Description
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Lead is one of the poor metals, also called a post-transition metal which has a blue grey color in its natural solid state. It is a soft, malleable, metal that is resistant to corrosion. Lead has an atomic weight of 207.2, a melting point of 621.43 °F, and a boiling point of 3180 °F. Some common uses of lead include: as a component in ammunition, to make wearable shields to protect against x-ray radiation, as a component in some types of materials, and in the manufacture process of some glasses.
Isolation
Lead does occur in its free native form in nature, but it is very rare. More often, lead is found in minerals ores, and it is extracted from these ores for commercial use.
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Lead minerals such as anglesite, cerussite, and galena are used for sources of lead that is extracted and isolated for commercial use. Galena has the highest concentrations of lead, approximately 86%, and it is used most often as a lead source. The isolation of lead is rarely performed on a small scale laboratory basis as lead is toxic and available commercially.
The beginning of the isolation process of lead begins with crushing the ores that it occurs in and then using froth flotation to further concentrate the lead. Froth floatation uses surfactants and wetting agents to separate sulfide ores from minerals. Next, the ore mixture is roasted which results in a mixture of lead oxides, sulfates, and silicates. Lead oxide is collected and reduced through the roasting process in a coke-fired blast furnace. Further treatment in a reverberatory furnace removes any contaminates to result in a highly isolated lead compound. Smelting this compound removes silver contaminants, and the Parkes process removes any gold contaminants.