Yunnan Celestite Ore Beneficiation Process Pilot Study

In this test studying, the celestite ore sample contains the main useful mineral is celestite. the main gangue minerals are calcite and silicate. And the run of mine contains a mass of mud, in addition, the embed size of celestite is too fine, so it is too difficult to liberation. Test had adopt the fine grinding, in advance desliming, gravity concentration, flotation and acid leaching. Finally the in advance desliming—flotation—acid leaching was ascertained as the beneficiation flowsheet. This studying also preliminary investigation the Mechanism of adsorption of sodium dodecylsulfonate on celestite and calcite.Desliming (-30 μm ) , grinding the ore to 98%-200 mesh, using sodium dodecylsulfonate as the flotation collector, and sodium silicate, citric acid, hexa-meta-phosphate and carboxy methyl cellulose as gangue minerals depressant with certain dosages in flotation. Experiment result indicates that, in rougher, the appropriate dosages of sodium dodecylsulfonate was 3000 g/t, and for sodium silicate, citric acid, hexa-meta-phosphate, the appropriate dosages were 15000g/t, 500g/t and 0g/t, respectively. Afte a beneficiation flowsheet of one rougher, five cleaning, gather partial middlings and return to the circuit, a celestite concentrate whose grade is 81.84% and recovery is 80.13% was obtained.Test result of high-grade run of mine flotation showed that the recovery of celestite concentrate improves obviously with run of mine grade increasing by. But the concentrate grade are well-balanced basically with the synthetical ore sample's concentrate grade. Although cleaning many times, however, have no way to gain above 90% high grade celestite concentrate.The surface properties of celestite(SrSO₄) and calcite(CaCO₃) in aqueous solutions of the anionic collector sodium dodecylsulfonate (NaDDSO₃) have been investigated making use of zeta potential, adsorption, infrared spectroscopy and microflotation techniques. A range of pH (3 to 11) and surfactant concentration (10^-6to 10^-3 M) were tested. The zeta potential studies showed that the isoelectric point (IEP) of celestite and calcite took place at pH 3 and 8, respectively. In the presence of dodecylsulfonate ion the DEP of both minerals shifted to lower pH values. The adsorption isotherms obtained for both minerals showed marginal adsorption up to certain surfactant concentration and precipitation of the salt (strontium or calcium dodecylsulfonate) onto the mineral surface beyond such a concentration. The microflotation studies showed that celestite was activated even at pH values where its surface was negatively charged. Compared to celestite, the activation of calcite was lower. It is suggested that the dodecylsulfonate ion adsorbed on the surface of celestite and calcite by a chemisorption mechanism giving rise, under certain circumstances, to the formation of the corresponding salt at the mineral-water interface.High temperature sulfuric acid leaching test results indicates that, when the concentration of sulfuric acid is 15%,the temperature is 70℃, condition time is 30 minutes, the solid weight/liquid weight is 1: 2,using sulfuric acid leaching a ceiestite flotation concentrate(80.90%),finally obtain a concentrate whose grade is 90% above.