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中南大学学报(自然科学版)

Journal of Central South University

第43卷    第2期    总第210期    2012年2月

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文章编号:1672-7207(2012)02-0418-06
硅锌矿在(NH4)2SO4-NH3-H2O体系中高液固比下的
浸出动力学
刘志宏,曹志阎,刘智勇,李启厚,李玉虎

(中南大学 冶金科学与工程学院,湖南 长沙,410083)

摘 要: 通过实验研究硅锌矿在(NH4)2SO4-NH3-H2O体系中高液固比下的浸出动力学。采用粒径为96~109 μm的纯硅锌矿样品,在液固质量比为200时,考察搅拌速度、反应温度及总氨浓度对锌浸出率的影响。研究结果表明:提高温度和总氨浓度能显著提高浸出速率,而当搅拌速度大于250 r/min时,其对浸出速率的影响较小;浸出过程遵循孔隙扩散控制粒子模型,扩散与化学反应并非仅发生于颗粒外表面,而是发生在整个外表面及孔隙内部,浸出速度受孔隙扩散控制;浸出过程的表观活化能与反应级数分别为71.35 kJ/mol和4.27。

 

关键字: 硅锌矿;(NH4)2SO4-NH3-H2O体系;高液固比;浸出动力学;粒子模型

Leaching kinetics of willemite in (NH4)2SO4-NH3-H2O system at
higher mass ratio of liquid to solid
LIU Zhi-hong, CAO Zhi-yan, LIU Zhi-yong, LI Qi-hou, LI Yu-hu

School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China

Abstract:Leaching kinetics of willemite in (NH4)2SO4-NH3-H2O system were investigated by using pure mineral of willemite as raw materials when mass ratio of liquid to solid was 200. The effects of factors on the leaching rate, such as stirring speed, temperature and total ammonium concentration, were studied experimentally. The results show that increasing temperature and total ammonium concentration can enhance the leaching rate remarkably, while when the speed is larger than 250 r/min, the stirring has no obvious effect on the leach. The leach process obeys the grain model with porous diffusion control, indicating that the diffusion and chemical reaction take place, not only on the outer surface of the particles, but also on the out surface together with the cavities of the porous particles. Kinetic studies demonstrate that the leach process is controlled by the porous diffusion, determining the apparent active energy and reaction order to be 71.35 kJ/mol and 4.27, respectively.

 

Key words: willemite; (NH4)2SO4-NH3-H2O system; high ratio of liquid to solid; leaching kinetics; grain model

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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