碱酸法提纯石墨及除硅动力学研究
发布时间：2018-08-23 08:52
【摘要】：石墨是一种重要的战略资源,它在国民经济及许多高科技领域中均发挥着重要作用。石墨作为一种矿产资源转化为石墨材料在技术上必须对其提纯,然后再根据其用途在粒度和改性上进行加工。随着科学技术的快速发展,各领域对高品质石墨材料的需求日益增多,我国现有的石墨提纯技术与我国国民经济和现代化工业发展不适应,一些技术含量高的石墨产品还需从国外进口,制约我国石墨行业发展的关键性问题就是石墨的提纯问题。我国的石墨资源居世界首位,探索合理的提纯工艺技术对充分发挥这一优势资源,促进经济发展具有重要意义。试验以内蒙古某石墨精矿为研究对象,石墨含碳量为84.32%,主要脉石矿物为石英、云母、赤铁矿,SiO2含量为4.82%,Fe2O3含量为4.78%,Al2O3含量为1.80%。采用加碱焙烧-酸浸工艺流程对石墨进行提纯,考察了氢氧化钠用量、焙烧温度、焙烧时间等因素对石墨纯度的影响。采用X-射线衍射(XRD)、红外光谱(FTIR)、扫描电镜(SEM)测试方法对石墨提纯过程产物进行分析,并对杂质SiO2和Fe2O3的反应进行了动力学研究。碱酸法提纯石墨试验得到最佳工艺条件为:氢氧化钠与石墨的质量比0.4;焙烧温度600℃;焙烧时间120 min,盐酸与石墨的质量比0.4;盐酸浓度1 mol/L;酸浸时间45 min。石墨含碳量由84.32%提升到了99.51%。碱酸法对不同粒级石墨的提纯效果不同,在相同试验条件下,石墨粒级越大,提纯效果越好,试验使+0.589 mm的石墨纯度达到了99.92%。流程中各因素对试验影响由大到小依次为:NaOH用量、酸浸时间、焙烧时间、焙烧温度、盐酸用量和盐酸的浓度。XRD结果表明加碱焙烧过程主要是石英和云母发生了结构改变,酸浸过程对赤铁矿的结晶情况影响较大。红外光谱测试结果表明加碱焙烧过程中二氧化硅与氢氧化钠反应生成了硅酸钠。扫描电镜与XRD分析结果均表明,碱酸法提纯石墨对石墨的结构影响较小,很好的保持了石墨的性质。石墨中SiO2、Fe2O3反应动力学研究表明:碱酸法对SiO2和Fe2O3具有很好的去除效果。SiO2与NaOH的反应受表面化学反应和扩散混合控制。
[Abstract]:Graphite is an important strategic resource, which plays an important role in national economy and many high-tech fields. As a kind of mineral resource, graphite must be purified technically and then processed on granularity and modification according to its use. With the rapid development of science and technology, the demand for high quality graphite materials in various fields is increasing day by day. The existing graphite purification technology in China is not suitable for the development of our national economy and modern industry. Some high technology graphite products need to be imported from abroad. The key problem to restrict the development of graphite industry in China is the purification of graphite. The graphite resource of our country ranks first in the world. It is of great significance to explore the reasonable purification technology to give full play to this advantage resource and promote the economic development. The main gangue minerals are quartz, mica, hematite and SiO2 (4.82%). The content of Fe _ 2O _ 3 is 4.78% and the content of Al _ 2O _ 3 is 1.80%. Graphite was purified by alkali roasting-acid leaching process. The effects of sodium hydroxide dosage, calcination temperature and calcination time on the purity of graphite were investigated. The products of graphite purification process were analyzed by X-ray diffraction (XRD),) infrared spectrum (FTIR), scanning electron microscopy (SEM) and the reaction kinetics of impurity SiO2 and Fe2O3 was studied. The optimum conditions for purification of graphite by alkali acid method are as follows: mass ratio of sodium hydroxide to graphite 0.4; calcination temperature 600 鈩，
本文编号：2198536
[Abstract]:Graphite is an important strategic resource, which plays an important role in national economy and many high-tech fields. As a kind of mineral resource, graphite must be purified technically and then processed on granularity and modification according to its use. With the rapid development of science and technology, the demand for high quality graphite materials in various fields is increasing day by day. The existing graphite purification technology in China is not suitable for the development of our national economy and modern industry. Some high technology graphite products need to be imported from abroad. The key problem to restrict the development of graphite industry in China is the purification of graphite. The graphite resource of our country ranks first in the world. It is of great significance to explore the reasonable purification technology to give full play to this advantage resource and promote the economic development. The main gangue minerals are quartz, mica, hematite and SiO2 (4.82%). The content of Fe _ 2O _ 3 is 4.78% and the content of Al _ 2O _ 3 is 1.80%. Graphite was purified by alkali roasting-acid leaching process. The effects of sodium hydroxide dosage, calcination temperature and calcination time on the purity of graphite were investigated. The products of graphite purification process were analyzed by X-ray diffraction (XRD),) infrared spectrum (FTIR), scanning electron microscopy (SEM) and the reaction kinetics of impurity SiO2 and Fe2O3 was studied. The optimum conditions for purification of graphite by alkali acid method are as follows: mass ratio of sodium hydroxide to graphite 0.4; calcination temperature 600 鈩，
本文编号：2198536
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