Fly Ash Silicate Aggregate Hydrothermal Synthesis
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Solution Overview
Problem
The low activity strength of fly ash at an early stage limits its effectiveness as a concrete admixture, necessitating a method to fully activate its potential throughout all stages of use.
Innovation Solution
A preparation method for hydrothermal synthesis of fly ash silicate aggregate using an inorganic-organic composite activator, comprising potassium hydroxide and sodium metasilicate to activate Si—O and Al—O bonds, and an inorganic-organic hybrid excitation monomer to further enhance hydration, resulting in a more active and efficient silicate aggregate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If fly ash is used as a concrete admixture, then it can reduce environmental impact by utilizing industrial waste, but its low activity strength at early stage limits its effectiveness
Solution Approach 1:
The patent applies preliminary action by pre-treating fly ash particles with potassium hydroxide and sodium metasilicate before concrete mixing. This pre-activation process modifies the fly ash surface and internal structure in advance, creating more reactive sites that will participate in hydration reactions earlier and more effectively during concrete curing, thus resolving the contradiction between environmental benefit and early-stage strength
Solution Approach 2:
The patent changes the chemical parameters of fly ash by introducing inorganic activators (potassium hydroxide and sodium metasilicate) that alter the chemical composition and reactivity of fly ash particles. These parameter changes transform the low-activity fly ash into a high-activity material capable of early-stage hydration reactions, maintaining environmental benefits while improving reliability
2Strength
If traditional sintered ceramic particles are used for artificial lightweight aggregates, then high cylindrical compress strength and low water absorption are achieved, but production equipment complexity and energy consumption increase
Solution Approach 1:
The patent replaces the mechanical sintering process with a chemical hydrothermal synthesis process. Instead of using high-temperature furnaces and complex sintering equipment to achieve strength, the invention uses chemical reactions between fly ash, carbide slag, and inorganic activators under controlled hydrothermal conditions to form strong silicate aggregates, thereby reducing equipment complexity while maintaining strength
Solution Approach 2:
The patent changes the processing parameters from high-temperature mechanical sintering to lower-temperature hydrothermal conditions with inorganic activators. This parameter transformation enables the formation of strong silicate aggregates through chemical reactions rather than mechanical compression, simplifying equipment requirements while achieving comparable or superior compressive strength
3Volume of stationary object
If hydrothermal synthesis is used to produce silicate aggregate, then low bulk density and high compressive strength are achieved, but the process requires precise control of temperature and pressure conditions
Solution Approach 1:
The patent optimizes the hydrothermal synthesis parameters by establishing specific temperature (180-200°C) and pressure (1.0-1.3 MPa) ranges that favor the formation of low-density, high-strength silicate aggregates. These parameter optimizations create favorable conditions for hydrothermal reactions while maintaining practical controllability in industrial settings
Solution Approach 2:
The patent introduces inorganic activators (potassium hydroxide and sodium metasilicate) as intermediaries that facilitate the hydrothermal synthesis process. These activators mediate between the reactants (fly ash and carbide slag) and the hydrothermal environment, enabling the synthesis to proceed efficiently within moderate temperature and pressure ranges, thereby reducing the complexity of condition control
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 achieves a significant increase in the compressive strength and reduced water absorption of fly ash silicate aggregates, with specific properties such as bulk density and cylinder compressive strength, while utilizing industrial waste materials to reduce environmental impact.
Implementation Method 1
potassium hydroxide and sodium metasilicate are used as an inorganic component to mainly activate the activity of fly ash at an early age, and promote a fracture of Si—O and Al—O bonds on a surface of fly ash particle to form an unsaturated bond
Implementation Method 2
an inorganic-organic hybrid excitation monomer is used (octahydroxy terminated POSS (polyhedral oligomeric silsesquioxane)) as an inorganic-organic hybrid component to further active the activity of fly ash in a later hydration stage by slowly releasing OH—
Implementation Method 3
hydrothermal synthesis of silicate aggregate is an artificially synthesized aggregate proposed based on a method of autoclave curing and hardening
Implementation Method 4
temperature of 180° C., and pressure of 1 MPa
Data Source
AI summary
The present disclosure provides a preparation method for hydrothermal synthesis of fly ash silicate aggregate including: mixing sodium metasilicate, potassium hydroxide, and inorganic-organic hybrid excitation monomer as raw materials to obtain an inorganic-organic composite activator; preparing a silicate aggregate raw material, mixing measured fly ash, carbide slag, quicklime, and vitrified micro bubble by mass, adding the inorganic-organic composite activator and continue stirring to produce a mixture; forming a ball disc, wetting an expanded perlite that forms a core of the ball by spraying water, adding a prepared mixture, spraying water while adding, standing and curing, performing a maturation and activation treatment in an autoclave, undergoing a silicon calcium reaction for a hydrothermal synthesis to obtain the silicate aggregates. The present disclosure obtains silicate aggregates with high-performance by accelerating an internal activity of fly ash at an early stage and fully activating the activity of fly ash in all process.