| The comprehensive utilization of zinc dust and secondary zinc resources is one effectual way to solve this problem in the current zinc resources supply increasingly tense situation,about 30%of the world's zinc produced annually comes from renewable zinc resources,the recovery of zinc dust and other secondary zinc resources increasingly urgent.The deep eutectic solvent(DES)as a new type of green solvent,because of its low toxicity,biodegradable,low cost,simple synthesis,etc.,as a solvent to deal with zinc dust,is expected to overcome the leaching system,complex components,separation difficulties and other issues,which has importamtly theoretical guiding significance and broad application prospects.In this paper,the deep eutectic solvent was used as the research system,and the pure metal oxide was used as the object of study.Through the behavior of the pure metal oxide in the deep eutectic solvent,deep eutectic solvents based on choline chloride was used to elute all kinds of metal oxides of the pure material,and the composition of the complex zinc dust leaching.The solubilities of zinc oxide in ChCl-urea and CC-OA DES,the influence of temperature on the viscosity,The effects of ZnO concentration and temperature on the conductivity of ChCl-urea-ZnO was determined.The existence of ZnO in two systems was analyzed by mass spectrometry.The electrochemical behavior of zinc in ChCl-urea-ZnO was investigated by cyclic voltammetry,and the effect of particle size and morphology was determined by the change of ZnO concentration.The effects of various factors on the leaching rate of zinc were investigated by single factor experiment and response surface design experiment.The preliminary study on the treatment of zinc dust by CC-OA DES system provided experimental guidance for the later treatment of zinc dust.The major research results are drawn as follows:(1)The synthesized deep eutectic solvent can be present in the liquid state at room temperature,which accord with the requirement of the follow-up study on the melting point of the system.The temperature has a significant effect on the viscosity of the two systems;And the logarithm 1n? of the viscosity of the two systems is in good linear relationship with the reciprocal of the temperature 1/T;The solubility of ZnO in two systems is greatly influenced by temperature;The solubility of ZnO in the experimental temperature range is consistent with the leaching requirements of zinc dust;The forms of ZnO dissolved in the two systems were[ZnOCl · urea]-and[ZnO · HC2O4]-,respectively.(2)The temperature and the concentration of ZnO have a significant effect on the conductivity of ChCl-urea-ZnO system,the conductivity increases with the increase of temperature,increases with the increase of ZnO concentration.When CZnO>0.24 mol·L-1,the conductivity of the solution tends to be constant with the increase of ZnO content,which is mainly due to the larger ion radius of the ions lead to reduced mobility of the system,increased viscosity.Electrochemical tests in the electrochemical window of the ChCl-urea system,show that the initial reduction potentials(EZn(?)/Zn)and the cathode peak potential of zinc are shifted positively with the increase of ZnO concentration and temperature,it is concluded that the reduction process of Zn(?)on the tungsten electrode is a quasi-reversible process controlled by diffusion,and the diffusion coefficient of Zn(?)in solution at 343K can be calculated by the linear relationship between the peak current and the square root of the sweep and potential difference of cathode and cathode.The morphology of zinc deposit is closely related to the concentration of ZnO,with the increase of ZnO concentration,the particle size becomes larger,when the concentration of ZnO is 0.32 mol·L-1,the deposited layer is more smooth and dense.(3)Using ChCl-urea deep eutectic solvent as solvent and nitrilotriacetic acid(NTA)as chelating agent,zinc can be effectively leached from zinc dust,the results show that the leaching temperature and liquid-solid ratio have a significant influence on the leaching rate of zinc.The influence of zinc leaching rate was studied by analyzing the response experiment design,leaching temperature>leaching time>NTA concentration>Iiquid-solid.The use of CC-OA on the leaching of zinc oxide dust and found that by cooling and diluted with water can be anti-dissolving,separate zinc and iron from zinc dust.CC-OA-ZnO and CC-OA-zinc dust solution Dissolution system roasting precipitates,its structure is square and long strip,the microstructure of the layered porous structure,the smallest composition of nano-scale particles. |
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