HUANG Xiao-fen1, ZHANG Qin2,3,4,5*

(1. College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China; 

2. Guizhou Academy of Science, Guiyang 550001, China; 

3. National & Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas, Guiyang 550025, China; 

4. Guizhou Engineering Laboratory of Efficient Utilization of Superior Mineral Resources, Guiyang 550025, China; 

5.Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources, Guiyang 550025, China)

Abstract: Grinding is an important pre-treatment process before flotation. It not only provides the selected materials with suitable particle sizes and sufficient mineral liberation for flotation, but also affect the surface properties of minerals, thus affecting the floatability of minerals. In this paper, we have carried out a study on the morphology and floatability of fluorapatite particles produced through the ceramic rod and ceramic ball media grindings by using various methods including the single mineral flotation test, scanning electron microscopy (SEM), Atomic Force Microscope (AFM) and BET surface area measurement. The results show that the fluorapatite particles produced by the rod milling have better floatability than those produced by the ball milling when the NaOL solution was used as collector, and accordingly they have more advantageous than those produced by the ball milling to the flotation of fluorapatite. The SEM analyses confirm that fluorapatite particles produced by the rod and ball millings are both in irregular gravelly shape, with clear angular edge and uneven fracture surfaces. There are little differences in the shape coefficients and distribution intervals of Ro and EW values of fluorapatite particles produced by the two grindings. However, the roughness of fluorapatite particles produced by the rod milling is larger than that of the particles produced by the ball milling. The wettability test shows that fluorapatite particles produced by the rod milling have better hydrophobicity than those produced by the ball milling, because their critical surface tensions are smaller than those of the particles produced by the rod milling. This result accords with the Wenzel and Cassie's surface wettability theory, that is, the wettabilities of hydrophobic surfaces of fluorapatite particles are decreased with the increase of roughness values of the particles.

Keywords: grinding media; fluorapatite; surface properties; floatability

ACTA MINERALOGICA SINICA Vol. 43, No. 5, 2023, Page 708