Evaluation and Optimization of Phosphate Recovery from Coarse Rejects Using Reverse Flotation

Abstract

Phosphorus is a vital nutrient essential for plant development and numerous biological functions. It is primarily obtained from phosphate rock through a process known as beneficiation. However, the declining reserves of high-grade phosphate rock, combined with the uneven global distribution of phosphorus and the environmental impacts associated with its extraction and use, highlight the need for a more efficient management of this critical resource. Increasingly, alternative sources of phosphorus, such as extraction from waste materials, are being explored. This study aims to assess the feasibility of recovering phosphorus from coarse rejects produced during phosphate beneficiation at a phosphate washing plant. Before conducting laboratory preparation and reverse flotation tests, the sample underwent initial laboratory examination and analysis. The sample was found to contain low-grade apatite minerals with a phosphorus pentoxide (P2O5) content ranging from 19% to 20%. Additionally, carbonate and quartz were identified as the primary accompanying minerals. Flotation experiments yielded a phosphorus recovery rate of 29% P2O5, with a carbonation rate of 1.6. Although this recovery rate is slightly below the commercial phosphate standard of 30% P2O5, it represents a significant improvement and demonstrates potential for further optimization to meet industry requirements. Consequently, these coarse discarded rejects could serve as a supplementary source of phosphorus in the future.