Acid treatment as a beneficiation method for phosphorite waste of Kyzylkum phosphorite plant

Abstract

This article addresses matters relating to the recycling of waste from the Kyzylkum phosphorite plant in the form of phosphorite slimes, the mass of which exceeds 3 million tons at present. The treatment of slime with sulfuric acid having the concentrations from 2 g/l to 40 g/l made it possible to determine the most optimal concentrations (up to 10 g/l), at which the salts of alkali and alkaline earth metals, uranium and other elements are separated. This method permits obtaining a richer fraction of the useful component, phosphorus(V) oxide (up to 19.1%). At the same time, the pH value of the medium remains in the neutral range. Mass spectroscopy showed that such treatment with sulfuric acid having the concentrations up to 10 g/l allows selectively dissolving carbonates without decomposing phosphates. IR spectra of phosphorite slime after acid treatment do not contain absorption bands characteristic of CO32– groups. In accordance with the obtained results, a low-cost technological scheme for the phosphorite slime utilization was developed, followed by its introduction into the production process without violating the main technological regulations. The enriched slime fraction corresponds in quality to the burdened phosphorite ore and can be used as an additional product.