磷石膏基发泡建筑石膏的制备与性能研究

Study on Preparation and Properties of Phosphogypsum-based Foamed Building Gypsum

摘要:

为探究不同配合比对磷石膏基发泡建筑石膏物理力学性能的影响规律,提高磷石膏的资源化利用率,试验采用单因素试验分析和微观形貌检测方法,系统研究了三种不同配合比下的磷石膏基发泡建筑石膏的物理力学性能、热学性能和孔隙结构。利用扫描电镜(SEM)深入观察并分析了不同配合比下的磷石膏基发泡建筑石膏的微观形貌和各组分之间的相互作用机制,揭示了微观结构与宏观性能变化之间的内在联系。试验结果表明:磷石膏基发泡建筑石膏的表观密度和力学性能随发泡剂掺量的增加而减小;最佳配合比:磷石膏掺量为60%、水泥掺量为20%、矿渣粉掺量为10%、石膏晶须掺量为10%、缓凝剂掺量为胶凝材料的0.1%、水固比为0.5。与之对应的最优的十二烷基硫酸钠(K12)发泡剂掺量为12.5%,由其制备的磷石膏基发泡建筑石膏的绝干强度达到最优水平;SEM试验表明,石膏晶须填充了晶体搭接之间的孔隙,使试块的密实度提高,且石膏晶须在试块的微缝处形成搭接,阻碍了微裂缝的产生和扩张,改善了试块的内部孔隙结构,提高了磷石膏基发泡建筑石膏的综合性能。

Abstract:

To explore the influence laws of different mix ratios on the physical and mechanical properties of phosphogypsum-based foamed building gypsum, in order to improve the resource utilization rate of phosphogypsum, the experiment adopted single-factor experimental analysis and microscopic morpho-logy detection methods to systematically study the physical and mechanical properties, thermal properties and pore structure of phosphogypsum-based foamed building gypsum under three different mix ratios. The microscopic morphology of phosphogypsum-based foamed building gypsum under different mix ratios and the interaction mechanism between each component were deeply observed and analyzed using scanning electron microscopy (SEM), revealing the intrinsic relationship between the microstructure and macroscopic performance changes. The test results showed that the apparent density and mechanical properties of phosphogypsum-based foamed building gypsum decreased with the increase of foaming admixture content; the optimal mix ratio was: phosphogypsum content of 60%, cement content of 20%, slag powder content of 10%, gypsum whisker content of 10%, retarder content of 0.1% of the cementitious material, water-to-solid ratio of 0.5. Correspondingly, the optimal sodium dodecyl sulfate (K12) foaming agent content was 12.5%, and the phosphogypsum-based foamed building gypsum prepared with this foaming agent reached the optimal level of absolute dry strength; SEM tests indicated that gypsum whiskers filled the pores between crystal connections, increasing the density of the test block, and gypsum whiskers formed connections at the micro-fissures of the test block, preventing the generation and expansion of micro-cracks, improving the internal pore structure of the test block, and enhancing the comprehensive performance of phosphogypsum-based foamed building gypsum.