钒渣加Mg(OH)2焙烧提铬的研究

Study on chromium extraction from vanadium slag and Mg(OH)2 roasting

摘要:

从环保角度考虑，目前国家对传统钒渣提钒工艺提出改进建议，新工艺要求对钒渣中钒和铬充分提取，使得浸出渣中铬含量尽可能低．经热力学的计算发现，相同的条件下铬比钒更难提取，而且添加Mg(OH)2的提铬效果要比添加MgO的更好．因此，采用将钒渣粉与碱性Mg(OH)2粉末的混合样进行高温氧化焙烧，焙烧后再用硫酸酸浸的方法提取钒渣中铬．同时，研究了Mg(OH)2含量、焙烧温度、焙烧时间及酸浸pH值对铬提取的影响．实验结果表明：铬的提取率随着碱渣比、焙烧温度、焙烧时间的增加而增加，随酸浸pH值的降低而增大；在焙烧温度为1000 ℃、碱渣比为1.0、焙烧时间为2 h、酸浸pH=0.1的条件下，铬的提取率为63%．

Abstract:

From the perspective of environmental protection, the state puts forward suggestions for improving to the traditional vanadium slag extraction process. The new process requires full extraction of vanadium and chromium from the vanadium slag, so that the chromium content in the leaching residue is as low as possible. According to thermodynamic calculation, it is found that chromium is more difficult to extract than vanadium under the same conditions, and the effect of adding Mg (OH)2 to extract chromium is better than that of adding MgO. Therefore, we studied the high-temperature oxidation roasting of vanadium slag powder and alkaline Mg (OH) 2 powder, and then extracting chromium from vanadium slag by sulfuric acid leaching. At the same time, the effects of Mg (OH)2 content, roasting temperature, roasting time and pH value of acid leaching on the extraction of chromium were studied. The extraction rate of chromium increases with the increase of alkali-slag ratio, the increase of roasting temperature, the increase of roasting time and the increases with the decrease of acid leaching pH. The results shows that the best extraction rate of chromium is 63% when the roasting temperature is 1000℃, the ratio of alkali to slag is 1.0, the roasting time is 2 h, and the acid leaching pH is 0.1.