Abstract: The subject of the invention is the method of preparation of multicomponent fertilizers based upon the decomposition process of mineral phosphate material by ammonium sulphate and sulphuric acid. This method has application in chemical industry.The invention concerns the method of preparation of multicomponent fertilizers relying upon the decomposition of mineral phosphate material by sulphuric acid and ammonium sulphate. The basis of the method relies upon the mineral phosphate material undergoing wet milling with the acid and sulfate and as a result of which mechanically-induced chemical processes occur the decomposition of the apatite structure of material takes place. The milled mixture is introduced into reactors-crystallizers, where further decomposition of the phosphate material and phosphate gypsum crystallization takes place.

Abstract: A method according to this invention is used for washing waste phosphogypsum produced at decomposition of a mineral phosphoric raw material with sulphuric acid, wherein the said washing is carried on in countercurrent on a multi-zone filter; to the last zone of this filter there is supplied water while filter washings with highest concentration of the component being washed-off are returned to the decomposition stage. The essence of this method consists in that to the washing liquids there is introduced sulphuric acid solution of a concentration of sulphuric acid ranging within the limits from 20 up to 98 percent by weight of sulphuric acid in the amount of 1 to 30 percent of sulphuric acid amount used for decomposition of a phosphoric raw material.

Abstract: In the process according to the invention, raw phosphate rock is decomposed with an aqueous solution of sulfuric acid and ammonium sulfate recycled from the conversion step of phosphogypsum into chalk, and then the decomposition liquor stream is divided into a partial acid plant stream (Liquor I) to be converted into phosphoric acid and a partial fertilizer plant stream (Liquor II) to be processed to a multi-component mineral fertilizer. From the acid plant stream (Liquor I) constituting up to 30 per cent by weight of the total decomposition stream, ammonium sulfate is precipitated and introduced into the fertilizer plant stream (Liquor II), all the above mentioned processes of decomposition, separation and precipitation being carried out continuously.