Flue Gas Desulfurization Fly Ash Hydration Acceleration
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Solution Overview
Problem
Fly ash from flue gas desulfurization, primarily composed of β CaSO4 anhydrite, is challenging to hydrate under standard conditions, limiting its usability in building materials due to high production temperatures, making it difficult to create environmentally friendly and strong compositions.
Innovation Solution
Mixing fly ash with binder reactants at a 9:1 ratio, comprising 70% CaSO4.½H2O, 10% Na2SO4, 10% CaO, 5% NaOH, and optional cement and starch, accelerates the hydration process of CaSO4 anhydrite when combined with 30-40% water, enabling the production of building materials with comparable strength to cement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fly ash from flue gas desulfurization is used directly as building material, then environmental pollution is reduced, but the material strength is insufficient due to slow hydration
Solution Approach 1:
The patent introduces binder reactants (CaSO4.1/2H2O, Na2SO4, CaO, NaOH) as intermediary substances that facilitate the hydration process of β-CaSO4 anhydrite. These binder reactants act as mediators between the fly ash and water, accelerating the chemical reaction and enabling the formation of strong building materials. The binder reactants composition (70% CaSO4.1/2H2O, 10% Na2SO4, 10% CaO, 5% NaOH, 0-5% cement, 0-5% starch) specifically catalyzes the hydration reaction that would otherwise be too slow under standard conditions.
Solution Approach 2:
The patent changes the chemical composition parameters by adding binder reactants containing CaSO4.1/2H2O, Na2SO4, CaO, and NaOH to modify the hydration characteristics of β-CaSO4 anhydrite. This parameter change accelerates the hydration reaction rate and improves the strength development of the resulting building materials, transforming the material from weak and slow-hydrating to strong and fast-hydrating.
2Power
If high temperature combustion is used to produce fly ash, then energy generation efficiency is improved, but the fly ash becomes difficult to hydrate under standard conditions
Solution Approach 1:
The patent converts the harmful effect of high temperature combustion (which creates difficult-to-hydrate β-CaSO4 anhydrite) into a benefit by using the same high-temperature process to produce the fly ash, then treating it with binder reactants that accelerate hydration. The high temperature production is maintained for energy efficiency, while the post-treatment with binder reactants solves the hydration difficulty, turning a disadvantage into an advantage.
3Strength
If binder reactants are added to accelerate hydration, then material strength is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent merges multiple functions into the binder reactants composition: CaSO4.1/2H2O provides the primary binding mechanism, Na2SO4 and CaO accelerate hydration, NaOH controls pH and enhances reactivity, and optional cement and starch provide additional binding and workability. This consolidation of multiple chemical functions into a single binder reactants mixture simplifies the manufacturing process while achieving the desired strength acceleration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The accelerated hydration process allows for the creation of building materials like non-structural cement mortar, bricks, and fire-resistant walls that meet standard construction strength requirements with only 10% binder reactant by weight, offering a variety of applications and environmentally friendly solutions.
Implementation Method 1
When the binder reactants are mixed with fly ash and water (30% to 40% of the above total weight), the hydration process of CaSO4 anhydrite is accelerated.
Data Source
AI summary
Composition for building materials comprises of fly ash from flue gas desulfurization. The fly ash (β CaSO4 anhydrite), obtained from circulating fluidized bed flue gas desulfurization, is mixed with binder reactants at a ratio of 9:1. It's mainly used for non-structural cement mortar, bricks for paving walkways, brick wall decors, fire-resistant walls for interior partitions, plasterboards and so on. The binder reactants compose of 70% CaSO4.½H2O, 10% Na2SO4, 10% CaO, 5% NaOH, 0˜5% cement and 0˜5% starch. When the binder reactants are mixed with fly ash and water (30% to 40% of the above total weight), the hydration process of CaSO4 anhydrite is accelerated.