Improved Flotation Recovery and Selectivity of an Ultra-Fine Brazilian Phosphate Ore Using Eriez’ Column Flotation Technology

Abstract

Eriez Flotation Division recently completed column flotation testing of two igneous phosphate ore samples from the Tres Estradas deposit as part of Aguia Resources’ bankable feasibility study for the greenfield project. Due to fine dissemination of the phosphate and associated grinding requirements, column flotation was selected for the metallurgical test program to address the inherent limitations of fine particle flotation using conventional mechanical flotation cells. Eriez’ column flotation cells with Cavitation-Tube spargers are a commercially-mature and efficient technology for flotation of fine particles that may otherwise not be feasible using conventional flotation machines. Accordingly, continuous column flotation pilot tests were conducted by Eriez on two ultra-fine (212x0 µm) samples of Tres Estradas carbonatite ore (fresh and oxidized) to determine flotation responses and develop an industrial circuit design. Using Eriez’ automated multi-stage column flotation circuit, the fresh carbonatite ore was upgraded from 3.6-4.1% P2O5 to 30-32% P2O5 at a P2O5 recovery of 71-80% using a rougher-scavenger-cleaner-cleaner circuit configuration. Similarly, the oxidized (saprolite) carbonatite ore was upgraded from 10.0-11.5% P2O5 to 32-33% P2O5 at a P2O5 recovery of 85-90% using a rougher-cleaner column circuit configuration. The benefits of Eriez’ column flotation technology realized from this test work include a higher degree of selectivity, increased recovery, and reduced collector dosage as compared to bench-scale mechanical flotation. Specifically, the recovery of fresh carbonatite and oxidized (saprolite) carbonatite ore by column floatation increased 2-3% and 5% respectively, while collector dosage was reduced by 20-40% and the required number of cleaning stages to achieve the target concentrate grade was reduced.