A mechanism of calcium fluoride-enhanced vanadium leaching from stone coal
A mechanism of calcium fluoride-enhanced vanadium leaching from stone coal
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DOI：
10.1016/j.minpro.2015.06.013
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发表时间：
2015-12-10
影响因子：
--
通讯作者：
Liu, Juan
中科院分区：
文献类型：
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作者：
Wang, Fei;Zhang, Yimin;Liu, Juan
结果表明，氟化钙能显著提高石煤中钒的浸出效率，加快浸出速度。采用电感耦合等离子体原子发射光谱、钒的价态、X射线衍射仪、X射线光电子能谱、F-19液体核磁共振、扫描电子显微镜和热力学等分析方法，对氟化钙强化石煤中钒的浸出机理进行了研究。氟化钙强化浸出钒的整个过程是氟化钙与硫酸反应生成Hf(AQ)，方解石溶解在酸中，绿泥石和金云母被彻底分解，生成石英、M+、Mg2+、[SiF6](2-)、[AlF5](2-)和Al3+，释放出来的V(III)被空气中的O-2氧化成VO2+。氟与含钒金云母晶格中的铝、硅结合生成[SiF6](2-)和[AlF5](2-)的过程有利于石煤中钒的浸出。该过程降低了金云母的Delta G级分解，降低了化学反应对钒浸出的影响，加快了钒的浸出速度，提高了钒的浸出效率。(C)2015爱思唯尔B.V.保留所有权利。
A comparison between unassisted and calcium fluoride-enhanced leaching demonstrated that calcium fluoride can markedly boost the efficiency and accelerate the rate of vanadium leaching from stone coal. Analysis methods were adopted to identify the mechanism of calcium fluoride-enhanced vanadium leaching from stone coal, including Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), valence state of vanadium, X-ray Diffractometry (XRD), X-ray Photoelectron Spectroscopy (XPS), F-19 liquid Nuclear Magnetic Resonance (NMR), Scanning Electron Microscope (SEM) and thermodynamics. The whole calcium fluoride-enhanced vanadium leaching process was that calcium fluoride reacted with sulfuric acid and then generated HF(aq); calcite was dissolved into the acid; chlorite and phlogopite were thoroughly disintegrated and subsequently generated quartz, M+, Mg2+, [SiF6](2-), [AlF5](2-) and Al3+; the released V(III) was oxidized to VO2+ by O-2 from the air. It is the procedure that fluorine combined with aluminum and silicon in the lattice of vanadium-bearing phlogopite to generate [SiF6](2-) and [AlF5](2-) that facilitated the vanadiumleaching from stone coal. This generation decreased the Delta G degrees of phlogopite disintegration, declined the effect of chemical reaction on vanadium leaching, accelerated the leaching rate of vanadium and boosted the leaching efficiency of vanadium. (C) 2015 Elsevier B.V. All rights reserved.