Lead is a soft but quite dense low-melting metal that only comes second to gold when talking of the density. Lead is what forms a large constituent of batteries, with the battery industry using up about 75% of lead. It is because of it's density that it is effectively used as a barrier against X-rays and also in sound barriers. Additionally, lead is very durable, no wonder it is usually added to paints and used as roofing material. Because of its high resistant to corrosion caused by water, lead plays a very crucial part in the plumbing industry.
Lead is normally extracted from ore and over 60 minerals have some traces of lead, although only 3 mineral are mostly mined for the production of lead, with galena being the leading mineral, followed closely by cerussite and anglesite. Apart from the ore, very few raw materials are needed for lead refining. The ore concentrating process requires xanthate, lime, alum, and pine oil, while iron or limestone ore is added to the lead ore at a later stage during the roasting process.
Once the ore has been extracted from the mine, it will be treated at a concentrating mill for purposes of separating lead from waste rock. First off, the ore has to be crushed into very tiny pieces, which will then be diluted in water and poured in a tank known as a flotation cell. A tiny percentage of pine oil or a chemical similar to it is added to the slurry (mixture of water and ground ore). The tank is stirred to shake the mixture fiercely as the pine oil attracts impurities such as sulfide particles.
The refining process of lead then goes to filtering stage which gets rid of around 90% of water and then taken to the smelter. Note that the lead concentrate has to be further refined to get rid of sulphur hence is put on a sinter plant, mixed with sand, limestone, and other lead-bearing products and heated on a moving grate. From here it goes to blasting where more refining takes place and once the end product comes from the blasting furnace, the molten lead will be around 95-99% pure lead, which at this juncture is referred to as base bullion.
Further refining has to take place to get pure commercial lead, whereby the base bullion is put in a lead drossing kettle and melted at around 626?F (330?C). Once this process is done, one is left with lead that is 99-99.99% pure.
Gas and oil companies have been around for over a 100 years, and so many brands have come and gone. Some oil brands just disappeared or dissolved while others have merged with other companies, and their name has changed.. The there are some that have been around...