广东乐昌铅锌尾矿的酸化潜力

利用净产酸试验(NAG)和净产酸潜力试验(NAPP)方法,研究了广东乐昌铅锌尾矿的产酸潜力.该尾矿的黄铁矿的硫和总硫含量分别为12.57%和18.68%,NAG和NAPP值分别为H₂SO₄ 220 kg·t^-1和326 kg·t^-1,NAG和NAPP的试验结果都表明该尾矿有着很高的产酸潜力.由于黄铁矿硫不会完全被氧化,NAG比NAPP可更为准确地预测尾矿的产酸潜力.2个剖面的分析表明,因氧化难以进入尾矿深部,酸化主要发生在尾矿表面0～20cm,且对下层尾矿的影响很小.尾矿的pH值与EC值显著负相关,表明酸化促进乐昌尾矿中盐分的溶解和重金属的迁移,在酸化的表层,有效态Pb、Zn、Cu和Cd含量显著高于未酸化的下层,而Pb、Zn、Cu和Cd的总量却显著低于未酸化的下层.

Acid Producing Potential of a Lead/Zinc Mine Tailings at Lechang, Guangdong Province

The acid producing potential of a Pb/Zn mine tailings at Lechang City, Guangdong Province were studied using both net acid generation (NAG) and net acid production potential (NAPP) methods. The pyritic and total sulfur contents of the tailings were 12.57% and 18.68% respectively. The NAG and NAPP values were H2SO4 220 kg.t-1 and 326 kg.t-1, and both the NAG and NAPP results indicated that the tailings had high acid forming potential. NAG was more accurate than NAPP in predicting acid forming potential of the tailings due to the uncompleted oxidization of pyritic sulfur. Analysis of samples from two profiles test indicated that the acidification major occurred on the surface (0-20 cm) of the tailings because of limited oxygen diffusion and had little effects on the tailings at lower horizons. pH values were negatively related to EC, indicated that the acid released accelerate dissolution of the solid matrix and increase in both cations and actions in solution, the extractable Pb, Zn, Cu and Cd at the acidifying tailings surface.