Cadmium is silvery white, shiny metal, melting temperature 320.9 ℃, boiling point 765 ℃, the density of 8650 kg/m3; . With toughness and ductility. Cadmium in wet air oxidation and slow loss of metallic luster, heating surface oxide layer, brown if heated to boiling point above, will produce cadmium oxide of smoke. High temperature response to cadmium and halogen halide cadmium. Can also be directly combined with sulfur, cadmium sulfide. Cadmium, soluble in acid, but not soluble in alkali. Cadmium oxidation state of + 1, + 2. Solubility of cadmium cadmium oxide and hydroxide are small, they are soluble in acid, but not soluble in alkali. Cadmium can form a variety of complex ion, such as Cd (NH3), Cd (CN), CdCl, etc.
Bigger toxicity of cadmium, cadmium pollution of air and food to human body harm is serious, and in the human body metabolism slower, Japan for cadmium poisoning appeared "pain pain disease".
A variety of methods available from smoke or cadmium containing cadmium residue (such as coal or carbon reduction or sulfuric acid leaching method and dust replacement) of metal cadmium. Further purification available electrolytic refining and vacuum distillation. Cadmium is mainly used in steel, iron, copper, brass and other metal plating, corrosion resistant ability of alkaline substances. Cadmium can be used in the manufacture of small volume and large capacity of battery. Cadmium compounds are also used in the production of large amounts of pigments and phosphors. Cadmium sulfide, cadmium selenide cadmium telluride used in the manufacture of photovoltaic cells.
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