METHOD OF PRODUCING FOOD GRADE SODIUM TRIPOLYPHOSPHATE Russian patent published in 2010 - IPC C01B25/41 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical engineering of food grade products which can be used in meat and diary and fish industries, cheese-making and other similar industries, and specifically to methods of producing food grade sodium tripolyphosphate. The method of producing food grade sodium tripolyphosphate involves formation of anhydrous sodium tripolyphosphate based on phosphoric acid and soda, its hydration in a water-salt solution in the presence of a nucleating agent, separation of the suspension which contains ammonium and/or alkali metal sulphate salts, and hexahydrate of sodium tripolyphosphate, as well as drying the latter. The hexahydrate is dried in two steps, using a hexhydrate suspension containing 10-25 wt % water at the first step, and keeping temperature in the 80-100°C range at the first step, and in the 150-200°C range at the second step.

EFFECT: invention allows for achieving up to 56,3-57,0% diphosphorus pentoxide in the end product, increasing content of polyforms to 97,9-98,2%, and reduce pH of 1% aqueous salt solution to 8,9-9,2.

3 tbl, 6 ex