硅锌矿在(NH_4)_2SO_4-NH_3-H_2O体系中的浸出机理  

Leaching mechanism of willemite in (NH_4)_2SO_4-NH_3-H_2O system

作　　者：刘智勇[1] 刘志宏[1] 曹志阎[1] 李启厚[1] 杨天足[1] 

机构地区：[1]中南大学冶金科学与工程学院,长沙410083

出　　处：《中国有色金属学报》2011年第11期2929-2935,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家重点基础研究发展计划资助项目(2007CB613604)

摘　　要：对硅锌矿在(NH4)2SO4-NH3-H2O体系中的浸出行为进行了系统研究,揭示浸出反应机理,阐明其难以浸出的内在原因。结果表明:硅锌矿浸出反应方程为Zn2SiO4(s)+(2i-4)NH3(aq)+4NH4+=2[Zn(NH3)i]2++SiO2(s)+2H2O(l),i=1～4。浸出中,硅锌矿中的硅溶解进入溶液,再以无定形SiO2形态从溶液中析出。SiO2在(NH4)2SO4-NH3-H2O体系中的溶解度很低,仅略高于0.3 g/L,而其从溶液中的析出速度非常缓慢,是硅锌矿在该体系中难以浸出的主要原因。当液固质量比从5提高至500时,锌浸出率将从2.72%提高至84.15%。The leaching behavior of willemite in（NH4）2SO4-NH3-H2O system was investigated in details,in order to reveal the leaching mechanism and the reasons of willemite difficult to leach.The results show that the reaction formula of the leaching is as follows： Zn2SiO4（s）＋（2i-4）NH3（aq）＋4NH4＋=2[Zn（NH3）i]2＋＋SiO2（s）＋2H2O（l）,i=1-4.During the leaching process,zinc and silica in willemite dissolve simultaneously into the solution,and then silica precipitates from the solution in the form of amorphous SiO2.The solubility of silica in（NH4）2SO4-NH3-H2O system was measured to be very low,only higher than 0.3 g/L,additionally,the precipitation rate of dissolved silica from the leaching solution is extremely slow,resulting in willemite difficult to leach in（NH4）2SO4-NH3-H2O system,especially under the condition of lower mass ratio of liquid to solid.Increasing the initial mass ratio of liquid to solid in the leaching slurry from 5 to 500 results in a sharp raise of zinc leaching efficiency from 2.72% to 84.15%.

关 键 词：硅锌矿 (NH4)2SO4-NH3-H2O体系 浸出 机理 

分 类 号：TF803.21[冶金工程—有色金属冶金] TF813