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脱硝粉煤灰中NH4HSO4在粉煤灰水泥复合体系的留存释放规律及影响
Retention and Release of NH4HSO4 in Denitration Fly Ash in Fly Ash Cement Composite System and Its Effect
投稿时间:2019-12-11  修订日期:2020-04-22
DOI:103969/j.issn.1007 9629202103029
中文关键词:  脱硝粉煤灰  NH4HSO4  留存  释放  规律  影响
英文关键词:denitration fly ash  NH4HSO4  retention  release  law  influence
基金项目:国家自然科学基金资助项目(51872032)
           
作者单位
刘振华
LIU Zhenhua
重庆大学材料科学与工程学院,重庆400045
College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China
王智
WANG Zhi
重庆大学材料科学与工程学院,重庆400045
College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China
贺云飞
HE Yunfei
重庆大学材料科学与工程学院,重庆400045
College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China
秦洪一
QIN Hongyi
重庆大学材料科学与工程学院,重庆400045
College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China
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中文摘要:
      通过外掺NH4HSO4的模拟手段,研究了脱硝粉煤灰中NH4HSO4在粉煤灰水泥复合体系(简称复合体系)的留存与释放行为规律,以及二者对复合体系的影响.结果表明:脱硝粉煤灰中的NH4HSO4在复合体系中分解,释放出氨气,部分留存在复合体系中.将30%脱硝粉煤灰掺入水泥中,所留存的NH4HSO4对复合体系pH值的降低程度较小且集中在前1h,对复合体系后期pH值基本无影响;脱硝粉煤灰中的NH4HSO4对水泥水化的影响也集中在早期,降低了水泥水化放热峰、延缓了放热峰的出现,后期虽然水泥水化不断进行,但其对水泥水化热和水化产物基本无影响;随着氨含量的提高,复合体系氨气释放量增大,释放速率加快,NH+4和NH3·H2O的留存比例也越大;氨气释放导致硬化后的复合体系孔隙率增加,大孔数量增加;脱硝粉煤灰中氨含量增加、浆体搅拌、浆体水灰比增大均会加快复合体系的氨气释放速率.
英文摘要:
      The retention and release behavior of NH4HSO4 in fly ash cement composite system(composite system for short) and the influence of NH4HSO4 on the composite system was studied by means of simulation. The results show that NH4HSO4 in denitration fly ash decomposes in the composite system and releases ammonia, part of which remains in the composite system. When 30% denitration fly ash is added into cement, the remaining NH4HSO4has little effect on the pH value of the composite system, and it is concentrated in the first 1h. The influence of retained NH4HSO4 on cement hydration is also concentrated in the early stage, which reduces the hydration exothermic peak and delays the appearance of exothermic peak. With the continuous hydration of cement in the late stage, it has no effect on the hydration heat and hydration products of cement. With the increase of ammonia content, the release amount and content of ammonia in the composite system increase, and the retention ratio of NH+4 and NH3·H2O also increases; the release of ammonia leads to the increase of porosity and the number of macropores after hardening of the composite system; the increase of ammonia content in denitration fly ash, paste mixing and water cement ratio of the composite system will accelerate the release of ammonia.
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