城市污泥作为型焦粘结剂的工艺及机理研究

Technology and Mechanism of Municipal Sludge as Formed Coke Binder

以城市污泥为粘结剂的基础组分,采用化学方法活化,考察了活化剂种类和活化条件对型焦性能的影响,并对型焦的固结机理和结构进行分析。结果表明:磷酸对污泥的活化效果最好,当磷酸浓度为30%、浸渍比为5.3 g/m L、浸渍时间为24 h时,生块和熟块的抗压强度均大于5000 N、落下强度分别为7次和8次,耐水性能(浸水24 h干燥后的抗压强度)分别为2575 N和3015 N。生块的热解分为三个阶段,其中磷酸盐分子间发生脱水缩聚最终生成-P-O-M-O-P-高分子结构是粘结兰炭末成型的主要原因。型焦熟块与兰炭末红外吸收峰的位置基本相同,但强度有明显减弱,未出现与磷有关的振动吸收峰,说明磷在型焦中残留量很少。

Municipal sludge was chosen as a base component of binder to form coke. And the sludge was activated with chemical method. Both the kinds of activator and activation conditions were considered on the formed coke properties, and the consolidation and structural mechanisms of formed coke were analyzed. The results show that the phosphate works best in activating sludge, when the concentration of phosphoric acid of 30% , the impregnation ratio of 5.3 g,/mL, dipping time of 24 h, both the compression strength of raw block and ripe block are greater than 5000 N. The dropping strength were 7th and 8th, and the water resistance were 2575 N and 3015 N respectively. Pyrolytic reaction of block was divided into three stages. Dehydration condensation among phosphate to form macromolecular structure of -P-O- M-O-P- was the mainly reason to the forming of semi-coke powder. Infrared absorption peak position of cooked coke and semi-coke powder was basically the same, but the intensity of cooked coke decreased significantly, and phosphorus-related vibration absorption didn＇ t appear, indicating that there was little phosphorus in formed coke.