Bayer vanadium sludge (BVS), discharged during the Bayer alumina production, is a promising secondary resource for the supply of vanadium. Previous vanadium extraction process involving Pb5(VO4)3OH precipitation by PbSO4, H2SO4 and (NH4)2SO3 leaching, (NH4)2S2O8 oxidation followed by ammonium vanadate precipitation, suffered from large amounts of reagent consumption and discharge of ammonia-containing waste. In this study, a cleaner and cost-efficient process based on H2SO4 pre-treatment, H2O2 leaching, hydrolytic precipitation, and preparation of V2O5 through oxidative roasting was proposed to reduce reagent consumption and waste. Results show that the maximum vanadium leaching efficiency reached 99.7 % under the most suitable conditions of H2SO4 pre-treatment with H2SO4/Pb5(VO4)3OH molar ratio of 6.5, pulp density of 250 g/L at 90 °C for 4 h followed by H2O2 leaching with H2O2/V molar ratio of 3.0 at 15 °C for 10 min. Furthermore, 96.5 % of vanadium was precipitated in the forms of V5O12∙6H2O and V10O24∙12H2O by heating the leach liquors to 100 °C for 60 min, followed by the oxidative roasting at 400 °C for 2 h to prepare V2O5 product with a purity of 99.2 %, with only H2O as a by-product. This research provides new insights into vanadium extraction in a cleaner, cost-efficient, and sustainable industrial process which saves 147.4 $/t Pb5(VO4)3OH.

中文翻译：

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采用拜耳钒污泥中回收的 Pb5(VO4)3OH，经 H2SO4 预处理、H2O2 浸出、V5O12∙6H2O 和 V10O24∙12H2O 沉淀以及 400 ℃氧化焙烧制备 V2O5


拜耳氧化铝生产过程中排出的拜耳钒污泥（BVS）是一种很有前景的钒供应二次资源。以往提钒工艺采用PbSO4、H2SO4、(NH4)2SO3浸出沉淀Pb5(VO4)3OH，(NH4)2S2O8氧化，然后沉淀钒酸铵，存在大量试剂消耗和含氨废水排放的问题。本研究提出了一种基于 H2SO4 预处理、H2O2 浸出、水解沉淀和通过氧化焙烧制备 V2O5 的清洁且经济高效的工艺，以减少试剂消耗和浪费。结果表明，在H2SO4/Pb5(VO4)3OH摩尔比为6.5、矿浆密度为250 g/L、90 ℃、4 h的H2SO4预处理最适宜条件下，钒的最大浸出率可达99.7%。 H2O2 浸出，H2O2/V 摩尔比为 3.0，15 °C，浸出 10 分钟。此外，通过将浸出液加热至100°C 60分钟，然后在400°C氧化焙烧2小时，以V5O12·6H2O和V10O24·12H2O的形式沉淀出96.5%的钒，以制备V2O5产品纯度为 99.2%，仅副产物 H2O。这项研究为更清洁、经济高效且可持续的工业流程中提钒提供了新见解，可节省 147.4 美元/吨 Pb5(VO4)3OH。