Home – Home – Jornals – Chemistry for Sustainable Development 2017 number 4

The paper justifies factors and causes of hard washability of finely disseminated copper-nickel ore, the main of which are incomplete and insufficiently selective expansion of sulphide and rock-forming mineral aggregates due to low mechanical interactions in ball mills, with the result that a large number of non-ferrous and precious metals pass to concentration production wastes adding to technogenic accumulations. Technological possibilities of high-energy and high-velocity impact grinding in a disintegrator, wherein increased destructive effects lead to an increase in expansion of aggregates, were explored. The opportunity to control energy and free kick speed allows carrying out the destruction mainly along the boundaries of mineral intergrowths and reducing the amount of the fine fraction slurry in grinding products. However, an increase in the disintegration rate to 7200 rpm did not result in obtaining flotation size products –0.071+0.02 mm, and a substantial part of ore remains in the larger, difficult-to-float condition. With a view to optimising opening of mineral associations by granulometric composition, the principle of stage grinding that allows consistently in the regimes of increasing energy effects regrinding larger ore fractions and liberating minerals from genetic associations with increased strength was proposed. This methodological approach allowed in the optimum rate mode destructing sulphide minerals and obtaining during flotation separation concentrates with increased content of non-ferrous metals, which offers opportunities for improvement of metallurgical methods for processing concentrates. More high-energy destruction allows liberating residual amounts of sulphides in rock associations and transferring into reject materials to 50 % of ore rocks. It is noteworthy that herewith, a large number of nickel compounds found in aggregates with rock formations are released, which is of great importance for increasing nickel extraction into concentrates. The carried-out research demonstrates that high-energy grinding is an advanced method for selective destruction of aggregates and mineral liberation in finely impregnated ores prior to concentration processes.