Enhancing selective calcite and dolomite flotation in the phosphate ores: Investigation, modeling, and automated mineralogy assessment

Abstract

This paper presents a comprehensive study on the selective flotation of a multi calcium-bearing minerals ore, focusing on the efficient removal of dolomite and calcite impurities from a carbonaceous sedimentary phosphate ore. Commercial fatty acid (FA) and phosphate ester collectors were investigated in a reverse flotation process, assessing the impact of flotation pH, collector dosage, and type on the selectivity and recovery of calcite and dolomite. The efficiency of FA-based collectors was recognized as they provided higher quality concentrates with reduced carbonated-fluorapatite contents. The response surface methodology was employed to review and model the effects of pH and dosage of each fatty acid collector on flotation performance. Accurate regression models were developed, forming the basis for an optimization study to determine the optimal operating conditions for achieving selective carbonate flotation with high carbonate grade and recovery while minimizing the carbonated-fluorapatite (CFA) content. Automated mineralogical microscopy was conducted on the phosphate ore and the recovered carbonate and phosphate concentrates, confirming the success of flotation while attributing the presence of 12% CFA (≈ 4 % de P2O5) in the carbonate concentrate to mineral associations and fines entrainment.