The Research Of The Preparation Of Sphalerite Structure ZNS And To Transform The Wurtzite

ZnS is widely used as Phosphor, analytical reagent, photoconductors materials, dyes, pigments, coatings, curing-oil, glass manufacturing, etc. Compared with the sphalerite structure ZnS, wurtzite structure ZnS has a wider band gap administered with better optical performance, and has a great market prospect. In order to make full use of zinc resources and sulfur resources from the production of precipitated barium sulfate of an enterprise in Guangxi, to comparative the method of liquid-phase preparing ZnS, to choose the best source of Zinc and Sulfur. First, explore a synthetic process of reducing pollution and recycled, and research the best technology of preparation of the sphalerite structure ZnS. Then heating under the condition of Cutting off the air, the sphalerite transforms the wurtzite, to explore a better process conditions of the sphalerite structure ZnS phase-change. Finally the by-product ammonium acetate prepares zinc acetate, resource recovery and recycling, to explore its best technology. The result is as follows:(1) Therefore, needing to select the best source of zinc (zinc acetate, zinc sulfate) and sulfur source (ammonium sulphide, hydrogen sulfide, sodium sulfide). Ammonium sulfide as the source of sulfur, zinc acetate as source, to prepare zinc sulfide, Under the 120 ℃ vacuum drying, ammonium acetate that the main impurities zinc sulfide package decompose. The purity of zinc sulfide by this technique of preparing is sulfidehighest,97.23%.(2) Ammonium sulfide solution and zinc acetate solution as raw material prepare the sphalerite zinc sulfide (β-ZnS). A better process for Preparation of β-ZnS:zinc and sulphur molar ratio and concentration ratio is 1:1, the reaction concentration for 0.3 mol/L, the drying temperature for 120 ℃, the drying time for 6 t, the stirring speed is 400 r/min, the reaction time for 10 min, reaction temperature for 50 ℃. The purity of the β-ZnS is maximum, more than 97%.(3) In the process of the sphalerite transforms the wurtzite in the heat, the crystal temperature and reaction time were the most important factor. When the crystal temperature below 1000 ℃, the sphalerite can not transforms the wurtzite; When the crystal temperature at 1000 ℃ to 1150 ℃ range increases, the content of α-ZnS increases; When the crystal temperature above 1150 ℃, the sphalerite can transforms the wurtzite completely. When the crystal temperature is 1150℃ and the reaction time above 60 min, the content of a-ZnS to 100%.(4) when the time of phase transformation for constant, the higher the phase transition temperature, the higher the content of α-ZnS, The greater the particles of the mixed crystal type ZnS. Therefore, By changing the phase transformation temperature to control the content α-ZnS and the size of the mixed crystal ZnS.(5) In the experiments of ammonium acetate waste liquid and zinc oxide to prepare zinc acetate, The influence of various factors on the reaction were bigger. The better process:the concentration of NH4Ac is 1.3 mol/L, the reaction temperature at 70 ℃, the reaction time for 80 min and liquid-solid ratio is 4 mL/g, the stirring speed is 500 r/min. The concentration of Zn(Ac)2is higher than 0.5529 mol/L, can be used as zinc source return system.