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酸性氯化物体系钒、铬、铁萃取分离基础研究
张国之
学位类型博士
导师齐涛
2017-07
学位授予单位中国科学院研究生院
学位授予地点北京
学位专业化学工艺
关键词酸性氯化物溶液 分离
摘要

攀西红格地区大宗特色高铬型钒钛磁铁矿为铁、钒、钛、铬等典型多金属共伴生矿产资源,开发利用意义重大。现有的工艺难以实现我国高铬型钒钛磁铁矿高效、清洁和综合利用,存在有价金属(钒、铬和钛)的回收率低、能耗高和环境污染等问题。本研究团队提出一条处理高铬型钒钛磁铁矿精矿的新工艺,包括选择性还原高铬型钒钛磁铁矿精矿,磁选分离后得到铁精粉和含钒铬钛渣,含钒铬钛渣用盐酸浸出得到含钒、铬等的酸浸液,钛在固相中成为富钛渣,从而有可能提高该矿产资源中铁、钒、铬和钛的综合利用率。该新工艺中的盐酸浸出液为含钒和铬等的酸性氯化物溶液,其特点是酸度高、杂质多和铁浓度高,从该氯化物溶液中选择性分离与回收钒、铬和铁是该新工艺的关键工序之一,目前针对酸性氯化物溶液中钒、铬、铁与钙、镁、铝、锰、钛、硅的分离工艺研究尚未见报道。本论文系统研究了从酸浸液中进行有价元素钒、铬、铁与杂质的选择性分离,为酸性氯化物体系中钒、铁、铬资源的高效分离利用提供了一条新的途径,取得的主要研究成果如下:1)酸性氯化物溶液中优先提取钒、铬的研究。研究结果表明采用优化的D2EHPA作萃取剂时,经过两级萃取钒的萃取率虽达 97.1%,但铁的萃取率为9.8%,铬的萃取率为7.9%,分离效果尚不够理想。同时,对萃取钒后的萃余液进行铁与铬分离研究发现,萃取法(研究了不同种类的萃取剂、不同的萃取条件、不同的还原剂、添加掩蔽剂)、水解法和磷酸盐沉淀法均未能达到铬的选择性提取实现铁、铬分离的目的。2)酸性氯化物溶液中优先萃取铁的研究。通过上述研究证实在大量铁存在的情况下,钒和铬的回收困难,所以需要先进行铁的分离以便后续钒、铬的回收。为了强化萃取过程,开发了一种新型协同萃取铁体系TBP-MIBK,该体系具有萃取动力学快速、分离效果好、铁反萃容易等优点。首先对该协萃体系萃取行为进行研究,在优化的萃取条件下,铁的一级萃取率达86.7%,钒和铬几乎不被萃取;其次对该协萃体系反萃行为进行研究,在优化的反萃条件下,铁的一级反萃率达91.6%;最后用热力学计算软件和光谱表征对TBP-MIBK协同萃取剂萃取高酸性体系中铁的机理进行研究,MIBK的增溶作用使TBP-MIBK混合萃取剂的萃取能力比单一萃取剂大幅度提高。3)酸性氯化物溶液中选择性萃取钒的研究。针对萃取铁后的萃余液中钒的有效萃取分离,为了强化萃取过程,开发了一种新型协同萃取钒体系Aliquat 336-TBP,该体系具有萃取动力学快速、分离效果好、钒反萃容易等优点。首先对该协萃体系萃取行为进行研究,在优化的萃取条件下,钒的三级萃取率达90.2%,铬几乎不被萃取;其次对该协萃体系反萃行为进行研究,在优化的反萃条件下,钒的一级反萃率达92.4%;最后用热力学计算软件和光谱表征对Aliquat 336-TBP协同萃取剂萃取高酸性体系中钒的机理进行研究,Aliquat 336的增溶作用使Aliquat 336-TBP混合萃取剂的萃取能力比单一萃取剂大幅度提高。4)酸性氯化物溶液中高效萃取铬的研究。针对铁的萃取去除和钒的回收后的萃余液中铬的高效萃取,为了强化萃取过程,开发了一种新型协同萃取铬体系D2EHPA-异辛醇,该体系具有萃取铬能力强、萃取动力学快速、萃取分相良好、铬反萃容易等优点。首先对该协萃体系萃取行为进行研究,研究了不同的工艺参数对铬的萃取的影响,确定了优化的萃取条件;其次对该协萃体系反萃行为进行研究,研究了不同的工艺参数对铬的反萃的影响,确定了优化的反萃条件;最后用热力学计算软件和光谱表征对D2EHPA-异辛醇协同萃取剂萃取酸性氯化物体系中铬的机理进行研究,由于异辛醇使D2EHPA的二聚分子环打开,为萃取反应提供了更多的萃取位,所以使D2EHPA-异辛醇混合萃取剂的萃取能力比单一萃取剂大幅度提高。5)酸性氯化物溶液中选择性提取铬的研究。经过铁的萃取去除和钒的回收,实际高铬型钒钛磁铁矿的酸浸液中还含有钙、镁、铝、锰、钛、硅等杂质。D2EHPA-异辛醇协同萃取体系虽然可以实现铬的高效萃取,但是不能实现铬的选择性分离。为了实现酸性氯化物体系中铬与杂质的分离,采用添加可以与三价铬络合的硝酸根离子,使三价铬的离子形态与杂质的离子形态不同,用Cyanex 923作萃取剂达到铬选择性分离的目的。首先对Cyanex 923的萃取行为进行研究,研究了不同的工艺参数对铬萃取的影响,确定了优化的萃取条件;其次对Cyanex 923的反萃行为进行研究,研究了不同的反萃剂对铬反萃的影响,确定了优化的反萃条件。结果表明钙、镁、铝、钛、锰、硅杂质元素均不影响铬的萃取,同时可以实现铬的高效反萃。

其他摘要

High-chromium vanadium-bearing titanomagnetite in Hongge District is a giant iron-polymetallic deposit containing vanadium, titanium, chromium and other valuable elements. For processing high-chromium vanadium-bearing titanomagnetite, the existing technologies are unsuitable due to their low recoveries of valuable metals, high energy consumption, and serious environmental pollution. Therefore, a new process for comprehensive exploitation of high-chromium vanadium-bearing titanomagnetite concentrates has been developed by our research group. The new process involves several steps: partial reduction of the concentrates, magnetic separation, hydrochloric acid leaching of the titanium-bearing tailing. The obtained leach solution from the new process is the high-acidity chloride solution containing high concentrations of many impurities. The separation of V, Cr, and Fe as the valuable metals from the chloride solution which contains many impurities such as Ca, Mg, Al, Mn, Ti and Si has not been reported. In this thesis V, Cr, and Fe in the chloride solution selectively separated from impurities was systematically investigated. A novel process for the effective recovery of iron, vanadium and chromium from the chloride solution was developed. The research reults are listed as follows:1) The selective separation of vanadium and chromium has been studied. D2EHPA was selected as the extractant for the vanadium separation from iron and chromium. The effects of various parameters on vanadium separation were investigated. Under the optimal extraction conditions, the extraction of vanadium, iron, and chromium under two stages was 97.1%, 9.8% and 7.9%, respectively. Vanadium could be partially separated from iron and chromium. As the concentration of iron is higher than that of chromium, the separation of chromium from iron has been investigated. The solvent extraction method was investigated and the effects of extractant, pH, concentration of iron, reducing agent and masking agent on chromium extraction were studied. The precipitation methods were also investigated. However, the investigation shows that chromium could not be separated from the chloride solution containing 36 ~ 39 g/L iron.2) As the existence of large amounts of iron in leaching solution adversely affected the subsequent recovery of vanadium and chromium, iron was firstly removed. A synergistic extraction system for removing iron from the high-acidity chloride leach solution was developed. TBP-MIBK synergistic system was suitable for iron removal due to its fast extraction kinetics, negligible extraction of other metal ions, and ready stripping of iron. The effects of various parameters on the extraction of iron were investigated. Under the optimum extraction conditions, the extraction of iron under one stage was 86.7%. The effects of various parameters on the stripping of iron were investigated. Under the optimum stripping conditions, the stripping of iron under one stage was 91.6%. The mechanism of iron extraction using synergistic system was studied, and the extraction ability was significantly improved due to the solvating ability of MIBK.3) After iron was removed, a synergistic extraction process for recovering vanadium from the high-acidity chloride leach solution was developed. Aliquat 336-TBP synergistic system was suitable for vanadium recovery due to its fast extraction kinetics, negligible extraction of other metal ions, and ready stripping of vanadium. The effects of various parameters on the extraction of vanadium were investigated. Under the optimum extraction conditions, the extraction of vanadium under three stages was 90.2%. The effects of various parameters on the stripping of vanadium were investigated. Under the optimum stripping conditions, the stripping of vanadium under one stage was 92.4%. The mechanism of vanadium extraction using synergistic system was studied, and the extraction ability was significantly improved due to the solvating ability of Aliquat 336.4) After iron was removed and vanadium was recovered, a synergistic extraction system for recovering chromium from the chloride leach solution was developed. D2EHPA–isooctanol synergistic system was suitable for chromium removal due to its high extraction efficiency, fast extraction kinetics, fast phase separation, and ready stripping of chromium. The effects of various parameters on the extraction of chromium were investigated, and the optimum extraction conditions were obtained. The effects of various parameters on the stripping of chromium were investigated, and the optimum stripping conditions were obtained. The mechanism of chromium extraction using synergistic system was studied, and the extraction ability was significantly improved because isooctanol destroyed the dimer structure of D2EHPA, providing more extraction sites.5) After iron was removed and vanadium was recovered, in the real chloride leach solution, some components such as Ca, Mg, Al, Mn, Ti and Si were leached together with chromium. D2EHPA–isooctanol synergistic system shows high extraction ability of chromium. However, chromium can not be selectively separated by the D2EHPA–isooctanol synergistic extractant. Nitrate ion was added to form the complex compound with chromium, changing the species of chromium. Therefore, chromium can be selectively separated by Cyanex 923. The effects of various parameters on the extraction of chromium were investigated, and the optimum extraction conditions were obtained. The effects of various parameters on the stripping of chromium were investigated, and the optimum stripping conditions were obtained. Ca, Mg, Al, Mn, Ti and Si could not decrease the extraction of chromium, and chromium could be effectively stripped from the loaded Cyanex 923. 

语种中文
文献类型学位论文
条目标识符http://ir.ipe.ac.cn/handle/122111/24233
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张国之. 酸性氯化物体系钒、铬、铁萃取分离基础研究[D]. 北京. 中国科学院研究生院,2017.
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