Work lead

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Work lead is still unclean raw lead , which accumulates in the lower part of the furnace during the smelting process and contains up to 5% impurities such as copper , tin , antimony , arsenic , bismuth or precious metals such as silver and gold in varying proportions. The silver-rich alloy is called Güldischsilber .

The lead leaves the furnace at approx. 900 to 1000 ° C and, as soon as it cools down, it eliminates the impurities that are poorly soluble in the lead at lower temperatures. These are drawn off as slip and either returned to the oven or processed separately.

Depending on the smelter, the lead has a different composition, is usually not on the market, but is further refined into smelting lead or fine lead .

The pyrometallic refining of lead is a multi-stage process. Antimony, zinc, arsenic, copper, nickel, cobalt and silver are extracted here using different processes. This purification and marketing of some of these by-products and primarily the precious metals increased the profitability and profitability of lead smelters considerably.