Technology Research, Use Of Zinc Dust Preparation Of Ultrafine Zinc Oxide

Preparation of activated zinc oxide and complexional ultra-fine zinc oxide from zinc dust has been investigated in this subject. The process of leaching of zinc dust by sulfuric acid and ammonia to prepare activated zinc oxide and complexional ultra-fine zinc oxide has been adopted in this paper. The whole flow of preparation of activated zinc oxide and complexional ultra-fine zinc oxide from zinc dust and pilot test has been completed systemically. Testing showed that this subject was feasible. Some main results of testing research were as fellows:The leaching of zinc dust by sulfuric acid was studied, and the effects on the leaching percent of the zinc and iron were analyzed; the method of iron-removal using the goethite process and oxidation-hydrolysis process, the oxidizing method of iron-removal using ammonium persulphate and the purification by adding zinc power was adopted. The optimal processing conditions of leaching as fellows: the concentration of sulfuric acid of 1.0 mol/L, liquid-to-solid ration is 7:1, leaching temperature is 60℃, leaching time is 2.5h. Under this condition, the leaching percent is 97%.The result gets high-purity zinc sulfuric solution by purifying.The thermodynamic analysis of carbonation process has been carried out, the result shows: Precursor was Zn5(CO3)2(OH)6, It could got ultra-fine Zinc Oxide which was spherical structure and the average size of particles was about 0.4μm under conditions of calcination temperature 350℃and calcination time 3.0hThe new process of leaching of zinc dust by ammonia to prepare high-purity solution ware studied. The results show that under the leaching conditions of the sum concentration of ammonia 9.0 mol/L,reaction temperature 40℃,the pH value 11.0-11.5,mixing speed 400 r/min and liquid-to-solid ratio 4,the leaching percent of zinc is 83.3%; lixivium was purified with two-stage and impurities were removed; The result gets high-purity solution by purifying.The thermal decomposition process of zinc hydroxide carbonate(Zn3CO3(OH)4·H2O) that absorbed NH4+ was studied by TG,DTA,DTG.The mechanism model was deduced and was inferred as one-dimension diffusion model.Preparation of complexional ultra-fine Zinc Oxide under conditions of calcination temperature 350℃and calcination time 1.5h from Zn3CO3(OH)4·H2O.The result show particle size was about 200nm,Uniform particle size, good dispersibility and spherical structure,hexagonal appearance.The precursor and calcined samples were characterized by TG-DTA-DTG, FT-IR, XRD,SEM and ultraviolet-visible pectrophotometer, and it discussed colored mechanism of complexional Zinc Oxide. The results as follows: The chief constituent of precursor by Controlled-release Precipitation was (Zn3CO3(OH)4·H2O) that absorbed NH4+. when preparation of complexional Zinc Oxide under calcinations, the Nitrogen atom or N-H turn into Zinc Oxide crystal lattice that causes the movement of micromechanism lead to the movement of behaviour. N-doped Zinc Oxide was red. It contains fine UV shielding and wide Absorption wavelength range.The results show that Preparation of complexional Zinc Oxide from zinc dust was technical feasibility. the research of this experiment was of importance in research value of application,to achieve a solid waste recycling.