Stannous Chloride Dihydrate Usage And Synthesis

Stannous Chloride Dihydrate Usage And Synthesis

Introduction to Stannous Chloride

Stannic chloride, chemical formula SnCl2, is also called tin dichloride. There are anhydrous and hydrated substances. The former is transparent crystals with a melting point of 246℃, a boiling point of 652℃, and a relative density of 3.95. It is soluble in water and oxidized in the air to form insoluble chloride oxides. It is hydrolyzed in water to form basic stannous chloride 〔Sn(OH)Cl〕precipitate. When preparing its solution, it needs to be dissolved in concentrated hydrochloric acid and then diluted to inhibit hydrolysis. Since it is easily oxidized by air, adding metallic tin particles to the solution can prevent oxidation. Dihydrate SnCl2·2H2O is a colorless monoclinic crystal or flaky crystal with a melting point of 37.7℃ and a relative density of 2.71. It loses crystal water when heated to 100℃. Stannous chloride is often used as a reducing agent, mordant, decolorizing agent and analytical reagent in chemical industry production; it is used for tin plating in the electroplating industry. Anhydrous stannous chloride is obtained by the direct reaction of chlorine and molten tin; hydrated stannous chloride can be obtained by treating flaky tin with hydrochloric acid, followed by evaporation and crystallization.

Uses

Used for colorimetric determination of silver, lead, arsenic, molybdenum, etc., and also used as a reducing agent and mordant.

Stannous chloride dihydrate is mainly used in acidic tin plating as the main salt. Tin is in a divalent state in the plating solution, with high cathode efficiency, and the general dosage is 40-60 kg/L. It can also be used in the glass mirror industry as a sensitizer for silver nitrate plating to make the coating brighter. When this product is added during ABS electroplating, the coating is not easy to fall off.

Stannous chloride can be used as a reducing agent for the manufacture of dye intermediates. Component of ultra-high pressure lubricating oil. Used as a bleaching agent. Used for sensitization treatment of mercury plating in mirror making, the silver film formed is brighter, and the mercury is firmly combined with the product. It is used for tin plating and copper-tin plating of mechanical parts in the electroplating industry. It is used for chemicalbook sensitization treatment during ABS plastic electroplating to make the coating not easy to fall off. It is also used in the synthesis of pharmaceuticals, catalysts for organic synthesis, and activators during the vulcanization of butyl rubber products. Mordant during dyeing and anti-dyeing agent in the printing discharge process. Stabilizer for spice industry. Food reducing agent, antioxidant, such as canned asparagus and pineapple juice.

Production method

The hydrochloric acid method first melts the metal tin, then pours cold water into it to form tin flowers. Then add hydrochloric acid and tin flowers into the reactor in a certain ratio for reaction. When the solution concentration reaches about 40°Bé, put it into the enamel evaporator for chemicalbook concentration. First, add tin flowers to the evaporator, pass steam to heat it, so that the hydrochloric acid and tin continue to react. When the solution concentration increases to 73-77°Bé, filter it while hot, and then cool it for crystallization and centrifugal separation to obtain the finished stannous chloride.