Crude lead: Is lead toxic?

　　Important casting materials for lead are bearing alloys and lead lettering alloys; casting products include bearings, type plates, counterweights, sealing washers, warheads, ballast counterweights, and even monolithic castings of radiation shields for large nuclear power plants. So crude lead: is lead toxic?

　　Crude Lead: Is Lead Toxic?

　　Lead is toxic. Lead is a soft and ductile weak metal and a heavy metal. The original color of lead is pale, and the surface is quickly covered with dark gray oxide in the air. It can be used in construction, lead-acid batteries, slugs, welding materials, fishing gear, fishing tackle, radiation protection materials, trophies, several alloys.

　　Lead is a silvery white heavy metal with blue color, melting point 327.502 degrees, boiling point 1740 degrees, density 11.3437 g/cm3, hardness 1.5, soft texture and low tensile strength.

　　Lead without oxide layer has bright color, high density, very low hardness and high ductility. The electrical conductivity is quite low and the corrosion resistance is high, so it is often used as a container for anti-corrosive substances such as sulfuric acid. The addition of small amounts of antimony and other metals will further improve the corrosion resistance.

　　Crude lead: How to refine lead?

　　(1) Lead sulfide in galena is converted into lead sulfate, and the two further react to get metallic lead. Lead sulfide is melted into lead oxide, and then melted with coke and limestone in a blast furnace to produce metallic lead.

　　(2) Refining methods include: fire refining. Melt the crude lead first, then add sulfur, sodium hydroxide, sodium chloride and sodium nitrate to separate the impurities into slag. Electrolytic refining. Using crude lead as the anode and pure lead as the cathode, pure lead can be obtained.

　　Crude lead: How is the distribution of lead industry?

　　According to the distribution and construction conditions of lead and zinc mines in China, after more than 40 years of development and construction, China's lead and zinc industry has formed five major lead and zinc mining, smelting and processing production bases in northeast, Hunan, Guangdong, Yunnan, Sichuan and northwest China. Their lead production accounts for more than 85% of the total national output and zinc production accounts for 95% of the total national output.

　　(1) Northeast Production Base

　　Northeast China is one of the earliest lead and zinc production bases in China.

　　(2) Hunan Production Base

　　Hunan is rich in lead and zinc ore resources, with many rich ores, most of which can be developed and utilized. The lead-zinc mining plants in this base were built in the 1950s and 1960s.

　　(3) Production bases in Guangdong and Guangxi

　　The two regions of Guangdong and Guangxi are rich in lead-zinc resources and are one of the large lead-zinc production bases in China formed in the 1970s. The Guangdong Fankou lead-zinc mine and the Shaoguan smelter are the main ones, followed by the Bincun lead-zinc mine, the Changhua lead-zinc mine and the Dajiangshan lead-zinc mine. Guangxi Siding lead-zinc mine, Daxin lead-zinc mine, He San lead-zinc mine, Liuzhou zinc products factory and Dazhan Mining Bureau.

　　(4) Yunnan and Sichuan Production Bases

　　Yunnan is rich in lead-zinc ore resources.

　　(5) Northwest Production Base

　　There are also abundant lead-zinc ore resources in the northwest, mainly in Gansu, Shaanxi and Qinghai provinces. The exploration reserves in the western metallogenic belt have increased substantially and the resource prospect is very promising.