Fly Ash Production Using Aluminosilicate Additives
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Solution Overview
Problem
Existing methods for producing fly ash do not consistently meet the standard requirements for use in concrete, such as pozzolanic activity, strength activity index, and loss-on-ignition, which are crucial for its application in cementitious compositions like Portland cement and concrete.
Innovation Solution
Combusting fuel in the presence of a mineral additive comprising aluminosilicate, which is added before or during combustion, to enhance the pozzolanic activity, strength activity index, and reduce loss-on-ignition of the fly ash, thereby improving its properties to meet the required standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional combustion methods are used to produce fly ash, then the production process is simple, but the fly ash does not consistently meet standard requirements for pozzolanic activity, strength activity index, and loss-on-ignition
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the combustion process through the addition of silicate minerals. Specifically, it controls the SiO2 content at 30-70 wt%, Al2O3 at 10-40 wt%, and CaO at 5-20 wt% in the mineral additive, which transforms the fly ash composition to achieve consistent compliance with ASTM C618 and EN 450-1:2012 standards for pozzolanic activity and strength activity index.
Solution Approach 2:
The patent employs composite materials by combining fuel with silicate minerals (such as quartz, tridymite, cristobalite, or glass) during combustion. This creates a composite combustion system where the mineral additive integrates with the fuel matrix, producing fly ash with enhanced and consistent pozzolanic properties that meet construction material standards.
2Manufacturing precision
If mineral additive is added to enhance pozzolanic activity, then the pozzolanic activity increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-mixing the mineral additive with the fuel before combustion. This pre-combination ensures uniform distribution of silicate minerals throughout the fuel matrix, simplifying the manufacturing process while guaranteeing consistent pozzolanic activity in the resulting fly ash without requiring complex post-processing steps.
3Manufacturing precision
If fuel combustion is performed without mineral additive, then the production process is straightforward, but the loss-on-ignition is high and properties are inconsistent
Solution Approach 1:
The patent applies parameter changes by adjusting the chemical composition parameters of the combustion system through controlled addition of silicate minerals. By maintaining SiO2 at 30-70 wt%, Al2O3 at 10-40 wt%, and CaO at 5-20 wt%, the process reduces loss-on-ignition to below 5% while producing fly ash that consistently meets international standards, transforming the combustion outcome without requiring complex equipment modifications.
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 method increases the pozzolanic activity and strength activity index of fly ash while decreasing loss-on-ignition, ensuring that the fly ash meets the standard requirements for use in concrete, as specified by ASTM C618 and EN 450-1:2012, thereby enhancing its performance and applicability in cementitious compositions.
Implementation Method 1
combusting fuel in the presence of a mineral additive, wherein the mineral additive comprises at least one silicate wherein the at least one silicate is an aluminosilicate
Implementation Method 2
the fly ash comprises silica (SiO2), alumina (Al2O3) and calcium oxide (CaO), all of which may be present in amorphous and/or crystalline forms
Data Source
AI summary
A method of making fly ash comprising combusting a fuel in the presence of a mineral additive, wherein the mineral additive comprises at least one silicate, fly ash obtained by said method and the use of said fly ash as a pozzolan, for example for use in a cementitious composition such as cement and concrete.