Measurement of non-isothermal oxygen potentials in a Cu–Fe–Ca–S–O liquid during reduction of chalcopyrite in lime and carbon mixtures

Abstract

The reduction of Indian chalcopyrite concentrates from the Ghatshila mines with carbon was studied in the presence of lime in the temperature range of 1123–1573 K. An attempt was made to determine the oxygen potential corresponding to the selective separation of two metals, copper and iron, during the reduction of chalcopyrite by carrying out electro-motive force (emf) measurements under isochronal heating rate conditions using an yttria-stabilised zirconia solid electrolyte cell with Cu/Cu₂O as the reference electrode. The isochronal rate data for oxygen potential measurements were analysed by comparing them with the data from isothermal kinetics studies on the reduction of natural and synthetic chalcopyrite minerals in the above temperature range. The analyses of phases formed were carried out using the X-ray powder diffraction and scanning electron microscopic techniques, which showed the presence of a new quinary solid solution C_III phase. The solid solution phase C_III [Cu₂S-C_II(FeS⋅CaO)] forms as a result of mixing between the two rhombohedral lattices: high-temperature form of Cu₂S and C_II (FeO⋅CaS) compounds. The mechanism of reduction of chalcopyrite with carbon in the presence of lime is illustrated by the explanation of the role of the intermediate phases, C_II, C_III and matte phases.

Keywords

Chalcopyrite Carbothermic reduction Non-isothermal Oxygen potential Stabilised zirconia

Get full access to this article

View all access options for this article.

References

Biswas,

A. K.

and Davenport,

W. G.

. 1994a. Extractive metallurgy of copper, 3rd edn, 261, Oxford, Pergamon Press.

Biswas,

A. K.

and Davenport,

W. G.

. 1994b. Extractive metallurgy of copper, 3rd edn, 273, Oxford, Pergamon Press.

Biswas,

A. K.

and Davenport,

W. G.

. 1994 c. Extractive metallurgy of copper, 3rd edn, 264–265, Oxford, Pergamon Press.

Bronson,

P. C.

and Sohn,

H. Y.

. 1983. The carbothermal reduction of nickel sulfide in the presence of lime, Metall. Trans. B, 14, 605–615.

Ford,

J. D.

and Fahim,

F. A.

. 1975. Kinetics of cobalt sulfide reduction in the presence of calcium oxide, Metall. Trans., 6, 461–63.

Hultgren,

, Desai,

P. D.

, Hawkins,

D. T.

, Gleiser,

, Kelly,

K. K.

and Wagman,

. 1973. in Selected values of the thermodynamic properties of binary alloys, 44–49, 737–741, Metals Park, OH, American Society for Metals.

Jha,

and Grieveson,

. 1992a. Carbothermic Reduction of Pyrrhotite in the presence of lime for the production of metallic iron - part 2. The kinetics and mechanism of reduction, Scand. J. Metall., 21, 50–62.

Jha,

and Grieveson,

. 1992b. Carbothermic reduction of chalcopyrite in the presence of lime, part-III, production of iron and copper, Scand. J. Metall., 21, 127–137.

Jha,

, Grieveson,

and Jeffs,

J. H. E.

. 1989. Scand. J. Metall., 18, 31–45.

10.

Jha,

, Igiehon,

U. O.

and Grieveson,

. 1991. Carbothermic reduction of pyrrhotite in the presence of lime for the production of iron, Part 1. Phase Equilibria in the Fe-Ca-S-O system, Scand. J Metallurgy, 20 (5), 270–278.

11.

Jha,

, Tang,

and Chrysanthou,

. 1996. Phase equilibria in the metal-sulfur-oxygen system and selective reduction of metal oxides and sulfides: Part I. The carbothermic reduction and calcination of complex mineral sulfides Metall. Trans. B, 27, 829.

12.

Kerby,

R. C.

. (1973). In IR 73–4, 50, Carbothermal reduction of nickel sulphide minerals, Bureau of Canadian Institute of Mines Report.

13.

Koch,

and Trömel,

. 1977. Archiv für das Eisenhüttenwesen, 48, 133–138.

14.

Rao,

Y. K.

and Abramowitz,

. 1978. IMM Trans. Sect. C, 87, 180–188.

15.

Rao,

Y. K.

and El-Rahaiby,

. 1984. Metall. Trans. B, 15, 1157–1166.

16.

Rao,

Y. K.

and El-Rahaiby,

. 1985. Direct reduction of lead sulfide with carbon and lime; Effect of catalysts: Part i. and Direct reduction of lead sulfide with carbon and lime; Metall. Trans. B, 16, 465–475. Part ii. analytical model experimental, Metall. Trans. B, 16, 15, 477–488.

17.

Rosenqvist,

. 1978. Phase equilibria in the pyrometallurgy of sulfide minerals, Metall. Trans. B, 9, 337–351.

18.

Turkdogan,

E. T.

. 1980. Physical chemistry of high temperature technology, 1st edn, 2–25, Academic Press, London.

19.

Weast,

R.C

. (ed.). 1983/1984. Handbook of physics and chemistry, 63rd edn, B210–B213. CRC Press, Boca Raton, Florida USA.