| Copper,one of China’s important strategic resources,which plays an important part in the national economy.With the exploitation of copper resources,copper sulfide ore resources which are easy to select decrease gradually.And the exploitation and utilization of compound copper ore and copper oxide ore is of great significance.Researches in this paper were respectively made on the pure malachite mineral and actual ore.The pure malachite mineral was from Shilu copper mine in Guangdong.Through hand sorting,the pure mineral contained 56.50%copper and its purity was 97.98%.Actual ore was from Meigu copper mine in Sichuan,which contained 0.77%copper and 8.2g/t silver.Copper in the actual ore consisted mainly of chalcopyrite and malachite,and the oxidation rate was 26.88%.It was a compound copper ore.In order to improve the mineral processing index of oxide copper mineral,a study on the mechanism of ammonium sulfate in the sulphidizing flotation of malachite was made from three aspects,including the pure malachite mineral,artificial compound ore and mineral surface vulcanization mechanism.Research results were applied into the actual ore dressing test.Through the flotation tests of malachite pure minerals,the effects on flotation results of ammonium sulfate were respectively investigated under conditions of different pH value,sodium sulfide dosage,collector dosage and agitation intensity.The results show that mixed dosing of sodium sulfide and ammonium sulfate decreases the effects of pH value,sodium sulfide dosage and agitation intensity on the malachite flotation,compared with the single use of sodium sulfide as curing agent.The butyl xanthate required for optimum flotation recovery decreases from 6×10-4mol/L to 4×10-4mol/L.The test results of artificial mixed ore show that the addition of mixed dosing is beneficial to the improvement of flotation index and reduces the adverse effects of sodium sulfide dosage and agitation time on malachite flotation,which were consistent with that of pure malachite mineral flotation.By using Zeta potential determination,contact angle determination,adsorption capacity determination,scanning electron microscopy and energy spectrum element semi-quantitative analysis,the enhanced sulfide flotation mechanism of ammoniumsulfate were analyzed.The research shows that mixed dosing of sodium sulfide and ammonium sulfate makes the zeta potential of malachite in larger pH a higher negative potential;the contact angle is expanded between xanthate and malachite surface;the adsorption volume and strength of butyl xanthate on malachite surface is enhanced;the stability of the vulcanized film on the surface of malachite is enhanced.The improved conditions are beneficial to malachite flotationThe mechanism study shows that ammonium sulfate promotes the dissolution and complexion of copper ion in solid phase and changes the mineral surface structure to promote the adsorption of CuX2;[Cu(NH3)4]X2 in the liquid phase and butyl xanthate generates[Cu(NH3)4]2+ which is absorbed on the mineral surface and enhances the stability of collecting process.Besides,the ionization of ammonium sulfate and the hydrogen ions produced by hydrolysis inhibite the hydrolyze and ionization of sodium sulfate,and eliminate the excess sulfur ions in the solution,which reduce the inhibition effects of excess sulfur ion.Combined with the research results on flotation and mechanism of pure malachite mineral,flotation tests on practical ore were carried out.The test results showed that two sulfide ore roughing,one selecting,one oxide ore roughing,one scanning,two selecting and middling returning in order were used.Under the effects of sodium sulfate and ammonium sulfate,the oxide copper mine was floated with butyl xanthate as flotation regents;a concentrate grade of copper of 24.48%grade and 88.09%recovery was obtained;the silver grade and recovery were 258.21g/t and 87.23%respectively;the recovery of oxide copper mineral was17.13%and the grade was 17.56%.Compared with no addition of ammonium sulfate,the copper recovery and grade of oxide copper mine were increased by 13.82%and 7.27%respectively. |
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