Catalyst Slurry Preparation with Two-Stage Milling to Prevent Clogging
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Solution Overview
Problem
Existing methods for preparing catalyst slurry require long milling times due to the use of large media, which can lead to clogging of milling devices and reduced productivity.
Innovation Solution
A two-step milling process using first and second milling devices with different media sizes to efficiently reduce the particle diameter of inorganic oxide powders, allowing for continuous milling without clogging and reducing overall milling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large media are used in milling to reduce milling time, then productivity is improved, but the slit for separating powder and media may be clogged
Solution Approach 1:
The milling process is divided into two sequential stages using two different milling devices. The first milling device with larger media performs coarse grinding to rapidly reduce particle size, while the second milling device with smaller media performs fine grinding to achieve the final particle size without clogging the separation slit. This segmentation of the milling process allows each device to be optimized for its specific function, resolving the contradiction between productivity and reliability.
2Reliability
If small media are used in milling to prevent clogging, then reliability is improved, but milling time increases
Solution Approach 1:
The first milling device with larger media performs preliminary coarse grinding to reduce the particle size of inorganic oxide powder to an intermediate range (5-13 μm) before the second milling device processes it further. This preliminary action removes the bulk of the particle size reduction requirement, allowing the second device with smaller media to complete the fine grinding (to 1 μm or less) efficiently without being burdened by coarse particles that would cause clogging, thus preventing reliability issues while maintaining productivity.
3Manufacturing precision
If long milling is performed to achieve fine particle size (1 μm or less), then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The invention changes the parameter of media size between two sequential milling devices. The first device uses larger media (1-10 mm) for coarse grinding, and the second device uses smaller media (0.1-0.5 mm) for fine grinding. This parameter change allows each device to operate in its optimal range, achieving fine particle size distribution (1 μm or less) efficiently without requiring excessively long milling times, thus resolving the contradiction between manufacturing precision and productivity.
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 significantly shortens milling time by efficiently miniaturizing powder particles while preventing device clogging, thereby improving productivity and enabling the production of catalyst slurry for exhaust gas purification.
Implementation Method 1
a first milling step of milling the slurry-manufacturing-material using a first milling device including first media until the powder included in the slurry-manufacturing-material has an average particle diameter of 5 μm or more and 13 μm or less
Implementation Method 2
a second milling step of, after the first milling step, milling the slurry-manufacturing-material using a second milling device including second media with a smaller average particle diameter than the first media until the powder included in the slurry-manufacturing-material has an average particle diameter of 1 μm or less
Implementation Method 3
until the powder included in the slurry-manufacturing-material has an average particle diameter of 5 μm or more and 13 μm or less based on a laser diffraction/scattering method
Implementation Method 4
until the powder included in the slurry-manufacturing-material has an average particle diameter of 5 μm or more and 13 μm or less based on a laser diffraction/scattering method
Data Source
AI summary
The present disclosure provides a method for preparing a slurry with a shorter milling time. The method disclosed herein includes a material preparing step of preparing a slurry-manufacturing-material including first inorganic oxide powder, a first milling step of milling the slurry-manufacturing-material using a first milling device including first media until the powder included in the slurry-manufacturing-material has an average particle diameter of 5 μm or more and 13 μm or less, and a second milling step of, after the first milling step, milling the slurry-manufacturing-material using a second milling device including second media with a smaller average particle diameter than the first media until the powder included in the slurry-manufacturing-material has an average particle diameter of 1 μm or less. Second inorganic oxide powder is mixed in the slurry-manufacturing-material before the first milling step, or after the first milling step and before the second milling step.