state and right side It is in minus two oxidation state So oxygen is getting reduced and that's why the reduction of oxygen takes place and But the title is reduction of ores. No, actually, I haven't given you the full thing here The reduction of concentrated ore into its oxide actually. Okay, I haven't given you here See this should be reduction of concentrated ore into its oxide. So better you write down concentrated or into its Yeah, the meaning is half then right into its oxide or you write on metallic oxide that would be better metallic oxide So it does not mean the reduction of ore is taking place The reduction is taking place here and the metal is converting into its oxide. That's the thing Okay, so better you write down reduction of concentrated or into its metallic oxide fine Okay, so these are the two a process we use for the reduction of concentrated or into its oxide So basically first we have the, you know lump will do the grinding of that will get fine fine powder of that Oh, then we do the concentration of or where we remove the all those impurities gang and all and then we do the Reduction of concentrated or into its oxide. So finally we are actually we are forming the Oxides of the metal right now from this you see the last step. We have here that is the reduction of Calcinated or calcined or roasted ores into its metal. Now you see these are the metals we are getting right Right here. You see all these metals is in plus two oxidation state Right when the reduction of this metal oxide or sulphides sulphates takes place This converts into what converts into metal. That's what the last step we have here Which is a fourth step, which is the reduction of right down the fourth step Reduction of Roasted calcium ores into metal Right, so we'll get this metal and then we'll do the refining of it. That is it. Okay Now when reduction it is there, right? So we know the you know the electrode potential of various metal when it reacts with that So one metal can displace others according to that the basic idea is that only okay one point in this you write down The extraction of metals from its oxide here you write down the extraction of metals from its oxides I process Involving a process involving by a process involving melting is known as smelting Okay, but I buy a process involving melting in which the melting takes place that process We call it as smelting as M. E. L. T. I. N. G. So reduction of a metal oxide By a process in which the melting takes place that process we call it as smelting process. Okay write down the roasted or Write down the roasted or contains non-fusible impurities contains non-fusible impurities such as silica silicate metallic oxide etc comma comma and Additional substance is added to the furnace and additional substance is added to the furnace During the process of smelting This you know smelting process I I guess they have asked this question and I don't know if it's true I think it's true Smelting this you know smelting process I I guess they have asked this Question in board exam. Okay, so definition. That's why it's important Okay, and when you write down all these definitions, so you must write down one example also that is important Okay, and additional substance is added to the furnace during the process of smelting during the process of smelting to remove those impurities To remove those impurities is Known as flux Flux right which forms the those additional Compound that you add during the process of smelting. We call it as flux flux What it does this flux actually combines with those non-fusible impurities Okay, or gang that you have G a n g u e this is what this is non-fusible So when flux combines with this gang non-fusible it forms slag Which is actually fusible and we can remove this easily That's the purpose of adding flux into it. So definition of flux. You must remember now next thing in this is it is a reduction of Roasted ore we have so there are chemical reactions into this so write down this Reduction can be done in three different ways like here. Also. We have three possibilities First one is chemical reduction chemical reduction chemical reduction you see in this we can use carbon as the reducing agent carbon as reducing agent Right, for example, you see any metal oxide M e tl metal oxide When reacts with carbon when you heat this it gives you metal Plus carbon monoxide co. Okay. So like you see a few examples here PBO plus C You heat this you'll get lead plus carbon monoxide Similarly ZnO plus C Heat this you'll get Zn plus carbon monoxide like this. We can have many other examples as an O2 Plus C you heat this you'll get metal plus to CO Right, so these are the metal you are getting so last step in this will be what that will be the refining of this metal That is what the purpose we have right? We have to get the pure purest form of the meta purest possible form of the metal, okay? so Okay, there are few reactions also that we use carbon monoxide as the reduces the one thing where carbon is a reducing agent We have also few reaction in the carbon monoxide as Reducing agent we can use that is you see three two three reactions. I'll give you fe 304 plus co and When you heat this you'll get iron plus For co2 right we have Cuo plus co When you heat this you'll get copper plus co2 so this is the first Reaction we have that is chemical reaction aluminium also you can use as a reducing agent, okay? Like you see CR 203 Plus aluminium it forms what? 203 plus chromium This is what we get the other few reactions basically where the reduction takes place, okay? Now there are few reactions in which the be Second process here. We have that is auto or self reduction process, okay? auto or self reduction process Like the name suggests in this process. We do not require any reducing agent Okay, so the first thing you should write here No reducing agent required Okay, in this you write down the sulphides of less electro positive metals This is just a displacement reaction according to the electro electrode potential, okay? Zn O plus C what happened? What is the doubt that also you can write Zn O to Zn O plus C gives you Zn plus co2 That is also possible Actually two steps reaction we have Zn O plus C gives Zn plus co again Zn O plus Co gives you Zn plus co2 Right when you add those you see Co-co gets cancelled so that also you can write See co2 when you get when you have excess of see when carbon oxygen reacts, okay? When excess of oxygen we have then we'll get co2 Otherwise first in that also first co forms and then co2 will get Okay, so that also you can write not a big deal Anyways so autos and self reduction right on to this like I said that this reaction is based on the electrode potential of the metal So in this you write down the sulphides of less electro positive metals the sulphides of less electro positive metals such as mercury copper lead tin the sulphides of less electro positive metals such as mercury copper lead tin are reduced on On itself are reduced on itself few reactions you see Hg s Plus three or two to Hgs plus three or two gives two H Go plus co2 and then again this Hg o Combines with Cinnabar which is Hgs forms Hg Plus so to so this is the metal you are getting in this also you see actually this reaction takes place into a step First we get Hg o then this again converts into Hg similar reaction you see To see you to us copper glands. We also call it as okay three or two Gives you to see you to oh That's to s o2 You also we should write to s o2 and then this to see you to oh reacts with see you to s Gives you six see you Plus so to two step reaction again. Do you see the metal you are getting like this this reaction takes place, okay? now the third a B we have done the third Process in this electrolytic Reduction like a reduction method when the chemical reaction method When the chemical reaction method is not applicable when the chemical reaction method is not applicable then we use electrolytic reduction Then we use electrolytic reduction depending upon the oxide Depending upon the oxide This process may takes place at high temperature at high temperature in bracket You write down in absence of water may take space at high temperature in absence of water or at low temperature using water so actually this process may takes place in two different condition High temperature without water and low temperature with water So this we use high temperature when the oxides are stable oxides are stable like in the case of oxide Oxides of alkali or alkaline earth metal alkaline earth metal so basically the oxides of Alkali and alkaline earth metal are stable so for those oxides we use high temperature without H2O for this process Since it is a stable so to dissociate this we require high temperature. That's the reason write down in this when the oxides are heated at high temperature When the oxides are heated at high temperature the metal reacts with carbon to form carbides okay These metals react with carbon to form carbide and hence such metal cannot be extracted by reduction of their oxides By reduction of their oxides with carbon you write down and such metals cannot be extracted by reduction of their oxides with carbon and hence for those method for those metals and for those metals we use electrolysis process electrolysis process this is process in which the metals are Liberated at cathode in which the metals are liberated at cathode, right? So for all these stable oxides alkali and alkaline earth metal if you try to reduce this with the help of carbon Right, so you required high temperature for this reaction. Why because the oxides are stable So when you heat it heat this oxides at high temperature Then the metal may get free from oxygen but that metal will combine with carbon to form carbides and hence the you know Isolation of metal is not possible in this. Okay, you are not having oxides, but you will have carbides then Okay, so for those kind of metals we don't use carbon reduction method, but we use electrolytic reduction Right and electrolytic reduction, you know that we have where metals Will get at cathode right reduction takes place at cathode so metal will get at cathode, right? So there are many Reaction into it fusion will take with NaCl, okay? And then reduction that basically electrolysis process we have that you keep in mind, okay So these are the basically the process we have for You know the extraction of any metals, right? This is the fourth process we will use for any metal to extract depending on the property We use calcination or roasting for concentration We use grinding pulverization or we use what or we use leaching or we can use The gravity settling process or we can use the magnetic separation method. Okay anything all these Processes we can use according to the properties of the ores and the minerals or impurities. We have okay So for different different metals, we may have different different process But all those process will be one of these only that we have already discussed, right? So anyways, this is the general method of extraction of any elements, you know any metals we have done right now The last thing in this is the purification or refining of metal Okay, so the last thing you write down purification or refining of metal The last into this the metal that you get here we used to purify that or refine that So for that you write down the last thing purification or refining of metal so in this you write down This method is used for the purification of this method is used For the purification of this method is used for the purification of Metals like copper, zinc, silver, gold, tin Copper, zinc, silver, gold, tin Nickel, aluminum, etc. Now in this you write down the few information you should keep in mind For cathode it is made up of it is made up of thin strip thin strip of Pure metal whatever metal we have to purify Pure metal of that will take thin strip of pure metal of metal will take into that Okay, and the metal should be same which is used this thin strip will be of the same metal Which is used to purify. Okay, anode here large slab of impure metal of Impure metal means this slab is made up of the metal which is to be refined The light that we use here purification we do by the electrolysis method electrolyte that we use here it will be the aqua solution of of a suitable salt a suitable salt Of the same metal same metal So at cathode you see the reaction that takes place here at cathode will be m n plus Plus any electron gives metal solid the reaction will be types of reaction here m n plus Plus an electron the impurities that you have here xn plus Gives you half of x2 plus an Electron this x is nothing but the impurities right So this reaction we want this reaction to be there Who takes place right because when this from the large slab that you have let me draw this also okay This is the electrolyte and in this where is one cathode and one anode and anode we write on the left side Sorry, this should be like this This is anode and cathode is a thin strip So it is this and this is connected with the external source here. This is the anode we have made up of impure metal cathode It is pure metal. So here the reaction is this anode the reaction is this okay And what we want from this particular slab this reaction takes place and this Electron is taken up by this ion here and the metal deposit it will get here solid metal. Okay, so now in this one The anionic part right there is a concept of that we have started in electrochemistry that Let me tell you there is one concept of Overpotential right one concept of over potential that concept We can apply over here. Okay, but we're not going into all those things because that is not required The only thing you have to keep in mind here write down the anionic part of The electrolyte is to be the anionic part of the electrolyte Is to be selected in such a way the anionic part of the electrolyte Is to be selected in such a way That the anodic reaction to this is the first reaction we have of anode and this is a second reaction of anode that the anodic reaction to Does not takes does not take place and hence and hence the metallic Sorry, just a second And hence The metal starts depositing at cathode the metal starts depositing at Cathode one note you write down here the metallic impurities having lower oxidation potential metallic impurities having lower oxidation potential lower oxidation potential then the metal then the metal are separated out are separated out in the form of anode mud and That anode mud we can know show over here. This is an old mud Okay, so whatever the anionic part of this electrolyte will take here Their oxidation potential must be more than the impurities More than the oxidation potential of impurities here so that this reaction won't takes place Right this second reaction won't takes place This reaction will takes place and then the metal starts depositing by this reaction on cathode. That's what the You know objective of all these process we have Okay, so these are the you know processes that we use for extraction of metals and then you know purification Okay We'll see the extraction of Metals also like few one or two examples will see that the extraction of silver will see extraction of copper also will see Okay, and then one important thing we'll see that is and then one important thing we'll see That is you know Elingham diagram. Okay, so that is again important for your boat point of view also many times They have asked this question in the board, right? So just you write down the next one here. This is done the extraction of this the general Thing is done. Next you write down. I'll give you the flow sheet of this. Okay, so that you can Memorize this easily. Okay, that will be Easy away. Okay Next you write down extraction of silver extraction of silver Okay, in this you write down This is done by the cyanide process name. You must remember Cyanide process The other name of this is Mac Arthur Arthur and forest process Cyanide process or Mac Arthur forest process The ore that we use here for the extraction of silver is Argentite The formula of this is AG to S. This also you have to memorize or also they are sometimes The flow sheet you write down the flow sheet of this We have Argentite ore Which is AG to S We'll do the grinding and pulverization of this to get the small Right, no fine particles of this ore, right? That is obviously will do so. I'll just write down here grinding and then pulverization after this We'll do what the concentration of ore, right? Concentration the second step Now the concentration that we the process that we use here for the concentration of ore The process that we use here for the concentration of ore Right, this process here is froth Flotation process, okay, this again you'll have to memorize froth flotation process Okay, now in this froth flotation process like I have discussed we use some frothers some stabilizers and then some You know to make that froth stable, right all this process that we use, okay? Now in this what happens the reaction you have here the powdered ore plus water plus Pine oil Right, I have discussed this just now. What is the purpose of this pine oil? We have examples air in this reaction it gives it gives the froth that you form that you get over here for froth carries Sulfide particles Sulfide Particles so this froth are generally the carriers of this sulfide particles. Okay, which is nothing but AG to S Okay now in this now in this cyanidation process we use Right, what it means what it means that this Sulfide that you have AG to S We're using sodium cyanide here, and that's why you're calling it a cyanidation There are other process also by which you can Do the extraction of silver but like I discussed in the beginning that the process we use that process must be cost effective Right, so according to that we'll use the extraction of any metals Okay, there's no point wasting so much of money for the extraction of one particular type of metals, right? so we use the best process in which the The cost the input of the cost is minimum. That's the logic we have for no no for you know Choosing any particular type of process that okay now when this AG to S reacts with sodium cyanide Okay, this reaction is reversible in nature this forms a complex of sodium Argento cyanide which is and a AG CN2 Sodium Argento cyanide write down the name plus sodium sulfide also we get here and it was this any to s in presence of oxygen water converts into sodium sulfate and a to SO 4 Plus hydroxide which is any over this reaction is not balanced reaction. Okay. I'm just giving you the product plus We'll get sulfur over here now in this. I'll just try and just copy it down I'll just write down in the next slide next page now this sodium Argento cyanide that we have From this we have our purpose is to extract this silver. Okay, so from this silver We have to extract and for this we use Any metal you can use which has which is more electro positive than Silver right because then only the displacement reaction takes place, right? So any metal we can use here, which is more electro positive than silver. Okay, so here you see in this the next slide I'll just add that is precipitation of silver precipitation of AG and Like the metal we can use here is Zinc Why zinc like I said because this zinc is what it is more electro positive than silver When any electro positive metal we know that can displace the another metal which is comparatively less electro positive in nature. This is more Electro positive positive then AG okay, so reaction in this process you see the sodium Argento cyanide which is NA AG CN2 react with zinc and It forms silver plus NA2 ZN CN4 Now fusion of this metal takes place with an electrolyte that is electro refining process That is electrolytic refining that we have so we'll take an electrolyte, which is AG KNO3 and it forms silver metal or Solid we can write this we get after cooling. So here what happens the anode and electrolytic refining process that we have here Electrolytic refining in this What cathode and anode we are taking That you should keep in mind you are taking here since cathode is made up of impure Metal right so impure what metal we have silver so impure silver AG plate What about anode oh, sorry, this is not cathode. This is anode and Anode is impure. No cathode will be what it is pure silver plate thin strip of pure AG, right? pure silver plate Anode on the left hand side cathode on the right hand side you must like take that Revise that thing. This is on the left hand side And this was on the right hand side and drawn the diagram that I have drawn right and like this It is connected with the external source right and here we have the electrolyte This is anode and this is cathode the larger one is anode anode is impure AG plate, right? electrolyte we can use here that is AG NO3 AG NO3 solution Plus HNO3 and in this when the electrolysis takes place pure silver deposited at cathode That's what the process we have in this reaction here. There's one more point you write down in this process The impurities oxide oxidized impurities oxidized and raised as as scum on The surface which we can Separate out easily from the surface, right? So this is what the process we have for the extraction of silver Okay, they won't ask you the you know Maybe in board they may ask you how do we extract silver? For like competitive exam, they may ask you what is the ore we use for extraction of silver, right? What is the process name like this Mac Arthur and forest process once they have asked in one competitive exam? Maybe in Medical need or any other exam, but this name they have asked once okay, and then What metal we can use here like I said? Jink we are using here for the precipitation of silver. This metal must be more electropositive so that it can displace silver Okay, so that's again one important thing we have here, okay? Now you see the next one is extraction of Copper extraction of copper you write down Okay extraction of okay, all that we use here is mainly copper pie right copper we use here The process is Smelting so copper pie right the formula is cu f e s 2 you see the flow sheet cu f e s 2 copper pie right first of all it is you know the grinding and pulverization right so that will be crossed Right now in this also the concentration of ore is done by fourth froth flotation process Concentration of ore first let me draw this flow sheet and I'll write down the key things into this the next Process here is roasting R O A S T I N G Roasting is takes place in presence of air We have discussed already After this we have smelting in blast furnace in presence of air Okay, so let me write down all those reactions and the points that is important here Concentration is done by Here you write down froth Flotation process flotation process Right and in this we add what potassium Zenthed potassium Zenthed We'll add these two continuous agitation will do into this So in this what happens the impurities set us down in the bottom Because of this continuous agitation impurities Settles down okay in roasting what happens The concentrate or concentrated ore right the concentrated ore strongly Right and the reaction in this we have the sulfur Plus o2 gives so to our scenic all these are impurities actually our scenic plus o2 This is not actually that much important. I'm just giving you the reaction here. Yes, two o3 and The other one is Antimony 302 To SB 203 these two are actually volatile Okay, so it can be removed easily This as a to also we'll remove over here as to gas forms It will also be moved and these two are volatile in nature can be removed easily Okay, now it's melting what happens in presence of air, right? So all these Iron sulfide that we have the various reaction we have here right in this you see the sulfur Arsenic and all these presence as impurities and then it's oxidized on then it's reacts, right? So what happens here one more thing in roasting is the copper pyrite that you have which is to see you FES to With oxygen we are heating this and the product that we get here is see you to s plus FES Plus o2 and we have already discussed the some of the oxides some of the sulfides in this process converts into what? Oxides that will be see you to oh and this FES converts into F. E. Oh, this thing We have discussed in roasting process. So I'm not discussing those things again right now in This is melting process the roasted or right that or that we get from here. This process is mixed with mixed with Coke silica Coke and silica Now the reaction that you have here Whatever iron sulfide which is left over here all these suppose if it is not oxidized or converts into its oxides So whatever it is left here That will also converts into its Oxide oxides like FES forms FEO Plus see you to s Right, and then this FEO Combines with this silica as I o2 forms FES I o3 Si o3 which is slag which can be removed easily and this see you to s combines with oxygen forms oxide Plus to s o2 This is the reaction this silica that you have Whatever FEO we get here all these FEO converts into FES I o3 and from here all iron all FE is removed in The form of this slag as slag now the next step We have here Next step here is See one type of question that they ask sometimes in the no Like exam also that what is the purpose of adding silica here, right? So since this iron is present as an impurities right so this you have to remove So when we add silica into this all these oxides of iron converts into FES I o3, which is a slag of Fusible slag which can be removed easily So that is the purpose of adding silica most of the time silica we add to form slag Always that's the purpose of silica to add right now the next step we have here that is best summarization Okay, next step you write down be double se Bessemerization process this takes place in Bessemer converter Right that the machine that we call it as Bessemer converter now in this also Similar kind of reaction we have and here also some amount of silica added The purpose is again same if any iron oxide Left that will also convert into slag that is the purpose we have so again the same kind of reaction here FES 2 Plus 302 Gives you iron oxide Fe o Plus 2s o2 because this process also takes place in presence of air In presence of air so there are chances that if any iron is left over there that will oxide in that will oxidize into its Oxides right so to remove that oxide again the silica will be added here Right, so the reaction here that is how the iron oxide forms and this iron oxide again reacts with Si o 3 Si o 2 it forms Fe Si o 3 Right and this copper sulphide Plus 302 again converts here into Si o 2 o plus 2s o2 Same kind of reaction this Now in this what happens that important thing here that this Si o 2s and Si o 2 o auto reduction takes place right Si o 2s plus Si o 2 o Auto reduction takes place So it forms what sulphur dioxide and copper metal we get Six see you this reaction. We have seen already plus Si o 2 Auto reduction. Okay, this copper we call it as blister copper blister Copper which is 98 percent pure Okay, 98 percent pure now the last method here is electrolytic refining Again this metal that we get we have to refine this so electrolytic Refining and this the anode that we use Anode is again it is impure. So again it is impure Cu copper plate cathode will be cathode will be pure copper plate Electrolyte we use here that is Cu s o 4 plus h 2 s o 4 Okay, and the pure copper we get at again cathode deposited at cathode Okay, so this is the again extraction of copper Okay, so like this we can have another metal also extraction process. Okay, but again Before going into that like this on different different processes we have and then some reactions and what is the Element of compound we are adding what is the purpose of that so that again you can go through any book if you have it So few like iron and all you can go through right but before that since We have to discuss Ellingham also which is important more important than all these because these are just you have to memorize You just have to see the Processor and you have to memorize general thing. We have discussed that is the only thing we are Following in all these extraction processes. Okay, so first we'll discuss Ellingham here and then possibly we'll see the another Method of this I've given you to just now. Okay, we'll discuss first the thermodynamics of Reduction processes reduction process Okay, we'll take a break over here ten minutes break will take and then we'll start this. Okay, this is important Okay, Ellingham is important diagram is also important in board. Also. I have seen many times they have asked question on to this Okay, so this Ellingham diagram is important. So I'll take a break for ten minutes. Okay, it's 4 18 now will start at 4 30 Okay, we'll start at 4 30 and we'll finish this Ellingham today Okay, we can finish this in half an hour, but there are many things into this But yes, he'll finish this. Okay. Okay So we'll start now thermodynamics of Okay, thermodynamics of reduction process. Okay, you see the thermodynamics of reduction process, which is nothing but this That also we use that reaction in what we say the Extraction of metals. Okay, so so all these reactions since we are dealing with reaction. So we must have the So we must have the you know, or The thermodynamics of that reaction. We should see that for Nikhil for Jay means like we cannot say it's it's a complete theoretical Topic right there is nothing logic into it whatever till now I'm explaining like this is a process from rotation and all these reactions are there Calcination roasting they only ask theoretical question into this If you ask me the vet is it is not that much if you ask me like if you have to go through any Question into this just a little bit of you know information that I gave that I gave you and Little bit of information you should have for this Ellingham diagram Ellingham diagram is important for your board also and for Jay also, but yes, if you ask me what is it's not I think it's not Certain right you cannot say anything. They may ask you one question Maximum one question. They may not ask you any question from this chapter But yes for board exam this Ellingham thing is important and again the extraction of your limits is also important in board They can ask you directly. Okay, right down the extraction process of silver right down the extraction process of copper For Jay means it is not that much important. Okay. So anyways, so extraction you see in This one the dynamics of a reduction process and that we understand by Ellingham diagram Okay, so that is what we are going to see here So you write down the heading here Ellingham diagram write down a few points into this and then we'll discuss it right right on This diagram Usually consists of usually consist of the plot of Del G and temperature Del G not versus temperature This is the pros. This is the plot of gifts free energy change and Temperature for various reaction okay now since you're talking about the thermodynamics of Reduction process in metallurgy Right, so we'll talk about the formation of oxides into this Okay, see any oxide if it forms right suppose if I write down the example here That is 2 x m Solid Plus it combines with o2 gas to give 2 m x o Solid This is the oxide we are forming right, so this particular diagram is Actually, you know valid for oxides of various elements But we can draw the similar kind of diagram for sulfites and halides also that I'll give you after sometime But just you write down one thing here You just one thing you try to understand this oxygen is a gaseous molecule and this is a solid molecule We are getting so entropy is what from gas to solid it is going so entropy is decreasing Right, so whenever the oxide formation is there Del s of this reaction will be less than zero Because gas to solid conversion we have so entropy obviously Decreases right so right down into this this diagram is right on this diagram involves the formation of Involves the formation of oxides of various elements oxides of various elements similar diagram we can draw For sulfites and halides also similar kind of diagram. We can draw for Sulfides and halides also Next line the formation of oxides Formation of oxides takes place by decrease in entropy Decrease in entropy Okay, so when this season when now you see when this del s is less than zero So the reaction or the equation we have del g is equals to Del H minus t delta s okay, so as temperature increases This means what? T delta s T delta s Becomes more negative Becomes more negative. This means what delta s is decreasing and T is increasing So T delta s becomes more negative. It means the value of T delta s will decrease Right now when the value of T delta s will decrease so obviously del g value will increase T delta s value is more negative means this negative negative positive so del H value will increase right so del g value will increase or we also call it as Del g becomes Less negative Means it is increasing next line So the point is as temperature increases del g increases that is what you have to keep in mind now When we see the graph you can correlate this okay, but before that you see you write down one point here The free energy changes the free energy change energy change The free energy change that occurs just a second write down the free energy change That occurs energy change that occurs When one gram molecule one gram molecule of a common reactant a common reactant and in this case The common reactant is oxygen Which is oxygen in this case because we are talking about the formation of oxide that only takes place with oxygen right one Gram molecule of a common reactant is used is used The free energy change that occurs when one gram is used Sorry is used Or the molecule of a common reactant is used used may be plotted Graphically against may be plotted graphically Against temperature against temperature for a number of metals For a number of metals their oxides This graph is Ellingham diagram What is the meaning of this that I've given you you will understand when you see the diagram this graph is Ellingham diagram Now the important thing here is what the diagram is and what is the key features of the diagram? Right, so first of all, I'll show you the diagram Okay, and then we'll see the key features of this diagram that is important sometimes in the board exam They ask what is Ellingham diagram and state some key features of Ellingham diagram. Okay, I'll show you that just a second Okay Now you see the Ellingham diagram See this is the Ellingham diagram we have okay, so now you see this in all these diagram The important thing is this The relation of del G and temperature we know already This is the Del G axis we have Right, and this is the temperature X axis is temperature now for all these elements you see magnesium aluminium silicon Chromium Zinc and all we have the We have the diagram of temperature right so all these diagram you see if you one or two exceptions if you leave the slope of this Line is positive right all these line the slope is positive and The value of gifts free energy you see here the value of for all this graph the value of gifts free energy increases with increasing temperature and that is what we have discussed what we have discussed that this Del G Del G is equals to del H minus T delta S Delta S decreases because the oxygen is Decreases because oxygen is converting into O2 gas is converting into solid so entropy is decreasing So with increase in temperature you see if you go from this side to this side the temperature is increasing with increasing temperature T delta S decreases and hence del G value will increase that