Knowledge Management System Of Institute of process engineering,CAS
我国是世界钒产业大国，钒资源储量、钒制品产量及消费量均居世界首位。石煤为我国特色含钒矿物资源，因其分布区域广、储量大，而成为我国钒制品生产的重要原料之一。石煤传统提钒方法为高温焙烧-酸浸法，该方法生产流程简单、工艺技术成熟，但存在着钒资源回收率低、三废排放量大等问题，难以满足国家现行环保排放标准。本论文针对我国石煤提钒行业清洁生产技术升级的迫切需求，以石煤钒矿全湿法酸浸清洁提钒工艺为基础，首先对国内不同地区的石煤钒矿进行了工艺矿物学分析，确定了矿物结构、钒赋存状态以及矿物类型，提出了适宜的提钒工艺技术路线，然后对石煤钒矿酸浸提钒过程钒及伴生组分的浸出行为规律进行了研究，分析了影响钒浸出率的关键控制因素，获得了最佳工艺参数，可为工业应用提供理论基础和设计依据。本论文主要取得了如下进展：（1）选取陕西商洛、湖南怀化和甘肃敦煌三个地区的石煤钒矿为研究对象，开展了工艺矿物学研究，确定了矿物结构、钒赋存状态及矿物类型。研究结果表明，陕西商洛的石煤钒矿主要物相为石英、正长石，含有少量白云母以及金云母。钒主要赋存于铁氧化物、钒的吸附态及钒游离态氧化物、硅酸盐矿物以及有机质中，分布率分别是27.71%、25.80%、25.05%、和13.35%，在云母类铝硅酸矿物中较少，是典型的风化型石煤钒矿，钒较容易提取。湖南怀化的石煤钒矿主要物相与陕西商洛石煤钒矿物相组成基本一致，含钒物相为白云母和钒钛氧化物，属于半风化型石煤钒矿。甘肃敦煌的石煤钒矿云母类衍射峰强度较强，钒主要赋存于硅酸盐矿物，分布率为92.44%，钒在铁氧化物中分布率为5.63%，在其它矿物中分布率均小于1%，属于原生型难处理石煤钒矿。（2）确定了适合不同类型石煤钒矿的最佳提钒工艺路线，并优化了工艺条件。针对陕西商洛和湖南怀化的石煤钒矿，采用直接酸浸工艺处理就能得到较好的钒提取效果，在30%硫酸浓度、液固比2:1、反应12 h的工艺条件下，钒的浸出率分别达到92.8%和80.6%。对于甘肃敦煌的原生型难处理石煤钒矿，拌酸熟化-稀酸浸取工艺可实现较好的提钒效果。最佳熟化工艺条件：矿物粒度-150 μm、拌酸量73.6%、熟化温度250℃、熟化时间30 min；最佳酸浸工艺条件为：浸出温度80℃、浸出时间60 min、液固比2:1。在以上最佳工艺条件下钒浸出率94.3%。（3）研究了石煤钒矿硫酸熟化-酸浸提钒过程中，钒伴生组分的浸出行为。研究结果表明，Fe、Ca所属矿物优先浸出；同属于云母成分的V、Al、Mg、K等几种元素浸出行为相似。对熟化反应进程影响最大的因素为温度、拌酸量和时间，三种影响因素条件下熟化反应历程相同：云母在硫酸作用下首先分解生成KAl(SO4)2和KV(SO4)2，然后在硫酸作用下继续反应生成Al2(SO4)3和VOSO4。 ;China is one of the greatest vanadium industry countries in the world, and has an abundant vanadium-bearing resources. Both the production and consumption of vanadium products occupy the first place in the world. As a characteristic vanadium-bearing mineral resources in China, stone coal is one of the important raw materials for producing vanadium products due to its broad distributions and rich reserves. High temperature roasting-acid leaching process is the traditional method of extracting vanadium from stone coal. The method is of short flowsheet, and the process technology is mature. However, the recovery rate of vanadium is low. Moreover, the disposal of industrial wastes cannot meet the standards of national environmental emission. Aiming at the urgent need of the clean production technology upgrading for vanadium extraction from stone coal in China, a suitable technological route of extracting vanadium was proposed based on the process of clean vanadium extraction from vanadium-bearing stone coal by hydrometallurgical method. Firstly, the occurrence state of vanadium and mineral types of stone coal, the process mineralogy of vanadium-bearing stone coal from different regions was characterized to determine the mineral structure. Subsequently, the effect of acid leaching process on the leaching behaviors of vanadium and associated elements were investigated. The key control factors that affected leaching rate of vanadium were discussed to obtain the optimum technology parameters. The experimental results can provide the theoretical and design basis for industrial applications.The main innovative progress is summarized as follows:(1) The process mineralogy of vanadium-bearing stone coal from Shangluo, Shaanxi Province, Huaihua, Hunan Province and Dunhuang, Gansu Province was investigated to ascertain the mineral structure, occurrence state of vanadium and mineral types of stone coal. The results showed that quartz, orthoclase, muscovite and phlogopite were the primary phases in vanadium-bearing stone coal from Shangluo, Shaanxi Province. Furthermore, the distribution rates of vanadium in iron oxides, adsorbed and free vanadium oxides, silicate minerals and organic matter were 27.71%, 25.80%, 25.05% and 13.35%, respectively. The distribution rate of vanadium in aluminosilicate minerals was low. Thus, it is easy to extract vanadium from this kind of stone coal, which is considered as a typical weathering type stone coal. The phase composition of stone coal from Huaihua, Hunan Province was consistent with that from Shangluo, Shaanxi Province. Nevertheless, it belongs to a semi-weathering type stone coal. Muscovite, vanadium and titanium oxides were the major vanadium-bearing minerals. The diffraction peak intensity of mica minerals in vanadium-bearing stone coal from Dunhuang, Gansu Province was strong. Vanadium was mostly found in silicate minerals. Particularly, the distribution rates of vanadium in silicate minerals and iron oxides were 92.44% and 5.63%, respectively. The distribution rate of vanadium in other minerals was less than 1%. As a result, it was a kind of primary stone coal.(2) The most suitable processing technology for vanadium extraction from different kinds of vanadium-bearing stone coal was proposed, and the optimum technological conditions were obtained. For the vanadium-bearing stone coal from Shangluo, Shaanxi Province and Huaihua, Hunan Province, a high extraction rate could be obtained by simple acid leaching method. 92.8% and 80.6% of the vanadium leaching efficiency could be achieved under the following conditions: the H2SO4 concentration of 30%, the liquid-solid ratio of 2 mL/g, the leaching time period of 12 h. For the vanadium-bearing stone coal from Dunhuang, Gansu Province, an excellent leaching efficiency of vanadium could be reached via sulfuric acid baking followed by acid leaching. Under optimized conditions (mineral particle size of -150 μm, sulfuric acid addition of 73.6%, baking temperature of 250 °C, baking time period of 30 min, acid leaching at 80 °C for 60 min, and liquid/solid ratio of 2 mL/g), the leaching rate of vanadium reached 94.3%.(3) Leaching behaviors of associated elements of vanadium in stone coal minerals during sulfuric acid baking followed by acid leaching was investigated. The results indicated that Fe and Ca were leached preferentially from Fe and Ca bearing minerals, and V, Al, Mg, K, etc were leached synchronously from mica. The key factors that influenced the baking process were baking temperature, sulfuric acid dosage and baking time. The effects of the three factors on the baking process were same. Firstly, mica decomposed at the presence of sulfuric acid, and KAl(SO4)2 and KV(SO4)2 were generated. Then, Al2(SO4)3 and VOSO4 were formed under the function of sulfuric acid.
|董玉明. 石煤钒矿全湿法硫酸常压浸取清洁提钒工艺研究[D]. 中国科学院大学,2019.|
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