Flotation Technology Research Of Desilication And Iron-depresstionon Bauxite With High-grade Silicon And Iron

In recent years, with sharply rose of imports of alumina and bauxite, costs of the alumina production continued to increase in our country. These factors gave a new chance to the bauxite with high-grade silicon and iron which could not be utilized by the original high cost of production, so many manufacturers injected funds into the technology development of high iron bauxite. The current technology all faced the problem of high energy-consumption. The utilization technology of the diaspore-kaolinite bauxite with high-grade silicon and iron from Guangxi was studied. The mechanism study of desilication and iron-depresstion was also studied.Monomineral flotation tests had been carried out to compare the flotation behavior of diaspore, kaolinite and hematite. The tests showed that comparing with the solely used sodium oleate and nonyl hydroxamicacid, the selectivity and collecting ability of combined collector between them was better. Sodium hexametaphosphate could selectively depress kaolinite and hematite preferably when using combined collector.The grade of A12O3, SiO2, Fe in actual ore are43.67%,13.66%,17.65%, respectibely, and alumina-silica ratio is only3.2. The process mineralogy showed that diaspore, kaolinite and hematite disseminated complexly and were difficult to dissociate effectively. Using sodium oleate and heptyl hydroxamic acid as combined collector, sodium carbonate and sodium hexametaphosphate as regulator, adopting one-stage roughing, three-stage scavenging and two-stage cleaning, and the flotation indexes were as follows:the alumina-silica ratio was8.09, Al2O3recovery was74.36%, and the grade of Al2O3, SiO2and Fe were87.85%,7.15%,11.25%, respectively. Results showed that the separation of alumina and silica were achived and the grade of Fe were decredsed. The tests also showed that the sodium hexametaphosphate could depress the hematiteand kaolinite selectively, and the selectivity of combined collector with sodium oleate and heptyl hydroxamicacid was better than each collector alone, which all verified the results of monomineral flotation tests.The mechanism of the interaction between the reagents and minerals was studied by zeta potential measurements, infrared spectroscopy analyses and adsorption measurements. The results showed that nonyl hydroxamicacid and sodium hexametaphosphate adsorbed on the surface of diaspore and hematite by chemisorption. Sodium hexametaphosphate could effectively reduce the adsorption of nonyl hydroxamicacid on the surface of hematite. While with larger dosage, the adsorption on the surface of diaspora were also reduced.