The hydroxamic acid reagents are extremely pervasive in the collector of scheelite flotation. The high flotation cost is caused by its large dosage and high price. A novel auxiliary collector 4-methodybenzoicacid (4-MBA) was used in combination with benzohydroxamic acid (BHA) to optimize the flotation reagents system for scheelite in the study. A single 4-MBA has weak collection capacity for scheelite. Nevertheless, the combination of 4-MBA and BHA optimized the flotation system of scheelite by ensuring its recovery and reducing the reagent consumption. The results of solution surface tension and contact angle measurements showed that the surface tension of the mixed reagent solution is a relatively lower and the hydrophobicity of the scheelite surface is a relatively higher in the BHA and 4-MBA mixed reagent system. Additionally, a synergistic effect between BHA and 4-MBA on Pb 2+ activated scheelite is revealed by the Zeta potential measurements, infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The addition of 4-MBA promoted the physical and chemical adsorption of BHA. The results of molecular dynamics simulation (MDS) further explained that the collector adsorption layer of the surface of scheelite (1 1 2) is more compact under BHA and 4-MBA mixed reagent system, which prevents the vertical entry of water phase and improves the hydrophobicity of scheelite. Finally, the bench-scale flotation experiment verified that the addition of 4-MBA enhanced scheelite flotation with BHA, and decrease the flotation cost of scheelite.
Prometheus stole fire for mankind, but tungsten brought light to mankind. Wolframite is beneficiated through froth flotation and used as a raw material to produce tungsten. However, the flotation of wolframite using the surfactants as the collector at low temperature is still one of the most significant problems in industry. In this paper, a novel hydroxamic acid surfactant dodecanediohydroxamic acid (DHA) was synthesized and firstly used in wolframite ore flotation, which was compared with the conventional monomolecular collector sodium oleate (NaOL). The results of flotation test indicated that the changes of the temperature did not significantly influence DHA’s collecting power in floating wolframite. At 0 °C, wolframite concentrate with WO 3 recovery of 83.65 % and grade of 55.25 % was obtained by using 200 g/t DHA. Density functional theory (DFT) calculations suggested reactive sites of DHA were two –C(O)NHOH groups, and DHA showed superior electron-donating ability and chemical reactivity that may promote its flotation performance.
Tao Liming,Wang Jianjun,Liao Dejin,Jia Wenkai,Zhao Zihan,Che Wenfang,Qi Zhongxu,Sun Wei,Gao Zhiyong
Flotation is the most common method to obtain concentrate through the selective adsorption of collectors on target minerals to make them hydrophobic and floatable. In the hydrometallurgy of concentrate, collectors adsorbed on concentrate can damage ion-exchange resin and increase the chemical oxygen demand (COD) value of wastewater. In this work, we proposed a new scheme, i.e., desorbing the collectors from concentrate in ore dressing plant and reusing them in flotation flowsheet. Lead nitrate and benzohydroxamic acid (Pb-BHA) complex is a common collector in scheelite flotation. In this study, different physical (stirring or ultrasonic waves) and chemical (strong acid or alkali environment) methods for facilitating the desorption of Pb-BHA collector from scheelite concentrate were explored. Single-mineral desorption tests showed that under the condition of pulp pH 13 and ultrasonic treatment for 15 min, the highest desorption rates of Pb and BHA from the scheelite concentrate were 90.48% and 63.75%, respectively. Run-of-mine ore flotation tests revealed that the reuse of desorbed Pb and BHA reduced the collector dosage by 30% for BHA and 25% for Pb. The strong alkali environment broke the chemical bonds between Pb and BHA. The cavitation effect of ultrasonic waves effectively reduced the interaction intensity between Pb-BHA collector and scheelite surfaces. This method combining ultrasonic waves and strong alkali environment can effectively desorb the collectors from concentrate and provide “clean” scheelite concentrate for metallurgic plants; the reuse of desorbed collector in flotation flowsheet can reduce reagent cost for ore dressing plants.
危险品化学品经营许可证（带存储）