硫酸铵低温焙烧中低品位氧化锌矿

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H₂SO₄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^-、HCO₃^-与Zn²⁺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Zn₄（CO₃）（OH）₆·H₂O,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 Grade Zinc Ore by Low Temperature Roasting Using（NH4）2SO4

The roasting clinker was successfully obtained by low temperature roasting employing low grade zinc ore as row material and ammonium sulfate as reaction medium.The influence of baking temperature in Zn extraction rate was investigated.The results show that the Zn extraction rate reaches to the maximum of 91.8%at 450°C.The reaction was not sufficient at low temperature,in the contrary,the reaction rate decreased due to the decomposition and volatilization of H₂SO₄.The ZnSO₄ solution was prepared through digestion and filtration processes,and then the pure ZnSO₄ solution was gained through purification.The basic zinc carbonate precursor was prepared using homogeneous precipitation employing the ZnSO₄ solution as raw materials and the ammonium carbamate as precipitant,and the ultrafine ZnO powder was obtained by calcining the ZnO precursor.XRD,SEM and chemical components analysis were adopted to characterize the as-prepared precursor and the ZnO powder.The results show that the precursor was obtained since the OH^-and HCO₃^-hydrolyzed from ammonia carbamate reacted with Zn²⁺ in solution,which was calcinated to prepare the ZnO powder through the dehydration and decomposition. The precursor is basic zinc carbonate of Zn₄（CO₃）（OH）₆H₂O with adhesive spheric particles,and the ZnO powder is of hexagonal wurtzite structure with uniform spheric size and good dispersity.