掺加矿粉胶凝固化垃圾焚烧飞灰中重金属的研究

Research on solidification of heavy metals in burned refuse fly ash by adding mineral powder

通过单因素实验探究了矿粉质量分数、激发剂(NaOH)投加量和加水量对掺加矿粉胶凝固化垃圾焚烧飞灰中重金属的影响,并初步探究了固化机理。结果表明,矿粉质量分数和激发剂投加量对重金属的固化影响较大,而加水量影响不大。综合考虑增容比、重金属浸出浓度和抗压强度,矿粉质量分数15%、激发剂投加量3%(质量分数)、加水量37.5%(质量分数)为有效稳定固化重金属的最佳条件,此时重金属浸出质量浓度分别是Ba 19.091mg/L、Cd 0.041mg/L、Ni 0.216mg/L、Pb 0.196mg/L,含水率为27.04%,满足《生活垃圾填埋场污染控制标准》(GB 16889-2008),抗压强度为9.61 MPa,可进入垃圾填埋场填埋。所制备胶凝材料的最终水化产物主要为水化硅酸钙、水化铝硅酸钙和钙矾石,它们可以通过包裹和吸附对重金属进行固化。

The effects of mineral powder mass percentage,activator(NaOH)dosage and water addition on the solidification by single factor experiments were explored.In addition,the mechanism was simply explored.Results showed that mineral powder mass percentage and activator dosage were conducive to the solidification but water addition not.Considering the volume ratio,the leaching concentration of heavy metal and compressive strength,the optimal condtions were that mineral powder mass percentage was 15%,activator dosage 3%(mass percentage)and water addition 37.5%(mass percentage).Under the optimal conditions,the leaching concentration of heavy metals was Ba 19.091 mg/L,Cd 0.041 mg/L,Ni 0.216 mg/L and Pb 0.196 mg/L with moisture content 27.04%and compressive strength 9.61 MPa,meeting"Standard for pollution control on the landfill site of municipal solid waste"(GB 16889-2008),which could be entered into the landfill site.The main hydration products of solidified material were calcium silicate hydrate,calcium aluminosilicate hydrate and ettringite.They could solidify heavy metals by inclusion and adsorption.