低阶煤反浮选中粒度效应及界面作用研究

发布时间：2018-01-09 23:05

本文关键词：低阶煤反浮选中粒度效应及界面作用研究　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：煤炭是一种重要能源,而低阶煤又在我国煤炭保有资源储量中占有重要地位。随着世界炼焦煤资源日益紧张,提高低阶煤的利用率意义重大。现有细粒低阶煤提质利用方法基本为强化浮选,但存在药剂量大、效果不显著等问题,急切需要新的工艺对低阶煤进行分选。本研究将低阶煤劣势转化为优势,采用反浮选方法对低阶煤进行降灰提质,探索反浮选中的粒度效应,研究药剂在矿物颗粒表面的作用机制,并提出选择性絮凝-反浮选方法对低阶煤进行脱灰提质。论文首先通过XPS,FTIR,SEM等方法研究了低阶煤(次烟煤)的基础表面物理化学性质,发现次烟煤水分含量较高,表面存在较多含氧官能团,亲水性官能团的存在将会降低次烟煤表面疏水性。次烟煤空间结构比较松散,含有一定的孔隙和沟壑,这将导致较大的孔隙率和比表面积,增加浮选难度。通过Zeta电位测试后发现,次烟煤的等电点(pH 3)与煤中主要脉石矿物石英(pH 2)和高岭石的等电点(p H 1.8)接近,所以当选用阳离子铵盐Lilaflot D817M作为捕收剂时,抑制剂的添加很有必要。对次烟煤传统浮选试验和反浮选试验结果进行了对比,发现传统浮选方法药剂消耗量大,浮选效果差。在次烟煤反浮选的条件优化试验中,发现在一定条件下,当捕收剂Lilaflot D817M用量为2 kg/t,可得到灰分为8.23%的精煤产品,可燃体回收率为86.87%,分选效率为71.45%。因此,在药耗量较小的情况下,使用反浮选方法对低阶煤(次烟煤)进行分选可得到较好的分选效果。本研究从三个角度出发研究次烟煤反浮选中的粒度效应。当用不同粒度的次烟煤和石英配成人工混合矿进行浮选时,发现只有浮选入料组成为粗颗粒或中等颗粒煤和细颗粒石英时,可以得到很好的反浮选分选效果。通过对反浮选产品进行粒度筛分及相关计算,发现-74+53μm煤颗粒对糊精的反应效果最好,-104+74μm脉石颗粒有最好的浮选效果。通过对比不同浮选入料(去除超细粒煤和未去除超细粒煤)的反浮选试验结果,发现超细粒煤的存在降低了石英的浮选速率和回收率,恶化了反浮选分选效率。通过总有机碳分析仪(TOC)测试矿物吸附药剂前后溶液中总碳/氮量,计算矿物对药剂的吸附量。结果发现,次烟煤对糊精的饱和吸附量相对石英较高。同时通过Zeta电位测试发现,吸附糊精后的石英和次烟煤,等电点升高,表面负电位均有所降低。用Washburn动态法测定矿物吸附药剂前后表面润湿性的变化规律。研究发现,被糊精作用后次烟煤表面亲水性增强,而石英表面亲水性稍微减弱。在对铵盐Lilaflot D817M的吸附过程中,发现次烟煤对铵盐的吸附量始终高于石英,且很难达到饱和。阳离子铵盐Lilaflot D817M能显著改变次烟煤和石英表面的动电位,使次烟煤和石英等电点显著增加。被相同浓度的铵盐作用后,石英表面疏水性的增强程度远远大于次烟煤,说明吸附量和表面润湿性改变程度无直接关系。为解决超细粒煤影响反浮选分选效率问题,提出选择性絮凝-反浮选分选方法。被PAM作用后,次烟煤和石英的表观粒径均增大,次烟煤颗粒能形成较大絮团。但在对PAM的吸附过程中,石英的吸附量大于次烟煤。PAM作用后,次烟煤表面亲水性增强,石英表面亲水性稍微减弱。次烟煤和石英吸附PAM后,表面官能团发生了改变。在次烟煤选择性-絮凝反浮选试验中,糊精的抑制效果较PAM较好,合适的PAM用量以及转速对选择性絮凝-反浮选很有必要。研究发现,当絮凝剂用量为50 g/t时,可得到精煤灰分为12.50%,相对常规反浮选精煤灰分降低1.6个百分点,分选效率从58.39%提高至66.07%。
[Abstract]:Coal is an important energy source, and low rank coal in China's coal reserves occupies an important position. With the reserves of coking coal resources in the world is increasingly tense, improve the utilization of low rank coal was significant. The existing fine low rank coal upgrading method using basic for flotation, but there are large dosage, the effect is not the problem obviously, in urgent need of new technology for separation of low rank coal. In this study, the low rank coal disadvantage into advantage, by reverse flotation method for reducing ash quality of low rank coal, explore the size effect of reverse flotation reagents in the study, the mechanism of mineral particle surface, and puts forward the upgrading of removing ash low rank coal selective flocculation flotation technique. Firstly, through XPS, FTIR, SEM and other methods to study the low rank coal (subbituminous coal) based surface physical and chemical properties, found high bituminous coal moisture content, there are more surface oxygen Officer Can group, hydrophilic functional groups exist will reduce sub bituminous surface hydrophobicity. Subbituminous spatial structure is loose, with some pores and ravines, which will lead to high porosity and specific surface area, increasing the difficulty of flotation by Zeta potential. After the test found that sub bituminous isoelectric point (pH 3) and the main the coal gangue minerals in quartz and kaolinite (pH 2) the isoelectric point (P H 1.8) close, so when using cationic ammonium Lilaflot D817M as collector, it is necessary to add. Inhibitors of subbituminous coal flotation tests and compares the traditional reverse flotation test results, found that the traditional agent consumption flotation method a large amount of poor flotation effect. In the sub bituminous coal reverse flotation condition optimization experiment, it was found that under certain conditions, when the collector dosage is 2 Lilaflot D817M kg/t, can get the ash 8.23% coal product, the combustible recovery rate is 86.87%, sorting Efficiency is 71.45%. therefore, in drug consumption is small, the use of reverse flotation method of low rank coal (subbituminous coal) separation can get good separation effect. This research from the three angles of subbituminous coal reverse flotation in size effect. When the sub bituminous coal with different grain size and quartz with artificial mixed ore flotation, flotation feed composition found only as coarse or medium coal particles and fine particles of quartz, reverse flotation can get a good separation effect. Through sizing and calculation of reverse flotation, found that the best reaction effect of -74+53 m on coal particle cyclodextrin, -104+74 m have the best flotation gangue particles. By comparing the different flotation feed (removal of ultra fine coal and removal of super fine coal) anti flotation experiments, found that ultra fine coal reduces the quartz flotation rate and recovery rate of evil The reverse flotation separation efficiency. The total organic carbon analyzer (TOC) test before and after adsorption chemical carbon / nitrogen in solution, the adsorption amount of minerals on the chemical calculation. The results showed that the saturated adsorption capacity of sub bituminous coal relatively high. At the same time dextrin quartz by measuring Zeta potential is quartz and sub bituminous coal adsorption dextrin, isoelectric point increased, negative surface potential decreased. Determination of variation of surface wettability and mineral adsorption agent using Washburn dynamic method. The study found that after being dextrin sub bituminous surface hydrophilicity enhancement and quartz surface hydrophilicity somewhat diminished. In the process of adsorption of ammonium in Lilaflot D817M the adsorption amount of sub bituminous coal, found on ammonium salt is always higher than that of quartz, and difficult to reach saturation. The cationic ammonium Lilaflot D817M can significantly change the time dynamic potential of bituminous coal and quartz surface, the sub bituminous coal and quartz isoelectric point Increased significantly. By the same concentration of ammonium, enhancement of the surface hydrophobicity of quartz is much larger than the time that bituminous coal, adsorption capacity and surface wettability change degree has no direct relationship. In order to solve the effect of super fine coal reverse flotation separation efficiency, the selective flocculation and reverse flotation separation method. By PAM, time bituminous coal and quartz apparent particle size increased, a bituminous coal particles can form a larger floc. But in the adsorption process of PAM, the adsorption amount of quartz is greater than that of sub bituminous coal after.PAM, sub bituminous surface hydrophilicity enhancement, quartz surface hydrophilicity slightly weakened. Subbituminous coal and quartz adsorption after PAM occurrence the change of surface functional groups. In the selective flocculation flotation test of bituminous coal, the inhibitory effect of dextrin is PAM better, the appropriate amount of PAM and the speed is necessary for selective flocculation flotation. The study found that when flocculating agent In the case of 50 g/t, the ash content of the refined coal is 12.50%, which is 1.6 percentage points lower than that of conventional reverse flotation, and the separation efficiency is increased from 58.39% to 66.07%..

【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD94;TD923

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