摘要:
针对湖北某难处理石煤钒矿的矿石性质及岩相分析结果,采用短流程提钒工艺即沸腾焙烧—助浸剂酸浸—萃取—沉钒工艺进行提钒试验研究。重点考察了焙烧温度、焙烧时间、添加剂用量、硫酸浓度、液固比、浸出温度及浸出时间对钒浸出率的影响。结果表明,在焙烧温度750℃下焙烧20 min,该焙烧料在助浸剂用量5%、硫酸浓度15%、液固比2∶1、浸出温度95℃、浸出时间6 h的条件下,浸出率可达91.32%。采用N235为萃取剂,经3级正萃3级反萃,98%以上钒能从浸出液中分离出来并富集。富钒液经除杂后沉淀出偏钒酸铵,偏钒酸铵热解后可获得纯度99.75%的五氧化二钒产品。该工艺具有提钒流程短、提钒效率高及产品纯度高的优点,对难处理型石煤原矿适应性好。
关键词:
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石煤提钒 /
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沸腾焙烧 /
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助浸剂 /
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萃取
Abstract:
Based on the properties and petrographic analysis of a refractory stone coal from Hubei province,a novel vanadium extraction process of fluidized roasting-acid leaching with additive-solvent extraction-precipitation was proposed.The effects of roasting temperature,roasting time,dosage of additives,sulfuric acid concentration,liquid to solid ratio,leaching temperature and time on leaching ratio of vanadium were given a special concern.Results show that under the optimum conditions of roasting at 750 ℃ for 20 min,leaching additive dosage of 5%,sulfuric acid concentration of 15%,liquid to solid ratio of 2 ∶ 1 and leaching at 95 ℃ for 6 h,vanadium leaching efficiency can reach 91.32%.Using N235 as extractant,more than 98% of vanadium can be separated and concentrated from the leaching solution by three stages of counter-current extraction and three stages of counter-current stripping. Ammonium metavanadate can be precipitated from the vanadium concentrated solution after impurities removal,and then vanadium pentoxide with purity of 99.75% could be obtained after thermal decomposition of metavanadate. This vanadium extraction process has advantages of short procedure,high efficiency and high purity of product,showing well adaptability to refractory stone coal.
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