散煤运输用膜型抑尘剂的制备及性能研究

On the preparation of the membrane-cover suppressant and its characteristics in coal transportation

采用水溶液聚合法,以氧化淀粉、丙烯酸(AA)、二甲基二烯丙基氯化铵(DMDAAC)为原料,通过接枝共聚制备了一种软膜型抑尘剂(抑尘剂液体干燥后形成具有一定韧性的软膜)。与聚乙烯醇类壳型抑尘剂(干燥后形成很脆的壳层)相比,软膜型抑尘剂提高了煤粉固化层的抗破裂能力。由抗震荡性试验可知,使用膜型抑尘剂后,经过18 h的震荡,煤粉的损失率仅为1.91%,而使用壳型抑尘剂后煤粉的损失率为4.85%。还测定了2种抑尘剂的保湿性和耐破度。利用红外光谱对产物的结构进行了表征,采用SEM观察了该产物在煤粉表面形成的膜层形貌。试验结果表明,散煤运输中膜型抑尘剂在减少煤粉损失和控制扬尘污染方面性能优于壳型抑尘剂。

The present paper is inclined to introduce our method of synthesizing the membrane-type dust suppressant by graft copolymerization with acrylic acid（AA）,diallyldimethyl ammonium chloride（DMDAAC） and oxidized starch as raw materials in the aqueous solution.The membrane-type dust suppressant prepared in this way enjoys a very tough film when it was spread.Compared with the shell type dust suppressant,such as PVA series,the membrane-like dust suppressant can get improved due to its anti-rupture performance of the cured layer.For this purpose,we have measured and tested the performances of moisture retention,anti-shake and bursting strength respectively in this paper through experimentally investigating of its moisture retention with coal（crushed into 60-100 mesh particles）.Moreover,we have mixed two kinds of dust suppressants（30 mL） with coal and moved it into a glass-surface vessel so that it could be desiccated for a week in an incubator at the temperature of 25 ℃.The results show that the two types of dust suppressant are better than the ordinary distilled water for the pulverized coal,thus bringing about the best moisture retention effects of the membrane.In addition,we have also simulated the vehicle vibration during the transportation by means of an oscillator and found that the coal losing rate was 1.91% after 18 hours of vibration when the mixed suppressant we have developed was used,whereas that was 4.85% by using the PVA dust suppressant.Thus,it has proved that the membrane-type dust suppressant is superior to all other types of dust suppressant.Besides,the bursting strength of the soft film was also measured and defined： 30 mL membrane type dust suppressant（mass fraction of 2.5%） was transferred to the specially designed flat groove（internal surface area 100 cm2） made by polytetrafluoroethylene（PTFE）,and desiccated at 25 ℃ for 2 day. And,subsequently,the soft film was removed from the groove to measure the value of bursting strength,whose results can get to 53.2 kPa.However,the bursting strength of shell type can not got damned as its friability.The membrane type suppressant was characterized by IR,and the surface morphology of the film was observed by SEM.