Continued growing demand for metals in emerging markets has led to increased use of chemicals and reagents in ore processing, raising both operational costs and environmental concern. The chemicals used in flotation processes especially invoke high costs of handling and disposal due to their hazardous nature. Developing more economical, greener processes, these hazardous materials should be replaced with by-products or wastes produced by another industrial sector. Biosolids, cheaper and greener than chemical frothers and collectors, have been tested successfully in flotation processes. This work evaluates the use of different collectors (Conventional Collector (CC), biosolids (and their main components), and mixtures of CC and biosolids main components) in the froth flotation of copper sulfide ores. Tests were carried out in Denver Cells, at fixed collector, frother, and pH levels, to estimate metallurgical and kinetic parameters. In rougher flotation tests, biosolids were shown to be the most efficient non-conventional collectors, achieving a recovery of 64.1% Cu, while CC allowed 76.2% Cu in the concentrate and none of the biosolids main components achieved values over a 60% Cu. The total replacement of main collector by biosolids and their main components showed a depressor effect in the copper concentration. In the kinetics studies, only the partial replacement of CC, by 50% of Humic Acids (HA) or biosolids, allowed a similar copper recovery (~81% Cu) to be obtained with a fast kinetic constant (~0.88 min-1). For molybdenum, partial replacement of CC produced better recovery and kinetics constants (k of 0.83 min-1 and R∞ of 66.10% to 50% CC/50% HA and k of 0.90 min1 and R∞ of 61.79% to 50% CC/50% biosolids). The results show that different combinations of biosolids/CC or HA/CC could achieve optimal flotation conditions. The most optimal combinations would allow considerable reductions in energy and chemical consumption to be achieved.
展开▼
