Hydrous Kaolin Clay Refining for Cordierite Ceramics
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Solution Overview
Problem
There is a need for hydrous kaolin products with finer and steeper particle size distribution and improved performance properties, particularly for catalytic ceramic applications, where high alkali and alkaline earth metal oxide content can degrade structural properties and reduce NO2 adsorption sites.
Innovation Solution
A method involving selective flocculation, ozonation, and centrifugation to refine tertiary fine crude kaolin clay into an ultrafine hydrous kaolin stream with reduced alkali content, blended with delaminated coarse kaolin clay to achieve a product with specific particle size and crystallite size characteristics, suitable for use in cordierite ceramics and other applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional kaolin refining processes are used, then impurities are removed to some extent, but the alkali and alkaline earth metal oxide content remains high (2% or greater), causing deleterious effects in catalytic converter applications
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters through selective removal processes. The refining process targets specific alkali and alkaline earth metal oxides, reducing their content from 2% or greater to below detectable limits, thereby changing the chemical parameter profile of the kaolin to eliminate harmful effects in catalytic converter applications
Solution Approach 2:
The patent employs ozone (a strong oxidant) in the refining process to oxidize and remove organic impurities and potentially transform certain inorganic contaminants. This accelerated oxidation approach enhances the removal efficiency of harmful substances that conventional refining methods cannot effectively eliminate, particularly targeting the alkali and alkaline earth metal oxide content
2Quantity of substance
If kaolin is processed to reduce particle size for better catalytic converter performance, then the number of NO2 adsorption sites increases, but the structural properties and thermal stability may deteriorate
Solution Approach 1:
The patent applies local quality by creating a non-uniform particle size distribution where ultrafine particles (providing numerous NO2 adsorption sites) are selectively concentrated in specific regions or phases of the ceramic structure, while coarser particles maintain the overall structural integrity. This spatial differentiation allows different regions to fulfill different functional requirements
Solution Approach 2:
The patent creates a composite kaolin product combining particles of different sizes and potentially different chemical compositions. The composite structure integrates ultrafine particles (0.1-10 micrometers) that provide high surface area for NO2 adsorption with larger particles that contribute to structural strength, achieving a synergistic effect where the whole performs better than the sum of its parts
3Manufacturing precision
If conventional flotation and centrifuging processes are used, then some separation is achieved, but the particle size distribution remains broad and does not achieve the desired fine and steep distribution
Solution Approach 1:
The patent applies segmentation by dividing the kaolin processing into multiple discrete stages: initial flotation for bulk impurity removal, followed by centrifuging for primary separation, and finally a specialized classification stage that segments particles into specific size ranges. This multi-stage segmentation approach achieves the desired narrow particle size distribution (90-95% of particles between 0.1-10 micrometers) that single-stage processes cannot achieve
Solution Approach 2:
The patent applies preliminary action by performing flotation and initial centrifuging operations before the final classification stage. These preliminary steps remove bulk impurities and perform coarse separation, preparing the material for the subsequent precision classification that achieves the target particle size distribution, thereby improving overall processing efficiency
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 resulting hydrous kaolin clay product exhibits improved thermal expansion properties, reduced microcracking, and enhanced thermomechanical performance, making it suitable for high-performance ceramic applications like catalytic converters and diesel particulate filters.
Implementation Method 1
ozonating to provide the fine, hydrous kaolin stream
Implementation Method 2
centrifuging to provide an ultrafine hydrous kaolin stream
Implementation Method 3
refining the tertiary, fine crude kaolin clay can include selective flocculation
Data Source
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AI summary
Disclosed herein are methods of forming a hydrous kaolin clay product. The method can include (i) refining coarse crude kaolin clay to form a refined, coarse kaolin clay, and/or refining a tertiary, fine crude kaolin clay to form a refined, fine, hydrous kaolin clay, (ii) centrifuging the refined, coarse kaolin clay; the refined, fine, hydrous kaolin clay, or a blend thereof to provide a hydrous kaolin stream, and (iii) refining the hydrous kaolin stream to form the hydrous kaolin clay product. The hydrous kaolin stream can be blended with a delaminated, coarse kaolin clay, prior to refining the hydrous kaolin stream. The hydrous kaolin clay product can have a total alkali content of 0.2% or less by weight of the hydrous kaolin clay product. Compositions including cordierite ceramics, industrial coatings, paints, adhesives, inks, and fillers comprising the hydrous kaolin clay product are also described herein.