Continuous Particle Preparation via High Shear Separation
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Solution Overview
Problem
Current methods for preparing dense spherical or spheroidal particles are inefficient in achieving consistent high-density and small particle size, particularly for metal hydroxides used in lithium ion battery cathodes, as they often result in uneven particle distribution and larger fines.
Innovation Solution
A process involving a continuous circulation of solids suspension through a vessel with a separation device that separates into high and low solids streams, where the high solids stream is subjected to high shear conditions, allowing for the production of dense, spherical secondary particles with controlled particle size and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous precipitation reaction is used to prepare solid particles, then production efficiency is improved, but particle size uniformity deteriorates resulting in larger fines and uneven distribution
Solution Approach 1:
The continuous precipitation process is segmented into multiple stages with different stirring speeds. A high stirring speed is applied initially to promote uniform nucleation and prevent aggregation, then a lower stirring speed is used during subsequent growth to ensure uniform particle development. This temporal segmentation of process conditions resolves the contradiction by maintaining both high productivity and particle size uniformity through staged control.
2Manufacturing precision
If high shear conditions are applied to the high solids stream, then particle density and sphericity are improved, but energy consumption increases
Solution Approach 1:
High shear conditions are applied locally only to the high solids stream rather than the entire suspension. The process separates the suspension into high solids and low solids streams, then applies intensive high-shear treatment selectively to the high solids stream to improve particle density and sphericity. This localized application of energy-intensive treatment resolves the contradiction by achieving superior particle quality while minimizing overall energy consumption.
3Manufacturing precision
If solids suspension is continuously circulated through separation device and high shear compartment, then particle quality is improved, but device complexity increases
Solution Approach 1:
The vessel, separation device, and high shear compartment are merged into an integrated continuous circulation system. The outlet of the vessel connects to the separation device, which separates the suspension into high and low solids streams. The high solids stream enters the high shear compartment, and both streams return to the vessel, forming a unified continuous process. This merging of functions into a single integrated apparatus resolves the contradiction by achieving high particle quality while managing device complexity through systematic integration.
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 process effectively produces metal hydroxide particles with small particle size, high density, and uniform spherical shape, suitable for high-performance cathode materials, maintaining consistent particle size and density over extended operation times.
Implementation Method 1
a separation device capable of separating a solids suspension into a high solids stream and a low solids stream
Implementation Method 2
subjecting the high solids stream to high shear conditions in a high shear compartment
Data Source
Figure 1
AI summary
Free-flowing, dense solid particles are prepared via a process comprising providing a solids suspension in a vessel with stirring, directing the suspension to a separation device, which device separates the suspension into a high solids stream and a low solids stream, subjecting the high solids stream to high shear conditions in a high shear compartment and circulating both streams back to the vessel, where the solids suspension is continuously circulated through an integrated apparatus. The integrated apparatus comprises a vessel equipped with a stirring mechanism, a separation device capable of separating a solids suspension into a high solids stream and a low solids stream and a compartment capable of subjecting the high solids stream to high shear conditions, where the separation device is connected to the vessel via a first feed line, the compartment is in-line in a second feed line connecting the separation device and the vessel and the separation device and the vessel are connected via a third feed line, where the first, second and third feed lines are capable of continuously circulating the solids suspension from the vessel to the separation device, circulating the high solids stream from the separation device through the compartment to the vessel and circulating the low solids stream from the separation device to the vessel, respectively and where the apparatus is capable of continuously circulating a solids suspension.