The Effect of Surface Charge on the Separation of Pyrite from Serpentine by Flotation

• Main Authors: Tao Long, Xiaotao Huang, Wei Xiao
• Format: Article
• Language: English
• Published: MDPI AG 2019-10-01
• Series: Minerals
• Subjects: heterogeneous reunion; mg²⁺ ion dissolution; surface potential; fine serpentine
• Online Access: https://www.mdpi.com/2075-163X/9/10/629

Serpentine, a magnesium silicate mineral with positive surface charge in many sulfide ores around the world, usually deteriorates the flotation behavior by covering the target mineral surface. In this paper, the effect of surface potential regulation on serpentine flotation was revealed by flocculation experiments, zeta potential measurements, infrared spectrum analysis, and DLVO theoretical calculations. The experimental results of flocculation and sedimentation show that heterogeneous coagulation easily occurs between serpentine and pyrite particles, which reduces the floatability of pyrite. Reducing the surface potential of serpentine is an effective way to eliminate heterogeneous coagulation between minerals. The key to regulating the surface potential of serpentine is Mg²⁺ ion dissolution from the serpentine surface to the liquid phase. Phosphates, especially sodium hexametaphosphate, can enhance Mg²⁺ ion dissolution from the serpentine surface to the liquid phase and react with Mg²⁺ ions in the liquid phase to form stable soluble complexes.