Novel Selective Depressant of Titanaugite and Implication for Ilmenite Flotation

Abstract

This paper studies the effects of sodium polystyrene sulfonate (PSSNa) used as a depressant upon the separation of ilmenite from titanaugite through flotation when sodium oleate (NaOl) is used as a collector by performing single mineral flotation experiments. The depression mechanism of PSSNa on titanaugite flotation was studied by electrokinetic potential and adsorbed amount measurements together with FTIR and XPS detection. Single mineral flotation experiments show that PSSNa is a selective depressant for the separation of ilmenite and titanaugite via flotation with NaOl as the collector. The results of the adsorbed amount tests show that the biggest distinction is in terms of the amount of NaOl adsorbed on the surfaces of ilmenite and titanaugite; the amount is expanded from 2.28 × 10−7 to 9.34 × 10−7 mol/m2 when the dosage of PSSNa is 1 mg/L, as compared with no PSSNa, suggesting that PSSNa is a selective depressant when separating ilmenite and titanaugite through flotation. FTIR testing shows that chemisorption has occurred between the –SO3− groups of the molecular PSSNa and titanaugite surfaces. The results of further XPS testing reveal that PSSNa chemically interacts with Ca/Mg/Al/Fe on the titanaugite surface. The test results of FTIR in combination with XPS confirm that PSSNa stops NaOl from interacting with Mg, Fe, Al, and Ca on the titanaugite surface, and this outcome is the main reason for the widening of the adsorption quantity gap of NaOl on titanaugite and ilmenite surfaces, and titanaugite flotation is suppressed. The results of the comparison flotation testing on actual Panzhihua titanic iron ore (TiO2 grade: 15.63%) with titanaugite as the main gangue show that a better effect is obtained by replacing sodium silicate (SS) with PSSNa, and the recovery of TiO2 using PSSNa is higher than that when using sodium silicate. In a closed circuit flotation test, ilmenite concentrate is obtained with a TiO2 grade of 45.97% and a recovery of 76.32% by using PSSNa as a titanaugite depressant.