Introduction to lead basic knowledge

January 19, 2024

Lead is a chemical element whose chemical symbol is Pb (Latin Plumbum) with an atomic number of 82. Lead is a soft, heavy metals, which is toxic, is a kind of extension of a main group metal. The true color of lead is blue-white, and its surface is quickly covered with a layer of dark gray oxide in the air. Lead was used as building materials, lead acetate used in batteries, as bullets and artillery shells, solder, trophies, and some also lead alloys. Lead is the highest atomic number among all stable chemical elements. The lead without the oxide layer is bright, high in density, very low in hardness, and highly extensible. It has a very low electrical conductivity and high corrosion resistance, so it is often used as a container for corrosive substances such as sulfuric acid. Adding a small amount of niobium or other metals can increase its corrosion resistance. Humans have known lead as early as 7,000 years ago. It is widely distributed, easy to extract, easy to process, ie has high ductility, is very soft, and has a low melting point. Lead has been mentioned in the Bible - Exodus.
The alchemist thought that lead was the oldest metal and connected it to Saturn. Lead is a widely used metal in human history.
Since the mid-1980s, the use of lead has begun to plummet. The main reason is the physiological role of lead and its pollution to the environment. Today, gasoline, dyes, solders and water pipes are generally free of lead.
Pure lead in nature is rare. Today, lead is mainly smelted and extracted together with metals such as zinc , silver and copper . The most important lead ore is galena (PbS), which has a lead content of 86.6%. Other common lead-containing minerals are leucite (PbCO 3 ) and lead bismuth (PbSO 4 ). The world's largest lead producers are China, the United States, Australia, Russia and Canada. More than half of the lead today is recycled.
Lead ore is generally mined by means of drilling or blasting. The ore is mined and then mixed with water and other chemicals. In the container of this mixed liquid, bubbles rise, and the lead-containing mineral rises to the surface to form a layer of foam as the bubble rises. This layer of foam can be collected. This process can be carried out multiple times, with 50% lead. The collected foam was baked and melted to give 97% lead. This melt is slowly cooled, and the impurities rise lightly to the surface and can be removed. The remaining lead is melted again. Cold air is blown into the melt, and more impurities rise and are removed to give 99.9% lead.

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