Colloidal ZnCO₃ as a Powerful Depressant of Arsenopyrite in Weakly Alkaline Pulp and the Interaction Mechanism

• Main Authors: Youguo Guan, Pingtian Ming, Zhuohong Xie, Fei Li, Qingqing Xing, Zhen Wang
• Format: Article
• Language: English
• Published: MDPI AG 2020-03-01
• Series: Minerals
• Subjects: colloidal zinc carbonate; depressant; flotation; adsorption; arsenopyrite
• Online Access: https://www.mdpi.com/2075-163X/10/4/315

The effects of ZnSO₄ on arsenopyrite depression were studied with sodium carbonate and sodium isobutyl xanthate (SIBX) as the pH regulator and collector, respectively. In both micro and real ore flotation tests, ZnSO₄ showed better depression on arsenopyrite (pH 7.5–9.0 adjusted by Na₂CO₃) compared with sodium humate. The depression mechanism of ZnSO₄ on arsenopyrite flotation was studied by electrokinetic potential, adsorbed amount measurements, scanning electron microscope (SEM) observation and energy dispersive spectra (EDS) detection. The electrokinetic potential measurement results show a potential increase forpleas the arsenopyrite treated with ZnSO₄ in the pH range 7.5–9.0, which could be attributed to the formation of the precipitated zinc carbonate (ZnCO_3(S)). For arsenopyrite treated with both ZnSO₄ and SIBX, the electric surface potentials also display an increase, to approximate the values with solely ZnSO₄ treated, at pH 7.5–9.0, indicating the inhibition of ZnCO_3(S) upon the SIBX adsorption onto arsenopyrite. Adsorption results demonstrated that SIBX adsorption onto arsenopyrite indeed was inhibited at the pH 7.5-9.0 through the sharp decrease in SIBX adsorbed amount with ZnSO₄ as the depressant at this pH range. SEM observation and EDS detection results verify the formation of colloidal ZnCO₃ on the arsenopyrite, with ZnSO₄ as the depressant in combination with Na₂CO₃.