PRODUCTION OF POTASSIUM POLYPHOSPHATES FROM PHOSPHATE ACID SLUDGES

摘要

1406813 Potassium polyphosphate OCCIDENTAL PETROLEUM CORP 8 Sept 1972 [10 Sept 1971] 41705/72 Heading C1A Potassium polyphosphate is produced by mixing the phosphate acid sludge with potassium hydroxide and/or a potassium salt (e.g. potassium chloride, sulphate, carbonate, sulphide or polysulphide or mixture thereof) to form a reaction mixture in which the mole ratio of potassium to phosphorus (K 2 O : P 2 O 5 ) is from 0À3 to 2À0, heating the mixture to form a homogeneous melt (e.g. to 750‹ to 1100‹ C.) comprising potassium polyphosphate and solidifying the melt. A sodium salt (e.g. sodium chloride, sulphate, nitrate, sulphide or polysulphide or mixture thereof) and a magnesium compound (e.g. magnesium sulphate, oxide, chloride, orthophosphate or mixture thereof) may be added to the mixture in the mole ratios Na 2 O : K 2 O equals 0À2 to 1À0 and MgO : K 2 O 'equals 0À2 to 1À0. A micronutrient (e.g. Mn, B, Mo, Zn, Co, Cu salts or mixture thereof) may be added to the reaction mixture which may be preheated to 100‹ to 150‹ C. to remove water therefrom prior to heating to form the melt which may be subsequently cooled by air quenching or use of an inert liquid quench (e.g. CCl 4 ) and may be subsequently ground and used as fertilizer.