Study On The Flotation Process Of Refractory Copper Sulfide Ore And The Separation Mechanism Of Copper And Sulfur

The industrial types of copper resource deposits in China are relatively complete,most of which are mainly copper sulfide deposits.Copper sulfide ore is a common ore type in copper sulfide ore.Chalcopyrite and pyrite are typical sulfide minerals in copper sulfide ores.Flotation is an important processing link for obtaining copper and sulfur materials from this kind of ore.With the deepening of mining and the reduction of ores,the characteristics of copper sulphur resources are increasingly poor,fine and miscellaneous.The dense symbiosis and inlay relationship between minerals is more complex and changeable,and the flotation separation of copper and sulfur is difficult because of the natural floatability of the iron sulfide and copper sulfide minerals.In order to realize the selective flotation separation of copper and sulfur,the high alkali?p H>12?flotation process of lime as a inhibitor is widely used to separate copper and sulfur.However,because of the addition of a large number of lime,the scale of the equipment and pipeline is caused by the addition of a large amount of lime,which leads to the reduction of the comprehensive recovery rate of the associated elements and the environment of the mine.It is easily polluted by waste water from mineral processing.Therefore,it is of great practical significance to carry out the selective green separation of copper and sulfur under low alkalinity,and to overcome the shortcomings of the separation of copper and sulfur under the high alkalinity process.In this paper,the flotation process of copper sulfide ore and the mechanism of flotation separation of copper and sulfur are studied.First,the factors affecting the floatability of chalcopyrite and pyrite are investigated,and an important theoretical basis is provided for the inhibition behavior of pyrite in the separation of copper and sulfur.The flotation test results of pure mineral in the one element system show that the recovery rate of chalcopyrite is about 90%under the conditions of p H 8 and a butyl xanthate dosage of 1.5×10^-33 mol/L.When pyrite is used at p H=8,the recovery rate of butyl xanthate is about 90%under 1×10^-3mol/L.The increase of Ca O dosage has little effect on the recovery rate of chalcopyrite.When the dosage of Ca O is 2.5×10^-3mol/L,the recovery rate of chalcopyrite reaches the maximum value of about87%.With the increasing amount of Ca O,the recovery rate of pyrite is decreasing.When the amount of Ca O is 4.91×10^-3mol/L,the recovery of pyrite is reduced to about 20%,but the p H value of the pulp is up to 13.5.When the dosage of calcium hypochlorite increased from 0 mg/L to 200 mg/L,the recovery rate of pyrite decreased by nearly 50%.When the dosage of calcium hypochlorite is 200mg/L,the recovery rate of chalcopyrite and pyrite is almost 50%.The experimental results show that a chalcopyrite:Pyrite ratio is 1:1,pulp p H=8,calcium hypochlorite dosage200mg/L,butyl xanthate dosage of 1.5×10^-3mol/L,copper sulfur flotation separation can be realized,as a result copper concentrate with 28.13%Cu grade of 28.13%and Cu recovery rate of 89.99%can be obtained..The results of the study on the inhibition mechanism of calcium hypochlorite on pyrite are as follows:?1?the results of infrared spectroscopy showed that after adding Ca?Cl O?₂,the reflection of Ca SO_4?Ca CO₃ and Fe?OH?₃ of pyrite on the surface of the pyrite was very weak,resulting in an increase in the transmittance of 45%,which may be an important reason for the inhibition of pyrite by calcium hypochlorite;?2?the results of solution component detection showed that in the aerated and stirred solution system,the concentration of iron ions?CFe?and the concentration of sulfate ion(CSO₄^2-)were 452 mg L^-11 and 1185 mg L^-11 respectively.After adding 100 mg/L calcium hypochlorite,the concentration of iron ion?CFe?and the concentration of sulfate ion(CSO₄^2-)in the solution increased respectively.The addition of calcium hypochlorite promoted the oxidation of the pyrite surface in the solution;?3?the simulation results of Visual MINTEQ model show that the addition of hypochloric acid will induce the transformation of S component on the surface of pyrite and Ca²⁺ions to Ca SO₄ and calcite,and the adsorption of Ca²⁺ions on the pyrite surface will be an important source of the inhibition of the calcium component on the pyrite surface;?4?the results of XPS show that the concentration of O1s atoms on the surface of pyrite is up to 42.16%after adding 200 mg/L Ca?Cl O?₂,while the concentration of Fe2p and S2p is significantly lower than that of the previous two.Calcium hypochlorite promoted the oxidation of pyrite surface and the formation of oxidation products,thus enhancing the hydrophilicity of pyrite;?5?the results of semi quantitative analysis of TOF-SIMS surface elements show that the addition of 200mg/L calcium hypochlorite in solution p H=8 leads to the transformation of S and Fe on the surface of pyrite toSO₄^2-,Fe²⁺,Fe³⁺ions,and Ca ion component?Ca⁺,Ca OH⁺?,and calcium component precipitation?Ca SO₄ minerals?and hydroxyl iron are adsorbed on the pyrite surface.The hydrophilic species of pyrite mainly take Ca⁺and Ca OH⁺as the order of Ca⁺,Ca OH⁺,hydroxyl iron,Ca SO₄ and Ca CO₃;?6?the TOF-SIMS depth analysis shows that,after the addition of calcium hypochlorite 200mg/L,the Fe OH⁺ion intensity on the pyrite surface is reduced,but Fe OH⁺is permeated to the topsurface of pyrite,and the adsorption thickness of hydrophilic hydroxyl iron species on the surface of the mineral is increased,and the thickness of the adsorption is greater than 18.37 nm.Based on the theoretical study in the early test,the process of copper sulphur ore with TCu grade of 0.61%and sulfur grade of 3.88%is used in the process of mixed flotation,coarse concentrate regrinding and combination inhibitor copper sulfur separation.In p H=8,the regrinding fineness of-320 mesh of coarse concentrate is97.01%,Ca O+Ca?Cl O?₂ of combination inhibitor is 2.14+4.2×10^-3mol/L,and finally the concentrate is obtained.The flotation grade of copper is 19.69%and copper recovery is 79.4%.This paper provides a theoretical basis and technical support for the green separation of similar copper sulfide ores under low basicity.