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Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
Alkali-activated complex binders from class C fly ash and Ca-containing admixtures.
Xiaolu Guo1, Huisheng Shi, Liming Chen
1Key Laboratory of Advanced Civil Engineering Materials, Tongji University, Ministry of Education, 1239 Siping Road, Shanghai 200092, China.
Journal of Hazardous Materials
|September 22, 2009
Summary
Alkali-activated complex binders (AACBs) effectively utilize industrial solid wastes like class C fly ash (CFA) with calcium-rich admixtures. These sustainable binders achieve high compressive strength, offering promising applications in construction and waste stabilization.
Area of Science:
- Materials Science
- Civil Engineering
- Environmental Science
Background:
- Industrial solid wastes require efficient utilization processes.
- Class C fly ash (CFA) and calcium-containing admixtures present opportunities for novel binder development.
Purpose of the Study:
- To investigate the feasibility of creating alkali-activated complex binders (AACBs) using CFA and various calcium-rich admixtures.
- To evaluate the mechanical performance and reaction products of these novel AACBs.
Main Methods:
- AACBs were synthesized using CFA with sodium hydroxide and sodium silicate solutions.
- Admixtures included Portland cement (PC), flue gas desulfurization gypsum (FGDG), and water treatment residual (WTR).
- Mechanical performance (compressive strength) and microstructural analysis of reaction products were assessed.
Main Results:
- Optimized AACB formulations, particularly CFA100, CFA60-PC40, CFA90-FGDG10, and CFA90-WTR10, exhibited superior mechanical properties.
- Maximum compressive strength reached 80.0 MPa.
- Reaction products included geopolymeric gel, sodium polysilicate zeolite, and various calcium-based hydrates like Ca(OH)2, C-S-H gel, and ettringite.
Conclusions:
- The utilization of CFA and Ca-containing admixtures in AACBs is technically feasible.
- These binders demonstrate potential for widespread application in building materials and waste solidification/stabilization.
- AACBs offer an environmentally benign solution for industrial waste management.
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