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Fundamental Study On Oxygen-Rich Side-Blown Bath Smelting Process Of Copper Dross And Its Application

Posted on:2023-07-27Degree:DoctorType:Dissertation
Country:ChinaCandidate:H XiaoFull Text:PDF
GTID:1521307070477844Subject:Non-ferrous metallurgy
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Containing heavy,noble and rare metals like Cu,Pb,Bi,Sb,Au,Ag and Sn,copper dross is not only a secondary resource of high economical value,but also a material with hazardous environmental effect.Therefore,developing a clean and efficient processing technic for copper dross will benefit the cycling of valuable metal resources and sustainable development of nonferrous metallurgical industry in China,which is of great importance in both social and economic concerns.Aiming at the problems related with the development of copper dross bath smelting technology,such as the obscure element distribution behavior,the un-known relationship between technic index and operation parameters,this thesis proposed to investigate the fundamental theories lie in the problems using the combination of laboratory smelting experiments,industrial sampling analysis and thermodynamic/hydrodynamic simulation,the results obtained are as follows:(1)The optimal smelting condition was obtained with the single parameter experiment method as FeO/SiO2=1.9,CaO/SiO2=0.6,3 wt%sulfur/copper dross,10 wt%iron scrao/copper dross,5 wt%coal/copper dross,6 wt%Na2CO3/copper dross.Metal partitioning ratios of Pb,Bi and Sb were 83.43%,99.09%and 43.62%,matte partitioning ratios of Cu and As were 44.10%and 88.80%,dust partitioning ratio of Sn was 78.58%in the optimal conditions,which realized efficient metal separation.(2)The partitioning behavior of Pb,Bi,Cu,Sb and As were calculated by Factsage software and a two-step simulation method was proposed.Comparing with the one step simulation method,two step simulation method enhance the coincidence between the contents of simulated metal/matte and those of the industrial samples.The diviation between the simulated Pb,Sb and Cu contents of the metal and those of the industrial samples were reduced to 7.7 wt%,0.6 wt%and 1.0 wt%,respectively.Simulation of the element distribution behavior indicated that increasing the smelting temperature from 1050℃to 1250℃led to the increase of gas partitioning of Bi and Pb from 1.2%and 1.7%to 12.3%and 14.2%,speiss partitioning of Sb,As and Cu from 60.1%,32.3%,27.5%to 81.6%,67.8%,47.2%.Meanwhile,increasing separation temperature from 400℃to 700℃resulted in the rising of metal partitioning of Sb and Cu from 0%and 2.7%to 15.2%and 13.3%,while decreasing the speiss partitioning from 81.0%and 43.4%to 66.6%and 39.2%.These results suggested that speiss partitioning of As and Sb can be raised by increasing smelting temperature and decreasing separation temperature,achieving better sparation of As and Sb.(3)Hydrodynamic model based on CFD-PBM theory was proposed to simulate the fluent flow behavior in the oxygen-rich side-blown bath smelting furnace.The effects of gas injection velocity,feed rate,gas injection method and the width of furnace on the gas fraction in the molten slag and the flow velocity of the melt were calculated.The results suggested that gas injection velocity of~200 m·s-1,feed rate of 15 t·h-1and interval gas injection from both sides of the furnace facilitated mixing of reactants in the furnace,which provide useful information for furnace design.Transition simulation of gas injection in theOSBF showed that the reactor could quickly response to the adjustment of operation and steady state could be built in only 4s,reflecting the strong mass and heat transfer capability and steady operation.(4)Copper dross oxygen-rich side-blown bath smelting process was conducted steadily in an industrial oxygen-rich side-blown furnace(3.6m2).Recovery of Cu,Pb,Bi and Sb reached 87%,96%,97%and 60%,respectively.Monitoring on key points of the process and composition of molten slag in a typical industrial operation period indicated that the period can be divided to oxidative and reductive smelting steps.In the first step,Pb,Cu,Sb,As and Sb contents were 20 wt%,1.9 wt%,2 wt%,~0.5 wt%and~0.5 wt%;in the latter step,the contents of Pb,Cu and Sb quickly dropped to 2.8 wt%,0.2wt%and 0.3 wt%,while those of As and Bi were dropped to~0.15 wt%.EPMA analysis for the slag indicated that the reduction slag and quenched slag were in spinel primary phase field,suggested that a smelting temperature of 1300℃will be conducive for operating the process in a steady way.
Keywords/Search Tags:Copper dross, Oxygen-rich side-blown smelting, element distribution, thermodynamic simulation, hydromechanical simulation, industrial parameters optimazation
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