Coal Ash Adsorption Reduction via Latex Polymer Coating
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Solution Overview
Problem
High carbon content coal ash poses challenges in cementitious applications due to variability in adsorption capacity, leading to inconsistent concrete performance and regulatory issues related to pollutant emissions, making it unsuitable for use in many applications.
Innovation Solution
Mixing coal ash with latex polymers to reduce its adsorption capacity, creating a diffusion barrier that enhances the flow properties of cementitious materials and makes high carbon content coal ash usable in a variety of cement applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high carbon content coal ash is used directly in cementitious materials, then the adsorption capacity is high, but this leads to inconsistent air content and premature concrete failure
Solution Approach 1:
A surfactant is introduced as an intermediary substance between the coal ash and air-entraining admixture. The surfactant competes with the coal ash for the air-entraining admixture, preventing the coal ash from adsorbing excessive amounts of the admixture and causing air content inconsistency. This mediator resolves the harmful adsorption effect while maintaining the beneficial air-entraining properties.
Solution Approach 2:
The chemical composition parameters of the cementitious mixture are modified by adding specific surfactants with controlled concentrations (typically 0.1-5% by weight of cement). This parameter change alters the adsorption characteristics of the coal ash, reducing its ability to variably adsorb air-entraining admixture and thereby improving concrete performance consistency.
2Adaptability or versatility
If high carbon content coal ash is used in cementitious materials, then material availability increases, but regulatory compliance becomes problematic due to pollutant emissions
Solution Approach 1:
The high carbon content, which was previously considered a harmful defect leading to regulatory non-compliance, is converted into a beneficial feature. By adding surfactants, the coal ash's adsorption capacity is harnessed to control air content more effectively, and the carbon content itself can contribute to pozzolanic activity and durability. The harm is transformed into a benefit through proper chemical modification.
3Adaptability or versatility
If coal ash with varied carbon types is used, then material sourcing flexibility increases, but adsorption capacity variability worsens
Solution Approach 1:
The surfactant addition creates a universal solution that works across all types of coal ash (inertinite, isotropic coke, anisotropic coke, and activated carbon). Rather than requiring separate handling for each carbon type, the surfactant provides a multi-functional approach that consistently reduces adsorption capacity variability across diverse coal ash sources, enabling both sourcing flexibility and performance consistency.
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 process effectively diminishes the adsorption capacity of coal ash, improving its suitability for use in cementitious materials, reducing water demand, and enhancing material flow properties, thus addressing regulatory concerns and performance inconsistencies.
Implementation Method 1
coal ash adsorption of air-entraining admixtures leading to inconsistent air content
Implementation Method 2
provides either a partial or full coating for coal ash particles which acts as a diffusion barrier, diminishing the adsorption capacity of the coal ash
Data Source
AI summary
Disclosed is a process for diminishing the adsorption capacity of coal ash comprising inter alia admixing a quantity of coal ash with a quantity of latex polymer, ultimately to form a cementitious mixture. The invention is useful inter alia for relieving an environmental burden of coal ash disposal and for imparting favorable properties to the cementitious mixture.