This book covers various metallurgical topics, viz. roasting of sulfide minerals, matte smelting, slag, reduction of oxides and reduction smelting, interfacial phenomena, steelmaking, secondary steelmaking, role of halides in extraction of metals, refining, hydrometallurgy and electrometallurgy.

Each chapter is illustrated with appropriate examples of applications of the technique in extraction of some common, reactive, rare or refractory metal together with worked out problems explaining the principle of the operation.

space between the two pipes helps in cooling the lance tip by extracting heat from the outer pipe. As a result, slag freezes on the surface of the pipe and provides protection to the lance tip. Cooling by helical swirl vanes causes rapid extraction of heat from the outer pipe into the blast and formation of a protective slag coating after solidification on outer surface of the lance is the unique feature of the Ausmelt technique. The Ausmelt furnace produces high-grade matte and slag containing

operation at Glogow [32] in Poland, Olympic Dam [33] in Australia, and in Zambia [34] and China [34]. The temperature of the furnace is controlled by adjusting the extent of O2-enrichment of the blast and the rate of combustion of fossil fuel. Direct production of copper from the chalcocite/bornite concentrates may be chemically represented as per the reaction: Cu2 S chalcocite Cu5 FeS6 bornite + O2 Cu l + FeO Fe3 O4 SiO2 slag blast + SiO2 + SO2 g flux 3 37 Oxygen supply is regulated to

tetrahedron can be estimated as follows by assuming, K1 = K2= K3 = K. Hence xSi2 O67 − = xSi3 O8− = 10 = xSi4 O10− 13 K xSiO4− 4 x O2 − K xSi2 O67 − xO2 − K xSi3 O810− xO2 − xSiO44 − 4 44 xSiO44 − = K 2 xSiO44 − = K 3 xSiO44 − 2 xO2 − xSiO44 − xSiO44 − 4 45 xSiO44 − 4 46 3 xO2 − where K is the composite equilibrium constant and, hence, the total silicate anions may be obtained as Nsilicate anions = xSiO44 − + xSi2 O67 − + xSi3 O810− + = xSiO44 − 1 + K = xSiO44 − xO2 − n + K 4 47

0.5, 1.0 and 10 atm, together with the curve for reduction of ZnO to liquid zinc. The latter intersects the curves for different vapor pressures of zinc at temperatures where liquid zinc and zinc vapor are in equilibrium. The Boudouard reaction 5.31 is also shown in Figure 5.4 with the gas ratio [1] for pCO = 0.1, 0.5, 1 and 10 atm. Both the equilibria represented by Equations 5.32 and 5.31 must be satisfied for continuous reduction of ZnO by carbon. This means reduction will take place at the

zr03 + r13 1 − z αρR 2 3 − 1 − z r12 2 3 5 91 170 REDUCTION OF OXIDES AND REDUCTION SMELTING TABLE 5.1 Summary of Kinetic Equations [10] Applicable to Reactions Controlled by Diffusion Through Nonporous Solid Product with the Geometry of a Spherea [1 − (1 − f )1/3]2 = k t 1− 23 f − 1−f 2 3 = kt 1. Jander’s equation 2. Crank, Ginstling and Brounshtein’s equation 3. Valensi’s equation [1 + (z − 1) f]2/3 + [(z − 1) (1 − f)2/3] = kt Approximate Applicable to most cases although not very