Pre-compacted Graphite Plate for Aluminum Cathode Bottom Sealing
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Solution Overview
Problem
Current cathode bottoms in aluminum electrolytic cells suffer from mechanical abrasion, chemical corrosion, and electrical resistance issues due to conventional carbon or graphite ramming materials, which reduce efficiency and increase costs, and pose health risks from toxic binders like coal tar.
Innovation Solution
A cathode bottom using a pre-compacted graphite plate made from expanded graphite and a graphite intercalation compound, which is compressible, thermally and electrically conductive, and self-healing, to fill gaps and cracks, ensuring sealing and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbon or graphite ramming materials are used to fill gaps between cathode blocks, then mechanical stability and sealing are achieved, but electrical resistance increases and effective cathode area is reduced
Solution Approach 1:
The invention changes the material parameters by using graphitized cathode blocks with specific graphite grades and controlled graphitization treatment, achieving lower electrical resistance compared to conventional carbon ramming materials while maintaining sealing capability
Solution Approach 2:
The invention uses composite construction by combining graphitized cathode blocks with specific binder materials that have low electrical resistance, creating a filled joint that maintains both sealing and high electrical conductivity
2Reliability
If conventional carbon or graphite ramming materials are used, then gap filling and sealing are achieved, but wear of the cathode bottom increases due to mechanical abrasion and chemical corrosion
Solution Approach 1:
The invention changes the chemical composition parameters by using graphitized materials with controlled impurity content and specific graphite grades, which exhibit superior resistance to mechanical abrasion and chemical corrosion from aluminum carbide formation and sodium incorporation
Solution Approach 2:
The invention uses consumable filled joints made of carbon-based materials that are designed to wear slower than the cathode blocks themselves, protecting the expensive cathode blocks from direct wear and extending their service life
3Strength
If coal tar-based binders are used in ramming mixes, then mechanical stability is achieved, but toxic polycyclic aromatic hydrocarbons are released into the atmosphere
Solution Approach 1:
The invention extracts and removes the harmful coal tar binder component from the ramming mix, replacing it with alternative binding mechanisms or materials that provide mechanical stability without releasing toxic polycyclic aromatic hydrocarbons
Solution Approach 2:
The invention changes the chemical composition of the binder material, transitioning from coal tar-based organic binders to alternative binders that eliminate toxic emissions while maintaining the necessary mechanical binding properties
4Reliability
If thin layers of coarse-grain ramming mass are implemented, then better sealing should be achieved, but mechanical stability is compromised due to ramming procedure limitations
Solution Approach 1:
The invention uses porous or fine-grained filled joint materials that can be densely packed in thin layers, achieving effective sealing while maintaining mechanical stability through the porous structure's ability to distribute stresses
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 pre-compacted graphite plate enhances the effective cathode area, reduces wear, and eliminates health hazards, while maintaining electrical and thermal conductivity, thereby improving the efficiency and longevity of the electrolytic cell.
Implementation Method 1
the pre-compacted graphite plate based on expanded graphite and a graphite intercalation compound... which is compressible, thermally and electrically conductive, and self-healing, to fill gaps and cracks
Implementation Method 2
a pre-compacted plate based on expanded graphite and a graphite intercalation compound
Implementation Method 3
which is compressible, thermally and electrically conductive
Implementation Method 4
which is compressible, thermally and electrically conductive
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The invention relates to a cathode bottom, to a method for the production thereof, and to the use thereof in an electrolytic cell for producing aluminum. The cathode bottom (1) comprises at least two cathode blocks (7) and/or at least one cathode block (7) and at least one sidewall block, which are arranged at a distance from each other, wherein the gap (5) is filled with a pre-compressed graphite plate (3), composed of expanded graphite and a graphite intercalation compound.