Composite Anode Unit for Hydrometallurgy
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Solution Overview
Problem
Current anodes used in hydrometallurgy for extracting metals like zinc, copper, nickel, and chromium face issues such as high cell voltage, low current efficiency, high energy consumption, short service life, and contamination due to corrosion and poor conductivity, particularly in environments with high chloride levels.
Innovation Solution
A composite anode unit comprising a metal core rod with a lead or lead alloy metal layer, a conductive ceramic layer of β-PbO2—Al2O3 composite oxide, and an active ceramic layer of γ-MnO2—Ti4O7 composite oxide, designed to enhance electro-catalytic activity and corrosion resistance, is developed. This anode unit is fabricated using extrusion coating and composite anodic electrodeposition methods to achieve a long service life and low cell voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lead and lead alloy anodes are used in hydrometallurgy, then the anode structure is simple and manufacturing is easy, but the cell voltage is high (3.4V to 3.8V), current efficiency is low (75% to 88%), energy consumption is high (3400 kWh to 4200 kWh per ton of Zn), and service life is short (half year to one year)
Solution Approach 1:
The patent applies composite materials by combining a metal core rod (aluminum or aluminum alloy) with a lead or lead alloy metal layer, and further coating with conductive ceramic layer (β-PbO2—Al2O3 composite oxide) and active ceramic layer (γ-MnO2—Ti4O7 composite oxide). This multi-layer composite structure reduces cell voltage and energy consumption while maintaining ease of manufacture through extrusion coating and electrodeposition processes.
2Ease of manufacture
If lead and lead alloy anodes are used, then manufacturing is simple, but the service life is short (half year to one year) due to corrosion and lead dissolution
Solution Approach 1:
The composite structure with metal core rod, metal layer, and dual ceramic layers provides both manufacturing simplicity and extended service life. The ceramic coating layers protect the underlying metal from corrosion and dissolution, while the extrusion coating and electrodeposition methods keep manufacturing straightforward.
Solution Approach 2:
The patent changes the chemical and physical parameters of the anode surface by applying conductive ceramic and active ceramic coatings with specific compositions (β-PbO2—Al2O3 and γ-MnO2—Ti4O7). These parameter changes enhance corrosion resistance and extend service life while maintaining electrical conductivity.
3Duration of action of stationary object
If lead-silver alloy anode is used, then service life is extended and corrosion resistance is improved, but silver loss occurs during recycling and local area corrosion causes hard crusts on anode slime that are hard to remove
Solution Approach 1:
The patent replaces silver-containing alloys with a composite structure using aluminum or aluminum alloy core with lead metal layer and ceramic coatings. This eliminates silver loss during recycling while extending service life through the protective ceramic layers that resist corrosion without forming hard crusts.
4Stability of the object's composition
If titanium-based dimensionally stable anode with plating surface is used, then dimensional stability is improved and cathode product quality is high, but the anode is expensive due to iridium and the coating becomes disactivated by manganese oxide precipitation
Solution Approach 1:
The patent uses a composite structure with metal core and ceramic coatings that provides dimensional stability similar to titanium-based anodes but with simpler structure and lower cost. The ceramic layers (β-PbO2—Al2O3 and γ-MnO2—Ti4O7) are resistant to disactivation by manganese oxide precipitation, maintaining stability without requiring expensive iridium.
5Reliability
If PbO2 anode prepared by electroplating is used, then insoluble anode property is achieved, but the PbO2 deposition layer is polyporous, rough, has strong internal stress, and is easily peeled off or eroded resulting in short service life
Solution Approach 1:
The patent improves upon electroplated PbO2 anodes by using a composite structure with dual ceramic layers. The conductive ceramic layer (β-PbO2—Al2O3) provides conductivity and the active ceramic layer (γ-MnO2—Ti4O7) provides catalytic activity. This composite approach eliminates the polyporous, rough structure with strong internal stress by using controlled extrusion coating and electrodeposition processes that create more uniform, adherent coatings.
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 composite anode unit exhibits improved electro-catalytic activity, corrosion resistance, and extended service life, while maintaining low cell voltage and inhibiting chlorine evolution, thus enhancing the efficiency and reliability of the hydrometallurgical process.
Implementation Method 1
a conductive ceramic layer coated on the metal layer, wherein the conductive ceramic layer comprises β-PbO2—Al2O3 composite oxide; an active ceramic layer coated on the conductive ceramic layer, wherein the active ceramic layer comprises γ-MnO2—Ti4O7 composite oxide
Data Source
AI summary
The present disclosure provides a composite anode unit, comprising: a metal core rod; a metal layer coated on the metal core, wherein the metal layer is lead or lead alloy; a conductive ceramic layer coated on the metal layer, wherein the conductive ceramic layer comprises β-PbO2—Al2O3 composite oxide; an active ceramic layer is coated on the conductive ceramic layer, wherein the active ceramic layer comprises γ-MnO2—Ti4O7 composite oxide. Methods for preparing the composite anode unit and an anode plate made from the composite anode unit are also provided.