Морфологічні різновиди гематиту та їх перерозподіл по продуктах збагачення відсіву дробильно-сортувальних фабрик шахт Криворізького басейну
| Autor: | A. V. Evtekhova, O. S. Demchenko, V. D. Evtekhov |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Вісник Дніпропетровського університету. Геологія, географія. 26:17-25 |
| ISSN: | 2409-9864 2313-2159 |
| DOI: | 10.15421/111802 |
| Popis: | The deposits of high-grade ores of the Kryvyi Rih basin are developed by seven mines and two open pits. Insufficient quality of extracted ore mass requires its beneficiation at the crushing and screening plants operating at each mine. Utilizing three-stage crushing and three-stage screening methods sinter ore having iron content of 57-61 mass % (fine-grained (less than 20 mm) beneficiation product) is produced. The beneficiation waste is coarse-grained (20-100 mm) screening with an average iron content of 43 mass %. The authors studied the possibility of using this material as a secondary raw material for the production high-quality iron ore concentrate. According to the results of petrographic studies, it mainly consists of particles of hematite quartzites with an admixture of high-grade hematite ores, low-iron and iron-free rocks. The screenings have two-component mineral composition – hematite + quartz with insignificant admixture of kaolinite, calcite, aragonite, dolomite, pyrite, marcasite, millstone, relic silicates (chlorite, biotite, cummingtonite). Hematite, being the main ore mineral, is represented by three morphological varieties such as martite, micaceous hematite and dispersed hematite. The hematite redistribution between ore-preparation products (crushing, grinding to particle size of less than 0.1 mm) and screenings beneficiation was studied. Martite, which is a product of the hypergenic replacement of primary magnetite, represents a fine-porous differentiated aggregate, very small, multidirectional scaly crystals of hematite. Because of this, martite is subject to overgrinding in the ore preparation. The method of gravitational separation, which was used by the authors for beneficiation, allows most of the martite (particle size more than 0.02 mm) to get in the concentrate; and overgrinded martite (less than 0.02 mm) gets in beneficiation waste. In the process of grinding coarse-grained micaceous hematite (specularite) is effectively released and, when beneficiated, it gets in the concentrate. Thin-scaly aggregates of dispersed hematite are crushed to a particle size less than 0.01 mm and almost completely go to beneficiation wastes. Besides released particles of hematite and quartz, intergrown peaces having different proportions of these minerals are also formed in the course of grinding. During beneficiation process, high-grade aggregates with a hematite content more than 75% get in concentrates, the ones having the lower grade get into wastes. The different behavior of hematite of three morphological varieties in the course of ore preparation and beneficiation must be taken into account when developing an optimal technological scheme for the production of high-quality (67-69 mass.% of iron) hematite concentrate. |
| Databáze: | OpenAIRE |
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