Electrolytic Manganese Dioxide Double Milling Compact Density
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Solution Overview
Problem
Current methods for producing electrolytic manganese dioxide do not achieve high enough compact density, which is crucial for optimal battery performance, as they fail to effectively modify particle distribution during the milling process.
Innovation Solution
A double milling process is employed, where electrolytic manganese dioxide pieces are first milled in a classifying mill to achieve a specific particle size distribution, and then further milled to enhance the compact density by modifying the particle size distribution, using a tumbling mill with non-metallic milling media, and optionally neutralizing and drying at various stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single milling process is used to reduce electrolytic manganese dioxide piece size, then processing time is reduced, but the compact density of the resulting particles is insufficient
Solution Approach 1:
The milling process is divided into two distinct stages: a first milling step using a classifying mill to achieve initial particle size reduction with a specific size distribution, followed by a second milling step using a tumbling mill to further reduce size and optimize compact density. This segmentation allows each milling stage to be optimized for its specific function, resolving the contradiction between processing speed and compact density.
2Manufacturing precision
If the electrolytic manganese dioxide is milled to very fine particle sizes to increase compact density, then the battery performance improves, but the processing time and energy consumption increase
Solution Approach 1:
The first milling step performs preliminary particle size reduction to achieve a specific size distribution before the second milling step. This preliminary action reduces the burden on the second milling step, allowing it to focus on optimizing compact density without requiring excessive processing time or energy for the entire size reduction process.
3Ease of manufacture
If the particle size distribution is not optimized during milling, then the milling process is simpler and faster, but the packing efficiency in batteries is reduced
Solution Approach 1:
The process optimizes specific parameters including the particle size distribution targets for each milling stage, the classification settings of the classifying mill, and the milling conditions of the tumbling mill. By carefully controlling these parameters, the process achieves both reasonable manufacturing complexity and high packing efficiency in the final product.
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 double milling process increases the compact density of the electrolytic manganese dioxide by at least 1% and maintains the alkaline potential, allowing for better packing efficiency and performance in alkaline batteries.
Implementation Method 1
electrolytic manganese dioxide pieces are milled in a classifying mill to produce first milled manganese dioxide particles having a first particle size distribution
Implementation Method 2
The first milled manganese dioxide particles are then milled a second time to produce second milled manganese dioxide particles having a second particle size distribution
Data Source
AI summary
A method for producing electrolytic manganese dioxide with high compact density where electrolytic manganese dioxide pieces are milled in a classifying mill to produce first milled manganese dioxide particles where 30% of the particles are larger than 200 mesh and up to 95% of the particles are smaller than 325 mesh. The first milled manganese dioxide particles are milled a second time to produce manganese dioxide particles having a second particle size distribution. Also, an electrolytic manganese dioxide particle composition, wherein when the particle size distribution of the composition is plotted as a function of base-10 logarithm of the particle size, a first peak is centered at a particle size from 40-100 μm and contributes a minimum of 20% of the area under the curve of the overall particle size distribution and a maximum of 45% of the area under the curve of the overall particle size distribution.