石煤灰渣酸浸提钒工艺中钒的浸出动力学

采用液-固多相反应的缩芯模型研究了石煤灰渣中V2O5的浸出动力学，考察了酸浸温度、硫酸浓度对V2O5浸出反应速率的影响. 结果表明，在实验温度范围内，V2O5的浸出过程为固膜扩散控制，浸出反应的表观活化能为29.96 kJ/mol. 当硫酸浓度小于6 mol/L时，浸出属化学反应控制过程；当硫酸浓度大于6 mol/L时，浸出过程为固膜扩散控制，其表观反应级数为1.199. 提高酸浸温度可提高V2O5的浸出率；在硫酸浓度小于6 mol/L时提高硫酸浓度，可提高V2O5的浸出率；而高于该值提高硫酸浓度对V2O5浸出率的提高无明显作用.

Leaching Kinetics of Vanadium Pentoxide from Ash of Stone Coal by Sulfuric Acid

The leaching kinetics of vanadium pentoxide from ash of stone coal by sulfuric acid was approached using the shrinking unreacted core model for the reaction between liquid and solid. The influences of temperature and sulfuric acid concentration on the reaction rate of vanadium pentoxide were investigated. The results show that the diffusion through the solid film was the rate limiting step in the leaching process of vanadium pentoxide within the selected temperature range from 30 to 115 ℃, and the apparent activation energy was calculated to be 29.96 kJ/mol. In the selected sulfuric acid concentration range from 3.0 to 6.0 mol/L, the rate limiting step changed from chemical reaction to diffusion through solid film when sulfuric acid concentration was over 6 mol/L. The apparent reaction progression was 1.199. The leaching rate was increased by enhancing the temperature. When sulfuric acid concentration was less then 6 mol/L, the leaching rate was remarkably increased by enhancing the sulfuric acid concentration. But the leaching rate was little affected as the sulfuric acid concentration was over 6 mol/L.