关键词: 铬铁矿, X射线智能分选, 强磁预选, 板式磁选机

Abstract: A systematic exploration of beneficiation process was carried out for a low-grade chromite ore in South Africa. The grade of Cr2O3 in the raw ore is 23.78%. The main metal mineral is chromite，and the main gangue minerals are olivine，plagioclase and quartz. The content of SiO2 is 22.37%. The test ad⁃ opted the combined process of crushing-classification-X-ray intelligent separation-dry high intensity mag⁃ netic separation-grinding-vertical ring roughing-plate cleaning. The specific process is as follows: the raw ore is crushed to -60 mm and then graded by 10 mm; the 60~10 mm grade is pre-selected and discarded by X-ray intelligent separator; the pre-selected concentrate is mixed with -10 mm grade and then milled to - 3 mm by high pressure grinding roller，and then subjected to one roughing and one scavenging dry magnetic separation by CFLJ magnetic separator. The obtained mixed concentrate of roughing and scaveng⁃ ing was ground to -0.15 mm，and then subjected to roughing by vertical ring high gradient magnetic sepa⁃ rator and cleaning by flat magnetic separator. Cr2O3 grade of 46.12% and recovery of 72.78% of qualified chromium concentrate products were obtained by the whole process test. The process effectively solves the problems of low-grade chromite and gangue minerals being closely embedded and difficult to monomer dis⁃ sociation，and significantly improves the concentrate grade and recovery rate. The research results provide a technical basis for the efficient development and utilization of low-grade chromite resources in South Afri⁃ ca，and can adjust the parameters such as discarding rate and grinding fineness according to the ore char⁃ acteristics of different mining areas，which has good industrial application prospects and promotion value.

Key words: chromite, X-ray intelligent sorting, high-intensity magnetic pre-concentration, plate mag? netic separator