复合硅酸盐水泥固化含氟污泥的试验研究

Research on resource utilization of fluoride sludge solidified by ordinary portland cement

摘要:

采用复合硅酸盐水泥对含氟污泥进行固化处理并制取了不同污泥掺量的水泥标准试块，考察了掺量对试块抗压强度、氟离子浸出量、物相转变和晶体形态的影响。结果表明，当含氟污泥掺量为10％时，试块强度高，氟离子浸出量低，是较为适宜的污泥掺加比例。10％掺量试块28天抗压强度达到22.2 MPa，满足一般垫层、基础、地坪及受力不大的结构强度要求；10％掺量试块在地下水和酸雨作用下的氟离子浸出量分别为0.16 mg/L和0.39 mg/L，远小于危险废物100 mg/L的标准限值，安全性较高；机理研究表明，氟化钙污泥的加入加快了水泥中C3A的水化速度，增加了早期AFt生成量，提高了试块早期强度。

Abstract:

The composite Portland cement was used to solidify the fluorine-containing sludge, and the cement standard test blocks with different sludge content were prepared. The effects of sludge content on the compressive strength, fluorine ion leaching amount, phase transformation and crystal morphology of the test blocks were investigated. The results show that when the amount of fluorine-containing sludge is 10%, the strength of test block is high and the amount of fluorine ion leaching is low, which is the more appropriate proportion of sludge. The 28 day compressive strength of the test block with 10% content reaches 22.2 MPa, which meets the strength requirements of general cushion, foundation, floor and structure with little stress.The fluoride ion leaching amount of 10% mixed sample under the action of groundwater and acid rain is 0.16 mg/L and 0.39 mg/L respectively, which is far less than the standard limit of 100 mg/L of hazardous waste and has high safety. Mechanism study shows that the addition of fluorine-containing sludge accelerates the hydration rate of C3A in cement, increases the amount of AFt in the early stage, and improves the early strength of the test block.