直接酸浸与焙烧酸浸钒萃取行为的研究

对某石煤矿采用直接酸浸和焙烧酸浸处理,并考察不同浸出过程中氟化物加入的影响。结果表明,该石煤适宜采用含氟化物作用的直接酸浸-萃取工艺,钒浸出率可达92.39%,预处理钒损失率为1.12%,每吨V2O5的CaO耗量为6.38t,钒萃取过程正常且三级萃取率达到98.05%。不同浸出工艺及是否加入氟化物对钒萃取过程有较大的影响:无氟化物加入的直接酸浸使石煤原矿中的有机物引入酸浸液,形成界面膜而导致乳化现象产生;空白焙烧可消除有机物的影响,但由于酸浸溶液中的杂质元素含量显著增加而可能导致乳化现象;氟在溶液中以AlF5]2-和SiF6]2-形式存在,可阻止含硅胶体和细微颗粒以及界面膜的生成,有利于萃取正常进行,但当溶液中杂质元素含量过高时,仍可能产生乳化。

Solvent Extraction Behavior of Vanadium from Direct Acidic Leaching and Roasting Acidic Leaching

Stone coal was direct acidic leached and roasting acidic leached respectively. The effects of introducing fluoride into leaching systems on vanadium extraction were investigated. The results show that it is reasonable to adopt direct leaching with fluoride and solvent extraction. The leaching rate of vanadium is 92.39%, pre-treatment loss efficiency of vanadium is 1.12%, CaO consumption is 6.38 t per ton V2O5, and a three-stage counter-current solvent extracting efficiency of vanadium is 98.05% with stable procedures. Furthermore, the choice between the two processes and introduction of fluoride into leaching system had significant effects on solvent extraction of vanadium. Direct acidic leaching may introduce organics from stone coal into aqueous solution. The organics form interfacial membrane during solvent extraction, which is an important factor to produce emulsification. Blank-roasting can remove influence of organics, but increase contents of various elements other than vanadium, which may also contribute to emulsification. Existing in the form of AlF5]2- and SiF6]2-, fluorine can facilitate solvent extraction by hindering production of silicon-bearing colloids, fine particles and interfacial membrane. However, emulsification may occur again with content of various elements other than vanadium reaching to a maximum value.