Related Experiment Video
Updated: Nov 21, 2025
11:14
Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
12.7K
Stabilization-solidification-utilization of MSWI fly ash coupling CO2 mineralization using a high-gravity rotating
Tse-Lun Chen1, Yi-Hung Chen2, Ming-Yen Dai1
1Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Road, Da-an District, Taipei City 10673, Taiwan.
Waste Management (New York, N.Y.)
|January 14, 2021
Summary
This study presents a novel wet-extraction and carbonation process using high-gravity technology to stabilize municipal solid waste incineration fly ash (MSWI-FA). The treated ash can be utilized as a supplementary cementitious material (SCM), reducing hazardous waste and Portland cement usage.
Area of Science:
- Environmental Engineering
- Materials Science
- Chemical Engineering
Background:
- Municipal solid waste incineration fly ash (MSWI-FA) is hazardous due to heavy metals, chlorides, and sulfates, requiring stabilization and landfilling.
- Treated MSWI-FA has potential as a pozzolanic material, reducing Portland cement consumption.
- Existing treatment methods for MSWI-FA are often energy-intensive and costly.
Purpose of the Study:
- To develop an integrated wet-extraction and carbonation process for MSWI-FA stabilization, solidification, and utilization.
- To apply high-gravity technology for efficient dechlorination and CO2 sequestration from MSWI-FA.
- To evaluate the feasibility of using carbonated MSWI-FA as a supplementary cementitious material (SCM) in cement mortar.
Main Methods:
- Benchtop experiments were conducted to demonstrate the wet-extraction and carbonation process.
- High-gravity technology was employed to enhance chloride removal and CO2 capture.
- Physical, chemical, and thermal characteristics of raw, extracted, and carbonated MSWI-FA were analyzed.
- Cement mortar workability and mechanical strength were evaluated with partial substitution of stabilized FA.
Main Results:
- Achieved a 36.35% chloride extraction ratio and a CO2 capture capacity of 258.5 g-CO2 kg-FA-1.
- Carbonated MSWI-FA exhibited significant calcium carbonate content, suitable for partial Portland cement substitution.
- Evaluated water-energy consumption for chloride removal and CO2 fixation, providing insights for process optimization.
- Continuous process tests identified key operational indexes for future scale-up.
Conclusions:
- The integrated wet-extraction and carbonation process using high-gravity technology effectively stabilizes MSWI-FA.
- Carbonated MSWI-FA can be utilized as a sustainable supplementary cementitious material (SCM), reducing hazardous waste and cement demand.
- The developed process offers a promising pathway for the valorization of MSWI-FA in the construction industry.
Related Concept Videos
01:21Pozzolans
316
Pozzolans are siliceous or aluminous materials blended with Portland cement. They interact with the calcium hydroxide produced during the hydration of Portland cement and contribute to improved strength and durability of concrete. The pozzolanic activity, a measure of a pozzolan's effectiveness, is typically assessed using the strength activity index, as defined in ASTM C 618-93, which calculates the ratio of the compressive strength of cement mixtures with and without pozzolan.
Fly ash is...
Fly ash is...
316
01:25Accelerated Curing of Concrete
324
Accelerating concrete curing is achieved by applying heat and additional moisture. This process accelerates the hydration of the cement, resulting in an earlier strength gain in the concrete. Steam curing is a method wherein the concrete products are either transported through a chamber on a conveyor belt or encased in plastic, allowing steam at atmospheric pressure to circulate freely around them. This process begins with a phase of moist curing that typically lasts between 3 to 5 hours, after...
324
01:24Hydration of Cement
533
Hydration of cement is a chemical reaction between cement particles and water. This process occurs primarily through two mechanisms: through-solution and topochemical. In the through-solution process, anhydrous compounds dissolve into their constituents, hydrates form in the solution, and then precipitate from the supersaturated solution. The topochemical process involves solid-state reactions at the cement particle surface. The through-solution process dominates the topochemical process at the...
533
01:26Alkali Aggregate Reaction in Concrete
307
The alkali-aggregate reaction in concrete involves natural siliceous minerals in aggregates reacting with alkaline hydroxides derived from cement alkalis. This reaction forms an alkali-silica gel that absorbs water, swells, and increases in volume, which is confined by the surrounding cement paste, creating internal pressures that crack and disrupt the concrete. The extent of expansion and damage can be partly attributed to the alkali-silica reaction's osmotic hydraulic pressure and the...
307
01:28Effects of Air-entrainment in Concrete
236
Air entrainment in concrete significantly enhances the material's durability, especially in environments subjected to freeze-thaw cycles. Introducing small air bubbles into the concrete mix acts as internal voids that accommodate the expansion of water when it freezes, thereby alleviating internal stress and preventing structural cracks. This function is crucial in climates with significant freezing and thawing, as it protects the concrete from repeated stresses that could lead to premature...
236
01:18Porosity in Cement Paste
324
The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
The balance of water to cement in the mix is...
The balance of water to cement in the mix is...
324