磷石膏热处理制备免烧建材

    Preparation of No Burning Building Materials by Phosphogypsum Heat Treatment

    • 摘要: 这是一篇陶瓷及复合材料领域的论文。磷石膏排放量大,利用率低,资源化利用迫在眉睫。该研究以磷石膏为原料,经过激发预处理的磷石膏在不同温度下热处理,研究热处理温度对磷石膏的物相和微观结构,以及将其制备成免烧建材样品后的抗压强度、物相、微观结构的影响规律。结果表明,随着热处理温度的升高,二水石膏晶体结晶度增加,晶型发生转变,经过80 ℃热处理后的二水石膏晶粒致密,并且部分转变为半水石膏,由半水石膏水化重结晶生成的二水石膏对空隙进行填充,形成了结构致密,晶体相互粘合的内部微观结构,大大提高了免烧建材的抗压强度。免烧样品(磷石膏与水泥质量比为4∶1)养护7 d和28 d抗压强度达到36.45 MPa和38.12 MPa,并且浸水24 h的样品仍能保持21.03 MPa的抗压强度。

       

      Abstract: This is an article in the field of ceramics and composites. Phosphogypsum has a large discharge and low utilization rate,and resource utilization is imminent. The heat treatment of phosphogypsum under different temperatures was studied. The influence of heat treatment temperature on the physical phase and microstructure of phosphogypsum, and the compressive strength, phase and microstructure of non burningsample of building materials by the treated phosphogypsum were studied. The results show that with the increase of heat treatment temperature, the crystallinity of gypsum increases and the crystal form changes. After heat treatment at 80 ℃, the crystal of gypsum is dense, and part of it is converted into hemihydrate gypsum. The Gypsum dihydrate formed by hydration recrystallization of hemihydrate gypsum fills the void, forming the internal microstructure of dense and mutual bonding of crystals, so the compressive strength of no burning building materials is greatly improved. After curing for 7 days and 28 days, the compressive strength of non burningsample (the mass ratio of phosphogypsum to cement is 4∶1) reaches 36.45 MPa and 38.12 MPa. The compressive strength of the sample soaked in water for 24 hours is still 21.03 MPa.

       

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