铝土矿硫酸法溶出及除杂研究
发布时间：2018-08-30 17:59
【摘要】：我国的铝土矿有98%以上属于一水硬铝石型,一水硬铝石在浸出方面难度很大,这是因为一水硬铝石型的晶型很完整,晶格能很大,其化学活性很差。由于用铝行业的迅速发展,导致我国的优质铝土矿资源减少,大部分铝土矿的铝硅比为3~6,很难满足拜耳法处理铝土矿的要求,严重制约了我国的氧化铝工业发展,用拜耳法来处理低铝硅比的一水硬铝石铝型铝土矿时,能耗较高,流程复杂,成本较高。本文用硫酸法处理中低品位的一水硬铝石型铝土矿,系统的研究了铝土矿硫酸法溶出的工艺条件;并在此基础上,对溶出液中的金属杂质进行去除,使其杂质含量降到了很低的水平;以除杂后的产物为原料,制取了氧化铝气凝胶,并初步研究了其制备工艺。研究结果如下:(1)研究了研磨和焙烧等预处理手段对氧化铝溶出的影响,并分析了焙烧铝土矿的机理。预处理的条件分别为铝土矿粒度100μm,焙烧温度650℃,焙烧时间为60min。(2)通过单因素实验研究了硫酸法溶出氧化铝的影响因素,并用正交实验优化了工艺,最佳工艺为:溶出反应温度180℃、硫酸浓度90%、液固比为8:1、溶出反应时间120min,在此条件下,氧化铝的溶出率达到90.23%。(3)溶出液为硫酸铝溶液,浓缩结晶分离出硫酸铝,分析可知硫酸铝中含有Al、Fe、Mg、Si、Ca、Na、K等元素。对铝土矿和溶出液硫酸铝进行了除杂研究:钛的去除在焙烧时进行,通过添加氯化剂且在还原气氛中焙烧铝土矿可以除去钛;用DDTC络合沉淀法进行除铁,并研究其影响因素;硅的去除在硫酸溶出铝土矿后的尾液中进行,通过添加絮凝剂使硅酸自聚再分离开来;钙、镁的去除是利用其氟化物溶度积小的特点,采用NH4F为沉淀剂除去;用氨法将溶液中的铝离子沉淀并分离开来,通过反复洗脱沉淀可使钠钾离子含量降到很低的水平,逐步去除杂质后,产物中的杂质含量均降到了0.05%以下,产物纯度达到了99.91%。(4)以除杂后的铝盐为原料,制备了氧化铝气凝胶,研究了制取气凝胶的工艺,并确定其工艺参数,其工艺条件为:4g Al(NO_3)_3·9H_2O、乙醇40ml、水40ml、乙二醇2ml、环氧丙烷15ml。
[Abstract]:More than 98% bauxite in China belongs to diaspore type, which is very difficult to leach out. This is because the crystal form of diaspore type is very complete, the lattice energy is very large, and its chemical activity is very poor. Due to the rapid development of aluminum industry, the high quality bauxite resources in China are reduced, and the Al-Si ratio of most bauxite ores is 3 ~ 6. It is very difficult to meet the requirements of Bayer process for the treatment of bauxite, which seriously restricts the development of alumina industry in China. Using Bayer method to treat bauxite with low Al-Si ratio, the energy consumption is high, the process is complex and the cost is high. In this paper, the sulfuric acid method is used to treat the bauxite of medium and low grade, and the technological conditions of sulphuric acid leaching of bauxite are systematically studied, and on the basis of this, the metal impurity in the solution is removed. The alumina aerogel was prepared by using the product of removing impurity as the raw material and the preparation process was studied preliminarily. The impurity content of alumina aerogel was reduced to a very low level and the alumina aerogel was prepared from the product after impurity removal. The results are as follows: (1) the effects of pretreatment such as grinding and roasting on the dissolution of alumina were studied, and the mechanism of roasting bauxite was analyzed. The pretreatment conditions were as follows: bauxite size 100 渭 m, calcination temperature 650 鈩，
本文编号：2213850
[Abstract]:More than 98% bauxite in China belongs to diaspore type, which is very difficult to leach out. This is because the crystal form of diaspore type is very complete, the lattice energy is very large, and its chemical activity is very poor. Due to the rapid development of aluminum industry, the high quality bauxite resources in China are reduced, and the Al-Si ratio of most bauxite ores is 3 ~ 6. It is very difficult to meet the requirements of Bayer process for the treatment of bauxite, which seriously restricts the development of alumina industry in China. Using Bayer method to treat bauxite with low Al-Si ratio, the energy consumption is high, the process is complex and the cost is high. In this paper, the sulfuric acid method is used to treat the bauxite of medium and low grade, and the technological conditions of sulphuric acid leaching of bauxite are systematically studied, and on the basis of this, the metal impurity in the solution is removed. The alumina aerogel was prepared by using the product of removing impurity as the raw material and the preparation process was studied preliminarily. The impurity content of alumina aerogel was reduced to a very low level and the alumina aerogel was prepared from the product after impurity removal. The results are as follows: (1) the effects of pretreatment such as grinding and roasting on the dissolution of alumina were studied, and the mechanism of roasting bauxite was analyzed. The pretreatment conditions were as follows: bauxite size 100 渭 m, calcination temperature 650 鈩，
本文编号：2213850
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