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The lead ore most commonly mined in galena, which is the sulphide of lead (PbS). It forms intimately mixed with other metalliferous minerals, such as sphalerite (zinc sulphide), cooper pyrites and iron pyrites. The ore has to be concentrated, e.g., by flotation, in order to separate the galena from the sphalerite and other minerals that may be present.

Lead has been commonly used for thousands of years because it is widespread, easy to extract and easy to work with. It is highly malleable and ductile as well as easy to smelt. Metallic lead beads have been found in Çatalhöyük dating back to 6400 B.C. In the early Bronze Age, lead was used with antimony and arse.

Lead also refers collectively to the organic and inorganic compounds of lead, which are toxic. Lead poisoning was documented in ancient Rome, Greece, and China. In the 20th century, the use of lead in paint pigments was sharply reduced because of the danger of lead poisoning, especially to children. By the mid-1980s, a significant shift in lead end-use patterns had taken place. Much of this shift was a result of the U.S. lead consumers' compliance with environmental regulations that significantly reduced or eliminated the use of lead in non-battery products, including gasoline, paints, solders, and water systems.


Lead use is being further curtailed by the European Union's RoHS directive. Lead may still be found in harmful quantities in stoneware, vinyl such as that used for tubing and the insulation of electrical cords, and brass manufactured in China. Between 2006 and 2007 many children's' toys made in China were recalled, primarily due to lead in paint used to color the product.

Subsequent treatment of the concentrate thus obtained consists in roasting followed by reduction in a vertical-shaft furnace, a form of blast furnace. Roasting is basically performed by heating the lead ores, blended with suitable fluxing minerals, on a traveling endless grate through which air is sucked. In this way the material is sintered converted into lumps called sinter, which are then mixed with coke and charged into the shaft furnace (Fig.2). Air is forced into the furnace at the bottom.

The coke, which uses as fuel and reducing agent, reacts with the sinter to reduce the oxides and yield liquid lead, which is, however, contaminated with other metals like silver, copper, zinc, tin, antimony, bismuth, arsenic, etc. The non reduced components form a liquid slag which floats on the liquid metal. Preparing the charge and operating the furnace call for great skill. In particular, the charge must contain the correct proportions of iron, lime and silica to produce a liquid slag that can readily be separated from the metal; it is also essential to maintain the proper balance of coke and sinter.

When the impure liquid lead (bullion) cools, some of the impurities, especially copper, separate out as drosses, which are further processed to extract the copper. Further removal of the copper may be effected by treatment of the bullion with sulphur. Antimony, tin and arsenic are removed by elective oxidation in a reverberatory furnace or by treatment of the bullion with chemical reagents to separate out these metals in the form of salt-type compounds.

On cooling, the zinc forms a dross or crust which contains nearly all the silver and other metallic impurities. The dross is skimmed off, and the silver is recovered from it in a separate process. The zinc is distilled off and used over and over again (Fig.3). After desilverizing, the lead may have to be debismuthized, which is done by a process somewhat like desilverizing but using calcium and magnesium instead of zinc to form dross with the bismuth.

An alternative method of treating the impure bullion is by electrolytic refining. The bullion is cast into plates which serve as anodes in electrolytic tanks. The electric current causes the lead at the anode to dissolve, and pure lead is deposited at the cathode. All these refining processes can produce pig lead of very high purity (99.999%).