Enriched Superphosphate and Ammophosphate Fertilizer Based on Washed Dried Phosphorite Concentrate

Development of a technology for obtaining enriched superphosphate and ammophosphate by processing washed and dried phosphorite concentrate (WDPC) in a single cycle. The optimal ratio P2O5WPPA:H2SO4mh :P2O5WDPC = 1:0.28:0.08 was found, at which the composition and properties of ammophosphate fertilizer are maximally improved and a single phosphorus fertilizer is additionally obtained. It has been established that on the basis of the solid part of the ammophosphate pulp, samples of enriched superphosphate are obtained with the following indicators (wt., %): Р2О5t. - 30.16-32.01; Р2О5ас.с.a. : Р2О5t. = 98.54-100; Р2О5water solubility (w.s.) : Р2О5t. = 54.3-55.5; N - 5.45-6.04. A sample of ammophosphate contains (wt., %): Р2О5t. - 52.43-53.31; Р2О5ас.с.a. : Р2О5t. = 94.81-96.27; Р2О5w.s. : Р2О5t. = 87.41-88.36; CaOt. - 4.01-4.26; N - 13.65-14.03 and SO3t. - 4.37-10.74. Ammophosphate consists of mono- and diammonium phosphate, ammonium sulfate and dicalcium phosphate. Superphosphate also contains activated phosphorite, complex salts and gypsum. The material balance of the process of their production in a single technological cycle has been calculated.