Abstract
In the process of developing magnetite quartzite deposits, hematite quartzites are simultaneously involved in mining, the enrichment of which is complicated due to mineralogical heterogeneity and low magnetic susceptibility. This leads to the accumulation of waste that negatively affects the environment. A comparative analysis of the chemical and mineral composition, structures, textures and technological properties of magnetite and hematite quartzites of the Kryvyi Rih iron ore basin of Ukraine was carried out. It was found that the total iron content in hematite quartzites is higher, due to partial leaching of quartz, and the content of magnetic iron is lower. Hematite quartzites also have increased porosity and a high content of hypergenic aluminosilicates. which determines the need to apply new technologies for their enrichment. A technology for complex processing of hematite quartzites in a vortex air-mineral flow is proposed, which is based on the use of gradients of physical properties (magnetism, density, mechanical strength) and morphological features of individuals and aggregates of ore-forming minerals. The technology provides simultaneous crushing, grinding and separation of ore without the use of water, flotation and other chemical reagents. As a result of laboratory tests, a concentrate with a total Fe content of over 68%, agglomeration and clinker ore, dry mineral pigments and quartz sand were obtained from hematite quartzites. The use of a vortex flow allowed to reduce the formation of magnetic flocs, increase the efficiency of crushing and enrichment and avoid the formation and accumulation of sludge waste. It has been established that in a dynamic air-mineral flow, particles of halite, sylvite, gypsum, kaolinite and weathered alkali silicates are quickly crushed, separated from harder and heavier particles of magnetite, hematite, goethite, and carried out of the working chamber of the technological equipment. This reduces the content of harmful impurities and additionally improves the quality of iron ore raw materials. The proposed technology is energy-saving, environmentally friendly and complies with the principles of a circular economy, which makes it a promising alternative to traditional methods of enrichment of hematite quartzites in the global mining industry.