全固废烧结砖的制备及性能研究

Study on preparation and properties of all-solid waste fired bricks

以建筑渣土、黄河沉积沙以及污泥为原材料制备全固废烧结砖,借助XRD、XRF、SEM等手段对原材料进行了详细的理化性质测试,确定了坯体的最佳制备方法及烧结制度,探究了含水率及黄河沉积沙掺量对烧结砖力学性能的影响规律。结果表明:含水率为25%时坯体水分挥发稳定,此时砖体烧结强度高;黄河沉积沙取代率为30%时坯体内形成完整的骨架结构,烧结砖强度增加;在每2个梯度间进行2 h保温处理,可为物质反应及气体挥发提供所需外部环境,提升烧结质量;烧结砖内部存在高温冷却后形成的由玻璃相以及主晶相构成的砖体骨架,使砖体具有良好的结构稳定性及力学强度;在含水率为25%、黄河沉积沙取代率为30%时,砖体强度达到29.3 MPa,吸水率为9.9%,符合工程用砖要求。通过原材料处理、配比设计、坯体成型、烧结工艺等方面对烧结砖的制备工艺进行研究,为全固废烧结砖的生产制备提供了理论依据。

Construction waste and Yellow River sedimentary sand and sludge were used to make the all-solid waste fired brick.The physical and chemical properties of raw materials were evaluated by using XRD,XRF,SEM and other methods.The best preparation method and sintering system have been determined.The influence of water content and addition of Yellow River sedimentary sand on the mechanical properties of fired bricks was investigated.The results show that when the water content is 25%,the moisture volatilization is stable,and the strength of fired brick is enhanced.When the replacement rate of Yellow River sedimentary sand is 30%,a complete skeleton structure is formed and the strength of fired brick is increased.2 h insulation treatment in every 2 gradient can provide the necessary environment for material reaction and gas volatilization,and can improve the strength of fired bricks.Inside the fired brick,glass phase and main crystal phase formed after high temperature cooling constitutes the brick skeleton,therefore the brick has good structural stability and mechanical strength.When the water content is 25%and the replacement rate of Yellow River sedimentary sand is 30%,the brick compressive strength is up to 29.3 MPa and the water absorption rate is 9.9%,which meets the requirements of engineering.In this paper,the preparation technology of fired bricks is studied from the aspects of raw material handling,proportioning design,raw brick forming and sintering process,and provides a theoretical basis for the production and preparation of all-solid waste sintered bricks.