本文關(guān)鍵詞： 微晶石墨 礦物學(xué) 提純 膨脹 吸附　出處：《西南科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：基于我國微晶石墨資源豐富但綜合利用程度低,迫切需要提高其產(chǎn)品附加值的背景,本論文在系統(tǒng)研究湖南郴州不同礦區(qū)微晶石墨的礦物學(xué)特征的基礎(chǔ)上,對原礦進(jìn)行了提純、氧化插層和膨脹處理,制得了符合GBT 2453-2009《鋰離子電池石墨類負(fù)極材料》要求的高純膨脹微晶石墨;系統(tǒng)研究了不同礦物學(xué)特征的微晶石墨在氧化插層和膨脹過程中結(jié)構(gòu)和導(dǎo)電性的變化規(guī)律,并分析了膨脹微晶石墨對Pb2+的吸附行為。本論文的研究根據(jù)微晶石墨礦物學(xué)特征的不同,提出了相應(yīng)的開發(fā)利用方向,有利于合理利用微晶石墨資源,提高其產(chǎn)品附加值。對湖南郴州不同礦區(qū)微晶石墨的礦物學(xué)特征研究表明,該市微晶石墨的固定碳含量為77.40%~86.39%,主要礦物相為石墨、綠泥石、石英、方解石和白云母等;晶體結(jié)構(gòu)以2H型為主,同時含有14.81%~21.63%的3R型結(jié)構(gòu),石墨化度較低,與我國晶質(zhì)石墨晶體結(jié)構(gòu)的完善程度相比存在一定差距;微晶石墨顆粒在堿性水溶液中有較好的穩(wěn)定性;導(dǎo)電性隨著結(jié)構(gòu)缺陷與無序度(ID/I G值)的增加而變差。樣品HL5-2T含有更多的結(jié)構(gòu)缺陷和微晶邊緣,電阻率比其他樣品高一個數(shù)量級。為獲得高純微晶石墨,分別采用堿浸酸浸提純法和超聲-混酸法對樣品HJC進(jìn)行提純。堿浸酸浸提純法由于水浴溫度的限制,Na OH不能完全破壞樣品中石英和云母等硅酸鹽礦物的晶體結(jié)構(gòu),導(dǎo)致提純效果有限。超聲-混酸法可快速解離并除去雜質(zhì),將固定碳含量提高至99.9%以上,且純化微晶石墨的層狀結(jié)構(gòu)未發(fā)生明顯變化。采用優(yōu)化的超聲-混酸法提純工藝對樣品HJC和HL5-2進(jìn)行提純,獲得了不同結(jié)構(gòu)缺陷與無序度的高純微晶石墨。以高純微晶石墨HJC-C和HL5-2C為原料,采用改進(jìn)的Hummers法制備氧化微晶石墨,經(jīng)900℃高溫制得膨脹微晶石墨。氧化插層階段,隨著氧化程度的增加,HJC-C-n KP系列樣品的結(jié)構(gòu)缺陷與無序度逐漸增加,而HL5-2C-n KP系列樣品的結(jié)構(gòu)缺陷在增加的同時,結(jié)構(gòu)無序度大幅減小;經(jīng)熱膨脹后,HJC-C-n P系列樣品的結(jié)構(gòu)缺陷與無序度整體減小,而HL5-2C-n P系列樣品的結(jié)構(gòu)無序度有所增大。樣品HL5-2C比HJC-C更易被氧化,且完全氧化時所消耗KMn O4的量也更多。兩個系列氧化微晶石墨樣品的結(jié)構(gòu)層均接有羥基、羧基和環(huán)氧基等含氧官能團(tuán);高溫膨脹后,含氧官能團(tuán)減少,層間距增大。微晶石墨原樣的結(jié)構(gòu)特點(diǎn)對膨脹微晶石墨的導(dǎo)電性具有重要影響,在相同條件下,樣品HJC-T及其反應(yīng)產(chǎn)物的電阻率均小于樣品H L5-2 T及其反應(yīng)產(chǎn)物。當(dāng)微晶石墨氧化后,其電阻率與ID/I G值不再呈現(xiàn)一定的相關(guān)性。經(jīng)提純、氧化插層和膨脹后,兩個系列膨脹微晶石墨的陰離子濃度、粉末壓實(shí)密度和微量金屬元素均達(dá)到了上述GBT2 4 5 3-2 0 0 9標(biāo)準(zhǔn)的要求,但綜合考慮層間距大小和導(dǎo)電性優(yōu)劣兩個方面,認(rèn)為低氧化程度的樣品HJC-C-0.4P和HJC-C-0.8P更適合應(yīng)用于鋰離子電池負(fù)極材料。高氧化程度的樣品HJC-C-1.6P和HL5-2C-1.6P具有豐富的網(wǎng)絡(luò)型孔隙結(jié)構(gòu)和高比表面積。對這兩個膨脹微晶石墨吸附Pb2+的行為進(jìn)行了研究,結(jié)果表明,兩個樣品對Pb2+的吸附行為受初始濃度、時間、p H、吸附劑用量和溫度的影響,吸附量與初始濃度、時間和p H呈正相關(guān),與吸附劑用量和溫度呈負(fù)相關(guān);對Pb2+的吸附為單分子層吸附,吸附過程符合Langmuir等溫吸附模型和準(zhǔn)一級動力學(xué)模型;對Pb2+的吸附為自發(fā)進(jìn)行的放熱吸附過程,屬于物理吸附,且吸附過程有序進(jìn)行。在相同條件下,樣品HL5-2C-1.6P的吸附量和初始吸附速率均大于樣品HJC-C-1.6P,樣品HL5-2C-1.6P的吸附性能更好。本論文的研究體現(xiàn)了從微晶石墨礦物學(xué)到礦物材料的研究特色,可為微晶石墨的開發(fā)利用提供基礎(chǔ)礦物學(xué)數(shù)據(jù)支持與應(yīng)用技術(shù)借鑒,具有重要的理論指導(dǎo)意義和顯著的社會經(jīng)濟(jì)價值。
[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.

【學(xué)位授予單位】：西南科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：P619.252;TD985

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