INCREASING THE SELECTIVITY OF USEFUL MINERAL DISCLOSURE WHEN PROCESSING DIFFICULT POLYMINERAL RAW MATERIALS WITH PRELIMINARY WEAKENING

Previous studies at a number of research centers in our country, including the Institute of Mining, SB RAS and the Institute of Nuclear Physics, SB RAS, showed the possibility of improving process parameters of flotation concentration of difficult mineral raw materials due to preliminary electron-beam processing, which allows weakening minerals and rocks. Obtaining the data on selective disintegration and disclosure of minerals during ore pretreatment is important for technological application. This study aims at receiving the experimental data confirming an increase in the selectivity of disintegration of mineral raw materials processed by a high-energy electron beam and an improvement in the disclosure of intergrowths of useful minerals. Complex experimental mineralogical and technological studies by the example of rebellious lead-zinc ore with a grain size of -3 mm provided the data on increasing the selectivity of disintegration of mineral raw materials and improving the disclosure of useful minerals. It is found that if in -0.071 mm size class of ground lead-zinc ore without processing, the fraction of free galena and wurtzite grains (sphalerite modification) is 40.7 and 65.7%, then the fraction of free grains of these minerals increases up to 66, 4 and 71.5% in ore pretreatment. It should be noted that ore processing by accelerated electrons allows obtaining the ground material, in which free mineral grains are less overground. For galena, the size of free grains increases from 2.6 to 4.0 μm, and for wurtzite - from 4.5 to 6.6 μm. Scientific novelty includes increasing the selectivity of disintegration and improving the disclosure of useful minerals through the effect of weakening of mineral raw materials in ore pretreatment.

Methods of Ore Pretreatment for Comminution Energy Reduction

The comminution of ores consumes a high portion of energy. Therefore, different pretreatment methods of ores prior to their comminution are considered to reduce this energy. However, the results of pretreatment methods and their technological development are scattered in literature. Hence, this paper aims at collating the different ore pretreatment methods with their applications and results from published articles, conference proceedings, and verified reports. It was found that pretreatment methods include thermal (via oven, microwave, or radiofrequency), chemical additive, electric, magnetic, ultrasonic, and bio-milling. Results showed that the chemical pretreatment method has been used at an industrial scale since 1930, mainly in cement production. The microwave pretreatment results showed positive improvements at pilot scale mining applications in 2017. The results of ore pretreatment using electric and ultrasonic methods showed up to 24% and 66% improvement in energy consumption, respectively. The former and the latter have been piloted for gold and carbonate ore, respectively. Findings also showed that magnetic, radiofrequency, and bio-milling methods have not led to significant reductions in comminution energy. Based on energy reduction, safety, costs, stage of application, and downstream benefits, microwave and electrical pretreatment methods may be focused for applications in the mining industry.