| The copper grade of complex polymetallic ore of Yunnan province is 0.49%,and bismuth grade is 0.18%,the composition of the ore is complex,bismuth is difficult to recover because of the small grain size.Only copper resources are recovered now in the ore,however,the bismuth completely lost,so that not only the quality of the copper concentrate has been affected,but also caused a waste of bismuth resources.Copper and bismuth are intertwined seriously in the concentrate obtained by conventional processes,however,copper bismuth separation is difficulty of polymetallic ore,good inhibitors mostly are toxic,and difficult to apply to the production practice,resulting the polymetallic mineral resources waste.Mineralogical studies have shown that:the ore contains a lot of silicon dioxide,copper and bismuth,respectively,in the form of chalcopyrite and natural bismuth,and the particle size of the bismuth is smaller,bismuth mainly wrapped in chalcopyrite,pyrite and other minerals such as galena,the encapsulated bismuth accounts for 60%of the total bismuth,and the main structure of the ore is inclusive structure and granular structure,which is the main reason for the difficult recovery of bismuth.A large number of explorations experiment have been carried out for the ore,and the results show that the ideal indicator cannot be obtained by using either priority flotation,mixed flotation or leaching.Combined with the characteristics of the ore,the iso-floatability flotation flow sheet of stage grinding stage beneficiation process has been taken,namely:firstly,a crude copper concentrate with less bismuth was obtained by copper-bismuth iso-floatability flotation in the coarse grinding fineness;secondly,re-grinding for the crude concentrate,and shaking table was used to obtain copper concentrate and bismuth concentrate 1,finally,a bismuth crude concentrate with sulphur was made by bulk flotation on copper tailings,then a bismuth concentrate 2 was obtained by regrinding and reconcentration on the bismuth crude concentrate;carrier flotation was adopted to recover bismuth according to the minerals disseminated relationship;and use the regulators of combination to replace the sodium cyanide,a good experimental indicators are obtained by the method,and the method provide a basis for the comprehensive utilization of the complex multi-metal ore.The experimental results show that the grinding fineness and the pyrite content have a great influence on the beneficiation of copper and bismuth;in terms of collecting capacity of the copper collector,Z-200 is better than dithiophosphate and xanthate;bismuth,copper and sulfur in the distribution of the particle size is basically same when the grinding fineness-74μ m accounted for 75%,and most of the particle size is small,this is the main reason why copper and bismuth is difficult to separate.Exploration test of copper-bismuth iso-floatability flotation adopted the process of "one stage roughing-two stage scavenging-four stage cleaning",and finally,a bulk crude concentrate with copper grade and recovery is 23.54%,59.77%,respectively,and bismuth grade and recovery is 1.01%,6.72%,respectively,was obtained.The best conditions of the copper-bismuth iso-floatability are:the content of-74μ m is 70%,the dose of lime is 3kg/t(pH = 10),the dose of sodium silicate is 1000g/t,the dose of ethyl xanthate is 40g/t,the dose of Z-200 is 120g/t,and "one stage roughing-two stage scavenging-four stage cleaning" process was adopted.However,copper and bismuth are intertwined seriously in the concentrate,and the effect of flotation separation of copper and bismuth is not obvious,so,gravity separation was adopted by shaking table after grinding the resulting concentrate.Ultimately,a copper concentrate with grade is 22.88%,recovery is 84%;a bismuth concentrate 1 with grade is 21.70%,recovery is 38.37%,were obtained.The bismuth grade in the copper tailings is very low,in order to ensure the recovery of bismuth,a bismuth-sulfur crude concentrate with bismuth grade of 3.96%by bismuth-sulfur bulk flotation was firstly obtained,then,re-grinding of the crude concentrate to further dissociate the minerals,at last,a bismuth concentrate 2 was obtained by bismuth and sulfur separation after re-grinding.Exploration test of bismuth crude concentrate showed that:part of bismuth in the concentrate present microfine disseminated in the galena,so,carrier flotation method by using diethyl-dithio-carbamate capture galena to improve the recovery of bismuth;meanwhile,the pyrite in the crude concentrate has a great influence on the recovery of bismuth,though the pyrite can be inhibited by sodium cyanide,and get a good experiment data,sodium cyanide is highly toxic and cannot be used in industrial production.After a large number of exploration experiments,mixed regulators(lime,sodium sulfide and sodium carbonate)were finally adopted,and the experiment’s indicators are basically the same as sodium cyanide is used as an inhibitor.The best conditions of the bismuth-sulfur iso-floatability flotation were identified as:grinding fineness-74μ m accounted for 85%;sodium sulfide dose is100g/t;sodium carbonate dose is 800g/t;collector dose(diethyl-dithio-carbamate:25#,thiophosphate = 1:1)is 240g/t;and the process of flotation is "one stage roughing-two stage scavenging-three stage concentration".Finally,a bismuth concentrate 2 with grade is 23.79%and recovery is 41.46%was obtained.The concentrate showing the property of galenobismuthite because part of the bismuth embedded in the galena.For the copper-bismuth complex polymetallic ore,the iso-floatability flotation process of stage grinding stage flotation was adopted,a copper concentrate with a grade of 22.88%and recovery of 84.00%was obtained;grade of bismuth concentrate 1 and bismuth concentrate 2 are 21.70%,23.79%,respectively,and the total bismuth recovery is 79.83%.The experiment not only got a good experimental index,but also avoided using sodium cyanide,achieved the purpose of comprehensive utilization of resources,the experiment provided the experimental basis for the comprehensive utilization of the copper-bismuth complex polymetallic ore. |
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