SU983057A1 - Method of producing cadmium sulphate crystals - Google Patents

Description

The invention relates to the preparation of crystalline cadmium sulfate from solution and can be used in the manufacture of chemical reagents, as well as in other areas of the chemical industry. A known method for producing sulfate. Cadmium is by dissolving metallic cadmium in a mixture of sulfuric and nitric acids. The solution is then evaporated, and the resulting crystalline product is recrystallized from water with Cl. The closest to the proposed technical essence and the achieved result is the method of obtaining cadmium sulfate in the form of crystals CСо150 8Н20 by treating the cadmium oxide pulp with sulfuric acid to form an aqueous solution of cadmium sulfate. The latter is purified from impurities, filtered and, after adjusting the pH to the desired value, is evaporated at atmospheric pressure and a temperature of 105-11 ° C until the precipitation of a solid phase, represented by -. cadmium sulfate monohydrate crystals. After the precipitation of the solid phase, the precipitated cryo- are hydrated. tal monohydrate. At the end of the hydration and complete cooling of the suspension, it is separated, the product is packaged, and it is dressed. The total npouecck time is 72-74 hours, of which 36 hours are required for evaporation and hydration. The product will appear as ZSsZ504-8 HgO crystals stable in the temperature range (-16.8) - (+43.5) ° C. At a temperature of 43.5-113 ° C, Cc15p monohydrate is a stable form of crystals. H “0. Above 113 ° C, anhydrous cadmium sulfate crystals are 12 0. A disadvantage of this method is its multi-stage nature, and the presence of a hydration stage prolongs the process (10-14 hours) and makes it difficult to control and prevents the formation of a stable composition. and homogeneity.

Claims (1)

Claim A method of obtaining crystalline cadmium sulfate, including purification of the initial solution, its precipitation and separation of the resulting suspension, characterized in that, in order to simplify the process by eliminating the hydration stage, obtaining a homogeneous product of the desired composition and intensifying the process, the initial solution is evaporated under vacuum at a residual a pressure of 10-200 mm RT.article temperature up to 7 ° C.