Effect of calcium lignosulfonate on the interaction forces between fine calcite and fluorite

Abstract

The separation of fluorite and calcite during flotation is challenging due to the complex interfacial forces that cause capping of fine-grained calcite on coarse-grained fluorite. In this paper, the micro flotation test, Zeta potential test, contact Angle test, scanning electron microscope and E-DLVO theoretical calculation were used to investigate the combination of sodium hexametaphosphate (SHMP) and calcium lignosulphonate (CLS) to disperse calcite on fluorite surface. The test results show that SHMP and CLS alone cannot effectively remove the cover, but the combination of the two can achieve good dispersion effect. In addition, Zeta potential shows that SHMP can significantly enhance the electrical properties of mineral surface, while CLS has a negligible effect on it. The contact Angle test proved that CLS adsorbed on the surface of mineral enhanced the hydrophilicity and hydration force of mineral. E-DLVO theoretical calculation further proves that CLS can not only enhance the hydration force between minerals, but also generate steric hindrance effect. When the distance between minerals is less than 1.8 nm, the steric hindrance force is greater than the repulsion force of hydration, and the steric hindrance force plays a dominant role.