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转晶剂对不同工业石膏制备α-半水石膏的影响

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磷石膏和脱硫石膏是堆存量最大的工业固废石膏,将其转化为半水石膏作为建筑胶凝材料是最主要的资源化利用途径.采用蒸压法制备α-半水石膏,以磷石膏和脱硫石膏为原料,天然石膏作为对照组,探究了十二烷基苯磺酸钠(SDBS)、硫酸铝[Al2(SO4)3]、复合转晶剂CM(硫酸铝、柠檬酸钠)对α-半水石膏晶体形貌的调控作用及其强度的影响.结果表明,于135℃下蒸压5 h,3种石膏均能稳定制备α-半水石膏,3种转晶剂对于半水石膏物相组成无影响,同时0.4%(质量分数)CM能够有效降低晶体的长径比;通过t检验法检测,转晶剂对脱硫石膏、天然石膏制备的α-半水石膏的抗压强度有显著性增强作用,α-半水石膏的抗压强度增加2倍以上,分别为13.59 MPa和17.45 MPa.而转晶剂对以磷石膏为原料制备的α-半水石膏的强度没有明显作用.脱硫石膏和天然石膏在0.4%CM的调控下晶体长径比降低,抗压、抗折强度显著提升,而磷石膏由于其杂质影响,转晶剂的作用效果不明显,研究结果可为工业石膏的工业化生产提供一定的理论指导.
Effect of crystal modifier on preparation of α-hemihydrates gypsum from industrial gypsum
Phosphogypsum and desulfurization gypsum are industrial solid wastes with the largest storage capacity,and transforming them into hemihydrate gypsum as building materials is the best way for resource recycle.The α-hemihydrates gypsum was obtained by autoclave method from different industrial gypsum including desulfurized gypsum(FGD),phospho-gypsum(PG)and natural gypsum(NG)as a control group.The effects of crystal modifiers including sodium dodecyl ben-zene sulfonate(SDBS),aluminum sulfate[Al2(SO4)3]and compound crystal modifier(CM)on the morphology and strength of α-hemihydrates gypsum were investigated.The results showed that under autoclaved pressure at 135℃ for 5 h,α-hemi-hydrate gypsum could be prepared by three types of gypsum stably,three types of crystal modifiers had no impact on the phase composition of hemihydrate gypsum.0.4%CM could reduce the aspect ratio of crystals effectively.Based on T-test,the crystal modifiers had significant enhancing effect on the compression strength of α-hemihydrate gypsum prepared from FGD and NG,which was increased by more than 2 times to 13.59 MPa and 17.45 MPa,respectively.However,the strength of α-hemihydrates gypsum prepared by PG had no obvious change by adding crystal modifiers.The results exhibited that 0.4%CM could reduce the aspect ratio of crystals and improved compressive and flexural strength significantly of α-hemihy-drates gypsum prepared from FGD and NG.The crystal modifier had no obvious impact on α-hemihydrates gypsum pre-pared from PG due to impurities.The results of the study provided a certain degree of theoretical guidance for the industrial production of different gypsum.

phosphogypsumdesulfurization gypsumα-hemihydrates gypsumcrystal modifiermechanical strength

王培雄、龚小梅、丁家琪、曹宏

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生态环境部长江流域生态环境监督管理局生态环境监测与科学研究中心,湖北武汉 430014

湖北省长江新材研究设计院有限公司,湖北武汉 430061

武汉工程大学材料科学与工程学院,湖北武汉 430061

磷石膏 脱硫石膏 α-半水石膏 转晶剂 强度

国家重点研发计划

2022YFC3203500

2024

无机盐工业
中海油天津化工研究设计院 中国化工学会无机酸碱盐专业委员会

无机盐工业

CSTPCD北大核心
影响因子:0.489
ISSN:1006-4990
年,卷(期):2024.56(4)
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