摘要
以铅锌尾矿砂为研究对象,提出一种新型植酸酶诱导磷酸铵镁(PIMAP)技术对其进行修复,并与传统磷酸铵镁水泥(MAPC)进行比较,通过无侧限抗压强度试验、重金属浸出毒性试验以及微观分析等手段,研究PIMAP和MAPC处理后铅锌尾矿砂的固化特性和重金属稳定化效果。研究结果表明:经PIMAP处理后重金属铅、锌、镉浸出毒性显著降低,均满足地下水标准要求;重金属从较活跃的离子交换态和碳酸盐结合态向较稳定形态转化。在固化剂质量分数为8%时,尾矿砂的无侧限抗压强度可达2.45 MPa,较MAPC处置后强度提升20%以上,可用作路基底基层;PIMAP固化过程产生的磷酸铵镁较MAPC的多,晶体尺寸更大,且固化后试样pH约为7.5,明显比MAPC固化试样的低。
Phytase induced magnesium ammonium phosphate(PIMAP)was used to repair lead−zinc tailings,and it was compared with traditional magnesium ammonium phosphate cement(MAPC).By means of unconfined compressive strength test(UCS),heavy metal leaching toxicity test and microscopic analysis,the solidification characteristics and heavy metal stabilization effect of lead−zinc tailings treated by PIMAP and MAPC were studied.The results show that the leaching toxicity of lead,zinc and cadmium decreases significantly after PIMAP treatment,which meets the environmental quality standards for groundwater,and the heavy metals transform from active ion exchange and carbonate bound species to more stable species.The UCS of tailing sand can reach 2.45 MPa at the dosage of 8%(mass fraction)curing agent,which is more than 20%higher than that of MAPC treatment,and can be used as subbase materials.The magnesium ammonium phosphate produced during PIMAP process is more than that of MAPC,and the crystal size is also larger.The pH of S/S treated tailings sample by PIMAP is about 7.5,which is significantly lower than that of MAPC treated samples.
作者
王梦淇
雷学文
韩丽君
李江山
WANG Mengqi;LEI Xuewen;HAN Lijun;LI Jiangshan(School of Urban Construction,Wuhan University of Science and Technology,Wuhan 430065,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《中南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2023年第8期3250-3259,共10页
Journal of Central South University:Science and Technology
基金
国家重点研发计划项目(2019YFC1804002)。
关键词
铅锌尾矿砂
植酸酶诱导磷酸铵镁
固化/稳定化
强度
浸出毒性
lead−zinc tailings
phytase induced magnesium ammonium phosphate
stabilization/solidification(S/S)
strength
leaching toxicity