Reseach On Recycling Of Low-grade Chromite

With a large amount of consumption of high quality chromite resources, low-grade chromite has become the main source of chromite production in China. Therefore, Efficient recycling the low grade chromite resource has important strategic significance.Main element content, mineral composition and content, as well as mineral dissemination size characteristics of an chromite from South Africa were investigated by some methods, such as XRD, XRF, main chemical analysis, and et al. The results show that the mine is a typical oxidized ore, in which main ingredients are olivine, chromite, and a small quantity of magnetite and the ore contains low sulfur and phosphorus. The Cr grade in the ore is only 7.23%, mainly existing in the form of chromite. The Fe and Mg grade in the ore are 10.38% and 12.47%, respectively. A small percentage of iron exists in the form of magnetite among the ore. Cr is the main recycling value element for the chromite.Based on the mineral characteristic and separating technique to chromite at home and abroad now, gravity separation, magnetic separation, flotation, as well as magnetic separation and flotation combination technology were researched to the sample of chromite. Also a joint technology solution of "Weak magnetic removed magnetite strong magnetic recycled chromium-reverse flotation removed silicon after regrinding" was designed. The optimum experiment conditions are determined as follows:magnetic induction intensity of wet magnetic separation is 1800 Oe, and 80.7% grinding ore is less than 74 ?m particle size, the obtained magnetite concentrate had a iron productive rate of 0.56%, and grade of 3.61%; magnetic induction intensity of high gradient magnetic separation of weak magnetic separation tailings is 9000 Oe, the obtained chromite concentrate had a chromium grade of 17.76% and recovery of 80.25%; high gradient magnetic separation concentrate is separated by flotation, after 90% grinding ore is less than 74?m particle size through regrinding, under the condition that starch is used as inhibitor, NaOH is used as adjusting agent, GE-609 is used as collecting agent, a circuit of one roughing, and three concentrating is adopted as reverse flotation flowsheet. By the closed-circuit test above, the obtained chromite concentrate had a chromium grade of 26.02% and an operating recovery of 89.00%, the comprehensive recovery rate of chromium iron ore, all grinding ore was less than 74 ?m particle size, in the whole process was up to 71.40%.