1、Flue gas desulfurization (FGD) fly ash as a sustainable, safe

In plants using flue gas desulfurization (FGD) processes, fly ash could contain high amounts of sulfur oxides, making its use in concrete inadvisable. However, the type of sulfur compound present in a fly ash strongly impacts its performance in concrete.

2、Resource utilization of flue gas calcium

Calcium-based desulfurization ash (CDA) is mainly produced in dry and semi-dry flue gas desulfurization processes. The property of CDA is extremely unstable because its main component, calcium sulfite, makes it difficult to be directly applied to the field of building materials.

3、Green Regeneration of Sodium Bicarbonate from Flue Gas

Desulfurization ash is a byproduct of the flue gas desulfurization (FGD) process. This study developed a novel green regeneration method incorporating electrodialysis metathesis (EDM) and a carbonization process for the production of sodium bicarbonate (NaHCO3) from FGD ash. The results show that under the optimized EDM process conditions of a current density of 30 mA·cm–2, a HCO3–:Na+ ...

Chemical and Physical Properties of Dry Flue Gas Desulfurization Products

Beneficial and environmentally safe recycling of flue gas desulfurization (FGD) products requires detailed knowledge of their chemical and physical properties. We analyzed 59 dry FGD...

Production and resource utilization of flue gas desulfurized gypsum in

Properties and production of FGD gypsum in China are given. Chinese government desulfurization measures during 2000–2019 are summarized. The application of FGD gypsum and its impact on the environment are analyzed. A possible closed-loop utilization of FGD gypsum is proposed.

Flue

Flue-gas desulfurization (FGD) refers to a process used to reduce sulfur dioxide (SO₂) emissions from coal-fired boilers, resulting in materials that can vary from wet sludge to dry powdered forms, predominantly consisting of calcium sulfite or calcium sulfate.

Recent advances in flue gas desulfurization gypsum processes and

Due to its abundance, chemical and physical properties, FGDG has been used in several beneficial applications. However, during the past decade, the rate of beneficially used FGDG has gradually decreased, while its production has drastically increased.

Use of flue gas desulphurisation (FGD) waste and rejected fly ash in

Flue gas desulphurization (FGD) sludge is a by-product from the air pollution control systems used in coal-fired power plants. The objective of this work was to investigate the performance of S/S waste binder systems containing these two waste materials (rFA and FGD).

Agricultural Uses for Flue Gas Desulfurization (FGD) Gypsum

calcium availability; in particular, fruits such as tomatoes and cantaloupes need calcium for skin strength, and growers may add calcium to produce fewer blemishes

Review of Design, Operating, and Financial Considerations in Flue Gas

The various flue gas desulfurization (FGD) technologies available in the market, for the reduction of sulfur dioxide emissions, are presented. The process descriptions are discussed and the capital and operating costs of the various methods are presented.

The feasibility, effectiveness, and application limitations of using flue gas desulfurization (FGD) ash as a calcium fertilizer require detailed analysis. Below is a comprehensive discussion on this topic:

1. Composition and Properties of FGD Ash

FGD ash primarily consists of calcium oxide (CaO), sulfur dioxide (SO₂), and trace amounts of other components. During the flue gas desulfurization process in coal-fired power plants, sulfur dioxide in the flue gas reacts with sorbents to form gypsum (calcium sulfate), while releasing calcium oxide. Consequently, FGD ash is rich in calcium oxide, making it a valuable industrial material.

2. Advantages of Using FGD Ash as a Calcium Fertilizer

a. Abundant Calcium Source

FGD ash contains high levels of calcium oxide, providing a rich source for calcium fertilizer production. Compared to traditional calcium sources like limestone, FGD ash has a higher calcium content, enabling the production of more calcium-based fertilizers.

b. Environmental Benefits

As an industrial byproduct, FGD ash generates far lower carbon emissions during production than conventional limestone mining. Its reuse reduces reliance on natural resources and supports environmental sustainability.

c. Economic Potential

While the production cost of FGD ash may initially exceed that of traditional fertilizers, its abundance and environmental advantages offer long-term economic benefits. Growing eco-consciousness and policy support could expand market demand for FGD-ash-based fertilizers.

3. Limitations of Using FGD Ash as a Calcium Fertilizer

a. Technical Challenges

The presence of sulfur dioxide (SO₂) in FGD ash may compromise fertilizer quality. SO₂ reacts with calcium to form calcium sulfite, reducing purity and weakening product performance. Additionally, impurities like iron (Fe) and aluminum (Al) in FGD ash can adversely affect fertilizer efficacy.

b. Processing and Purification Hurdles

Ensuring fertilizer quality requires rigorous processing to remove SO₂, Fe, Al, and other contaminants, as well as adjusting pH and solubility. These complex procedures increase costs, potentially undermining economic viability.

c. Market and Price Constraints

Despite its calcium-rich composition and environmental benefits, FGD ash faces market acceptance challenges. High-quality calcium fertilizers dominate current demand, while FGD ash’s variable quality and processing difficulties limit its appeal. Limited supply further impacts pricing competitiveness.

FGD ash can serve as a calcium fertilizer, but its practicality depends on overcoming technical, market, and processing barriers. While it offers environmental and resource-efficiency advantages, challenges related to impurities, cost, and market readiness persist. With advancements in technology and expanding market adoption, FGD ash holds promise as a sustainable fertilizer option.

Key Terms: FGD ash, calcium fertilizer, calcium oxide (CaO), sulfur dioxide (SO₂), environmental sustainability, impurities, processing costs.