Stannous Salt Proton family
Tin is one of the earliest discovered and used metals. As early as the Shang Dynasty, our ancestors will be able to produce bronze vessels with tin, copper and lead. Yunnan Gejiu tin mine as early as BC has been mined. Because tin is soft and ductile, chemical stability, corrosion resistance, fusibility, friction coefficient is small, tin salt non-toxic, so tin and tin alloy in modern defense, modern industry, cutting-edge science and technology and human life has been extensive application. China tin is rich in resources, has long been a large producer of tin, reserves and production are living in the forefront of the world.
Tin is a silver-white metal, with a strong luster, the relative density of 7.0, low melting point (230 ℃), hardness of 3.75, good soft ductility. The content of tin in the crust is only 2 × 10 ^ (- 6) to 10 × 10 ^ (- 6). Tin belongs to the family of copper elements, but in the upper part of the lithosphere and pro-sulfur and pro-sulfur characteristics of the two. Tin reacts with sulfur to form two compounds: tin sulfide and tin disulfide, which have strong volatility at high temperatures. Tin and oxygen can also be combined to produce tin oxide and tin dioxide. Although tin has two valence and four valence valence states,
, The tetravalent compound is more stable, especially tin oxide (SnO2), which is one of the most stable compounds on the crust.
There are more than 50 kinds of tin-containing minerals known in nature, and there are about 20 kinds of main tin minerals. At present there are economic significance is mainly cassiterite, followed by Huang tin mine. In some deposits, sulfur-tin-lead, mercury-antimony tin-lead, cylindrical tin, and sometimes black thannite tin, black boron tin, Malay stone, water tin stone, water magnesium tin ore can also be relatively rich Set, the formation of industrial value.
(1) The chemical composition of tinite is SnO2, Sn 78.8, O 21.2. Tetragonal system, crystal was double cone, cone column, sometimes needle-like. Often containing mixed iron, niobium, tantalum, in addition can still contain manganese, scandium, titanium, zirconium, tungsten and disperse elements iridium, gallium and so on. The presence of Fe3 + often affects the magnetic, color and specific gravity of the silica. Cistrate is the main source of tin.
(2) Huang tin mine, also known as tin tin, chemical composition of Cu2FeSnS4, Cu 29.58, Fe 12.99, Sn 21.61, S 29.82. Tetragonal system. Crystal rare, was false tetrahedron, false octahedral, plate and other forms. Huangxi mine is more common in Guangxi tin-containing sulfide metasomatic deposit and filled tungsten-tin deposit, Hunan high-temperature hot-liquid type lead-zinc deposit.
(3) The composition of the antimony tin-lead is Pb5Sb2Sn3S14, Pb 49.71, Sb 11.64, Sn 17.04, S 21.51, and the composition is iron, zinc and the like. Crystal thin plate, often curved, double crystal complex. The aggregates are massive, radial or spherical. With the antimony lead and yellow tin mine with the output, also produced in the tin ore veins.