Search Results (2)

The characteristics of iron minerals in cyanidation tailings with a low iron grade were determined via chemical composition analysis, iron phase analysis, and mineral liberation analysis (MLA). The results showed that the cyanidation tailings contained 15.68% iron, mainly occurring in the form of magnetite (19.66%) and limonite (79.91%), in which 16.52% magnetite and 65.90% limonite particles were fully liberated. Most ultra-fine magnetite grains were adjacent and wrapped with limonite to form complex intergrowths, which resulted in low-efficiency magnetite recovery in low-intensity magnetic separation (LIMS) and adversely affected the downstream high-gradient magnetic separation (HGMS) process. Thus, in this work, the optimization of the flow field was proposed to enhance the separation of ultra-fine magnetite from the cyanidation tailings using pilot-scale LIMS separation, and the controllable parameters (including feed flow, separation gap, drum rotating speed, and solid weight) affecting ultra-fine magnetite capture were investigated. Under optimized conditions, a high-grade magnetite concentrate assaying 63.31% Fe with 86.46% magnetite recovery was produced, which, respectively, increased by 0.76% and 15.22%, compared with those obtained from industrial production. In addition, from the flow dynamics simulation, it was found that the magnetite particles in the −6 µm ultra-fine fraction were lost much more easily than those of coarser fractions due to the relatively enhanced hydrodynamic drag force acting on the particles compared with the magnetic force. However, this loss would be effectively reduced with the regulation and control of the flow field. The iron recoveries in the −16~+6 µm and −6 µm fractions of magnetite concentrate increased by 3.66% and 4.42%, respectively, under optimized hydrodynamic conditions. This research outcome provides a valuable reference for the economic and effective utilization of iron resources from such solid wastes. Full article

High-phosphorus oolitic iron ore, treated by suspended flash magnetic roasting, contained 42.73% iron (mainly present as magnetite) and 0.93% phosphorus (present as collophane). Low-intensity magnetic separation (LIMS) was combined with reverse flotation to increase the iron and reduce the phosphorus contents of the roasted product. The results showed that an optimized iron ore concentrate with an iron grade of 67.54%, phosphorus content of 0.11%, and iron recovery of 78.99% were obtained under LIMS conditions that employed a grind of 95% −0.038 mm and a magnetic field of 0.10 T. Optimized rougher reverse-flotation conditions used a pulp pH of 9 and dosages of toluenesulfonamide, starch, and pine alcohol oil of 800 g/t, 1000 g/t, and 40 g/t, respectively; optimized scavenging conditions used a pulp pH of 9 and dosages of toluenesulfonamide, starch, and pine alcohol oil of 400 g/t, 500 g/t, and 20 g/t, respectively. Study of the mechanism of phosphorus reduction showed that the toluenesulfonamide could be adsorbed on the surface of quartz after the action of starch, but adsorption was significantly weakened. The starch inhibitor negatively affected adsorption on quartz, but positively influenced adsorption of phosphorus minerals. Full article