添加保水剂对煤矸石基质保水性能的影响

Effect of addition of water-retaining agent on the water-retaining properties of coal gangue matrix

煤矸石是煤炭生产过程中产生的固体废弃物,保水能力较低。大量煤矸石堆积形成的煤矸石山会造成严重的环境污染问题。当前对煤矸石山治理的主要途径是在煤矸石山上直接覆土再植被重建,但是矿区土壤缺乏且立地条件极端恶劣;因此,探究在土壤中添加不同比例的煤矸石和保水剂,对合理利用煤矸石并提高其保水性能十分必要。以灵武羊场湾排土场为研究对象,设置矸土比3∶1(CGM1)、1∶1(CGM2)和1∶3(CGM3)3种煤矸石基质类型,并分别添加比例为0.1%、0.2%和0.5%的丙烯酰胺丙烯酸钾交聚物型(CLP)保水剂和凹凸棒复合丙烯酸丙烯酰胺型(WT)保水剂,通过土柱模拟法,测定煤矸石基质的孔性、吸水性、持水性及入渗特性。结果表明:CGM2和CGM3的孔隙度、持水量和累积入渗量高于CGM1。随着添加CLP和WT比例的提高,煤矸石基质的吸水量和持水量呈现出增加的趋势。添加CLP对土壤水分入渗具有促进作用,且随着添加比例增加,其促进作用越明显;而添加WT用量与煤矸石基质累积入渗量呈反比。多因素方差分析表明,煤矸石基质类型是影响基质持水量的主要因素,保水剂种类对煤矸石基质的累积入渗量的影响程度最大。将21个处理进行系统聚类分析发现,类别Ⅲ仅包含在CGM2下施加0.5%CLP的处理,该种处理的水分吸持性和入渗特性均优于其他处理。综合来看,添加保水剂可提高煤矸石基质的保水性能,在矸土比为1∶1下施加0.5%丙烯酰胺丙烯酸钾交聚物型保水剂具有最佳的保水效果。

[Background]Coal gangue is a solid waste generated in the process of coal production,which has low water-retaining capacity.A large amount of coal gangue accumulation may cause serious environmental pollutions.At present,the main way to treat gangue mountains is to directly cover soil and vegetation reconstruction;however,usually the mining area is short of soil and the site condition is extremely adverse.Therefore,it is necessary to add different proportion of coal gangue and water-retaining agent in soil to make rational use of coal gangue and improve its water-retaining property.[Methods]Yangchangwan dump site of Lingwu in Ningxia Hui Autonomous Region was taken as the research object,and 3 types of gangue matrix were set up:the ratio of coal gangue to soil was 3∶1(CGM1),1∶1(CGM2)and 1∶3(CGM3).In addition,acrylamide-potassium acrylate crosspolymer type(CLP)and attapulgite composite acrylamide-acrylamide type(WT)water-retaining agent with ratios of 0.1%,0.2%and 0.5%were added respectively.The porosity,water absorption,water-retaining capacity and infiltration of gangue matrix were determined by soil column simulation.[Results]1)The porosity,water-holding capacity and cumulative infiltration of CGM2 and CGM3 were higher than those of CGM1.With the increasing of proportion of CLP and WT,the water absorption and water-holding capacity of these treatments showed an increasing trend.The addition of CLP promoted soil water infiltration,and with the increasing of the proportion,its promotion effect became more obvious.However,the addition of WT was inversely proportional to the cumulative infiltration of coal gangue matrix.In CGM2,the adding proportion of 0.5%CLP had the highest cumulative infiltration at 60 min,reaching 48.78 mL.2)A multi-way ANOVA demonstrated that the type of coal gangue matrix was the main factor affecting the water-holding capacity of the matrix,and the type of water-retaining agent had the greatest influence on the cumulative infiltration of coal gangue matrix.3)Cluster analysis was performed on 21 treatments,which were divided into 3 groups.GroupⅢonly included treatment adding 0.5%CLP under CGM2,which had better water retention and infiltration characteristics than those of other treatments.[Conculsions]Adding water-retaining agent can improve the water retention performance of coal gangue matrix.The best water retention effect is obtained when 0.5%acrylamide-potassium acrylate crosspolymer added to the ratio of coal gangue to soil 1∶1.