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- 建筑石膏与胶凝材料
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热压法制备脱硫石膏试块的实验研究
作者：赵华，廖洪强，程芳琴
（山西大学资源与环境工程研究所，国家环境保护煤炭废弃物资源化高效利用技术重点实验室，山西低附加值煤基资源高值利用协同创新中心，山西 太原 030006）
摘要：以脱硫石膏为原料，采用热压成型工艺制备石膏试块，研究了在不同成型压力、成型温度和成型时间条件下脱硫石膏试块的质量损失率和抗压强度分布特性，并通过正交试验对工艺条件进行优化。结果表明，热压脱硫石膏试块的质量损失率整体上随成型压力、成型温度和成型时间的增加而增大；试块的抗压强度随成型压力、成型温度和成型时间的增大均呈现先提高后降低的趋势。XRD和SEM分析表明，成型温度升高，试块中的二水石膏先转化为半水石膏后转化为无水石膏，相应出现棒柱状晶体转化为致密型纤维状晶体和多孔疏松型纤维状晶体。正交试验表明，成型温度是影响脱硫石膏试块强度的主要因素；当成型温度为120 ℃、成型压力为20 MPa、成型时间为30 min时，脱硫石膏试块的抗压强度可达43.9 MPa。
关键词：脱硫石膏；热压成型；工艺条件；正交试验；
中图分类号：TU526；TQ177.3+76 文献标识码：A 文章编号：1001-702X（2018）11-0048-04
Experimental study on preparation of FGD gypsum blocks by direct hot pressing
ZHAO Hua，LIAO Hongqiang，CHENG Fangqin
（Institute of Resources and Environment Engineering of Shanxi University，
State Environment Protection Key Laboratory of Efficient Utilization of Coal Waste Resources，
Shanxi Collaborative Innovation Center of High Value-added Utilization of Coal-related Wastes，Taiyuan 030006，China）
Abstract：The gypsum test blocks were prepared by hot pressing forming process with FGD gypsum as raw material in the experiment. The weight loss rate and compressive strength distribution of gypsum test blocks under different pressure，temperature and time were studied. The results showed that the weight loss rate of gypsum blocks almost increases with the forming pressure，temperature and time. The compressive strength of blocks increased first and then decreased with the increase of forming pressure，temperature and time. XRD and SEM test showed that the dihydrate gypsum in the test block is first converted into hemihydrate gypsum and then converted into anhydrite gypsum with the increase of forming temperature，and the corresponding columnar crystals changed into dense fibrous crystals firstly，and then into porous loose fibrous crystals with the molding temperature increases. Orthogonal experiments showed that the temperature is the main factor influencing the strength of FGD gypsum. When the molding temperature is 120 ℃，the molding pressure is 20 MPa and the molding time is 30 min，the compressive strength of FGD gypsum test blocks can reach 43.9 MPa.
Key words：desulfurization gypsum，hot pressing forming，process conditions，orthogonal test