The enrichment technology of slag from metallurgical processing of copper ore concentrate

Abstract

The purpose of this research is the development of a technology for the enrichment of slag from metallurgical processing of copper ore concentrate based on the results of spectral, chemical, sieve and petrographic analysis. The results of spectral analysis indicate the copper content in all three samples of mineral raw materials at more than 1 %. The results of chemical analysis indicated a high copper content in the samples from 13.4 to 17.1%, as well as a high iron content from 9 to 18%. Analysis of the results of the sieve analysis showed that the largest amount of copper is contained in the size classes 0.063–0.05 mm at from 18.6 to 24.1 % and 0.04 mm at from 15.6 to 38 %. In accordance with the petrographic studies, the size of copper grains varies from 0.1–0.3 to 1–5 mm. The most common sizes of copper grains in the studied samples are 0.2-0.3 and 1-2 mm. Based on the results of spectral, chemical, sieve and petrographic analysis, a technology for the enrichment of copper-containing slags has been developed. Gravity wet enrichment technology with a capacity of 5 t/h with Cu recovery in the range of 80–95 % suggests the grinding of raw materials with a constant water supply up to 40 m3/h from the sludge collector. The heavy fractions are fed to a magnetic separator and then to a classifier for the extraction of magnetic concentrate and slag, which after the separation of the fraction of 0.08-0.4 mm with the MVG screen can later be used as a raw material for the building industry. The light fractions after the concentration tables are fed to the classifier, on which the copper concentrate is released. The average density fractions are returned to the closed cycle for further grinding in a ball mill. However, such a wet enrichment scheme requires a continuous water supply and the sludge collector’s presence, which cannot always be ensured. Therefore, the technology of slag dry enrichment with a particle size of 0–100 mm has also been developed. The central apparatus in the proposed enrichment technologies is the MVG vibrating screen, which is designed to separate bulk materials by particle size from 20 microns to several millimeters. Polyfrequency oscillations in the frequency range from several Hz to kHz are implemented on the screen, eliminating blockage of the sieve cells, destruction of the formed aggregates of stuck particles, ensuring their intensive movement in the layer and efficient passage of particles reaching the sieve surface through the cells. This type of vibration makes it possible to achieve much greater efficiency of separation and dehydration of materials than in traditional screens and to ensure continuous self-cleaning of the mesh, which contributes to the process of separation and dehydration. Due to the lack of tension, high durability of the working surface is ensured. Due to the transfer of minimum loads on the base, the screen is installed without arranging special foundations, including on the floors of buildings and structures. A standard- sized row of screens was developed with a screening surface area from 1 to 4 m2 and a different number of tiers.