Study On The Recovery Of Valuable Metals From Two Kinds Of Zinc Secondary Resource

With the mineral resources being gradually exhausted, it is very important for resource sustainable development to recover metals from different kinds of metallic secondary resources actively. The aim of this paper is that the valuable metals in spent zinc containing catalyst and zinc electrolytic anode sludge have been comprehensively recovered and utilized:high-purity ZnO nanoparticles and NiO strips have been recovered from the spent Ni/ZnO catalyst by "leaching-precipitatation-thermal decomposition" process. Industry grade ZnSO4and electronic grade high-purity MnSO4have been recovered from zinc electrolytic anode sludge by "leaching-purification-concentrate crystallization" process.The spent Ni/ZnO catalyst has been leaching by15wt%HCl, and under the optimal leaching conditions, the extractions of zinc, nickel and iron achieved98.3%,95.1%and72.2%, respectively and the leach solution contained127.87g/L zinc,3.23g/L nickel and0.77g/L iron. Taguchi method with two L9(34) orthogonal arrays was successfully used to evaluate the zinc cementation method and the dimethylglyoxime (DMG) precipitation method for nickel removal from the iron removal leaching solution. Among these experiments, compared with zinc cementation, the attention has been attracted to the DMG precipitation method since it can achieve lower Ni residual concentration (0.6mg/L), be controlled more easily and recover nickel more easily from the precipitation. The nickel and zinc have been recovered as NiO strips and ZnO nanoparticles, respectively, and then the valuable metals in the spent Ni/ZnO catalyst have been comprehensively recovered and utilized.According to the characteristics of zinc electrolytic anode sludge, the zinc in the anode sludge has been recovered as ZnSO4by a "water leaching-iron and manganese removal by oxidation-concentrate crystallization" process and the ZnSO4product obtained in the process can meet the standard of industrial grade ZnSO4. MnSO4leaching solution has been gotten according to leaching the leaching sludge obtained in the water leaching process by H2SO4and FeSO4, and then the iron in the leaching solution has been purified by adding H2O2. A solvent extraction process to separate and concentrate the manganese from synthetic a MnSO4solution which contained Mn2+(60g/L), Ca2+(700mg/L), Mg2+(500mg/L), K+(500mg/L) and Na+(500mg/L) has been studied systematically. The results indicate that99.75%manganese can be selectively extract by4-stage countercurrent extraction with30%Caynex272at O/A of2/1, and the average Mn concentration in the load organic phase is29.95g/L; The Mn in the load organic phase has been stripped with2.5M H2SO4by2-stage countercurrent stripping process at O/A of4/1and the stripping efficiency of Mn reached99.94%; the stripping solution contained119.73g/L Mn and the concentrations of Ca2+, Mg2+, K+and Na+were all less than15mg/L.The lean organic phase can be returned to the extraction process, and high-purity MnSO4has been produced from the stripping solution by crystallization and concentration, and the MnSO4product meet the standard of material which could be used for producing high-quality battery.