Demchenko O. Technological mineralogy of waste from crushing and screening plants of Kryvyi Rih basin

Results of complex mineralogical studies of coarse-grained screenings from crushing and screening plants (CSP), which operate at all seven mines producing high-grade (hematite) iron ores in the Kryvbas. The extracted ore mass with iron content of 52-54% mass.% is separated into fine-grained (commercial agglomerat-ed ore having 57-60 mass.% of iron) and coarse-grained (CSP screenings having 43 mass.% of iron) products of three-stage crushing and screening. The screenings consist mainly of hematite quartzites with a small impurity of low-iron and non-ferrous rocks. Due to beneficiation imperfection, particles of high-grade ores fall into the screenings. Presence of significant volumes of screenings accumulated in the stockpiles (about 20 million tons) and the high content of iron led to the neces-sity of looking for a mineralogically grounded technology for their rebenificiation. Hematite (martite, iron mica, disperse hematite) and quartz are product-forming minerals. Other minerals are of insignificant contents. According to the results of genetic, systematic mineral studies and ones of typomorphism of screenings min-erals, granulormetric, magnetic and gravity methods of rebeneficiation were rec-ommended. Comparative mineral-technological experiments showed the gravity method to be the optimal one. It allows obtaining from screenings particles grinded to the size of less than 0.1 mm hematite concentrate with iron content of about 67 mass.% and about 39% of yield. The results of the work are used in the process flow chart of operating plants for the beneficiation of secondary hematite raw materials, which provide additional volumes of high-quality iron ore end-products of low cost, and contribute to reducing the technogenic load on the environment.