| With the rapid development of economic society and the increasing copperconsumption, the scale of the copper industries was expanding. Restricted by copper oreresoueces reserves, copper concentrate import dependency is increasingly high. Copperslag and dust is the two main types of solid by-products produced from copper smeltingprocess, both of them not only has Cu, Zinc, Pb, Sn, As, Sb, Bi, Te, Co, In, Ge and othervaluable elements, and it was a kind of potential secondary resources. If the solidby-products were not comprehensive recycling and utilization, not only will causeserious pollution to the environment, but also caused a lot of waste of resources. In theincreasingly heated contradiction between supply and demand of mineral resources,strengthen the comprehensive recycling and utilization of similar secondary resourceshas very important practical significance.In the present dissertation, the copper-smelting slag and ash was used as the rawmaterials. The copper-smelting slag contains0.5~0.9%copper and0.15%cobalt, andthe smelting ash contains50.46%,3.72%zinc and other valuable metals. According tosystematic experimental study, the conclusions were made as follow:(1) the coppermineral was found as the form of fine grain distribution in the copper slag by theprocess mineralogy analysis of Austin matt furnace slow cooling slag, and adopting“stage grinding and stage separating” process is helpful to achieve perfect beneficiationindexes. The slow cooling system was applied as water cooling24h and then naturalcooling24h in cinder ladle slow cooling was conductive to the recycling of copper inthe slag by the experimental research. The beneficiation experiments was conductedunder the conditions of the slow cooling slag ore grade was0.74%, with butyl xanthateas the copper collector and coarse grinding fineness below0.074mm was75%andsecondary grinding fineness below0.043mm was85%, the dosage of sodium sulfidewas95g/t, the dosage of butyl xanthate was90g/t, and the consumption of2#oil was85g/t in the experiments, the copper concentrate could be obtained by the grade of over16%and copper recovery rate was70%.(2) The copper was found as the main form ofSulfide state, with some copper exist as the form of metal and oxidation state, and asmall number of copper exists as the form of copper ferrite. A great deal of copper contains in the high grade converter copper slag made the grindability relatively poor,and extending grinding time is helpful to achieve liberated and recycling of coppermetal and interlocked copper minerals.The folation grinding experiments was conductedunder the condition of a grinding fineness as-200mesh contains75%and secondarygrinding fineness as-325mesh accounts for75~80%in experiments, the copperrecovery rate can reach96.5%.(3) The leaching experiments was conducted under theconditions of the concentration of H2SO4was30%, with leaching liquid-solid ratio was7:1(ml/L), the dosage of H2O2was2.00(mL/g), the leaching temperature was85℃, andthe leaching time was150min in the experiments, the leaching rate of Cu, Zn, Co, Fewas79.83%,82.37%,80.54%,72.32%, respectively.(4) The acid oxidation leachingprecess was applied in leaching Co from copper mill tailings under the optimumconditions, and the stirring intensity, the fineness of copper mill tailings and theleaching tempreture which has effect on the leaching rate of Co were investigated. Theresults of kinetic analysis for various experimental conditions indicate that1eachingprocess of Co in copper mill tailings followed the reaction zone model of lump ore，andthe macrokinetics equation is The apparent activation energy of reaction is about19.00kJ/mol, and the reaction iscontrolled by diffusion process.(5)the roasting experiments was conducted under theconditions of the roasting tempreture was600℃and the roasting time was100min inthe experiments by inert gas Ar protection, the remove rate of As was reached78.43%.(6) the pH=2-H2SO4-H2O2leaching system was applied under the condition ofthe leaching temperature at80℃, with the solid-liquid ratio at10:1(ml/g) and thedosage of H2O2at1.75ml/g, leaching for105min and the mixing speed at705r/min inleaching experiments, the leaching ratio of Zn was85.42%, and the removal ratio of Aswas78.25%.(7) The combination of inert roasting and pH=2-H2SO4-H2O2leachingprocess was applied in the comprehensive test, and the total remove rate of As wasreached81.98%，and the grade of As in the volatile was reached73.24%.(8) The (Fe/As)rate was controlled according to the concentration of Fe3+which contained in theleaching liquid produced from acid oxidation leaching Co from copper mill tailings andthe concentration of As which contained in the leaching liquid produced frompH=2-H2SO4-H2O2leaching system, and then adjusting the pH of mixed solution by adding calcium powder to about4.5with stirring reaction for a period of time, andabout99.8%As was converted into ferrous arsenate slag or calcium arsenate slag.The above research work provides a theoretical basis to achieve the upgrade andrenovation of comprehensive recycling the valuable elements from copper-smelting slag,with the pressure of the inventory of mill tailings contained Fe was reduced to someextent by adopting the Fe contained in the copper mill tailings to precipitation the Ascontained in the smelting ash, the hazards came from the toxic elements As on thewhole process to recycle Pb, Bi, Sn and other valuable elements from smelting ashwhich contained As was be decreased at the same time. It also has an important practicalsignificance on comprehensive recycling and utilization of similar secondary resources,and alleviated the contradiction between supply and demand of mineral resources. |
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