煤矸石酸溶物制备氧化铁红基础研究

发布时间：2018-05-31 20:11

  本文选题：煤矸石 + α-Fe_2O_3　； 参考：《昆明理工大学》2017年硕士论文

【摘要】：煤矸石是煤炭开采中的副产固废物,其大量堆存不仅污染环境,而且占用大量土地造成资源浪费。根据煤矸石的化学组成,提取其有效成分开发环境友好型技术工艺,对提高煤矸石资源化综合利用具有重要意义。为解决在煤矸石多金属提取中试研究中氧化铁红产品纯度不高以及机理不清等问题,本文以硫酸亚铁FeSO4·7H2O为原料,碳酸钠Na2CO3为沉淀剂,对Fe2+-CO32--H2O体系进行热力学分析,并借助X射线衍射仪、傅里叶变换红外光谱仪、扫描电镜、热分析仪等仪器综合分析氧化铁红中间产物α-FeOOH形成机理以及α-FeOOH热处理制备铁红α-Fe2O3机理;在此基础上,考察Na2CO3浓度、反应温度和Fe(Ⅱ)浓度等对煤矸石酸浸分离液制备氧化铁红的影响,为煤矸石酸溶物制备氧化铁红工艺提供一定的理论基础。在Fe2+-CO32--H2O体系中,α-FeOOH是由Fe2+-CO32--H2O体系沉淀产物Fe(OH)2氧化形成。体系反应过程中,pH对α-FeOOH的颜色、微观形貌及Fe(Ⅱ)氧化速率有很大的影响,pH在5.0～5.5范围,α-FeOOH质量较好。α-FeOOH的TG-DTG分析和固相反应动力学模型计算表明:α-FeOOH热解转化为α-Fe2O3,其反应机理模型为随机成核生长机理,热解动力学模型函数为-ln(1-x),其反应活化能Ea=140.49kJ·mol-1,反应级数为0.98。α-FeOOH的热解反应分两步进行,第一步脱去连接晶体之间的水;第二步脱去晶体内部结构水,最后转化为α-Fe2O3晶粒。α-FeOOH形貌变化为:随着热处理的温度提高,片状的α-FeOOH逐渐裂解变成小片状直至片状形貌消失形成粉末状晶体,温度继续升高,其细小粉末颗粒开始团聚结晶,到700℃时形成均匀的球状α-Fe2O3晶粒。响应曲面法优化煤矸石酸溶物制备氧化铁红工艺研究,确定出最佳工艺条件为:Na2CO3浓度107g/L、反应温度43℃、Fe(Ⅱ)浓度0.26mol/L。在此工艺下,进行放大实验,所得氧化铁红产品质量达到标准GB/T1863-2008《氧化铁颜料》中优等产品要求。
[Abstract]:Coal gangue is a by-product solid waste in coal mining, which not only pollutes the environment, but also occupies a large amount of land to cause waste of resources. According to the chemical composition of coal gangue, it is of great significance to extract its active components and develop environment-friendly technology to improve the comprehensive utilization of coal gangue. In order to solve the problems of low purity and unclear mechanism of iron oxide red product in the pilot-scale study of polymetallic extraction of coal gangue, the system of Fe2 CO32--H2O was thermodynamically analyzed using ferrous sulfate FeSO4 7H2O as raw material and sodium carbonate Na2CO3 as precipitant. The formation mechanism of the intermediate product 伪 -FeOOH of iron oxide and the mechanism of preparing iron red 伪 -Fe _ 2O _ 3 by heat treatment of 伪 -FeOOH were analyzed by means of X-ray diffractometer, Fourier transform infrared spectrometer, scanning electron microscope, thermal analyzer, etc. On this basis, the concentration of Na2CO3 was investigated. The effect of reaction temperature and Fe (鈪，

本文编号：1961132