Behind the glittering copper cathode, there hides a key role in determining purity, efficiency and
profit - copper anode. It is not a simple piece of metal, but the core “heart” of the electrolytic refining
system, and its quality and performance directly affect the lifeblood of the entire production line.
Understanding copper anode is the golden key to master the quality and cost control of electrolytic
copper.
The mission of copper anode: efficiently release pure copper ions
The core function of the copper anode is to conduct precise and controlled electrochemical dissolution driven by
the electric field of the electrolyzer:
Precise dissolution: Under the action of direct current, copper atoms (Cu) in the anode lose electrons and oxidize to
copper ions (Cu²⁺) into the electrolyte. This process must be uniform and stable in order to guarantee the efficiency
of cathodic deposition and the quality of the copper sheet.
Impurity control: The anode inevitably contains precious metals such as gold, silver, platinum and palladium, as well
as impurities such as nickel, arsenic, antimony, bismuth and lead. Ideal anode dissolution requirements: efficient dissolution
of copper, precious metals do not dissolve off the formation of anode mud, harmful impurities as little as possible into
the electrolyte. This is a prerequisite for obtaining high purity copper cathode.
Maintaining electrolyte balance: the concentration of copper ions dissolved in the anode should be matched with the
deposition rate of the cathode, and the concentration of the main components of the electrolyte (copper and acid)
should be kept stable to ensure the continuous and efficient operation of the process.
The core requirement of copper anode: quality creates value.
A high-quality copper anode plate is the cornerstone of efficient, stable and economic electrolysis production, and
must meet the strict requirements:
High purity: the grade of anode copper is usually required to be ≥ 99.5% (the national standard 1# standard cathode
copper requires higher anode copper). High purity is the basis for reducing the dissolution of harmful impurities and
improving the purity of the copper cathode.
Uniform and dense: the crystal structure is dense and uniform, without internal defects such as pores, slag, cracks, etc.
The structure defects will lead to uneven dissolution. Structural defects will lead to uneven dissolution, localized
detachment, and even short circuit, which will seriously reduce current efficiency and increase energy consumption
and residual electrode rate.
Accurate physical specifications:
Dimensional tolerances: Thickness, length, width, verticality, lug position, etc. should be highly consistent to ensure
precise alignment in the electrolyzer, reduce pole spacing deviation and optimize current distribution.
Flatness: The surface should be flat and smooth, reduce the bumps or depressions, avoid passivation or accelerated
uneven dissolution caused by high local current density.
Lug strength: lugs must have sufficient mechanical strength and electrical conductivity, to withstand self-weight and
operating stress, to ensure good electrical conductivity, hanging solid.
Optimized chemical composition:
Key element control: Strict control of oxygen and sulfur content (affecting conductivity and dissolution behavior), with
special attention to the content of impurity elements (e.g., arsenic, antimony, bismuth, nickel) that are a big burden to
the electrolyte purification system.
The Subtle Role of Phosphorus (P): The addition of phosphorus in the right amounts (typically 0.04% - 0.06%) is critical.
It promotes the formation of a strong, dense, well-conducting anode clay layer, prevents impurities from leaching out,
improves cathode copper purity, and reduces short-circuit rates.
Stable performance: In an electrolysis cycle of up to ten to twenty days, it is necessary to maintain a uniform and
controllable dissolution rate to avoid early passivation or excessive pulverization and shedding.
Anode Manufacturing Process: Melting and Casting to Settle the Score
The quality of copper anode plate is established as early as in the casting process:
Raw material control: Strictly screen qualified anode ingots or recycled materials produced by fire refining, accurately
batch and control the total amount of impurities.
Melting and refining: Melting in reflector furnace, rotary furnace or tilting furnace, redox refining if necessary, adjusting
oxygen and sulfur content, and removing volatile impurities in depth.
Critical step: phosphorus copper addition: before casting, phosphorus copper alloy is added to the copper liquid in precise
quantities to ensure uniform distribution of phosphorus elements.
Casting molding:
Mould design: Mould material (often cast iron), structure, cooling system design directly affects the solidification
organization, surface quality and stress distribution of anode plate.
Casting process: control the casting temperature, speed, cooling intensity, to obtain dense, uniform, low-stress ingot
structure. Automated quantitative casting, plate surface spray cooling, automatic plate pickup, etc. to improve consistency
and efficiency.
Surface treatment: Remove flying edge burrs, mill or level if necessary to ensure physical specifications are met.
Copper Anode Failures and Challenges: The Invisible Cost Black Hole
Poor quality or mismatched copper anodes can lead to a host of production problems, resulting in significant hidden costs:
Current efficiency plummets:
Short-circuiting: Deformation, bending or uneven surface of the anode leads to contact with the cathode, and the current
“short-circuits” and does not do any useful work.
Passivation: Dense oxide film or sulfate layer is formed on the surface, which prevents the dissolution of copper ions, and the
voltage of the tank rises, and the energy consumption increases dramatically.
Impurities: some impurities (such as lead, arsenic, antimony and bismuth) promote harmful side reactions (such as precipitation
of oxygen), consumption of current.
The quality of copper cathode decreases:
Physical defects: uneven anode dissolution leads to uneven cathode deposition (particles, nodules).
Chemical contamination: Excessive impurities dissolve in the electrolyte and eventually precipitate at the cathode, reducing the
grade of the copper cathode and even leading to a substandard product.
Increased operating costs:
High rate of residual electrode: Uneven dissolution leads to premature dissolution in some areas (perforation, falling off), forming
a large number of residual electrodes that need to be remelted back to the furnace, which increases the cost of treatment.
Anode mud abnormality: the anode mud layer is loose, falling off (pulverization), increasing the suspended matter of electrolyte,
polluting the cathode, clogging the pipeline and increasing the burden of filtration.
Frequent maintenance: Frequent handling of short circuit, cleaning sludge at the bottom of the tank, replacing broken anode
plates, increasing labor and production stoppage loss.
Risk of precious metal loss: Anode sludge falling off leads to loss of precious metal or decrease of recovery rate.
Optimization: Unlocking the Ultimate Value of Copper Anodes
Maximizing the value of copper anodes requires systematic optimization:
Strict control at source: Establish strategic cooperation with reliable anode suppliers to ensure that the copper grade,
phosphorus content and physical specifications of raw materials meet the standards consistently and stably. Establish
strict inspection standards for incoming materials.
Process matching: Customized optimization of anode composition (e.g. phosphorus content) and physical specifications
according to the characteristics of electrolysis process in the plant (current density, electrolyte composition, additive
system, cycle volume, etc.).
Fine operation:
Precise Arrangement: Ensure uniform spacing between poles.
Cycle management: set the replacement cycle scientifically according to the current density and anode dissolution.
Short circuit inspection: Strengthen the frequency of short circuit detection and treatment.
Management of residual electrode and anode sludge:
Efficient recovery of residual electrode: Optimize the process of residual electrode treatment and shorten the cycle of
returning to melting.
Value mining of anode sludge: Collect and process anode sludge efficiently to maximize the recovery of valuable elements
such as gold, silver, selenium, tellurium, etc., and turn it into an important source of profit.
Data-driven optimization: real-time monitoring of key parameters such as tank voltage, current efficiency, cathode quality,
electrolyte composition, etc., and analysis of their correlation with anode batch and usage cycle, so as to continuously
improve the performance of anode and process matching.
The future of copper anode: smarter, more efficient and greener
With the advancement of technology, the field of copper anode is also evolving:
Manufacturing intelligence: automation and digital control of melting and casting process are enhanced, and online quality
inspection (e.g. visual recognition of surface defects, ultrasonic thickness inspection) guarantees consistency.
Material and process innovation: Explore bimetallic composite anodes (e.g. stainless steel or titanium-based copper cladding)
to improve strength, flatness and life; optimize phosphorus addition and research on new additives.
Full life cycle management: Combine with Internet of Things technology to track the data of each anode from production, use
to residual electrode recycling, so as to realize more accurate performance prediction and optimization.
Green and low-carbon: Optimize the energy consumption of anode manufacturing, improve the dissolution efficiency of anode
(reduce electricity consumption per ton of copper), strengthen the recovery of valuable elements and rare metals in anode
sludge, and reduce the waste of resources.