The High Mud Cuprite Oxide Copper Flotation Tests And Theoretical Studies

The copper mine of Dishui in Xingjiang province contains 1%～1.3% copper, which has 200,000 tons proved reserves and 500,000 tons future reserves of copper metal, and the contents of calcium oxide and magnesium oxide are over 20%. The content of-20μm slime is more than 65% under the grinding fineness of-74μm contained 85%. The oxide copper minerals in the ore are mainly in the form of cuprite, malachite, chrysocollite and azurite, and the floatability is unsatisfactory because of many kinds of copper minerals. The ore has characteristics of high oxidation rate, high content of slime and acid-consuming gangaue minerals, which is very difficult to be treated. On the base of many experiments, the concentrator was constructed with the processing capacity of 1000t/d and designed copper recovery of 75%. However, the recovery in practice was only about 50%, and the collector consumption was over 2800kg/t, which caused a serious economic loss to the enterprise, and the copper ore had not been utilized sufficiently.Process mineralogy research of the ore has been studied, and the results indicate that cuprite is the main form of oxide copper minerals, which is difficult to be vulcanized and floated. Performance on sulphidizing flotation of three oxide copper minerals including cuprite, malachite and chrysocollite, has been investigated vain thermodynamic calculation of sulfuration reaction, tests of flotation, analysis of concentrates XRD and floatation rate of the three oxide copper minerals. Combined the results of thermodynamic calculation and experiment, it is found that it's easy to be floated for malachite but difficult for cuprite and chcysocollite. In the common floatation time, it is satisfied the kinetic equations of floatation for oxide copper minerals, and the floatation rate constant k of Dishui copper, cuprite, malachite and chrysocollite is 0.152,0.104,0.248 and 0.210 respectively. Therefore, it is necessary to add ammonium sulfate and iso-amyl xanthate for intensifying the processes of sulfuration and collection.Result of the experiments shows that the heavy slime not only consumes a large of collecting agent but also produces a serious influence on the closed-circuit, because the slime dropped into concentrate and tallings continuously decreases the concentrate grade and causes the copper metal loss in the tallings. Therefore, XRD, SEM-EDAX, electron microprobe analysis, surface energy and specific surface area measurement are used to understand the properties of-20μm slime. Based on the slime process mineralogy, the effect of frother, collector and temperature on the slime floatability is reseached in order to find the mechanism of the three factors on slime floatability.Slime process mineralogy indicates that the mineral gangues are mainly contained quartz, calcite, anorthose, dolomite, chlorite, muscovite and so on. The specific surface area of slime, quartz and calcite is 22.25m2/g,0.1003m2/g and 0.1365m2/g, respectively, with the computational method of BET. Using the date of contact angle and specific surface area, slime surface energe can be calculated at 3120.56J/g.The effect of frother on floatation shows that frother has an influence on water recovery, which could affect the entrapment of slime, consequently, a great deal of slime enters the concentrator with foam. Using UV spectrophotometer, adsorption of iso-amyl xanthate on the slime is 0.801mg/g, but the adsorption on quartz and calcite is too liltte to be measured, which shows that the dosage of collector has the effect on slime flotability. The result of pulp viscosity demonstrates that the viscosity decreases with the temperature increased, therefore, the slime recovery is reduced in respect that the pulp velocity becomes faster and the water recovery is declined. With the pulp temperature increased, the adsorption on slime is reduced.From the researches on sulphidizing flotation performance of oxide copper minerals and mechanism of slime floatability, it is found that pulp temperature and frother dosage are critical factors for the benefication of Dishui copper ore, therefore, the new technique of controlling temperature to depress slime and intensifying collection is applied for dealing with the copper ore.Experiments are conducted using the technique of controlling temperature to depress slime and intensifying collection, and the result shows that the grade and recovery of rough concentrate is 7.06% and 83.38% with the pulp temperature 20℃. And the closed-circuit test of one time of roughing, three times of scavenging and two times of cleaning is carried out, and the grade and recovery of final concentrate is achieved at 21.04% and 86.25%. Compared with the result of pulp temperature at10℃, the adverse influence of slime is reduced, and the floatation index is better.In industrial, closed-circuit of two-stage crushing, one grinding and two-stage classification flowsheet, making sure the slime content bellowed 60%. Underground water is used as the floatation water in order that the pulp temperature is above 15℃in the winter. Benefication flowsheet of one time of roughing, three times of scavenging and one or two times cleaning is employed, when the crude ore contains copper 1.08%, the grade and recovery can be achieved at 20.60% and 85.14%, and the effective utilization of resources is realize.