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以中低品位氧化锌矿为原料、硫酸铵为反应介质,通过低温焙烧得到热料,研究了焙烧温度对Zn提取率的影响。结果表明,培烧温度为450℃时锌的提取率最高,为91.8%。焙烧温度低反应不充分;焙烧温度过高H_2SO_4分解挥发,降低反应率。将熟料溶出过滤得到硫酸锌溶液,经净化除杂得到洁净的硫酸锌溶液。以硫酸锌溶液为原料、碳酸铵为沉淀剂,采用沉淀法制备出碱式碳酸锌前驱体,将其煅烧制备了微细氧化锌粉体。采用XRD、SEM及化学成分分析等手段对前驱体和氧化锌粉体进行了表征。结果表明,溶液中OH~-、HCO_3~-与Zn~(2+)共同作用得到前驱体,前驱体受热脱水、分解得到ZnO粉体。碱式碳酸锌前驱体为Zn_4(CO_3)(OH)_6·H_2O,呈类球形颗粒团聚体,氧化锌粉体为六方铅锌矿结构,颗粒呈球形,分散性良好。
Low and medium grade zinc oxide ore was used as raw material and ammonium sulfate was used as reaction medium. The hot material was obtained by calcination at low temperature. The effect of calcination temperature on the extraction rate of Zn was studied. The results showed that the highest extraction rate of zinc was 91.8% when the temperature was 450 ℃. The roasting temperature is low and the reaction is not sufficient; when the roasting temperature is too high, H 2 SO 4 decomposes and volatilizes, and the reaction rate is reduced. Dissolving the clinker to obtain a zinc sulfate solution, purifying the impurity to obtain a clean zinc sulfate solution. Taking zinc sulfate solution as raw material and ammonium carbonate as precipitating agent, a precursor of basic zinc carbonate was prepared by precipitation method, and then fine zinc oxide powder was prepared by calcining. The precursor and zinc oxide powders were characterized by XRD, SEM and chemical composition analysis. The results show that the precursor of OH ~ -, HCO_3 ~ - and Zn ~ (2+) are obtained by the solution. The precursor is dehydrated and decomposed to obtain ZnO powder. The basic zinc carbonate precursors are Zn_4 (CO_3) (OH) _6 · H_2O, which are aggregates of spherical particles. The zinc oxide powder is hexagonal PbZn structure and the particles are spherical with good dispersibility.