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杉木锯屑基高吸水抑尘材料制备及效果分析

Preparation and effect analysis of cedar sawdust-based super absorbent dust suppressant material

  • 摘要: 煤矿生产及运输过程中存在大量煤炭残渣和粉尘,对作业环境和当地居民造成极大影响,为提高抑尘剂的抑尘效率,改善作业空间及周边环境,笔者遵循废物利用原则,实现了废物再利用。提出了以杉木锯屑为原材料,经过NaOH、Na2SO3等溶液处理后获得脱木素木粉(DWF),通过微波辅助-原位合成的手段,制备了一种新型绿色高吸水抑尘剂(AA-DWF-PAM/GD)。试验结果表明:借助SEM、FTIR、TG-DTG及溶胀动力学试验手段,对AA-SW-PAM/GD的微观形貌、反应机理、热稳定性及吸水性能进行研究,发现该抑尘剂呈现网状空间结构且稳定性较高,DWF与丙烯酸(AA)和聚丙烯酰胺(PAM)反应良好,在73 ℃之前不会发生任何活性破坏,且最高吸水倍率为325倍,在NaCl、MgCl2、CaCl2三种盐溶液溶度为1%时,最高吸盐水倍率为100左右。在AA-DWF-PAM/GD与煤尘性能测试中发现,当风速14 m/s时抑尘率在90%左右;抑尘材料与煤混合后的燃烧后,热释放速率提高了4.53 kW/m2,燃烧时间延长了15 s左右,在喷洒使用后不会对煤的热值产生负面影响。分子动力学模拟(MS)结果表明抑尘剂主要作用于煤−水界面处,煤−水界面吸附层的厚度增大至28×10−6 mm (13×10−6~41×10−6 mm),促进了水分子在煤表面的扩散,吸引水分子向煤层方向迁移,添加AA-DWF-PAM/GD后水分子的自扩散系数(D)增加了4.3×10−9 m2/s,提高了煤层表面的润湿性。总的来说,该抑尘剂具有成本低、绿色环保、抑尘性能强的优势,有望使其在煤矿现场大规模应用推广。

     

    Abstract: Massive coal debris and dust are generated in the process of coal production and transportation, greatly affecting coal mine working environment and local residents. This study is aimed at promoting the dust suppression efficiency of dust suppressors and improving the working space and surrounding environment following the principle of waste reuse. Specifically, a new type of green superabsorbent dust suppressor (AA-DWF-PAM/GD) was prepared by treating the raw material, i.e., China fir sawdust, with solutions such as NaOH and Na2SO3 through microwave-assisted in-situ synthesis. The following findings were obtained. The microscopic morphology, reaction mechanism, thermal stability and water absorption performance of AA-SW-PAM/GD were investigated by means of SEM, FTIR, TG-DTG and swelling kinetics experiments. The results show that AA-SW-PAM/GD presents a network structure and boasts high stability. DWF reacts well with acrylic acid (AA) and polyacrylamide (PAM), and no activity damage occurs before 73 ℃. Besides, the dust suppressor has the highest water absorption rate of 325 times, and its highest salt water absorption rate is about 100 when the solubility of NaCl, MgCl2 and CaCl2 salt solutions is 1%. In the dust suppression performance test, AA-DWF-PAM/GD reaches a dust suppression rate of about 90% when the airflow velocity is 14 m/s. After AA-DWF-PAM/GD is mixed with coal for combustion, the heat release rate is increased by 4.53 kW/m2, and the combustion time is prolonged by about 15 s. That is, after being sprayed during its use, AA-DWF-PAM/GD will not pose a negative impact on the calorific value of coal. According to the results of molecular dynamics simulation, AA-DWF-PAM/GD primarily acts on the coal-water interface, raising the thickness of the coal-water interface to 28×10−6 mm (13-41×10−6 mm), enhancing the diffusion of water molecules on the coal surface and attracting water molecules to migrate toward the coal seam. Moreover, after its addition, the self-diffusion coefficient (D) of water molecules grows by 4.3×10−9 m2/s, which means that the wettability of the coal seam surface is promoted. Overall, considering its low cost, environmental friendliness and remarkable dust suppression performance, AA-DWF-PAM/GD proposed in this study is a promising dust suppressor that can be widely used in coal mines.

     

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