煤矸石骨料混凝土浸泡水特性及环境影响分析

Coal Gangue Aggregate Concrete Soaking Water Characteristics and Environmental Impact Analysis

以贵阳市花溪区麦坪乡煤矿区露天堆放的煤矸石为原料制备煤矸石骨料混凝土试样,利用天然降水和模拟酸雨液对不同煤矸石掺量的混凝土砌块进行连续浸泡及间歇浸泡试验,测定浸泡液中Fe,Mn离子浓度、p H值和电导率的变化,分析煤矸石骨料混凝土浸泡水的特性及环境影响.结果表明:(1)Fe离子在两种浸泡方式下均未析出,而Mn离子在两种浸泡方式下均有析出,且酸雨模拟液浸泡析出的离子浓度大于自然降水,间歇浸泡处理大于连续浸泡处理.(2)连续浸泡处理下,自然降水浸泡液的p H值出现先减小后增大再减小的趋势,而酸雨模拟液的p H值先增大后逐渐减小;间歇浸泡处理下,p H值整体逐渐减小.(3)两种浸泡方式下,煤矸石掺量较高的浸泡液电导率随时间变化先增大后减小.煤矸石掺量较低的浸泡液电导率随时间变化逐渐减小.(4)用此煤矸石为骨料制成的混凝土金属离子含量较低,可用作普通建材使用.但在酸性条件下,如酸性废水排水渠等,则不能用此类混凝土建材.

The coal gangue aggregate concrete samples were prepared from the open-air coal gangue of the coal mining areas in the Maiping Township, Huaxi District, Guiyang City. The continuous soaking and intermittent immersion tests of concrete blocks with different coal gangue contents were done by use of natural precipitation and simulated acid rain solution, the soaking liquid Fe and Mn concentration, pH value and conductivity were determined and the characteristics and environmental impacts of coal gangue aggregate concrete immersion wa- ter were analyzed. The results were as follows ： （ 1 ） when immersed in two solutions, Fe ions were not released, while Mn ions were all released. The concentration of irons released in the simulated acid rain solution was higher than that in the natural precipitation. The concentration of irons released in the intermittent water im- mersion was greater than that in the continuous water immersion. （2） In the continuous water immersion, the pH of the natural precipitation decreased firstly, then increased, and decreased lastly, while the pH in the simu- lated acid rain solution increased firstly, and then decreased gradually. In the intermittent water immersion, the pH all decreased gradually. （3） In two immersion solutions, the conductivity of high added coal gangue increased firstly, and then decreased gradually with time changing, while the conductivity of low added coal gangue decreased with time gradually. （4） The contents of the mental ions were low, so this kind of concrete made by coal gangue could be used as common building materials. But this kind of concrete materials couldn＇ t be used in acidic conditions such as the acid waste water drains.