ES215311A1 - Improvements in or relating to the smelting of zinc and lead-containing materials - Google Patents

Abstract

Metalliferous materials containing substantial amounts of lead and zinc are smelted with carbonaceous material in a blast furnace, the charge and/or the air blown into the furnace being preheated to such an extent that a reducing environment is maintained throughout the smelting charge and the proportion of carbonaceous material in the charge is not substantially greater than would be required if lead compounds were omitted from the charge. The charge may be preheated to at least 600 DEG C. and the air to at least 500 DEG C. The constituents of the charge may be separately heated, the carbonaceous material to 800-1000 DEG C. and the remainder of the charge to 500-750 DEG C. A charge containing zinc enriched slag from a conventional blast furnace smelting of lead ores and lead sulphide concentrates may be treated, the lead forming, for example, 9-85 per cent of the total of lead and zinc. A suitable quantity of carbonaceous material to be used is equal to the sum of about 90 per cent of the zinc to be volatilized and about 20 per cent of the slag to be formed. The gaseous product resulting from the smelting operation withdrawn from above the charge level may be treated with a controlled amount of an oxygen-containing gas thereby raising the temperature of the products by oxidation of some of the carbon monoxide to permit their travel to a shock-chilling condenser without oxidation of zinc, the carbon dioxide content of the resulting gases being not over 12 per cent. Specifications 572,961, 682,176, 682,179, 686,542, 686,585, 686,589, 726,530 and 741,243 are referred to.