【摘要】 针对传统三氧化二钒制备工艺中工艺流程较长、产生大量氨氮废水、制备产品纯度低等问题，以钒页岩酸浸液为原料，采用氯化精馏—无氨沉钒工艺制备三氧化二钒，考察了反应温度、反应时间和氯化铝添加量对氯化反应的影响，以及沉钒温度、沉钒时间和三聚氰胺添加量对沉钒过程的影响。结果表明：在反应温度170℃、反应时间2.0 h、钒与氯化铝的摩尔比为1∶4的条件下，钒提取率达到74.2%；在沉钒温度90℃、沉钒时间40 min、三聚氰胺与钒的摩尔比为0.6的条件下，沉钒率达到99.2%，最终制备的三氧化二钒产品纯度达到99.93%，且沉钒废水中不含NH₄⁺，简化了后续的废水处理工序。该工艺流程简单，钒杂分离效果好，制备产品纯度高，避免了氨氮废水生成。更多还原

【Abstract】 This research presents an innovative and environmentally sustainable approach for producing high-purity vanadium trioxide（V₂O₃） from vanadium-bearing shale acid leachate through an integrated chlorination distillation and ammonia-free precipitation process, effectively addressing the critical limitations of conventional methods including multi-step operations, substantial ammonia-nitrogen wastewater generation, and compromised product quality. This study establishes a comprehensive technical framework, beginning with detailed characterization of the acidic leachate from vanadium shale containing vanadium and significant impurities, including magnesium, iron, and aluminum. The process initiates with oxidative pretreatment using sodium chlorate under carefully controlled conditions（30 ℃ for 10 min with oxidant dosage at 0.4 times the V₂O₅ mass）, followed by precise pH adjustment to 5.5 using sodium carbonate solution to induce selective precipitation, resulting in a purified hydrolyzed intermediate product suitable for subsequent processing. The core innovation encompasses the development and optimization of a chlorination distillation process employing an AlCl₃-NaCl molten salt system with 4∶1 mass ratio, where systematic investigation revealed the crucial relationship between reaction parameters and extraction efficiency. Through meticulous single-factor experimentation, the study demonstrates that temperature elevation from 130 ℃ to 170 ℃ dramatically improved molten salt fluidity and mass transfer characteristics, thereby enhancing vanadium extraction rates from merely 11.3% to 72.8%. The optimized chlorination conditions established at 170 ℃ reaction temperature, two hours duration, and V-AlCl₃ molar ratio of 1∶4 achieve a vanadium extraction rate of 74.2%, representing improvement over conventional approaches. The research introduces advancement through the application of melamine as an environmentally benign precipitant, completely eliminating ammonia usage in the precipitation stage while maintaining exceptional efficiency. The optimization of precipitation parameters demonstrates that temperature significantly influences precipitation kinetics, with rates increasing from 39.5% at 10 ℃ to 98.9% at 90 ℃ due to enhanced ion diffusion and exposure of active sites on melamine molecules. The investigation establishes optimal precipitation conditions at 90 ℃ temperature, 40 min duration, and melamine-tovanadium molar ratio of 0.6, achieving an exceptional precipitation rate of 99.2%. Mechanistic studies employing advanced characterization techniques including FTIR and XPS analyses provide compelling evidence for the precipitation mechanism, confirming that VO₂⁺ ions coordinate specifically with amino groups and nitrogen atoms within melamine’s triazine ring through formation of stable N— V coordination bonds. The subsequent thermal treatment at 500 ℃ under nitrogen atmosphere utilizes melamine’s decomposition characteristics to generate insitu reducing gases that facilitated precise conversion to trivalent vanadium oxide, yielding a final V₂O₃ product with exceptional purity of 99.93% that substantially exceeds the requirements of Chinese National Standard GB/T 40301— 2021 for V₂O₃66 grade. Comprehensive materials characterization confirms the phase purity, homogeneous morphology, and optimal elemental composition of the final product. A particularly significant environmental advantage of this innovative process is the dramatic reduction in ammonium ion concentration, with precipitation wastewater containing merely 0.002 g/L NH₄⁺, effectively eliminating ammonia-nitrogen pollution concerns while substantially simplifying effluent management requirements. This integrated process demonstrates remarkable vanadium-impurity separation efficiency, shortened processing flow, and elimination of problematic waste streams, representing a substantial advancement in sustainable metallurgical processing of complex mineral resources. The research provides a technically robust and environmentally responsible pathway for producing high-purity vanadium trioxide, offering significant potential for advanced applications in energy storage systems including vanadium redox flow batteries and high-performance materials, thereby contributing to the green and sustainable development of vanadium resource utilization technologies while addressing critical environmental challenges associated with conventional vanadium extraction processes.更多还原