【作者】 王俊；

【导师】 王永田； 王磊；

【作者基本信息】 中国矿业大学 ， 矿物加工工程， 2021， 硕士

【摘要】 低阶煤机械规模化开采、洗选提质过程中产生大量原、次生劣质煤泥,具有粒度细、水分高、灰分高、黏性大等特点,处置十分困难。细粒煤泥最经济有效的提质处置方式为浮选法,但传统烃类油作为捕收剂时,一方面难以有效作用于低阶煤颗粒表面提高煤粒可浮性,另一方面在浮选过程中存在较高比例的微细粒高灰矿物质因夹带随水进入精煤产品中,从而导致分选效果不理想。工程实践表明,捕收剂是制约低阶煤煤泥浮选提质、分级利用的核心技术瓶颈,开发适配于低阶煤煤泥浮选的高效捕收剂是当前低阶煤煤泥综合利用研究中亟待解决的技术难题。本论文以复配非离子型捕收剂为着力点,以人工混合低阶煤煤泥(神东低阶超纯煤+非膨胀性高岭石、神东低阶超纯煤+膨胀性蒙脱石)为研究对象,研究了复配非离子型捕收剂对精煤产率、灰分以及可燃体回收率的影响规律,考察了不同复配捕收剂条件下两类黏土矿物的夹带行为,通过对药剂分散性、药剂界面张力、药剂与煤样反应的润湿热值以及药剂处理后的煤样接触角等测试分析探讨了复配非离子型捕收剂与低阶煤颗粒表面作用的机理,通过夹带理论计算及图像法分析了两类黏土矿物呈现不同夹带行为的内在成因。本试验所用煤样为人工混合低阶煤煤泥,由神东低阶超纯煤和纯高岭石矿物、纯蒙脱石矿物按照质量比2:1混合制备。低阶超纯煤灰分为2.41%,-74μm粒级含率占全粒级73.12%,表面含有较为丰富的含氧基团,疏水性较差;高岭石纯度为98%,-20μm含量为78.95%;蒙脱石纯度为96%,-20μm含量为78.52%。高岭石混合煤样的灰分为34%,蒙脱石混合煤样的灰分为32%。以非离子型表面活性剂ODEA(酰胺类)、OP-4(醚类)、Span-80(酯类)与煤油配制成质量浓度为5%、7.5%、10%的复配药剂作为捕收剂,以仲辛醇为起泡剂,对人工混合煤样进行浮选试验。结果显示,煤油作为捕收剂时,浮选精煤产率低、灰分高、可燃体回收率低,浮选效果较差。使用复配捕收剂时,综合浮选效果均得到不同程度改善,复配表现出较好的捕收性和选择性。其中,复配Span-80捕收剂的浮选效果最好,复配OP-4次之,复配ODEA相对较差。复配捕收剂中活性剂的质量浓度越高,浮选指标的改善程度越好。选用神东实际低阶煤煤泥对复配药剂进行浮选验证,发现复配药剂效果与浮选人工混合低阶煤煤泥试验结果基本一致。通过对捕收剂在水中的分散性、捕收剂的界面张力、捕收剂与煤样作用后的润湿热以及捕收剂改性煤样后接触角的测试结果进行分析,发现与煤油相比,复配捕收剂的分散性更好、界面张力更低、与煤样作用后的润湿热值更大、改性后接触角的增幅更明显,说明复配捕收剂能有效的改善低阶煤表面的疏水性,增加了与煤样表面接触的机会,更有利于捕收剂液滴在煤表面的吸附,与煤表面的作用程度更高,更有利于浮选试验进行。复配捕收剂在低阶煤表面的作用机理验证了其对浮选精煤可燃体回收率的影响规律。在相同药剂条件下浮选两类人工混合煤泥,复配捕收剂的浮选精煤灰分均低于煤油,且增加捕收剂中活性剂的质量浓度,精煤灰分降低。综合结果发现,精煤灰分受可燃体回收量和脉石夹带回收量共同决定。三种复配药剂都使得更多脉石夹带到精煤中,然而在药剂作用下可燃体回收量提高更显著,在精煤中所占比例更大,因此精煤灰分整体下降。在浮选过程中,两类黏土矿物呈现不同的脉石夹带行为。在相同药剂条件下,浮选高岭石混合煤泥得到的脉石夹带回收率、水回收率、脉石夹带率均高于蒙脱石混合煤泥。对于高岭石混合煤泥,复配Span-80捕收剂高岭石夹带回收率最高,复配OP-4次之,复配ODEA最低;而对于蒙脱石混合煤泥,蒙脱石夹带回收率在不同复配药剂的低、中、高药量下呈现不同的规律。此外,两类黏土矿物夹带行为的差异还与自身性质有关。浮选体系中,黏土矿物颗粒与低阶煤颗粒均无结构连接,高岭石浮选时夹带程度高,蒙脱石夹带程度低。本论文插图共50幅,表格7个,参考文献97篇。更多还原

【Abstract】 A large amount of primary and secondary inferior slime are produced in the process of mechanical large-scale mining,washing and upgrading of low-rank coal,which has the characteristics of fine particle size,high moisture,high ash content and high viscosity,so it is very difficult to dispose.Flotation is the most economical and effective way to improve the quality of fine slime.However,when traditional hydrocarbon oil is used as a collector,on the one hand,it is difficult to effectively improve the floatability of coal particles on the surface of low-rank coal particles.On the other hand,in the flotation process,there is a high proportion of fine high-ash ore material entrainment with water into the clean coal products,resulting in poor separation effect.The engineering practice shows that the collector is the core technical bottleneck restricting the flotation quality improvement and classification utilization of low-rank slime,and the development of high-efficiency collector suitable for low-rank slime flotation is an urgent technical problem to be solved in the current research on comprehensive utilization of low-rank slime.This paper takes the compound nonionic collector as the focus,and takes the artificial mixed low-rank coal slime(Shendong low-rank ultra-pure coal + nonexpansive kaolinite,Shendong low-rank ultra-pure coal + expansive montmorillonite)as the research object.The effects of compound nonionic collectors on clean coal yield,ash and combustible recovery were studied,and the entrainment behavior of two kinds of clay minerals under different compound collectors were investigated.The mechanism of the interaction between the compound nonionic collector and low-rank coal particles was discussed by testing and analyzing the dispersion of the reagent,the interfacial tension of the reagent,the wetting heat of the reaction between the reagent and the coal sample and the change of the contact angle of the coal sample after treatment.The internal causes of different entrainment behaviors of two kinds of clay minerals were analyzed by entrainment theory calculation and image method.The coal samples used in this test are artificially mixed low-rank coal slime,which is prepared by mixing Shendong low-rank ultra-pure coal,pure kaolinite minerals and pure montmorillonite minerals according to the mass ratio of 2:1.The content of loworder ultra-pure coal ash is 2.41%.The particle fraction of-74 μ m accounts for 73.12%of the total particle size.The surface is rich in oxygen-containing groups,and the hydrophobicity is poor.The purity of kaolinite is 98% and the content of-20 μ m mahogany is 78.95%.The purity of montmorillonite is 96% and the content of-20 μm of montmorillonite is 78.52%.The ash content of kaolinite mixed coal sample is 34%,and that of montmorillonite mixed coal sample is 32%.The results of the tests on the dispersibility of collector in water,interfacial tension of collector,wetting heat after the action of collector and coal sample,and contact angle after the collector modified coal sample are analyzed.It is found that the dispersion of the compound collector is better,the interfacial tension is lower,the wetting heat value after the action with coal sample is larger,and the contact angle increases more obviously after modification,It is shown that the compound collector can effectively improve the hydrophobicity of the surface of low-rank coal,increase the chance of contact with the coal sample surface,and is more conducive to the adsorption of the collector droplets on the coal surface,and the higher the degree of action with the coal surface,and is more conducive to the flotation test.The mechanism of the compound collector on the surface of low-rank coal verifies the effect of the collector on the combustible recovery of flotation clean coal.Under the same reagent condition,the flotation cleaned coal ash content of the compound collector is lower than that of kerosene,and the cleaned coal ash content decreases with the increase of the concentration of active agent in the collector.The comprehensive results show that the cleaned coal ash is determined by the recovery amount of combustible and gangue entrained.The three reagents all make more gangue entrainments into the cleaned coal.However,under the action of reagents,the recovery amount of combustible increases more significantly,accounting for a larger proportion in the cleaned coal,so the ash content of cleaned coal decreases as a whole.In the process of flotation,the two kinds of clay minerals show different gangue entrainment behavior.Under the same reagent condition,the gangue entrainment recovery and gangue entrainment rate of flotation kaolinite mixed slime are higher than that of montmorillonite mixed slime.For kaolinite mixed slime,the recovery rate of gangue entrainment is the highest,that of compound OP-4 is the second,and that of compound ODEA is the lowest.For montmorillonite mixed slime,the entrained recovery of montmorillonite showed different regularity under the low,medium and high dosage of different compound agents.In addition,the difference of entrainment behavior between the two types of clay minerals is related to their own properties.In the flotation system,there is no structural connection between clay mineral particles and low-rank coal particles,and the entrainment degree of kaolinite is high,while the entrainment degree of montmorillonite is low.There are 50 figures,7 tables and 97 references in this paper.更多还原