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复合浸出剂浸取石煤中的钒及矿物中钒分布研究
【作者】 麦毅；
【导师】 魏昶；
【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2009， 硕士
【摘要】 钒是一种具有战略意义的金属。目前,全世界钒的消费在10万吨以上,据预测2020年将接近15万t。钒在地球中少有单独的矿物,石煤是一种储量极为丰富的含钒资源,其矿物构成和钒分布复杂。过去几十年,钠化焙烧-浸出、钙化焙烧-碳酸盐浸出、氧化焙烧-浸出、氧压酸浸等工艺被用于提取其中的钒。钠化焙烧-浸出工艺由于污染严重和金属回收率低,已不符合发展的需要。其它工艺在环保和金属回收率方面虽然有一定的改进,但各有缺点,特别是适应性不广,提取效果波动大。石煤提钒的关键环节是浸出,本文采用本课题组自主创新的硫酸+助浸剂X1+氧化剂X2复合浸出剂,针对贵州某地、湖南某地、甘肃某地和四川某地的石煤进行了浸出研究,其中湖南某地石煤氧化矿是原矿的风化产物。各地石煤的成分、物相和形貌分析发现贵州某地石煤含钒相对较低、白云母较多,湖南某地石煤含钙超过5%、原矿中富含有机质,甘肃某地石煤伊利石含量较高、四川某地石煤有机质含量高达32%,并且含钒硅酸盐被有机质包裹。条件实验结果表明：贵州某地的石煤、湖南某地的石煤原矿和氧化矿随酸浓度、X1浓度、浸出温度、浸出时间等因素的强化,钒浸出率提高,在最佳条件下,浸出率都在80%以上。湖南某地的石煤氧化矿和原矿中钒的浸出率随各因素具有相同的变化规律,这表明风化对石煤中含钒物相性质影响不大,氧化矿和原矿可以一起处理,不必分开。甘肃某地的石煤虽然随各主要因素的强化,钒浸出率具有提高的趋势,但在同等条件下其浸出率明显低于贵州某地和湖南某地的石煤,仅为55%左右。四川某地的石煤在一定条件下,钒随各因素强化钒浸出率提高,但当浸出率增加到65%左右,继续强化浸出条件,浸出率几乎不再增加。这些结果表明,硫酸+助浸剂X1+氧化剂X2复合浸出剂浸取石煤中钒具有一定的适应性和波动性。本文还创造性地采用沉积岩中分步测量稀有元素的方法研究了各地石煤中钒在各物相中的分布。结果表明各地石煤中在硅酸盐矿物中的钒都在60%以上,吸附态的钒都少于5%,其它物相中的钒因石煤的性质不同有所不同。钒分布分析结果和浸出结果综合表明,虽然石煤中的钒都以存在于硅酸盐中为主,但是含钒硅酸盐性质存在差别,其浸出效果相差较大。硫酸+助浸剂X1+氧化剂X2复合浸出剂浸出效果与石煤中钒的品位、钙的含量和碳的含量没有直接的联系,主要取决于含钒硅酸盐的性质。
【Abstract】 Vanadium is a strategic metal. At present, Vanadium consumption around the world exceed 100,000 tons, according to forecast, it will be close to 150,000 t in 2020. Vanadium is a kind of decentralized element without separate minerals in the earth’s crust. Stone coal is extremely rich reserves which contain vanadium resources, their mineral composition and distribution of vanadium complex. Over the past few decades Na-roasting-leaching, calcification roasting-carbonate leaching, oxidation roasting-leaching, oxygen pressure acid leaching process used to extract the vanadium. Na-roasting-leaching process due to the high pollution and little metal recovery in recent years has been limited. Other pressures have developed in environmental protection and metal recovery, but have their own shortcomings, especially in adaptability and stability.Leaching is considered to be the key link of the extraction vanadium from stone coal. In this paper, The system of sulfuric acid+infusion X1+oxidizer X2 were chosen to leach the vanadium from the stone coal in Guizhou province, Hunan province, Gansu province and Sichuan province, the stone coal from Hunan province contain Oxide Ore and rude ore.The analysis of stone coal on composition, phase and morphology showed that vanadium in stone coal from Guizhou is relatively low and muscovite more, calcium in stone coal from Hunan surpass 5% and rude ore rich in organic matter, the stone coal from Gansu involve high content of illite, Content of organic matter in the stone coal from Sichuan Approach 32% and silicate-containing vanadium was wrapped by organic matter. The factors experimental results indicate that the leaching rate of vanadium from Guizhou and Hunan incease along with the acid concentration, X1 concentration, leaching temperature, leaching time and other factors strengthen. In the best conditions, the leaching rate exceed 80%.Vanadium leaching rate of Gansu stone coal have the same trend, but in the same conditions, the leaching rate is only about 55% and significantly lower than Guizhou and Hunan stone coal.The leaching rate of Sichuan stone coal under 65% increas when main factors strengthened, if over 65%, There is no way to make it improve in the system of sulfuric acid+infusion X1+oxidizer X2. The results above proove that effects of leaching in the systerm are unstable.In order to better understand the distribution of vanadium in stone coal, the method of fractional measurement of rare elements used in sedimentary was frist applied to study the distribution of vanadium in stone coal. The results showed that vanadium in silicate minerals are more than 60%, vanadium in the adsorption less than 5%, and vanadium in other material phase is different due to the different property of stone coal. The results of Vanadium distribution analysis and the leaching certify that vanadium in stone coal occurs mainly in silicate, but the silicates have deiffrence property. The leaching effect of the composite leaching systerm don’t depend on grade of vanadium、calcium and carbon in stone coal, but also the property of silicate-breaing vanadium.