Clean desulfurization of sulfur–rich tungsten concentrates by reverse flotation

Sulfur removal from mineral concentrates is urgently needed given the increasingly stringent environmental regulations and low−sulfur feedstocks required by smelters. However, current desulfurization technologies suffer from considerably drawbacks, such as high costs and harmful byproducts. In this study, we investigated the potential use and feasibility of reverse flotation to desulfurize sulfur−rich tungsten concentrates. Several important factors were evaluated by batch flotation tests. Results proved that sulfur could be effectively removed from sulfur−rich tungsten concentrates by carefully adjusting pH and reagent dosages. Industrial−scale tests conducted in Shizhuyuan Polymetallic Dressing Plant showed that reverse flotation was a feasible and reliable desulfurization method to remove sulfur and increase the grade of tungsten concentrates simultaneously. The average sulfur content in tungsten concentrates decreased from 4.53% to 1.77%. The average WO3 grade of tungsten concentrates increased from 37.50% to 41.14%. The low cost and environmental friendliness of this reverse flotation desulfurization technology indicated its potential for commercialization and widespread industrial application.