Precious metals losses in pyrometallurgical processing

CIM Bulletin, Vol. 83, No. 933, 1990

J.W. Matousek, and J.G. Whellock, Tolltreck International Limited, Englewood, Colorado

In spite of their importance to the economics of many metallurgical projects, the values and technical aspects of precious metals losses in smelting operations are relatively undeveloped subjects. This paper attempts to provide a condensed overview of precious metals losses in pyrometallurgy, using some of the limited production and experimental data available. It is intended for three general groups of metallurgists — operators attempting to improve recoveries, cost-accounting engineers making estimates of metal losses in new or modified smelting plants, and research engineers and students. Distribution coefficients of precious metals, the ratios of metal or matte assays to slag assays, are convenient means of comparing smelting processes and the tendencies of the different metals to enter the slag. For silver in lead blast furnaces this ratio is approximately 250; for gold and the platinum group metals in submerged-arc, electric furnaces it is 900. The ratio for gold and PC Ms in converters varies with the degree of oxidation of the charge. The over-all cycle-average for industrial installations is tentatively estimated to be 35.

Keywords: Pyrometallurgy, Precious metals, Smelting processes