湖南郴州微晶石墨矿物学及开发利用研究

发布时间：2018-03-01 19:15

本文关键词： 微晶石墨矿物学提纯膨胀吸附　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：基于我国微晶石墨资源丰富但综合利用程度低,迫切需要提高其产品附加值的背景,本论文在系统研究湖南郴州不同矿区微晶石墨的矿物学特征的基础上,对原矿进行了提纯、氧化插层和膨胀处理,制得了符合GBT 2453-2009《锂离子电池石墨类负极材料》要求的高纯膨胀微晶石墨;系统研究了不同矿物学特征的微晶石墨在氧化插层和膨胀过程中结构和导电性的变化规律,并分析了膨胀微晶石墨对Pb2+的吸附行为。本论文的研究根据微晶石墨矿物学特征的不同,提出了相应的开发利用方向,有利于合理利用微晶石墨资源,提高其产品附加值。对湖南郴州不同矿区微晶石墨的矿物学特征研究表明,该市微晶石墨的固定碳含量为77.40%~86.39%,主要矿物相为石墨、绿泥石、石英、方解石和白云母等;晶体结构以2H型为主,同时含有14.81%~21.63%的3R型结构,石墨化度较低,与我国晶质石墨晶体结构的完善程度相比存在一定差距;微晶石墨颗粒在碱性水溶液中有较好的稳定性;导电性随着结构缺陷与无序度(ID/I G值)的增加而变差。样品HL5-2T含有更多的结构缺陷和微晶边缘,电阻率比其他样品高一个数量级。为获得高纯微晶石墨,分别采用碱浸酸浸提纯法和超声-混酸法对样品HJC进行提纯。碱浸酸浸提纯法由于水浴温度的限制,Na OH不能完全破坏样品中石英和云母等硅酸盐矿物的晶体结构,导致提纯效果有限。超声-混酸法可快速解离并除去杂质,将固定碳含量提高至99.9%以上,且纯化微晶石墨的层状结构未发生明显变化。采用优化的超声-混酸法提纯工艺对样品HJC和HL5-2进行提纯,获得了不同结构缺陷与无序度的高纯微晶石墨。以高纯微晶石墨HJC-C和HL5-2C为原料,采用改进的Hummers法制备氧化微晶石墨,经900℃高温制得膨胀微晶石墨。氧化插层阶段,随着氧化程度的增加,HJC-C-n KP系列样品的结构缺陷与无序度逐渐增加,而HL5-2C-n KP系列样品的结构缺陷在增加的同时,结构无序度大幅减小;经热膨胀后,HJC-C-n P系列样品的结构缺陷与无序度整体减小,而HL5-2C-n P系列样品的结构无序度有所增大。样品HL5-2C比HJC-C更易被氧化,且完全氧化时所消耗KMn O4的量也更多。两个系列氧化微晶石墨样品的结构层均接有羟基、羧基和环氧基等含氧官能团;高温膨胀后,含氧官能团减少,层间距增大。微晶石墨原样的结构特点对膨胀微晶石墨的导电性具有重要影响,在相同条件下,样品HJC-T及其反应产物的电阻率均小于样品H L5-2 T及其反应产物。当微晶石墨氧化后,其电阻率与ID/I G值不再呈现一定的相关性。经提纯、氧化插层和膨胀后,两个系列膨胀微晶石墨的阴离子浓度、粉末压实密度和微量金属元素均达到了上述GBT2 4 5 3-2 0 0 9标准的要求,但综合考虑层间距大小和导电性优劣两个方面,认为低氧化程度的样品HJC-C-0.4P和HJC-C-0.8P更适合应用于锂离子电池负极材料。高氧化程度的样品HJC-C-1.6P和HL5-2C-1.6P具有丰富的网络型孔隙结构和高比表面积。对这两个膨胀微晶石墨吸附Pb2+的行为进行了研究,结果表明,两个样品对Pb2+的吸附行为受初始浓度、时间、p H、吸附剂用量和温度的影响,吸附量与初始浓度、时间和p H呈正相关,与吸附剂用量和温度呈负相关;对Pb2+的吸附为单分子层吸附,吸附过程符合Langmuir等温吸附模型和准一级动力学模型;对Pb2+的吸附为自发进行的放热吸附过程,属于物理吸附,且吸附过程有序进行。在相同条件下,样品HL5-2C-1.6P的吸附量和初始吸附速率均大于样品HJC-C-1.6P,样品HL5-2C-1.6P的吸附性能更好。本论文的研究体现了从微晶石墨矿物学到矿物材料的研究特色,可为微晶石墨的开发利用提供基础矿物学数据支持与应用技术借鉴,具有重要的理论指导意义和显著的社会经济价值。
[Abstract]:Based on our abundant resources and comprehensive utilization of microcrystalline graphite degree is low, the urgent need to improve the added value of the background, based on the mineralogical characteristics of Hunan Chenzhou system in different mining area of microcrystalline graphite on the ore by purification, oxidation intercalation and expansion processing, prepared with high purity graphite expansion GBT 2453-2009< lithium ion battery anode material graphite > requirements; microcrystalline graphite of different mineralogical characteristics in oxidation intercalation and swelling changes of structure and conductivity in the process, and the analysis of the adsorption behavior of microcrystalline graphite expansion on Pb2+. This paper according to different mineralogical characteristics of microcrystalline graphite, is proposed the development and utilization of the corresponding direction, conducive to the rational use of resources to improve the graphite, the added value of the products. The mineralogical characteristics of different mining areas in Hunan Chenzhou research microcrystalline graphite Show that the fixed carbon content of the microcrystalline graphite is 77.40%~86.39%, the main mineral phase is graphite, chlorite, quartz, calcite and muscovite; crystal structure with 2H type, 3R type structure with 14.81%~21.63%, the graphitization degree is low, compared with the degree of perfection of our crystal structure of Shi Mojing there is a certain gap; microcrystalline graphite particles are stable in alkaline aqueous solution; conductivity with structural defects and disorder degree (ID/I G) increased. The sample contains HL5-2T structure more defects and crystallite edge resistivity than other samples is an order of magnitude higher. In order to obtain high purity graphite, respectively by alkali leaching acid leaching purification method and ultrasonic method of mixed acid HJC samples were purified. Leaching purification method due to water temperature limit of alkali leaching acid, crystal structure of Na OH can not be completely destroyed quartz and mica in samples of silicate minerals, In the purifying effect is limited. The ultrasonic method can be used for fast dissociation and mixed acid to remove impurities, will increase the fixed carbon content to more than 99.9%, layered structure and purification of microcrystalline graphite is not changed obviously. The optimized ultrasonic mixed acid method purification process of samples HJC and HL5-2 were purified by high purity graphite with different structure the defects and the degree of disorder. With high purity graphite HJC-C and HL5-2C as raw materials, preparation of microcrystalline graphite oxide by modified Hummers method, the high temperature of 900 DEG C to prepare microcrystalline graphite oxide intercalated. The expansion stage, with the increase of oxidation degree, the structure defects of HJC-C-n KP series of samples and the disorder degree increased gradually, and the structure defects HL5-2C-n KP series of samples in the increase at the same time, the structure of disorder degree greatly reduced; the thermal expansion, structural defects of HJC-C-n P series of samples and the disorder degree of overall decreases, while the HL5-2C-n P series of sample structure The disorder degree increased. The sample HL5-2C than HJC-C more susceptible to oxidation and KMn O4 consumption and complete oxidation of the amount of more. Layer two series of oxidized microcrystalline graphite samples are connected with hydroxyl, carboxyl and epoxy functional groups containing oxygen; high temperature expansion, oxygen-containing functional groups reduced, layer spacing increases. Has an important influence on the conductive structure of microcrystalline graphite as the expansion of microcrystalline graphite, under the same conditions, HJC-T and resistivity samples of reaction products were less than H L5-2 T samples and reaction products. When graphite is oxidized, the resistivity of ID/ and I G values showed no certain correlation. After purification, oxidation intercalation and after the expansion, the anion concentration two series expansion graphite, compaction density of powder and trace metals have reached the requirements of GBT2 453-2009, but considering the size and spacing of layers of conductive. Two bad aspects, that low degree of oxidation of HJC-C-0.4P and HJC-C-0.8P were more suitable for the lithium ion battery anode material. A high degree of oxidation of the samples HJC-C-1.6P and HL5-2C-1.6P has a rich network of pore structure and high surface area. On the two of the Pb2+ Shi Moxi expansion microcrystalline behavior was studied. The results show that the adsorption behavior two samples of Pb2+ by the initial concentration, time, P H, effects of adsorbent dosage and temperature, adsorption capacity and initial concentration, time and P was positively related to H, and negatively correlated with adsorbent dosage and temperature; the adsorption of Pb2+ for the single molecular layer adsorption, the adsorption process accords with Langmuir isothermal adsorption model and kinetic model; adsorption of Pb2+ is exothermic adsorption process was spontaneous, belongs to physical adsorption, and the adsorption process in an orderly manner. Under the same condition, the adsorption amount and initial sample HL5-2C-1.6P The adsorption rate was higher than the sample HJC-C-1.6P, sample HL5-2C-1.6P better adsorption performance. The thesis embodies the characteristics of microcrystalline graphite from mineralogy to mineral materials, reference for the development and utilization of microcrystalline graphite provide basic mineralogical data support and application technology, has important theoretical significance and significant social and economic value.

【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P619.252;TD985

【相似文献】