脱硫石膏掺杂氧化锌转晶制备高性能建筑石膏

Preparation of high⁃performance building gypsum by desulfurization gypsum doped with ZnO crystal transformation

脱硫石膏经过热处理批量制备建筑石膏,不仅可以缓解环境污染问题,还具有一定的经济效益。以电厂脱硫石膏为原料,添加氧化锌为转晶助剂,通过热处理调控脱硫石膏煅烧产物的晶体结构,从而制备高性能的建筑石膏,并研究了氧化锌添加量和煅烧温度对建筑石膏性能的影响。结果显示,氧化锌助剂的添加拓宽了脱硫石膏煅烧成半水石膏的温度范围,还改善了煅烧产物的结晶度。脱硫石膏中添加0.6%氧化锌(以质量分数计),在180℃煅烧制备的建筑石膏性能最佳。水化2 h产物的形貌为相互交叉堆积的针状或纤维状晶体,2 h抗折和抗压强度分别达到3.8 MPa和9.2 MPa,符合3.0等级建筑石膏标准的要求,可以实现脱硫石膏的规模化资源利用制备高性能的建筑石膏。

The mass preparation of building gypsum from desulfurization gypsum after heat treatment not only alleviates en⁃vironmental pollution problems,but also has certain economic benefits.High⁃performance building gypsum was prepared by using desulfurization gypsum from power plant as raw material and adding ZnO as crystal transformation adjuvant to adjust the crystal structure of calcined products of desulfurization gypsum through heat treatment.And the effects of ZnO content and calcination temperature on the properties of building gypsum were studied.The results showed that the addition of ZnO broadened the temperature range for calcining desulfurization gypsum into hemihydrate gypsum,and also improved the crys⁃tallinity of calcined products.By adding 0.6%ZnO(calculated by mass fraction)to desulfurization gypsum,the performance of building gypsum calcined at 180℃was the best.The morphology of products with hydration of 2 h was needle⁃like or fi⁃brous crystals that were stacked with each other.The flexural and compressive strengths reached 3.8 MPa and 9.2 MPa at 2 h,respectively,meeting the standard requirements of grade 3.0 of building gypsum.It could realize the large⁃scale re⁃source utilization of desulfurization gypsum to prepare high⁃performance building gypsum.