Experimental Study on Flotation of Apatite Ore with Modified Waste Engine Oil at Room Temperature

In order to reduce the environmental pollution caused by waste engine oil, a novel collector was prepared based on waste engine oil by oxidation modification, and its application in flotation of low-grade apatite ore was investigated. The best oxidation effect was obtained at the aeration rate of 0.15 m³/h, the oxidation time of 24 h, the oxidation temperature of 110 ℃, and the potassium dichromate of 0.2%. The analysis results of IR and GC−MS showed that the C=C double bond in the waste engine oil was oxidized into hydroxyl and carboxyl groups after oxidation modification, which belonged to fatty acid collectors. The results showed that a good separation effect was obtained for the actual ore at the sodium silicate of 2000 g/t, the modified waste engine oil collector of 400 g/t, and the pulp temperature of 15 ℃. Apatite concentrates with P₂O₅ grade of 26.01% and recovery of 95.12% was obtained by one−step roughing, and the flotation effect was basically the same in the temperature range of 15−40 ℃. Oxidation modified waste engine oil would be used as a potential flotation collector for apatite.