减水剂与磷建筑石膏适应性研究

Study on the adaptability of water reducing agents with phosphorus building gypsum

磷石膏资源化利用的一条重要途径是磷石膏制备磷建筑石膏,磷建筑石膏存在拌和需水量大、耐水性差等缺点,在实际使用中需要使用减水剂,而部分减水剂在酸碱度变化时作用于磷建筑石膏的效果差异较大,分别利用3种减水剂对磷建筑石膏改性,探究减水剂种类、掺量对磷建筑石膏性能影响规律。通过将NaF引入天然石膏模拟磷建筑石膏,探究F-对半水石膏浆体中聚羧酸减水剂性能的影响。结果表明:聚羧酸减水剂具有缓凝增强的效果,掺量为0.4%时,样品绝干抗压强度提高了30.79%,且聚羧酸减水剂具有优异适应性,半水石膏浆体pH值在9.98附近时,0.2%聚羧酸减水剂使绝干强度提高了63.54%;同时Na F的引入会影响聚羧酸减水剂的缓凝性,且导致聚羧酸减水剂的分散性有一定下降。

An important way for vesource utilization of phosphogypsum is to prepare phosphorus building gypsum,which has disadvantages such as high mixing water demand and poor water resistance.In practical use,water reducing agents are needed,and some water reducing agents have significant differences in their effects on phosphogypsum when the pH changes.Three kinds of water reducing agents were utilized to modify phosphorus building gypsum to investigate the influence of water reducing agent type and dosage on the performance of phosphorus building gypsum,and the effect of F-on the performance of polycarboxylic acid water reducing agent in hemihydrate gypsum slurry was investigated by introducing NaF into natural gypsum.The results showed that:the polycarboxylic acid water reducing agent has the effect of retardation and enhancement,and the adiabatic compressive strength of the samples was increased by 30.79%when 0.4%was doped,and the polycarboxylic acid water reducing agent has excellent adaptability,and the adiabatic strength was increased by 63.54%by 0.2%polycarboxylic acid water reducing agent in hemihydrate gypsum slurry when the pH of hemihydrate gypsum slurry was near 9.98;at the same time,the introduction of NaF affects the retardation property of the polycarboxylic acid water reducing agent,and leads to certain decrease of the polycarboxylic acid water reducing agent dispersion.