Fly Ash Ceramic Membrane Support Preparation
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Solution Overview
Problem
The preparation of ceramic membrane supports from fly ash is hindered by issues such as poor melting temperature control due to glass microspheres, weakened porosity, high unburned residual carbon content, which leads to hydrophobic film formation, increased water demand, cracking during drying, and spontaneous combustion during sintering.
Innovation Solution
A method involving alkali washing and acid washing of fly ash to remove impurities, followed by extrusion molding and surface modification with a composite water-retaining agent containing glycerol, tung oil, and polyethylene glycol to enhance sintering and prevent cracking, combined with burying sintering and low-temperature slow sintering for uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fly ash is used as raw material for ceramic membrane support, then preparation cost is reduced, but sintering temperature control becomes difficult due to glass microspheres
Solution Approach 1:
The fly ash undergoes preliminary classification to remove excessive glass microspheres before being used as raw material. This pre-treatment action prevents the sintering temperature control issues that would otherwise arise from the presence of problematic microspheres, while still allowing the cost benefits of using fly ash to be realized.
2Adaptability or versatility
If fly ash is used as raw material, then resource utilization is improved, but porosity is weakened due to particle accumulation
Solution Approach 1:
The fly ash is pre-classified to remove excessive glass microspheres that cause particle accumulation. This preliminary action ensures that the remaining fly ash particles can form the desired porous structure without excessive accumulation, maintaining both resource utilization benefits and porosity requirements.
Solution Approach 2:
The particle size distribution of fly ash is modified through classification to optimize porosity. By removing excessive fine particles and controlling the size distribution, the patent achieves desirable pore formation while still utilizing fly ash as the primary raw material.
3Quantity of substance
If fly ash with high residual carbon content is used, then material availability is improved, but cracking occurs during drying due to hydrophobic film formation
Solution Approach 1:
The residual carbon in fly ash, which normally forms hydrophobic films causing drying cracks, is converted into a beneficial pore-forming agent. The organic matter undergoes controlled decomposition during sintering to create pores and channels, transforming the harmful hydrophobic effect into a useful porosity enhancement while maintaining material availability.
4Ease of manufacture
If fly ash with high residual carbon content is used, then cost is reduced, but spontaneous combustion occurs during sintering leading to thermal stress cracking
Solution Approach 1:
The fly ash undergoes preliminary classification and treatment to control the carbon content and distribution before sintering. This pre-treatment prevents the conditions necessary for spontaneous combustion during the sintering process, while still allowing the use of fly ash to maintain low production costs.
Solution Approach 2:
The sintering process parameters are optimized to control the decomposition of residual carbon. By adjusting temperature profiles and holding times, the patent ensures complete decomposition of organic matter before the sintering stage, eliminating spontaneous combustion risks while maintaining cost effectiveness.
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
This method improves the molding performance of fly ash particles, reduces the impact of glass microspheres, prevents cracking, and achieves a high-quality ceramic membrane support with consistent drying rates and desirable appearance.
Implementation Method 1
subjecting fly ash to alkali washing and acid washing to obtain pretreated fly ash
Implementation Method 2
subjecting fly ash to alkali washing and acid washing to obtain pretreated fly ash
Implementation Method 3
spraying a surface water-retaining agent on a surface of the green body to allow static curing
Implementation Method 4
conducting drying and sintering after the curing is completed
Data Source
AI summary
The present disclosure provides a preparation method of a fly ash-based ceramic membrane support, including the following steps: 1) subjecting fly ash to alkali washing and acid washing to obtain pretreated fly ash; 2) blending a raw material including the pretreated fly ash, and then conducting aging and extrusion molding to obtain a green body; and 3) spraying a surface water-retaining agent (including glycerol, tung oil, a diol, and polyethylene glycol) on a surface of the green body to allow static curing in a constant-temperature and constant-humidity environment, and then conducting drying and sintering after the curing is completed. The preparation method can effectively improve molding and sintering performances of the fly ash to obtain a fly ash-based ceramic membrane support with a qualified performance.