Enriched Superphosphate Based on Decomposition of Ordinary Phosphorite Powder with Phosphoric Acid Gypsum Slurry

Abstract

Complex, nitrogen-phosphate fertilisers are applied before seeding, with seeding and extra nutrition, while single phosphoric ones are the most effective under autumn ploughing. In that case, enriched superphosphate, more concentrated than single superphosphate, was obtained using phosphoric acid gypsum slurry semiproduct produced by the interaction of thermo concentrate with sulphuric acid and recycled phosphoric acid in accordingly dihydrate operation (60-80°C). However, the mix of sulphuric and phosphoric acids was not used those are usually applied in conventional ways for enriched superphosphate production. Phosphate raw material (PRM) is dosed into phosphoric acid gypsum slurry (PAGS) upon weight ratio of PAGS: PRM equal from 100: 15 to 100: 40 that provides a condition for slurry fluidity. Interaction of the components was performed at 70°С for 60 min. Then the superphosphate mass obtained was downloaded from reactor followed by ripening at 95-100°С, cooling, and obtaining final products. Since optimal weight ratio of PAGS: PRM is 100: 25 and 100:30 respectively depending upon the grades of PAGS in which samples of enriched superphosphate are obtained with high total and assimilated form of Р2О5 having of water-soluble that of Р2О5 no less 50%. It should be explained the requirement of agriculture on single phosphoric fertiliser possessing high content total and acceptable form of Р2О5 and water soluble that of Р2О5 no less 50% towards to total Р2О5.