贵州煤中氟的赋存状态及浮选过程中分配规律的研究

发布时间：2018-02-22 22:33

本文关键词： 煤氟赋存状态浮选分配规律　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：氟是煤中对生态环境有严重危害的微量元素之一,大气氟污染对人类健康构成了巨大的威胁。本文以贵州地区高氟煤为研究对象,对煤中氟的含量、赋存状态以及在浮选过程中的分配规律等一系列问题进行试验研究。对两个试验煤样做了XRF、XRD、SEM+EDS、粒度分析和密度分析。两个试验煤样的主要矿物质为高岭石和石英,粒度较细,均为较难选煤。建立了高温燃烧水解试验装置用于处理煤样,用离子色谱仪测定了煤中氟的总量,并与选择性电极法作了对比,确定了离子色谱法为后续试验中氟含量的测定方法。从浮沉试验、浸提试验、逐级提取试验以及煤中氟与磷的关系四个方面研究了贵州煤中氟的赋存状态。煤样含氟量的大小取决于矸石中矿物质成分的种类及其含量,氟主要趋向存在于粒度小、密度高的煤样中;煤样中氟主要赋存于难溶性的无机盐矿物中;残渣态氟是经强酸浸取后存在于硅酸盐矿物晶格中的氟,分别占两个煤样全氟的70.77%和57.98%。分步释放试验表明随着累计精煤灰分的降低,氟的累计脱除率逐渐增大,而磷的累计脱除率逐渐降低,表明煤样中氟和磷并不存正相关性,说明六盘水煤样中氟并不是以氟磷灰石的形态赋存。对试验煤样进行了浮选试验,考察了浮选时间、浮选浓度、捕收剂和起泡剂用量等因素对氟脱除的影响,分析得到较优化的浮选条件:浮选时间为3 min,浮选浓度为80 g?L-1,捕收剂和起泡剂的用量分别为150 g?t-1和100 g?t-1。在浮选流程的不同环节加入抑制剂,探讨了其对氟分配规律的影响。随着抑制剂用量的加大,精煤中的氟分配率逐渐减小,氟的脱除逐渐增大,说明在浮选过程中,煤中氟更倾向于在尾煤中富集。抑制剂六偏磷酸钠的加入改变了氟在浮选产品中的分配率,再次验证了煤中氟主要赋存于硅酸盐类矿物中.
[Abstract]:Fluorine is one of the trace elements in coal which is seriously harmful to the ecological environment. Air fluoride pollution poses a great threat to human health. A series of problems, such as occurrence state and distribution law in flotation process, were studied experimentally. Two test coal samples were studied by XRF XRDX SEM EDS, particle size analysis and density analysis. The main minerals of the two test coal samples were kaolinite and quartz with fine particle size. The high temperature combustion hydrolysis test device was established for the treatment of coal samples. The total amount of fluoride in coal was determined by ion chromatograph and compared with the selective electrode method. Ion chromatography was used as the method for the determination of fluorine in subsequent tests. The occurrence state of fluorine in Guizhou coal was studied from four aspects of step by step extraction test and the relationship between fluorine and phosphorus in coal. The content of fluorine in coal samples depends on the kinds and contents of mineral components in gangue, and fluorine tends to exist in small granularity. High density coal samples; fluorine in coal samples mainly occurs in insoluble inorganic salt minerals; residual fluorine is fluorine in silicate mineral lattice after strong acid leaching. 70.77% and 57.98 percent of perfluorine in two coal samples, respectively. The results of stepwise release test showed that the cumulative removal rate of fluorine increased gradually with the decrease of ash content in coal, and the cumulative removal rate of phosphorus decreased gradually, indicating that there was no positive correlation between fluoride and phosphorus in coal samples. The results show that fluorine does not exist in Liupanshui coal sample in the form of fluorine apatite. The effects of flotation time, flotation concentration, amount of collector and foaming agent on fluorine removal were investigated. The optimum flotation conditions were obtained: floatation time was 3 min, flotation concentration was 80 g? The dosage of collector and foaming agent was 150 g? T-1 and 100 g? T 1. The effect of depressants on the distribution of fluorine in different parts of flotation process is discussed. With the increase of depressant dosage, the distribution rate of fluorine in clean coal decreases gradually, and the removal of fluoride increases gradually, which indicates that in the flotation process, The addition of depressant sodium hexametaphosphate changed the distribution rate of fluorine in flotation products and proved that fluorine in coal mainly occurs in silicate minerals.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD94

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