沸石作稳定化剂固化/稳定化含汞危险废弃物试验

利用沸石对汞的吸附性,将沸石作为稳定化剂掺入水泥进行含汞危险废弃物固化/稳定化试验研究.同时,探讨了沸石作为稳定化剂的水泥固化技术处理含汞废弃物的影响因素,从而明确这种方法的可行性和最佳操作条件.结果表明,沸石的掺入能够促进汞的稳定,与单独使用水泥相比固化效率显著提高.当沸石用量为0.3g·g-1以上时,固化体浸出汞浓度低于国家标准(GB5085.3-2007),固化效率从单独使用水泥固化时的47%提高到95%以上.氯离子能够影响固化效率,即使在氯离子浓度为10mmo·lL-1时,含汞1000mg·kg-1以下的固体废弃物的固化效率仍能够大于90%.这说明即使存在氯离子干扰的情况下,沸石作稳定化剂固化含汞危险废物仍然是非常经济有效的方法.实验得到沸石作稳定化剂固化含汞危险废弃物的最佳操作条件为pH=6.0～7.0之间,沸石量为0.4g·g-1,水泥量为0.7g·g-1以上.

Stabilization/solidification (S/S) of mercury-contaminated hazardous wastes using natural zeolite and Portland cement

Since zeolite can absorb mercury, zeolite was mixed into cement to stabilize/solidify mercury in solid waste. Experiments were carried out to study the factors affecting the whole stabilization/solidification (S/S) process, and thereby certify the feasibility and the optimum conditions for this work. Compared with cement alone, adding zeolite into cement was more effective in stabilizing Hg in the waste surrogate. When 0.3 g·g-1 zeolite was added, the stabilization efficiency increased from 47% to 95%, and the concentration of Hg leaching from the solid was lower than the national standard. The Cl- content could reduce the stabilization efficiency. However, even though the Cl- concentration in the stabilization solution was 10 mmol·L-1, the stabilization efficiencies for the surrogate with less than 1000 mg·kg-1 Hg were over 90%, which indicated that whether or not Cl- is present, the (S/S) process of mixing zeolite into Portland cement is an effective technology to treat waste containing mercury. The optimum conditions for treating solid waste with mercury are pH=6.0~7.0, zeolite dosage 0.4 g·g-1, and cement content more than 0.7 g·g-1.