Minérios fosfáticos ígneos com ganga carbonática : estudos fundamentais

Abstract

The mineral industry is reinventing itself every day, in line with growing environmental demands to reduce waste and replace inputs by environmentally sustainable alternatives. Phosphorus is a strategic resource for the global food security and biodiesel production, obtained from non-renewable phosphate ores. Its complexity, i. e., association with silicate and carbonate ores, requires sophisticated beneficiation steps to supply the fertilizer industry. Vegetable oils are presented as a source of fatty acids, in varied proportions, for the production of collectors for phosphate flotation. The synergistic action of these compounds present in the collector can lead to advantages such as reduction in the consumption of reagents, better recovery and content, besides greater coverage of the mineral surface and stability of the foam. The grease sources of Amazonian origin present characteristics such as high availability, low extraction cost, selectivity for different flotation systems, besides providing development for the local communities. The present study evaluated the performance of Andiroba (Carapas guianensi) and Patauá (Oenocarpus bataua) oils, and Bacuri (Platonia insiginis) fat, in the flotation of apatite and carbonates, present in phosphate ore. Initially, the characterization of the minerals, grease samples and collectors was performed. The proportion of saturation in the collectors, obtained from the hot alcoholic saponification of the grease samples, affected the CMC and the adsorption process, in comparison to the collectors composed of pure fatty acids found in the oil samples. The CMC showed a direct relation with carbon chain saturation of collector. Regarding the adsorption process, mostly saturated collectors showed better performance in recovering dolomite, whereas collectors with high unsaturation were efficient in the collection of apatite and calcite. The positive impact of the conditioning time on particle recovery corroborates the hypothesis that this phenomenon occurs through chemisorption. Maximum selectivity was achieved with the Andiroba (20 mg.L-1) collector at pH 7.5 recovering 90.2% apatite, compared to 10.5% calcite and 8.2% dolomite. Finally, the Amazonian oil-based collectors based showed promising results for industrial application in phosphate flotation systems.