Purification of Phosphoric Acid from Impurities in Process of Extraction and Study of Obtaining High-Quality Nitrogen-Phosphoric Fertilizers

Abstract

Objective. The aim of the research is the removal of phosphoric acid from Central Kyzylkum phosphates by fluoride and sulphate additives during the extraction of phosphoric acid, iron and aluminium, calcium, magnesium, sulphate, fluorine during the ammonium phosphate acid extraction phase. Study the process of producing environmentally friendly and fully water-soluble ammonium phosphates.

Methods. The study used chemical, physico-chemical (photocolorimetric, pH-metric, electron-microscopic) and statistical processing of experimental data.

Results. The continuation of the phosphoric acid extraction process simplifies the process by removing fluorine and sulphate additives, by deep cleaning of iron and aluminium, calcium, magnesium, fluorine and other additives in the produced acid, the main nutrient element in the finished product - P₂O₅ has been achieved.

Conclusion. Studies have shown that simultaneous fluorination and desulphurization of wet-process phosphoric acid (WPPA) based on Central Kyzylkum phosphate can be achieved by adding calcium carbonate or washed burnt phosphoconcentrate (WСPC) to the extraction sludge. High-quality water-soluble ammonium phosphates can be obtained by partially purifying phosphoric acid during extraction and complete purification by extracting phosphoric acid with ammonia. The product is a water-soluble nitrogen phosphorus fertilizer and is used as a fertilizer for drip irrigation and for hydroponic cultivation of crops.