溶剂萃取-铵盐沉钒法从石煤酸浸液中提取五氧化二钒的研究

RESEARCH OF VANADIUM PENTOXIDE FROM AN ACID LEACHING SOLUTION OF STONE COAL USING SOLVENT EXTRACTION AND AMMONIUM PRECIPITATION

采用D2EHPA-TBP-磺化煤油混合体系萃取-硫酸反萃-酸性铵盐沉钒方法从石煤酸浸液中分离、回收五氧化二钒。结果表明:在酸性介质中钒萃取率取决于溶液pH值,当溶液初始pH值≤2.5,钒萃取率高,杂质离子不发生水解沉淀,利于钒的分离、富集。以10%D2EHPA、5%TBP、85%磺化煤油的有机相做萃取剂,在相比为1∶1,溶液初始pH值2.45的条件下,经7级逆流萃取,钒的萃取率为96.7%。以1.5mol/L的硫酸溶液做反萃取剂,在相比(O/A)为5∶1的条件下,负载有机相经3级逆流反萃取,钒的反萃率大于99%,采用酸性铵盐沉钒,在550℃条件下煅烧脱氨后得到的五氧化二钒产品纯度为99.01%。

Research of vanadium pentoxide from an acid leaching solution of stone coal using di（2-ethylhexyl） phosphate（D2EHPA） and tributyl phosphate（TBP） mixed solvent system for extraction,H2SO4 stripping and ammonium salt precipitation has been done.The results demonstrate that the extraction of vanadium determined by the pH value of the liquor phase.Vanadium extraction was high and impurity ions hydrolysis did not occur when solution initial pH lower than 2.5.The pH value is beneficial to vanadium extraction and concentration.Extraction isotherms was obtained using the solvent mixture was consisted of 10% D2EHPA and 5%TBP in sulfonated kerosene at phase ratio of 1 and liquor initial pH of 2.45,with 7 counter-current extraction a total extraction ratio of 96.7% was achieved.The loaded organic phases can be completely stripping by 3 counter-current stripping with 1.5mol/L H2SO4at phase ratio（O/A） of 5∶1.Vanadium in the stripping liquor was precipitation by ammonium salt under acidic condition.After calcination of the ammonium polyvanadate at 550 ℃,V2O5 product with purity of 99.01% was obtained.