磷Ⅱ型无水石膏制备及活性联合激发基础研究

Basic research on preparation and activity combined excitation of anhydrite-Ⅱphosphogypsum

以磷石膏为研究对象,首先借助差热分析确定了适宜煅烧温度,并研究保温时间、粉磨细度与磷Ⅱ型无水石膏(AⅡ)活性关系;其次,以强化AⅡ水化硬化、强度提升为目的,优选激发剂与表面活性剂复配并对其协同激发效应进行研究。结果表明:2.0%钾明矾和1.5‰LA-1复配效果最好,2.0%钾明矾单掺、2.0%钾明矾和1.5‰LA-1复配28d抗压强度分别为26.1MPa、36.5MPa,抗压强度提升了39.85%;通过体系的水化率和石膏颗粒表面zeta电位绝对值随表面活性剂掺量变化规律,结合SEM对其微观形貌进行分析,复配激发剂改变了石膏颗粒表面zeta电位绝对值,加速了AⅡ的水化,并且使少量生成的二水石膏晶型由原本的棱柱状转变为较为细小的棒状结构填补在棱柱状晶型交错的孔隙之间,进而使整体形成更致密结构。

In this paper,phosphogypsum was taken as the research object.Firstly,the suitable calcination temperature was determined by differential thermal analysis,and the relationship between holding time,grinding fineness and AⅡactivity was studied.Secondly,in order to strengthen the hydration hardening and strength improvement of AⅡ,the combination of activator and surfactant was optimized and its synergistic excitation effect was investigated.The results showed that the combination of 2.0%potassium alum and 1.5‰LA-1 had the best effect.The 28d compressive strength of 2.0%potassium alum,2.0%potassium alum and 1.5‰LA-1 was 26.1 MPa and 36.5 MPa,respectively,and the compressive strength increased by 38.71%.Through the change law of the hydration rate of the system and the absolute value of the zeta potential on the surface of the gypsum particles with the amount of surfactant,and the analysis of its microscopic morphology combined with SEM,the compound activator changed the absolute value of the zeta potential on the surface of the gypsum particles,accelerated the hydration of AII,and made a small amount of generated dihydrate gypsum crystal form from the original prismatic to a relatively small rod-like structure to fill in the interlaced pores of the prismatic crystal form,thereby forming a denser structure as a whole.