Reduction of amine consumption in iron ore flotation through direct reuse of process water on bench scale

This article aims to investigate the direct reuse effect of process water containing residual amine from tailings and concentrate pulps on the performance of the cationic reverse flotation of iron ore. An iron ore sample collected after the desliming operation in the Conceição Industrial Unit (Minas Gerais) was used for the bench-scale flotation studies. The experiments used recirculated water phase of bench scale flotation tests for five cycles, considering the amine residual concentration and just complementing the required dosage used in the Conceição industrial circuit. The residual amine concentration was determined through indirect quantitative analysis using a spectrophotometer. The average recovery of amine in the aqueous phase (process water) was 46%; consequently, the consumption of the new amine fed into the circuit was reduced. The experiment results indicated that the direct reuse of process water and reduction in reagent consumption could be performed without negatively affecting the quality of the final iron ore concentrate (68% Fe and 1.3% SiO₂). According to the results obtained in this work, process water containing this residual reagent, as a collector, can be reused in iron ore flotation without loss of concentrate quality or flotation performance. Amine consumption is one of the highest costs in industrial flotation plants. Any decrease in collector usage could result in a substantial decrease in the capital expenditures associated with industrial processes.