CHEMISTRY By-— Kumar Umesh This Booklet Belongs to Dae EDUCATION VIEW Gin es A Premier Coaching for- LSc. (11", 12"), IIT-JEE (Mains+Advance), NEET-UG Etc. ‘oe CHEMISTRY Dies AC Cee cd tr ea OC GCC etC le Cole &A.P. COLONY, OPPOSITE AAKASH INSTITUTE, GAYAMETALLURGY 1, | Introduction 01 2. | Concentration of the ore 01 3. | Conversion of concentrated 04 ore into oxide form 4. | Reduction of the metal oxide 06 5. | Refining of the metal 09 6. | Ellingham diagram 16 7. |_Exercise-I (Conceptual Question) 21 1 SCHOOL OF SCIENCE A PREMIER COACHING FOR- IIT-JEE (MAIN-+ADV) NEET-UG & I.Sc. (11°, 12") Introducing CMETALLURGY an 42 (ay @ INTRODUCTION Metallurgy : The branch of chemistry which deals with the method of extraction of metals from their ores by profitable means Metal : The element which tends to form positive ion is called a metal Minerals : The various compounds of metals which occur in the earth's crust and are obtained by mining are called minerals, In earth crust order of abundance of elements is, O > Si> Al> Fe ‘A mineral may be single compound or a mixture. Ore : The mineral from which a metal can be extracted profitably and easily is calléd an dre All ores are minerals but all minerals are not ores. (T/F) Type of Ores : () Combined Ore : Metals placed above H in electrochemical series ate generally reactive ie. why they generally found in combined state. (a) Halide ore / Sulphate ore / Oxy ore : Metals are highly reactive (LY, Mg) (b) 0» (©) Sulphide ore : Metal placed near H or below, (Pb, Hg, CuyNa) (ll) Native Ore : Metal placed below H in electrochemicalseriesare generally found in native state. (Ag, Au, Cu, Pt etc) Gangue or matrix : le ore : Reactive metal (Al to Sn) he undesirable impurities PRESENt in.an orBiaré"called gangue. Types of metallurgy poy ee Pyrometallurgy Fiydrometallurgy Electro metallurgy + Temp. is infolved Solitién is involved Electricity involved ¥ + + For Reawyimetals © ecording to E.C.S 1A, 11A, Al ¥ + Fe, Zn, Cu, H,, Por metals placed below H $0, ele + Cu, Ag, Au STEPS INVOLVED IN THE EXTRACTION OF METALS “Thelextraction of a metal from its ore is completed in the following four steps. (8) Concentration of the ore (8) Conversion of concentrated ore into oxide form. (©) Reduction of the metal (D) Refining of the metal Concentration of the ore or dressing or benefa ‘The removal of impurities from the ore is called its concentration or to increase the concentration of ore in ore sample. Two process ~ (1)Physical (2) Chemical PHYSICAL () Gravity separation (Levigation) : This method of concentration of the ore is based on the difference in the specific grauities of the ore and the gangue particles, Powtlered ore is agitated with a running stream of water. The lighter gangue particles are taken away by water while heavier ore particles settle down, Ex, Oxygenated ore ol02 i) Gangue ‘Suspended particles ore Ore particles Concentrated Hydraulic classifier Froth Floatation method ‘This method is mainly employed for the concentration of siliphid® ores. ‘The method is based on the different wetting characteristié¥ of the gangueantthe sulphide ore with water and oil. The gangue preferentially wetted by water and the ore by il, ‘The crushed ore along with water is taken in a floatation celiVarious'substances are added depending cn the nature of the ore and a current of airs blowin. The substances added are usually of three types. (a) Frothers :-They generate a stable\frath which rises #6 the top of the tank. Example of frother is pine oil, Eucalyptus oil, fatty/acids etc. (b) Collectors or floating agents :- These attath themselves by polar group to the granules of the ores which then become water repellent and:pass on into the froth Example: sodium ethyhxanthate, pine: ind fatty acid, (c) Froth stabili: Ex. Cresol, Aniline ete, (ad) Depressants’:- These reagents activate or depress the floatation property and help in the separation Of different,sulphide ores present in a mixture, eg. N&CN. Impurity of ZnS in PbS ore removed by NaCN NaC {PbS + ZnS] —>Na,[2n{CN),] + PS -> form froth Powdered Ore + Oil + Water ¥ ers : To stabilise froth: -¢—Compressed ait ight ore particle in froth $G5e00 Concentrated Ore Gangue [Froth floatation process]+ Sometimes, it is possible to separate two sulphide ores by adjusting proportion of oil to water or by using ‘depressants’ + For exatnple, in case of an ore containing ZnS and PbS, the depressant used is NaCN. It selectively prevents ZnS from coming to the froth but allows PbS to go along with the froth (ii) Magnetic separation: If either the ore or the gangue (one of these two) is capable of being attracted by a magnetic field, then such separations are carried out (e.g. in case of iron ores) eg. * SnO, having the impurities of FeWO, + MnWO,(Wolfrarnite) + FeO.Cr,0, having the impurities of SiO,, Finely ground ore Magnetic roller Magneti®particles Non-magnetic particles 2. CHEMICAL SEPARATION (LEACHING) : In this process we use suitable agent which react with ore to form water soluble complex while impurities remain insoluble. Applicable for Al, Ag, Au RedBauxite + AlJOY2H,0 +Fe,0, (Majorimpurity (a) Aluminium | White Bauxite S Al O, 2H,0 +SiO, (Majorimpurity () RED BAUXITE : Two processes (i) @Baeyer's process: NaOH is used. ‘A,0, + NAOH NaAlo, _*=8!/0 , AKOH), + NaOH FeO + NaOH —vinsohible Basic Hall's process : Na,CO, is used. 1,0, + Na,CO, —> 2NaAI0, — YG OH), + Na,CO, (1) WHITE BAUXITE : One process. Serpeck's process : (C+N,) is used AIO, + N, 822+ AIN _#,0_, Al(OH), + NH, 7 [not in NCERT] C+ Si0, + C0, t+ Sit 03(bo) (8) 04 ‘Ag and Au (CYANIDE PROCESS) (Ag Ag,S + 4NaCN > 2Na [Ag (CN),] + Na,SO, jn absence of O, reaction become reversible 2NalAg (CN),] + Zn —> Na, [Zn (CN)] + 2Ag L Oe (i) Aw Au+KCN+H,O >» K{Au (CN) + KOH KiAu (CN), + KOH + Zn —+K, ZnO, + KCN + H,0 + Aut Conversion of concentrated ore into oxide form Calcination and roasting (a) Calcination : Calcination is a process in which ore is heated, generally in the absence of ar, to expel water from a hydrated or hydroxide ore and oxide or carbon dioxide from a carbonate drenat temperature below their melting points. For Example: All carbonates, hydrated ore and hydroxide ore Bauxite ALO, 2H,0 + ALO, + 2H,0, 2AK{0H), > Al,O, + 34,01 Haematites 2Fe,0,, 3H,0 > 2Fe,0, + 3H,0 Limestone CaCO, > Cad + CO, Siderite FeCO, + FeO + CO, Calamine ZnCO, > ZnO + CO, Corussite POCO,-> PbO + CO, Malachite green CuCO,-CulOH),-» CuO + CO, + H,0) Advantages of Calcination :~ (0 Moisture is removed. (i) Organic matter is destroyed (ii) ‘The hydroxide and carbonates oré$ ate converted ifto their oxides. (iv) The ore become porous and Basily Workable (b) Roasting : The removal 6f the éxcess Sulfhurcontained in sulphide ores in the form of SO, by heating in ‘an excess of air is called roasting The concentrated sulphide ore is heated ih reverberatory furnace, below its melting point inthe presence of an additionof an external substance. excess of air with or without 22nS +30, ))22n0 +280}, 2nS 4/20, $ 2nSO,¥2nO #S0,* PbS 40, Baths ‘PbO + SO,t Thermalteduction ‘Some less stable metal oxide further decompose into metal and oxygen. Ag,S+0, Bg Ag,0 2 2Ag +40, t HgS + 0, Sg + HgO "= Hg + 5Op Partial roasting 2CueS, +O, —> Cu,S + 2FeS + $0,t Cu0 2FeO alter roasting [CuS + FeS + C40 + FeO1 Roasting in Fe metallurgy Fe,O, + FeO Haematite FeO, = Fe,0, + FeO Magnetite FeCO, + 4Fe0+-CO, t Siderite Roasting — to prevent wastage of Fe as slag in reduction step 2Fe0 +40, ->Fe,0, (does not form slag) Inreduction step FeO + SiO, = FeSiO, (Flux) (impurity) (Slag) Advantages of Roasting (Excess of sulphur is removed as volatile oxide. S+0,> SO, t (air) (i) The metal sulphide is converted into metal oxide (ii) Impurities of arsenic, antimony & phosphorous are removed as their volatile oxides. Sb, + 30, > 2Sb,0, As, +30, > 2As,0, 4 P, +30, > 2P,0, + For PbS, CuS and HigS partial roasting is carried out Because these Silphide ore easily convert into metal by auto reduction process. Match the following Ore Main element (A) Malachite P)Fe (B) Siderite {OnRo (C) Cerrusite AR) Zn, (D) Pyrolussite (§) Cu (E) Wurtzite. (1) Mp (1) AS, BQVeP, DT, ER 2) AS, BP, C-Q, D-T,ER G)AQ, BS, EP DER (4) AR, B-Q, CP, DT, ES Asserti¢n Froth floatation is concentration method mainly used for sulphide ores. Reasot: Metal sulphides are highly soluble in water. (ya (2B ac @D Assertion : In cyanide process, the leaching is accomplished using NaCN. Reason : CN" ion reduces Ag, Au & Zn ions in the process, (ya (2B (3)c @)D Match the ores listed in Column-I with their correct chemical formula listed in Colurnn-I Column I Column II (A) Cassiterite (p) FeCo, (B) Siderite (@Sn0, (C)Cenussite () PbSO, (0) Anglesite (3) Poco, QAqBp,Cs,Dr QA Bp,Cs,Dq — B)Ap,Ba.Cs,Dr (4) Aq, Bp, Cr Ds 05Which of the following contains both Mg & Ca (1) Magnesite (2) Calamnine (3) Carmelite (4) Dolomite 6. Argentite is an ore of:~ () Iron (2) Gold (3) Platinum (4) Silver 7. If Bauxite consists of SiO, as impurity, this process is employed — (1) Hall’s process (2) Bayer's process (3) Hoope’s process _(4) Serpeck's process 8. The imputities present in the ore is called:- (2) Shag (2) Flux (3) Alloy (4) Gangue 9. Ag,S + NaCN —>A, A+ Zn —> B B is a metal. Hence A and B (1) Na, (2Zn(CN),], Zn (2) NalAg(CN),J, Ag (3) NalAgiCN), Ag. (4) Na,lAgiCN),}, Ag 10. Chemical leaching is useful in the concentration of: (1) bauxite (2) copper purities __(3) cassiterite (@) None {C) Reduction to the metal : ‘The calcined or roasted ore is then reduced to the metallic state byfeither of the following method (Chemical reduction : () Reduction by carbon (Smelting) “Reduction of the oxide with carbon at high temperatiie is known asismelting’. The oxides of less electropositive metals ike PbaZiir Fe, Sn,Cwete. are reduced by strongly heating them with coal or coke, in the blast furnace Metal Oxide + Coke + flux > Metal + CO, +Slag! Example - Reaction in blast furnance :~ 3F 0,05 | CO 2Fes0, + COy (ron ore) FeO, + CO 3Fe0 + CO; CaCO, + C20-+ C0 2 500-800 K 1070 CaO +Si0, > Casio, (Slag) FeO +CO > Fe+CO5 C+CO,+2co (Cote} 1270K +0, CO, FeO +C+Fe+CO Blast of air and oxygen Solid waste Pig ironMetal oxide Coke Molten metal ZO + C + 2n+cCot mo} cy mercot | Athehten SnO0, + 2C —» Sn+2cot | FeO, + 3C —> 2Fe+3cot Fe,0,+3CO—> 2Fe +3Co,t PbO +CO —> Pb+CO,t SnO, +2CO —> Sn +2C0,t low temp. FLUX : Substance used to convert non fusible impurities into fusible one. Three typ of flux are used (a) Acidic Flux : Substance used to remove basic impurities (metal oxide) For example ca + Si0, —> Casio, (basicimpurity) {acidic fx) (Slag) Acidic flux are non metal oxide (SiO, PO, ete.) (©) Basic flux : Substance used to remove acidic impurities (nan Metal Oxide) Forexample CaQ_ + SiO, Sy” Casio, (basictiux) (acidic itaputities) (Slag Basic flux are metal oxide. (CaOsMgOvete,) (€) Neutral flux : Substance used in electrolitic reduction fo decrease the fusion temperature and to increase the conductivity of the solution byiprotading free ions. For example : (Na, Alf, “H\CaF, ) !@aCl, etc Shey Poape Smelting in Cu-metallurgy CUS + FeS Cu,0 + FeO} ofly.aét as fuel Inch RAY + Coke +'SiO, RP “CUS + FeS + slag a) {Copper matte) MS C= ¥M ACS, )AG =)+ve (non spontaneous) CuO" FES —¥ Cu,S + FeO FeO \+ Si0, SF eSiO, (slag) Hap! flux (i) Alumino thermite process or thermite welding process : In this process those metal oxide will be reduced which required high temperature and at high temperature carbon react with metal to from metal carbide In this process we use aluminium as a reducing agent due to (Alhas greater affinity towards oxygen as it forms most stable oxide (Al,0.) (i) This reaction is highly exothermic in nature and ones it start it will continue til all the metal oxide is reduced into metal ForCr, Mn, Fe: (a) Cr,0, + Al + ALO, + 2Cr (o) Fe,0, + Al ——+AL0, + 2Fe Note : Reaction (b) is used in welding of railway tracks. (i) Self reduction Compounds of certain metals are reduced to metal without using any additional reducing agent. ores of Cu, Pb, Hg ete 0708 Their sulphide ores are partially roasted to give some oxide. This oxide is now reduced to the metal by the remaining sulphide ore at elevated temperatures in the absence of air. The process is known as self reduction, Self reduction for Pb: 2PbS + 30, Be, 2PbO + 250, F (Galena) (air) PbS + 2PbO — jE > 3Pb + SO, P Ore + SiO, as (Set reduction) Self reduction in Cu Metallurgy or bessemerisation Cu,S + FeS + SiO, —> Blister copper + slag (fw) FeS + 0,—> FeO + $0, FeO + SiO,—-> FeSiO, (slag) gangue flux CuS +O, —> Cu,0 + SO, CuS + 2Cu,0—> 6Cu + SO, Self reduction for Cu: 2 Cu,0 + Cu,S —-46Cli+ SO, (Il) Metal displacement method : In thi method, compdiind isxeacted with a more electropositive & more reactive metal which displaces, the metal from the solution. For Example CuSO, + Zn $ 2nS0,F'Ga Kroll's Process TiCl, + Mg —s 2MgCl, + Ti (Mg acts.as reducing agent) (IV) Electrolytic rediietion This process is Mainly used fot the extraction of highly electropositive metals. 1A, IIA & Al Electrolysis is ried out in’ large cell and a small amount of another suitable electrolyte is added which (@) _ PBwerS the melting pointof the main electrolyte (0) 4 Bohancesits conductivity ©”) Reduces comston troubles €.g, Manufacture of metallic sodiurn (Down's process) ‘Molten NaCl containing a little CaCl, is electrolysed between graphite anode and iron cathode. The various reactions that take place are On Fusion : NaCl === Na’ + Cl (lons become mobile) On Electrolysis : At Cathode :- Na* + e+ Na (reduction) (Metallic sodiurn) At Anode :- 2Cr > Cl, (g) + 2e° Hall heroutt process : This process is used for extraction of Al from alumina. The extraction of Al from Al,O, is quite dificult because (Fusion temperature of Alumina is quite high (2050°C). Even more than boilling point of Al (150°C) (i) Ttisa bad conductor of electricity. To overcome these difficulties we mix some amount of neutral flux [Na,AIF, + CaF. Neutral fax provides free ions to the solution which decreases the fusion temperature of Alumina from 2050°C to 950°C.(i) From cryolite > AIF, — Al’? + 3F- At cathode : Al? + 3e > Al reduction) At anode: 2F3e > 3r, 3 F, reacts with ALO, 3F, + AO, —> 2AIF, + 20, So at anode O, gas is liberated which on reaction with graphite anode convert into CO, & destroy the anode. C+0,—+ 00,7 (i) From Al,0, At Cathode : AlS + 3e" > Al (reduction) At Anode = Ch) + 20% + COQ) + 4e ‘The main drawback of this process it that anode should be changed frequelitly Graphite anode Copper clamp Molten Al,O, + Na,AIF, Steel vessel with carbon lining (cathode) alurniniur Molten. aluminsin REFINING OF METALS Meals obtained bythe reduction ofits compound still contains some objectionable substance and have to be refined. Depending upon the naturé-of the fetal and impurities, the following methods are used for purification of the metals ( — Physiéal Process : ()\\ Liquation This method is used for the refining of metals having low melting point and are associated ‘with high melting impurities, Ex. Pb, Sn, Sb and Bi. ‘The impure metal is heated on the sloping hearth of a furnace ‘The pure metal flows down leaving behind the non- fusible impurities on the hearth 2000000007 Impure aK metal 09Distillation : Metals having low boiling point are refined by this method, for example, zinc, cadmium and mercury. (iii) Zone refining : Metals of very high purity are obtained by zone refining. This refining method is based on the fact that imputities tend to remain dissolved in molten metal. Ge, Si and Ga used as semiconductors are refined in this manner: Molten zone containing impurity Pure metal Mooving ci (1) CHEMICAL PROCESS :- () — Cupellation : This process is used to purify silver céntaining the impurities of Pb. This process is used when impurity have greatebaffinity towards O, while metal does not have. Impirty 0; — > VolAile oxide Impure metal + 0 Metal +0, —S X. Impusé metal (A8) Airholes (i) Poting : Used to purify Cu, Pb. ‘This protess is used forthe metal having the impurity of their own oxide. In this process a green wooden’ pole.is heated with molten metal, which provide C and H to metal oxide which reduce ‘impurity of metal dxide to metal 2Cw, +O, —> Cu,07 2Cu,0°%F CH,—> 6Cu + CO + 2H,7 Greenwood Impure metal Bessemerisation : Actually itis the key principle involve to removal of impurities by oxidation ‘with air being blown oxidise to molten metal Impure metal is heated in a furnace and a blast of compressed air is blown which oxidise the impunity into their oxides and that can be removed in the form of slag 2Mn +0, ——>2MnO Si +0, —>Si0, 10(I) ELECTRO-REFINING OF METALS Metals such as Cu, Ag, Zn, Sn, Pb, Al, Ni, Cr are refined by this method. ‘The impure metal is made the anode of an electrolytic cell, while cathode is thin plate of pure metal Electrolyte is the solution of a salt of the metal. On passing the electric current pure metal from the anode dissolves and gets deposited at the cathode. The soluble impurities go into the solution while insoluble or less electropositive impurities settle down, below the anode as anode mud or sludge. For Example Electrorefining of Copper Anode Blister copper (98%) Cathode Pure copper Electrolyte An aqueous solution of CuSO, (15%) + 5%/dillH,SO, ~ Electrorefining of Silver Anode Impure silver Cathode Pure silver Electrolyte Ag AgNO, + 1% dil HNOon passing electricity impure anode dissolves and pure Ag is deposited at thejcathode. Electrorefining of Pb (Betts process) Anode Impure lead... Cathode? : Purailead. Electrolyte A mixture of POSIF, andl SIF, Electroretining of Al (Hope's process) ‘Anode Impure Al, Cathode Pure Al Blectrolyte A mixture of.Na AIR, + CaF, (WV) Vapour Phase Refining (Thermal decomposition) () Van - Arkel process : This method is very tisefl for removing ‘ll the oxygen & nitrogen present in the form of impurity, () Employed 8iget thetalin very pire form of small quantities. (i) In this meth, the metals converted into a volatile unstable compound (e.g iodide), and impurities are not affected during compound formation (ia) The'ompound thus obtained is decomposed to get the pure metal jum and zirconium, {bsEEmployed for purification of metals like ti Tis) + 21, () 24 Tila) Impure Til,(a) 224-5 Tis) (pure)+ 21,9) (i) Mond’s process (i Nickel is purified by using CO gas. This involves the formation of nickel tetracarbonyl, Nigaspse) + 4CO —S24+ [N(CO}q] —BH> Niu) + 4CO 4 W1, Copper matte consists of (1) Copper oxide and ferrous sulphide (2) Copper sulphide and ferrous oxide (3) Copper sulphide and ferrous sulphide (4) Copper oxide and ferrous oxide 2. Product obtained after Bessemerisation is called as...because (1) Concentrated copper ; copper percentage is high (2) Copper matte ; of its appearance (3) Blister copper ; of its appearance (4) Ultra pure copper ; 100 percentieopper Matte is obtained after this step - (1) Froth floatation (2)Roasting (3) Smelting (4)Refining 4. Copper glance is ......type of ore ~ (1) Carbonate (2) Sulphide (3) Oxide (4) Sulphate 5. High purity copper is obtained by - (1) Zone refining (2) Poling (3) Eleetroltic reffting > (4) Cupellation 6. The function of flux during the smelting of ore is (1) To make the ore porous (2) To remove Gangue (3) To facilitate reduction (4)"To facilitate oxidation 7. The following equation repreasent3@ method of purification of nickel by Ni (impure) + 4CO __320K., Ni(CO), 2, Ni (pure))i¥ 4E0 (1) Cupelatiors (2) Mofis\process (3) Van Arkel method (4) Zone refining 8. The slag obidiled during’ the extraction of copper from copper pstities is composed of = (1) Cus (2).CuSiO, (3) FeSiO, (4) sio, 9. Whichyof the following reaction is a part of Halls process (1)) AO, + 2NaOQH — 2NaAlO, + HzO (2) Fey0z + 2Al -» 2Fe + ALO; (3) AIN + 3H,0 — ANOH); + NHs (4) AljO3.2H,0+2NayCO3—> 2NaAlOy+COy +2H,0 10. Which method of purification is represented by the following equations Ti+ 21, 523K , Til, 1700K_, Ti+ 21, (1) Cupellation (2)Poling (3) Van Arkel (4) Zone refining 12Ore - Bauxite Al,O,. 2H,0 Concentration Rai Baaxie ApOaHEO |S Baye Process Peo, oe or Hall's process Or purty J and heated at 1100°C Concentration by Sexpeck’s process an heated at 1100°C Finely divided ore bauxite AL0,.2H,0 ALO, [White Bauxite Al,0,.2H,0 [SiO, major impurity. Electrolytic reduction Hall-Harault process Purifigation by Pure Al Fioope's process LEBPUCAL Aul Ore - Auriferrous Rock 7 +0.5% NaCN sol. Residue (impurity), Finely and, divided non ore Aw ‘iteration Zn powder ‘ilterate| NafAw(CN),] 4NalAuICN),] + 4NaOH (Goluble) (b) —-2NalAulCN),] + Zn —> Na,l2n(CN),] + 2Aub (sohible) {sohible) 13Ore - Argentite Ag,S Ag Residue (impurity) Reaction involved : A-Impure Ag so,ciHo (a) Ag,S + ANaCN =» 2NalAgiCN) Nays —S Se Na,SO, + 'S' + 2NaOH =O, is used to make reaction irreversible which Hémove Na,S as Na,SO, + S b) 2NalAg(CN),] + Zn —>>Nayln(CN),] Ag + Finely | 5% NaCN sol.+0, divided aN Zn powder oreAgS| _ Filteration . —— (excess) and Filterate[ NalAB(CN) } preaion soluble complex Filterate Residue Na[Z0(CN).) [Aus Zn Cnde Ag purification 99.99% |, Electro refining a ene Pure Pure Ag E—AgNO,sol. te C-Pure Ag Cu Ore - CuFeS, copper'pyrites Finel Cone. or divided | SErétinfToatation JC °F? | Roasting at Smelting Ore Filterations | |yrittte sio, | moderate temp. CuFeSy Shg Bassemerisation in bessemer ¥ convertor Copper matte Cu,S + FeS Blister Cu ‘reduction Poting Pure Ce Electrorefining 39.99% = CuS0,,,+ dil. H.SO, | Pure Cu C— Pure Cu 14 A= Impure Cu Coke (only fuel) +Si0, Slag FeSiO,Reaction involved : fa) Roasting step CuFeS, +O, —> Cu, +FeS + S0,7 [cu,5 + FeS + Cu,0+ Feo] FeS +0, FeO +S0,7 7) very tess less less cu +0, —> Cu,0 + 80,1 (b) Smelting step = Cu,S remain unaffected again becoz carbon reduction occurs only for oxide and it for sulphide. FeS + Cu,O > FeO + Cu,S FeO + SiO, —> FesiO, 1 Slog CaO + S10, —> Casio, [Cu,S+FeS] copper Matte © Bassemer convertor reaction :~ FeS +0, —> FeO + $0,* FeO #510, —peFeSiO, slag CuS +0, —> Cu,0 +80, ClO Cus => 'eu + So, Blister Cu Fe Finely divided ore Calcifiation magnetite FeO, | tion f Concore |p, and haematite Fe,O, ravity sepatation x toasting Fe,0,+ Carbon reduction limonite Fe,0,34,0| ~SiO: Little $10; litle S10, Ore (8) part Siderite FeCO, Blast | +Coke (4) part Fumace | 4€3CO,(1) part (Pudding process) Molten iron taken in sh Wrought iron afurnace which [Pig Iron or Bg Ferelte is ned with Haematite } Cast Iron CeSiO, 0.25%C +0.3 to =C0, Fe+o.§ 0.459%S,.Mn.$i,P $0, Mn, Si, P MnSiO, ~Fe{PO,), Reaction involved : (1) Roasting step = Fe,0, > FeO + Fe,0, FeO reacts with SiO, to give FeSiO, as slag. FeCO, 1» FeO + CO,* Hence to prevent the formation of FeSiO,, FeO +0, > Fe,0, FeO is converted into Fe,O, which does not Fe,0,3H,0 —> Fe,0, + 3H,0T react with SiO, due to high LE 15GOLDEN KEY POINTS © Types of Iron Pig iron—>Cast iron —»Steel iron—> Wrought iron (Cast iron or pig iron Itis most impute form of Iron and contains the highest proportion of carbon (2.5 - 4 % j along with traces of S, P, Mn and Si. Cast iron contain 2.5 to 4.3 & pig contain 2.5 to 5%, (i) Wrought iron (Fibrous iron) or malleable iron Itis the purest form of iron and contains minimum amount of carbon (0.12 - 0.25%) and less than 5% of other impurities (ii) Steel Itis the most important form of iron and finds extensive applications. As far as ca¥bon content (impurity) is concerned it is midway between cast iron and wrought iron, it contains 0.25./2% carbon, Thus all the three forms of iron differ in their carbon contents, both iron and steel afe obtained from cast iron, Order of MP. WI> Steel > Cl or PI Useful gas NH, is evolved in the leaching of bauxite by serpeck’s proces. In the electrolytic reduction of AlpO;, cryolite (NagAlF,) is added aloniguiti CaF y{ffiorspar) to- decrease m.p. of AlLOs decrease viscocity of electrolyte (CaF is used) increase conductivity © Inthe electrolytic reduction, graphite anode gets corréded or finish@@dute to reaction with Oy liberated at anode, hence it had to be changed periodically © Inthe electrolytic refining (4th step) no electrodes are used. linthé Hoope's process molten pure Aliis used as cathode and molten impure Allis used an anode 4.3 THERMODYNAMICS OF REDUCTION PROCESSES (ELLINGHAM DIAGRAM) It is explanation of the feasibility of pyrométallurgical process by using gibbs equation [AG = AH TAS If AG=-ve Process is stable of Spontaneous AG = + ve or Biéss =e thien préceés.is Unstable or non-Spontaneous ‘When pyrometallutgical process contains more than one type of reaction then stability of reaction can be explain by Ellinghatn diagram/Fllinghain diagram contains plot [AG vs T] 0 400 300 200 100 0 -300 } -s00 ‘Age 7700 -800 -900 -1000 -1100 -1200 0 400800 1200 16002000 ™T 16LOCO] ——+> cao + [gATG] Cr + [GaO[MgO]ALO,] ——> c,0, + [AllMgiG] According to Elingham diagram, the metal below can reduce the oxide of metal above it in the Curve’ as affinity of metal below for oxygen is more. Example Al Metal can reduce Cr,O, but can not reduce MgO & CaO At very high T after 'A’ Point Al’ metal can reduce Mg@_béeatige Formation of MgO contains less - ve AG. ay we IC + 20, > 2c0,H) vo 7197 ‘According to diagram at high T (710°OR above 710°C) Oxidation of C contains more - ve AG so at high T'C’ is good Reducing agent. At Low T (below 710°C) Oxidation of CO contains more -ve AG so at Low T, CO is good Reducing agent. The appropriate flux for removitig FeO will be (1) Sio, (2) C20 (3) Mgo al Match the following Metallurgical process Methods (A) Gopper glance -»Cu_{P) Leaching by NaOH followed by electrolytic reduction (8) Bauxite >A (Q) Froth flotation, partial roasting & self reduction. (€)Cerussite +Pb {R) Heating in presence of dry HCI followed by electrolysis, (D) MgCl, 6H,O Mg _{S) Calcination followed by carbon reduction ()AR, BP, CS, D-Q 2)A.0, BP, CS, DR Q)AP,BQ,C-S,DR GAS, BP,C-Q,DR In the metallurgy of iron, during smelting process, CO is main reducing agent at the upper part of blast furnace, because (1) Itis less concentrated in upper atmosphere (2) The CO, formed can be easily removed (3) mn the lower atmosphere, there is no oxide to be reduced (4) The entropy change during CO/CO, is negative 17Favourable reducing agent for ZnO/2n is (1) Cat high temperature (2) CO at high temperature (3) Cuat high temperature (4) Cuat low temperature 5. Which of the following is true regarding recovery of copper from its low grade (lean) ores. (1) 2n is advantageous economically (2) Fe is advantageous economically (3) Both Fe and Zn can be used and are equally advantageous (4) None of them can be used because Cu is less reactive 6. The slope of a line on Elingham diagram for a process M/MO is :- ac as, Qe (2)-aS (3) 4S Ose 7. The true statement is at temperature T 6 (1) M(s)+ 20, (¢) MOG) ASis positive © (2) M'(s) +MO(s) + M'O(s) + M(s) AG is positive’ (8) MO(s)+MO(s)-+ Mls) +M(s) AGis negitive (4) M()+0,(a) > MOls) AS ifn@gative : B. Auto reduction process is used in extraction of acu (2) Ha Po (4) All ofthese 9. Which isnot the correct process-mineral matching. metallrg (A) Leaching: siver (B) Zone lining: lea. (C)Liguation tin (D) Van Arkel : Zr 10. Consider the following metallurgical processes =~ (i Heating impure metal with CO cistiling the rébulting volatile carbonyl (boiling point 43°C) and finally decomposing at 150°C to 200% to get the pure metal (i) Heating the sulphide ore in.air untila partis converted to oxide and then further heating in the absence of air to let the oxide react withiunchanged sulphide. (ii) Electrolysing the molten electrolyte, containing approximately equal amounts of the metal chloride and CaCl, to obtain the metal. The process used for obtaining sodiuin, Hickel and copper are, respectively, (1) Gi), Gi) and (ai (2), (ii) and Gi) (3) Gil, () and (i) (4) (i), @) and (ii) ANSWER KEY Que. ans[ 2] 3 [3 f[1[4f[4f[4]¢f[2fi o o Pisano tet Quel if[2]3]4][s5]e6,[7]8] 9] 10 ans/ 3 | 3 | 3 | 2/[3 [2{[2]3]4][3 Piso S aoe toed Quel i[2]3]4][s5]e6,[7][8] 9 Ji Ans| 1 | 2[4f[1/[2f[2f[4f[4f[2{3SOME IMPORTANT ALLOY 1 Bronze = Cu(75-90 %) + Sn (10-25 96) 2, Brass = Cu (60-80 %) +2n (20-40%) 3 Gun metal ~ (Cut Zn + Sn) (87:3:10) 4, German Silver ~ Cus2n+Ni 21:1) 5. Nichrome + (N+ Cr+ Fe) 6. Alloys of steel (@) Chromium steel Cr (2-4%) (0) Nickel Steel Ni (35%) (6) Stainless steel Cr (12-1496) & Ni (2-49) Cr forms oxide lager &Prétects Iron From Rusting (4) Invar (FAN) Ni (36%) 19APPENDIX LIST OF ORES AND THEIR NAMES TYPES OF ORES S.N. | FORMULA OF THE ORE NAME Oxide Ore 1 ZnO (Philosopher's Wool) Zincite 2 MnO, Pyrolusite 3 Sn0, Cassiteite (Tin stone) 4 cu,0 Cuprite (Ruby Copper} 5 Fe,0, Haeratite 6 ALO, 2H,0 Bauxite 7 FeO. Cr,0, Chrornite 3 FeO, Magnetite 9 Fe,0,.3H,0 Limonite 10. TiO, Rutile Sulphide Ore 1 2n8; Zific Blende (SPhalerite) 2 HgS Cinnabar 3 Pos Galena 4 AgS ‘Argentité’r Silver glance 5 Fe, Irén pyrite (Fool's gold) 6 CuFeS,, CuS FeS Coppet pyrites (Chalcopyrities) 7 Cu,S.Ag,S Copper silver glance 8 Ag,S.8b,8, Pyrargirite (Ruby silver) 9 Cu,S (Copper glance) Chaleocite Halide Ore 1 NaCl Rock Salt 2 AgGh Hom Silver 3 CaF, Flourspar 4 AIF, 3NaF Cryolite 5 KChMgCl, 6H,O Carmelite Carbonate Ore | 1 Msc, Magnesite 2 C260, Lime stone 3 MgCO,,Caco, Dolomite 4 ZaCO,,(Smithosonite) Calamine 5 POCO, Cemusite 6 FeCO, Siderite 7 CuCO,, CulOH), Malachite 3 2CuCO,,CulOH), Azurite Sulphate Ore 1 CaSO, 2H,0 Gypsum 2 MgSO,,7H,0 Epsomite Or Epsom salt 3 K,SO, AlSO,),.24H,0 Alum Nitrate Ore 1 NaNO, Chile: Salt Peter 2 KNO, Salt peter or Indian salt peter Phosphate Ore | 1 CaO), Rock Phosphate 2010. iy 12. 13. ns) Which of the following is not an ore of lron- (1) Haematite (2) Limonite (3) Cassiterite (4) Magnetite ‘Aluminium is obtained from Al,O, by this method (1) Thermal reduction. (2) Hydro metallurgical method (3) Electrolytic reduction. (4) Reduction by iron. Zine blende on roasting in air gives -— (1) Zine carbonate (2) SO, and ZnO (3) ZnS and ZnSO, (4) CO, and ZnO Litharge is a mineral of: (1) Magnesium (2) Lithium (3) Lead (4) Zine ‘The oxide cannot be reduced by coke (1) Cu,0, ZnO (2) Fe,0, ZnO (3) Ca, K,0 (4) PbO, Fe,0, Chemical formula of horn silver is: (1) Ag,S (2) AgCl (3) AgNO, (4) Ag,S. Sb,S, ‘An example of halide ores is:- (1) Galena (2) Bauxite (3) Cinnabar (4) Cryolite Which is not a basic flux (1) Silica (3) Calcite (2) Lime stone (4) Quick lime Iron pyrites ore is conéentrated by:- (1) Froth floatationtiom, ~ (2) Electrolysis (3) Roasting (4) Magnetic separation Which ofthe, fellowing metals extracted by electrolytic Yeduction process of its halide are = (1) Copper (2) Iron (3)Sodium (4) Aluriniurn Which of the following metal can not be extracted ‘by smelting process: (1) Lead (3) ron (2) Zine (4) Aluminium ‘The main reducing agent for the extraction of iron metal in a blast furnace is: (1) Coke (3) Carbon dioxide (2) Carbon (4) Carbon monoxide “The flux used in extraction of Iron from haernatite in the blast furnace is:- (1) Silica (3) Phosphonus chloride (2) Lime stone (4) Calcium phosphate 14. 15. 16. 17. 18. 19, 20. 21 22 23 24. [ERG] The reduction of Cr,0,, by heating it with ‘aluminium is known as:- (1) Smetting (2) Roasting (3) Calcination (4) Alurninotherrite process Which of the following is\obtained by hydrometallurgy (1) Copper (2yGold (3) Silver (4A of these ‘Aluminium is puitied by (1) Roasting (2) Sublimation (3) Electrolftic refining (4) Reduction with carbon In(Goldschmiat thermite process, reducing agent is (yFe (3) Ca (2)Na (@)al ‘Heating purites in air to remove sulphur isknown as:- (1) Roasting (2) Caleination (3) Smelting (4) Fluxing Liquation process is used for refining:- (1) Bismuth (2) Lead (3) Tin (4) All A mineral is called ore if (1) Metal present in the mineral is costly (2) A metal can be extracted from it (3) A metal can be extracted profitably from it (4) A metal can not be extracted from it ‘Autoreduction process is used in the extraction of: (1) Cu& Pb (2) Zn & Hg (3) Cu&Al (4) Fe & Pb In thermite process, thermite mixture is:- (1) Al powder + sulphide (2) Zn + oxide powder (3) Na + Oxide (4) Al powder + oxide The process of converting hydrated Alumina into anhydrous Alumina is called:- (1) Roasting (2) Calcination (3) Smelting (4) Dressing The metallurgical process in which a metal is ‘obtained in a fused state is called (1) Smetting (2) Roasting (3) Calcination (4) Froth floatation 2125, 26. 27 28. 29. 30. 31 32 33 34. 22 In the extraction of copper, metal is formed in the Bessemer converter due to reaction:- (1) Cu,S + 2Cu,0 — 6Cu + SO, (2) Cu,S > 2Cu+S (3) Fe + Cu,O + 2Cu+ Feo (4) 2Cu,0 + 4Cu +0, In the electrolytic refining of copper, Ag and Au are found: (1) On cathode (3) In the anodic mud (2) On anode (4) In the cathodic mud Consider :~ (a) Copper blende = Cu,O (b) Chromite = Magnetic separation (0 Bauxite = Al,0,.2H,0 (d) Liquation = Liquid metals e.g. Hg Which is/are not correctly matched (2) (@) only (2) (b) only (3) (@) only (4) (a) & (@) both, Silver can be separated from lead by (1) Distillation, (2) Amalgamation (3) Filtration (4) Cupellation blast furnace this is acting as reducing agent at lower part = (1) co 2H, ac (4) None ‘Which of the following metals can fit be Extracted by carbon reduction process (1) Po 2) Al (3) Sn (@\2n The maximum temperature obtained’ in the....region of the blast furnace used in extfaction of iron: (1) Reduction, (2) Combustion (3) Fusion (4) Slag formation The cofitent¥ation of chromite (FeO. Cr,0,)isdone by sy (1) Leaehing process 3), Froth -flotation (2) Magnetic separation (4) Calcination ‘Which of the following process involves smelting (1) 2 PbS + 30, > 2Pb0 + 280,7 (2) AlO3. 2H0 —Al,03 + 2H,0 (3) Fe,O + CO - 2Fe + 2CO, (4) Cry05 + 2Al > AlOs + 2Cr + Heat Out of the following, which ores are calcinated during extraction = (2) Copper pyrites (b) Malachite (c) Bauxite Correct answer is = (a,b,c Q)b, (3) Only a (4) All 35, 36. 37 38 39. 40. a1. 42. 43. Which of the following match are incorrect :- (a) Goldschmidt aluminothermite process - C203, (b) Mac Arthur cyanide process - Fe (d) Mond process - Ni (@) Van Arkel process ~ Au Mac Qed B)bd (ab Electro metallurgical process (electrolysis of fused salt) is employed to extract — (1) Lead (2) Sifver (3) Sodium (4) Copper In the extraction of coppef ffomr pyrites, iron is removed as:- (1) FeSO, (3) Fe,0, (2) Fesio, (4) Fe,0, Which one of the following metals can not be extracted by using Al asia reducing agent = (1) Na fromm,Na,O (2) Cr from Cr,0, (3) Ma ffom MnO,“ {4) V from V,0,, Inth@electrolytioéfinfi for aluminium extraction the electrolyte usetis:- (1) Fluorides of Al, Na and Ca (2) Al(Old), in NaOH solution (3) Anagueous solution of Aly(SO,), @) Molten Al,0, Which one is mismatched (1) Poling refining of copper (2) Cupellation ~ refining of silver (3) Smelting ~ An oxidation process (4) Roasting - An oxidation process Which metal can be purified by distillation (1) Cu (2) Ag (3) Fe (4) Hg Carbon cannot be used in the reduction of Al,O, because = (1) it is an expensive (2) the enthalpy of formation of CO, is more than that of ALO, (3) pure carbon is not easily available (4) the enthalpy of formation of Al,O, is too high Match list I with lis Il and select the correct answer using the codes given below the lists List T List Il A. Van Arkel method |. Purification of titanium B. Solvay process Il. Manufacture of Na,CO, C. Cupeliation Ill Purification of copper D. Poling NV. Refining of silver Codes : AB c D qt 0 vot @ m1 Mt Vv 8 vow 1 i @m 1 u v44. Anode mud obtained after electrolytic re copper contains (1) Ag (2) Au (3) Pe (4) All 45. Maite (1) CuS + FeS (2) CuO + FeS (3) CuO + Cus (4) FeS + SiO, 46. Which of the following reaction is not involved in themite process == (1) 3Mn,0, + 8Al —>9Mn + 41,0, (2) Cr,0, + 2Al —> ALO, + 2Cr (3) 2Fe + AO, —+ 2Al + Fe,0, (4) B,O, + 2A| —> 2B + ALO, 47. Alumino thermite process is used for the extraction of metals, whose oxides are :- (1) Strongly acidic (2) Not easily reduced by carbon (3) Not easily reduced by hydrogen (4) Stongly basic 48. Match the following 1 0 (A) Calcination a, 2Cu,$ + 30, > 2Cu,O\+ 280, (B) Roasting b, Fej0, "HH,O Fe,0, + nH,0 (C) Flux 1 Cr,0, + 2Al\> ALO, 4 )2cr (0) Thermife\.” d.$i0,4, FeO —FeSiO, ADB c D (0%, b c d (2) Yb a d c @) 4 a b © @ oc a b d 49. Main source of lead is PbS. It is converted to Pb by = A. Pos > p20 + so, —>Pb + co, B:PbS —“"8\"">PbO + PbS—> Pb + SO, Self reduction process is (aya (3) both, 2B (4) none 50. 51. 52. 53. 54. 55. When haematite ore is burnt in air with coke along with lime at 200°C, the process not only produces steel but also produces an important compound (A), which is useful in making building materials. ‘The compound (A) is (1) Sio, (3) FeO (2) Casio, (4) Fe,0, Match List-I with ListI and select the correct answer using the codes given bélow the lists. List-1 (Metals) Lista (Process/methods involvedvin extraction process) (@) Au 1. Self reduction (b) AL 2. Liquation (@ Pb 3. Electrolysis (@Sn A, Bayer's process @ (b) (C} (a) (yQ3 a 2 4 Ans 4 1 2 @ 4 2 4 3 14) 3 2 4 1 Main fnction of the collectors in metallurgy is: (1) Sti to the ore and then take it to rise upto the top {2) Convert the insoluble ore into soluble part (3) Make the ore hydrophobic (4) None Reducing agent of haematite in blast-furnace is = (1) Coke in furnace (2) Coke in upper part and CO in lower part of fumace. (3) CO in most parts of the furnace (4) CO in the furnace. PbS “> X, X + PLS —> Pb + S0,. x may be = (1) PbO (2) Pbo, (3) PbO and PbSO, (4) PbO, and Poo ‘Which one of the following statements is incorrect? (1) Tin is extracted by carbon reduction (smelting) (2) Aluminium is extracted by Hall's process which, involves carbon reduction, (3) Extraction of lead does not involve bessemerisation. (4) Silver is extracted by cyanide process. 2356. Extraction of zinc from zine blende is achieved by: (1) electrolytic reduction (2) roasting followed by reduction with carbon (3) roasting followed by reduction with another metal (4) roasting followed by self-reduction 59. In magnetic seperation method which one is true (1) either ore is being attracted by magnetic field (2) either gangue is being attracted by magnetic field (3) Both (4) None 60. In froth floatation method depresants are used for~ 57. Column-1 Column - It A) Mentwhich oceurinthe ie {) to enhance non wettability of mineral partes Metal which ovetr in (2) to made suspension of ore WithWater (2) The oxides of metal that (Q)Ti (3) to take forth upside can be commercially 0 seperate two sulphidesore reduced by Aluminorthermite (2) to seperate two sulphid reduction provess is 61. Which reaction shows falmaon of blistered copper. (3) van Arkel method is used (R) Cr for preparing ultrapure (1) 2FeS + 30, ——>2FeO + 280, metal of (A) Auto reduction processis (8) Ag (2) 2Cu$%30,—#Bcu,0 + 20,4 employed for the sulphide ore of 8).2Cu,0' + Cy,S 35 6cu + 50,7 ()AS,BR,CQ,DP ()AR,BS,CQ,DP BAPBS,CQDR (4)A-Q,BR,CS.DP 4) Cu,0 €@ 5 2cu + cot 58. Match the folowing £62, Which Yeaetion's involved in extraction of Ag by 1. Zincte P> Sulphide ore cyanide proces 2. Malachite Q halide ore (a))AgBr + Na,S,0, —__,Na, [Ag(S,0,),) 3. Hom siver R Oxide org 4. ron purities S Carbonate ore (2) AgCl + NHOH —yIAgiNH,) CL (8) Ag,S + NaCN __, NalAg(CN), W1-R, 2-P; 34Q) 4-8 (a) None Q1-R 2-8 8. 004-P @1-s 2-R%-P, 440 ()1-Q 2esy 3-Pa-R (Conceptual Que: Ores 3[4]5]e6]7][8]9][m[ u] 2] is] a] is 2{3{3]|2/4{1/1|s|/4a|4]/2 [a4] 4 18 [19 [20] 21 [22 | 23 [24 | 25 | 26 | 27 | 28 | 29 | 30 1/4{[3{/1[4/2,/1]/1/[3|4[4]|3]|2 | 33_[ 34 | 35 | 36 | 37 | 38 | 39 | 40 | a1 | 42 | 43 | 4a | 45 fAns| 2 | 2|3|/2|/3|3|/2{1[/1[3|/4|[4[1]4][1 Que] 46 | 47 | 43 | 49 | 50 | 51 | o2 | 53 | 54] 55 | 56 | 57 | 68 | 59 | 60 ans} 3] 2] 2,/2{2]2[1]3|3]2,/2]1[2|3]4 Quel 61 | 62 fAns| 3 | 3 24IMPORTANT NOTESIMPORTANT NOTES