黄铁矿氧化酸化及含铊重金属的迁移释放

ACID GENERATION FROM PYRITE OXIDATION AND RELEASE OF HEAVY METALS TOGETHER WITH Tl

矿山酸性排水(ARD)导致严重的重金属污染.本文用动态浸滤试验方法研究了黄铁矿氧化产酸的特征及重金属和金属铊在黄铁矿氧化产酸过程中向环境迁移释放的特征.研究表明:(1)受碳酸盐控制,前16周浸滤液呈中性;20周后受硫化物的氧化反应控制,浸滤液pH<4,开始酸性排放.(2)硫化物的氧化速率是非线性变化的,并随pH值下降而加快.(3)黄铁矿酸化过程中金属表现出不同的迁移释放特征:铊向环境的迁移随pH值下降而增强,而镉、铅、锌、铜等重金属呈现峰值,pH<3时,Fe3+参与金属硫化物的氧化反应,进一步促使镉、铅、锌、铜等重金属的释放.

Acid rock drainage（ARD）causes serious heavy metal pollution.The characteristics of acid generation due to pyrite oxidation was studied in this paper using the kinetic flood leaching method.The release of heavy metals together with Tl into the environment during the acid generation process was also investigated.Kinetic test showed that：（1）In the first 16 weeks,the drainage pH was controlled by carbonate and remained neutral.After 20 weeks the pH dropped to below 4 due to sulfide oxidation.（2）The rate of pyrite oxidation changed nonlinearly and accelerated at lower pH.（3）Different metals showed different release characteristics：Tl release to environment increased with lower pH;The release curve for Ni,Pb,Zn,Cd,Cu had a peak.Heavy metals released further after drainage pH3 due to the sulfide oxidation reaction with Fe3＋and metal sulfide dissolution.