About development of a new method of processing of low-quality phosphate raw materials

Abstract

Kazakhstan has huge reserves of phosphate raw materials. Nowadays high-grade phosphates are almost exhausted, and the ore is mainly represented by run-of-mine and low-grade phosphorites with small phosphorus content. Processing of low-grade phosphate raw materials by traditional methods is hindered. Formed large amounts of solid waste at phosphorus production require searching methods of their recycling or utilization. It also makes an urgent the search for new alternative ways of processing low-quality phosphate raw materials. Obtaining phosphorus oxyfluoride from low-grade phosphorites with its further processing into elemental phosphorus is one of ways of processing such phosphate raw materials, which allows to simplify the process and improve phosphates quality. According to the task, the process of calcium phosphates interaction with ammonium fluoride was investigated; thermodynamic analysis of possible reactions was carried out, which confirmed primary formation of monoammonium phosphate with the following its conversion into phosphorus oxyfluoride. The results of mass spectrometric analysis of samples of dicalcium phosphate and tricalcium phosphate in a mixture with ammonium fluoride confirmed the proposed mechanism of interaction. Based on the results obtained, possibility is shown and optimal parameters for processing low-grade phosphate raw materials into phosphorus were determined.