化工进展 ›› 2022, Vol. 41 ›› Issue (10): 5637-5644.DOI: 10.16085/j.issn.1000-6613.2021-2506

• 资源与环境化工 • 上一篇    下一篇

Ⅱ型无水磷石膏凝结硬化过程调控技术

张宇1(), 杨家豪1, 刘瑜1, 宋子玉1, 何涵潇1, 赵风清1,2()   

  1. 1.河北科技大学化学与制药工程学院,河北 石家庄 050018
    2.河北省固体废弃物技术创新中心,河北 石家庄 050018
  • 收稿日期:2021-12-07 修回日期:2022-04-02 出版日期:2022-10-20 发布日期:2022-10-21
  • 通讯作者: 赵风清
  • 作者简介:张宇(1997—),女,硕士研究生,研究方向为固体废弃物资源化利用。E-mail:1600445909@qq.com
  • 基金资助:
    中央引导地方科技发展专项(19943815G)

Regulating technology of setting and hardening process of anhydrite-Ⅱphosphogypsum

ZHANG Yu1(), YANG Jiahao1, LIU Yu1, SONG Ziyu1, HE Hanxiao1, ZHAO Fengqing1,2()   

  1. 1.College of Chemical and Pharmaceutical Engineering, Hebei University of Science & Technology, Shijiazhuang 050018, Hebei, China
    2.Hebei Technology Innovation Center of Solid Wastes, Shijiazhuang 050018, Hebei, China
  • Received:2021-12-07 Revised:2022-04-02 Online:2022-10-20 Published:2022-10-21
  • Contact: ZHAO Fengqing

摘要:

为改善Ⅱ型无水磷石膏水化活性低、凝结硬化缓慢的问题,研制了一种复合助剂(β-半水石膏6%、改性钢渣3%、K2SO4 2%、铝酸钙水泥0.5%)。研究表明,掺入复合助剂后Ⅱ型无水磷石膏初凝时间由744min(空白样)缩短至76min(改性样)。在此基础上添加25%的高炉矿渣微粉改善力学性能和耐水性,改性后的胶凝材料绝干抗压强度达到15.4MPa,软化系数达到0.83。研究了胶凝体系的水化率、液相离子浓度随时间的变化规律,结合X射线衍射(XRD)和扫描电子显微镜(SEM)对水化产物和水化硬化机理进行了分析。复合助剂加速了Ⅱ型无水磷石膏的溶解及二水石膏晶核的生成和长大,提高了Ⅱ型无水磷石膏的水化率,与矿渣协同作用促进生成3CaO·Al2O3·3CaSO4·32H2O、3CaO·Fe2O3·3CaSO4·32H2O等多种低溶度积复盐,改善了胶凝材料的凝结硬化性能和耐水性。

关键词: Ⅱ型无水磷石膏, 耐水性, 凝结性能, 复盐

Abstract:

In order to solve the problems of low hydration activity and long setting time of anhydrite-Ⅱ phosphogypsum, a composite additive was prepared which was composed of β hemihydrate gypsum 6%, sulfuric acid modified steel slag 3%, K2SO4 2% and calcium aluminate cement 0.5%. It was indicated that the initial setting time was shortened from 744min (blank) to 76min (modified). Blast furnace slag powder was used to further improve water resistance and mechanical strength for the cementitious system. With the addition of slag 25%, the compressive strength of cementing material was 15.4MPa and the softening coefficient was up to 0.83. The changes of hydration rate and liquid ion concentration with time were investigated. The hydration products and hydration hardening mechanism of cementitious materials were analyzed by using XRD and SEM. The results showed that the composite additive promoted the dissolution of anhydrite-Ⅱ phosphogypsum as well as the formation and growth of dihydrate gypsum crystal nucleus, increasing the hydration rate. The combined use of the composite additive and blast furnace slag promoted the formation of a variety of low solubility double salts such as 3CaO·Al2O3·3CaSO4·32H2O and 3CaO·Fe2O3·3CaSO4·32H2O, which helped to improve the mechanical strength and water resistance of cementitious material.

Key words: anhydrite-Ⅱ phosphogypsum, water-resistance, setting time, double salt

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