New Technology to Recover Fine Particles in the Flotation Process Using Surface Hydrophobized Materials (SHM)

摘要

The recovery of valuable minerals in flotation depends on many factors, being one of them the particle size. Fine particles (finer than 20 ?m) cannot be collected effectively given their inertia, because most of the fine particles are deflected by the streamlines generated by the rising bubbles. The previous condition is an unsolved problem using the current technologies, and it implies irreversible valuable mineral losses, which is discarded in the process tailings. This contribution presents a new technology based on the controlled hydrophobization of selected materials (patented preparation in progress). This new technology has been developed and validated using graphite particles (13 ?m) and mineral ore (100 % -500 mesh). The experiments were conducted using a 2.7 L standard Mechanical Flotation Cell. The mineral (mainly bornite) was ground from 2 mm to 14 ?m in a ball mill for 75 minutes (i.e., a-143-size reduction factor). The mineral pulp was prepared to be at 30 % solids, and pH equals to 10.5. The collector was sodium butyl xanthate (25 g/t), and frother was Polyglycol (10 ppm). Batch flotation kinetics tests were conducted considering: a) baseline (without hydrophobized materials), b) flotation with non-hydrophobized material c) flotation with hydrophobized material. The results demonstrated that the flotation kinetics constant increased 1.4 times on average, and the maximum attainable recovery rose from ~65 % up to ~90% (i.e., 40 % increase). Additionally, the new technology shifted the grade-recovery curve, promoting better metallurgical performance. In particular, no frother was necessary to stabilize the froth zone while hydrophobized material was used. In conclusion, the new technology shows a feasible approach to recover fine particles. This technology could be utilized to face the current and future challenges of mineral processing, specially those related to strongly disseminated ores, which are difficult to process.