矿山废石堆体内部酸碱性变化对治理矿山废石堆体引起的污染有重要指导意义。本文以磷矿废石和煤矸石为例,开展XRD和中和能力(ANC/BNC)测定试验,依据试验结果推算出100年后磷矿废石堆体和煤矸石堆体内的酸碱性。结果表明,1kg磷矿废石需0.206mol HNO_3使之中和,磷矿废石对酸具有较强的缓冲能力,100年内酸雨(p H≈4.5)提供的H+不足以中和磷矿废石中碱性物质,堆体内部水分的p H值将长期维持在自然p H条件(p H≈8.6);煤矸石堆体内部呈酸性(p H≈6.6),1kg煤矸石需0.053mol Na OH使之中和,在酸雨的作用下,废水的酸性会逐渐增强,采用投加碱性中和剂方法能够处理煤矸石产生的酸性废水。
The acidity change inside the waste mine rock pile has important guiding significance to the management of the waste mine rock pile pollution. This study employed XRD and neutralization capacity tests on the phosphate mining waste rocks and coal gangue to estimate their acidity after 100 years. Results showed that 1 kg phosphate waste rock can neutralize 0. 206 mol HNO_3,indicating the relatively strong buffering capacity of the phosphate waste rocks pile,the number of H+provided by the acid rain( p H≈4. 5) of 100 years are still not enough to neutralize alkaline substances of the phosphate waste rock pile,such the p H of moisture in the pile will maintain at natural( p H ≈ 8. 6) for a long time. Results also showed that the coal gangue pile is acidic( p H≈6. 6),1 kg coal gangue can neutralize 0. 053 mol Na OH,and the acid rain will further increase the acidity of the waste water,therefore,alkali neutralizers are needed to neutralize the acid waste water.