超（亚）临界水热活化联合盐酸酸浸提取煤矸石中硅、铝的研究

发布时间：2018-04-04 02:05

  本文选题：煤矸石　切入点：超(亚)临界水热活化　出处：《太原理工大学》2017年硕士论文

【摘要】：近年来,超临界流体技术,广泛应用于萃取分离、化学反应工程、环境保护、材料科学等方面,有很好的发展前景。煤矸石是采煤过程和洗煤过程中排放的固体废物。本文以煤矸石制备白炭黑和氧化铝技术开发为背景,将超临界流体技术用于固体废物的处理。论文重点研究超(亚)临界水中煤矸石活化的反应特性,考察超(亚)临界水热活化的反应条件对硅、铝溶出率的影响。实验结果表明,与传统的煤矸石活化方法相比,超(亚)临界水活化技术具有反应温度低、化学反应介质廉价和绿色环保的优势。基于此,本文提出了以煤矸石为原料,超(亚)临界水热活化联合盐酸浸提取煤矸石中的硅铝用于制备白炭黑和氧化铝的新工艺。选取五种煤矸石作为实验原料。首先,通过超临界水热活化实验,采用添加无机碱作为活化剂,对产物进行一系列的分析,获取SiO_2和Al_2O_3提取率的数据。初步建立实验方案、分析手段及计算方法。其次,对碱在煤矸石活化中的影响作了简要分析。通过XRD、ICP-OES等表征手段,发现当添加NaOH、Na2CO3和KOH时,对应的活化样品中主要的物相分布为钙霞石、方钠石和钾霞石,并且这些硅铝酸盐是能够溶于稀酸。所有的活化样品都采用盐酸酸浸用以获取SiO_2和Al_2O_3。当2.0 mol/L NaOH为活化剂时,SiO_2和Al_2O_3的溶出率分别为70.41%和65.74%;当2.0 mol/L Na2CO3为活化剂时,SiO_2和Al_2O_3的溶出率分别为77.03%和71.57%;当2.0 mol/L KOH为活化剂时,SiO_2和Al_2O_3的溶出率分别为71.46%和83.04%。为了拓宽活化实验的温度范围,考察了煤矸石的亚临界水热活化效果,同时探索提高分离出来的白炭黑和氧化铝的收率。借助XRD、ICP-OES、TG-DTG、FTIR、BET等测试方法,分析出二氧化硅的溶出率在50%以上,氧化铝的溶出率在80%以上。通过分离提纯可以制得比表面积最高可达818.1m2/g,纯度达到了96.3%的白炭黑产品和纯度达到99.17%的氧化铝产品。最后,在煤矸石为原料超(亚)临界水热法制备白炭黑和氧化铝工艺的基础上,经过简单的物料衡算和经济效益分析以及环境评价,证明它是一种产品附加值高,资源利用率高且环境友好的优良工艺。
[Abstract]:In recent years, supercritical fluid technology has been widely used in extraction separation, chemical reaction engineering, environmental protection, material science and so on.Coal gangue is the solid waste discharged during coal mining and coal washing.In this paper, supercritical fluid technology is applied to solid waste treatment under the background of technology development of coal gangue preparation of silica and alumina.In this paper, the reaction characteristics of coal gangue activation in supercritical water were studied, and the effect of reaction conditions on the dissolution rate of Si and Al was investigated.The experimental results show that the supercritical water activation technology has the advantages of low reaction temperature, cheap chemical reaction medium and green environmental protection compared with the traditional coal gangue activation method.Based on this, a new process for the preparation of silica and alumina from coal gangue by supercritical hydrothermal activation combined with hydrochloric acid leaching was proposed.Five kinds of coal gangue were selected as experimental raw materials.Firstly, through supercritical hydrothermal activation experiment, adding inorganic base as activator, a series of analysis was carried out on the product, and the data of SiO_2 and Al_2O_3 extraction rate were obtained.The experimental scheme, the analysis method and the calculation method are preliminarily established.Secondly, the effect of alkali on the activation of coal gangue is briefly analyzed.By means of XRDX ICP-OES, it was found that the main phases of the activated samples were calcium nepheline, calcinite and potassium nepheline when NaOHN Na 2CO 3 and KOH were added, and these aluminates were soluble in dilute acid.All activated samples were soaked with hydrochloric acid to obtain SiO_2 and Al _ 2O _ 3.褰，

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