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硅酸盐通报 ›› 2026, Vol. 45 ›› Issue (2): 517-527.DOI: 10.16552/j.cnki.issn1001-1625.2025.0861

• 资源综合利用 • 上一篇    下一篇

碱熔法从粉煤灰中制备羟基硅酸钙及其硅缓释性能研究

张梦甜1(), 王学凯1,2(), 徐子芳1,3, 扈霜月1, 李政1, 李佳韦1   

  1. 1.安徽理工大学材料科学与工程学院,淮南 232001
    2.安徽省煤基固废新材料产业共性技术研究中心,淮南 232001
    3.深部煤炭安全开采与环境保护全国重点实验室,淮南 232000
  • 收稿日期:2025-08-26 修订日期:2025-09-21 出版日期:2026-02-20 发布日期:2026-03-09
  • 通信作者: 王学凯,博士,讲师。E-mail:771381779@qq.com
  • 作者简介:张梦甜(2002—),女,硕士研究生。主要从事固废资源化利用方面的研究。E-mail:13781602640@163.com
  • 基金资助:
    安徽省高校自然科学研究项目(2023AH051204);安徽省高校协同创新项目(GXXT-2022-083);安徽理工大学引进人才科研启动基金(2023yjrc23);安徽理工大学引进人才科研启动基金(13230028)

Preparation of Calcium Silicate Hydrate from Fly Ash by Alkali Fusion Method and Its Silicon Slow-Release Performance

ZHANG Mengtian1(), WANG Xuekai1,2(), XU Zifang1,3, HU Shuangyue1, LI Zheng1, LI Jiawei1   

  1. 1. School of Materials Science and Engineering,Anhui University of Science and Technology,Huainan 232001,China
    2. Anhui Industrial Generic Technology Research Center for New Materials from Coal-Based Solid Wastes,Huainan 232001,China
    3. National Key Laboratory of Safe Mining and Environmental Protection in Deep Coal Resources,Huainan 232000,China
  • Received:2025-08-26 Revised:2025-09-21 Published:2026-02-20 Online:2026-03-09

摘要:

本研究以粉煤灰(CFA)为原料,通过碱熔-水热法实现了高活性可溶性硅的提取与纳米级羟基硅酸钙(CSH)的可控制备,为煤基固废的高值化利用提供了可行路径。具体流程包括:采用Na2CO3作为活化剂,在850 ℃煅烧2 h,煅烧产物与水以固液比1∶10溶解,80 ℃水浴90 min后固液分离,得到提硅液,硅提取率为45.7%;提硅液与CaCl2在80 ℃水浴中反应3 h,成功合成CSH。缓释研究表明:所制备的CSH在柠檬酸溶液中硅释放行为符合Higuchi扩散模型,最大硅缓释浓度为350 mg/L;在不同pH值环境下CSH亦表现出持续释放特性,当pH值为6和8时,硅缓释浓度在第3天分别达到150与100 mg/L。本研究实现了CFA的低成本资源化转化,制备的CSH对推动固废绿色资源化利用和农业可持续发展具有重要意义。

关键词: 粉煤灰, 羟基硅酸钙, 碱熔法, 缓释, 固废资源化

Abstract:

This study utilized coal fly ash (CFA) as raw material to achieve the extraction of highly reactive soluble silicon and the controllable synthesis of nano-sized calcium silicate hydrate (CSH) through an alkali fusion-hydrothermal method, providing a feasible pathway for the high-value utilization of coal-based solid waste. The specific procedure included: using Na2CO3 as an activator and calcining at 850 ℃ for 2 h. The calcined product was dissolved in water at a solid-liquid ratio of 1∶10. After 90 min in an 80 ℃ water bath, solid-liquid separation yielded a silicon extraction solution. This process achieves a silicon extraction rate of 45.7%. The silicon extraction solution was then reacted with CaCl2 in an 80 ℃ water bath for 3 h to successfully synthesize CSH. Slow-release studies demonstrate that the silicon release behavior of the as-prepared CSH in citric acid solution follows the Higuchi diffusion model, with a maximum silicon slow-release concentration of 350 mg/L. It also exhibits continuous release characteristics under different pH conditions, at pH value of 6 and 8, the silicon slow-release concentration reached 150 and 100 mg/L, respectively, on the third day. This research achieves the low-cost resource conversion of CFA, and the prepared CSH holds promise for promoting the green resource utilization of solid waste and the sustainable development of agriculture.

Key words: coal fly ash, calcium silicate hydrate, alkali fusion method, slow-release, resource utilization

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