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Lead, Zinc and related valuable metals

The majority of lead concentrates are sulfide-based. The traditional way of treating these materials is to roast them in a sinter machine, in order to obtain fully oxidized agglomerates, which are subsequently reduced in a blast furnace. This has increasingly been replaced by modern direct bath smelting processes (such as the BlueSmelter of SMS group), consisting of a combined roasting and smelting reaction followed by slag reduction. Existing technologies include QSL, KIVCET, Vanyukov, TBRC, TSL, SKS, and OBBF, which produce lead bullion and slag containing low quantities of lead. Recycled lead is produced using either short rotary furnaces or a combination of reverberatory furnace and slag reduction unit.

In addition to the main metal component, all non-ferrous metals concentrates contain various amounts of other metals, as shown in the Metal Wheel.

Metal Wheel Metal Wheel Metal Wheel Metal Wheel
Metal Wheel

Lead concentrates always have significant amounts of Cu, Zn, Sn, Ag, Bi, As, Sl, which makes the metallurgical recovery process more challenging. The objective is to recover all these metals as value-added byproducts, instead of disposing them of via the slag or other waste materials.

The third process route is direct leaching of the concentrates prior to electrowinning. Secondary materials such as dust from electric steel plants or jarosite from zinc leaching can be treated in electric furnaces, TBRC, Waelz kilns, or TLS to enriched zinc oxide.

Tin is processed by carbothermic reduction of oxide ore in either electric or reverberatory furnaces.

These furnaces have in common that they require a modern control system, advanced cooling/lining concept, low emission burners and a robust furnace design. SMS group offers several improvements and optimization for existing furnaces and offers solutions in the smelting and refining of these metals.