Effects of grinding media on the flotation performance of cassiterite

Grinding plays an important role in the beneficiation process. Different grinding media can determine the size distribution, shape, and even the surface properties of the produced material. However, comprehensive research related to the effect of grinding media on the flotation performance of cassiterite is lacking. In the current study, the effects on the flotability of the products obtained by grinding with ceramic and stainless steel media were investigated using micro-flotation, laser particle size distribution analysis, inductively coupled plasma optical emission spectroscopy (ICP-OES), chemical element analysis, zeta potential measurements, field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS), and X-ray photoelectron spectroscopy (XPS). The micro-flotation results demonstrate that the flotability of stainless steel ground cassiterite surpasses that of ceramic. The laser particle size distribution test reveals that the two grinding media do not have a strong impact on the particle size distribution. The ICP-OES and chemical element analysis results identify the higher iron content in the samples and pulp of stainless steel ground cassiterite as the principle influencing factor. The zeta potential analysis indicates that the dissolved iron ions absorbed on the cassiterite surface results in a positive shift of the mineral surface potential. This not only reduces electrostatic repulsion but also increases the active sites of salicylhydroxamic acid (SHA) chemisorption. FESEM-EDS results demonstrate the rougher surface and higher iron content of the stainless steel ground cassiterite compared to the ceramic ground cassiterite, thereby increasing the SHA adsorption. The stainless steel grinding cassiterite was observed to alter the chemical environment of Fe species on the cassiterite surface via XPS analysis, with Fe2+ exhibiting a stronger reactivity and stability towards SHA compared to Fe3+. Thus, the stainless steel media ground cassiterite demonstrates an improved flotability performance compared to the ceramic equivalent.