Study on Comprehensive Utilization of Aluminum and Iron Minerals in the Washing Tailings from Bauxite Ore
|School||Central South University|
|Course||Mineral Processing Engineering|
|Keywords||bauxite ore washing tailings flotation chemical leaching PAFS comprehensive utilization|
In the process of exploiting karst accumulative bauxite in Guangxi, the tailings of bauxite ore washing (hereinafter as tailings) is one of the main wastes. This type of tailings, due to large moisture content, high fine particles, large specific surface area etc., is difficult to settle down naturally. Mass accumulations of the tailings discharge, leads to not only occupation of land but also threatening the ecological environment of the mining area and the surrounding, which has been one of factors restricting sustainable development of enterprises. So it is essential to develop scientific, rational and economical new technologies and new ways to deal with this type of tailings.This type of tailing consists of large amount of aluminum and iron mineral and the total amount of Al2O3 and Fe2O3 is up to 52.53%. To accomplish comprehensive utilization of aluminum and iron mineral in the tailings, two aspects were studied:firstly, discussing the study of separation and enrichment of aluminum and iron minerals in the tailings; in the next place, carrying out preparation and application of PAFS from tailings of bauxite ore washing.During the study of separation and enrichment of aluminum and iron mineral, a lot of experiments were carried out, such as desliming, collector, inhibitor, dispersant, low concentration flotation, reverse flotation of bauxite ores, magnetic separation and so on, and analyzing mineral composition and mineral microstructure by XRD, SEM and so on. On the other hand, during the study of preparing PAFS, condition tests of acid leaching, multi-factor condition tests of polymerization and conditions optimized tests were carried out. Studying the effect of dosages, pH and ratio of amount of substance of Al3+:Fe3+ of PAFS on turbidity removal and COD removal. At the same time, flocculating mechanism, structure and distribution characteristics of effective components of PAFS were analyzed too.In the study of separation and enrichment experiment of aluminum and iron mineral in the tailings, we failed to get the qualified concentrates. This is mainly due to large amount of fine particles(d80≤10μm), complex mineral composition, incomplete dissociation of valuable minerals in the tailings. After experiments of preparation and application of PAFS, the ultimate parameters of technology condition were confirmed:when acid leaching, adding sulfuric acid one-time, concentration of sulfuric acid 35%～41%, heating time 30min, pulp concentration of water-bath 7.7%～9.1%, temperature of water-bath 50℃, time of water-bath 3h; when polymerizing, basifier 1mol/LNaHCO3, temperature of polymerization 80℃, pH of PAFS in the range of 2.8-3.1. The technology is easy to implement and performance of product was excellent, compared with commercial PAS under the same condition, turbidity removing rate and COD removing rate of self-made PAFS were up to 90% and 80% respectively, which were better than commercial PAS. The technology accomplish comprehensive utilization of aluminum and iron minerals in the tailings, and provide a new way to deal with this type tailings of bauxite ore washing scientifically and rationally.