水处理污泥陶粒的制备及其对重金属的固定

以湿态水处理污泥作为主要原料,混合粉煤灰和集料尾泥制备了陶粒,陶粒烧成过程模拟了回转窑工况条件。结果表明:当污泥掺入量较高时,污泥中有机成分的高温分解使陶粒坯体有较强的烧胀作用。当陶粒坯体中污泥质量含量为50%、粉煤灰和集料尾泥分别为25%时,1040℃短时烧结后的陶粒样品具有较为理想的轻集料性能,其堆积密度为760 kg/m3,筒压强度为5.2 MPa。浸出实验表明:随着污泥掺量的增加,从陶粒中浸出重金属离子量的增加幅度较小。这说明陶粒结构对污泥中的重金属有较强的稳定和固定作用,污泥陶粒的使用不会对环境造成二次污染。

Preparation and Heavy Metal Immobilization of Keramzite Spheres from Municipal Sewage Sludge

The lightweight keramzite spheres were prepared using wet sewage sludge from municipal sewage treatment plant with the gangue sludge and fly ash as aids.The fabrication process simulated the conditions of practical kiln firing.The results indicated that apparent bloating took place when the sewage sludge was the main component in green keramzite spheres due to its organic mass decomposition at high temperature.The desirable light weight keramzite spheres could be prepared at 1040 ℃ with short stay time as the sewage sludge was 50%,fly ash and gangue sludge were 25%,respectively.The as-prepared keramzite spheres had a bulk density of 760 kg/m3 combined with cylindrical compress strength of 5.2 MPa.With increasing amount of sewage sludge in the green samples,the leaching concentration of heavy metal increased slowly,suggesting that the keramzite structure had a strong stabilization and fixing ability of heavy metal and the as-prepared keramzite spheres were environmental friendly.