铬盐无钙焙烧渣加压硫酸浸出

对铬盐无钙焙烧渣进行加压硫酸浸出，考察了硫酸浓度、反应温度、铬酸酐加入量、反应时间、铬渣粒度对铬渣硫酸浸出效果的影响. 结果表明，焙烧渣主要物相组成为：铬铁矿(FeCr2O4)和镁铁矿Mg(Fe,Al)2O4]等尖晶石类矿物含量为73.11%，赤铁矿(a-氧化铁)为12.42%，钠霞石(NaAlSiO4)为10.02%. 铬高效溶出的最佳工艺条件为：硫酸浓度65%(w)，反应温度120℃，铬酸酐加入量为铬渣质量的10%，反应时间2 h，搅拌转速500 r/min，该条件下溶出率可达97.93%. 尾渣以硅物相为主，SiO2含量为80.8%. 浸出过程符合收缩未反应核模型，反应表观活化能为16.38 kJ/mol，反应速率为外扩散和化学反应混合控制.

Pressure Leaching of Chromium-containing Slag from Non-calcium Roasting with Sulfuric Acid

The pressure leaching process of chromium-contained slag from non-calcium roasting with sulfuric acid was studied. The effects of sulfuric acid concentration, reaction temperature, added amount of chromic anhydride, reaction time and particle size on the leaching of chromium were examined. The results show that the main phase components of the slag determined by systematic analysis and characterization are chromite (FeCr2O4), iron magnesium ore Mg(Fe,Al)2O4], the content of spinel minerals is 73.11%, hematite (a-iron) 12.42%, and sodium nepheline (NaAlSiO4) 10.02%. The optimum leaching conditions of chromium in the slag are obtained as: sulfuric acid concentration 65%, temperature 120℃, added content of chromium anhydride 10% of chromium slag, time 2 h, particle size 75 mm and stirring speed 500 r/min. Under the conditions, the leaching rate reaches 97.93%. The leaching residue is silica-based, with 80.8% SiO2. The pressure leaching of chromium-containing slag from non-calcium roasting with sulfuric acid can be modeled with the shrinking core model. The apparent activation energy is 16.38 kJ/mol. The leaching rate is controlled by external diffusion and interface chemical reaction.