In the field of metal smelting, electrolytic copper refining is like a master purifier, transforming impurity-laden
crude copper into high-purity copper that multiplies in value. This industrial technology, which began at the
end of the 19th century, still occupies a central position in the global copper industry. In modern factories,
neatly arranged electrolysis tanks operate around the clock, and through precisely controlled electrochemical
reactions, the purity of copper is increased to more than 99.99% to meet the demanding needs of precision
electronic components, high-end cables, and other special areas.
Process Principle of Electrolytic Copper Refining
The core of electrolytic purification lies in the construction of a precise sorting system in the electrolyzer by
utilizing the directional movement characteristics of the electric current. The anode is made of rough copper
plate of about 99% purity, while the cathode is made of pure copper starter plate or titanium plate with flat
surface. When direct current is passed through the electrolytic system containing a copper sulfate solution, the
anode copper atoms lose electrons and enter the solution as copper ions, and these charged particles migrate
in a directional manner driven by an electric field, ultimately acquiring electrons on the cathode surface to be
reduced to pure copper atoms.
The electrolyte system needs to maintain specific parameters to ensure the purification efficiency. The acidity is
controlled at 180-220g/L sulfuric acid concentration, the copper ion concentration is maintained in the 40-50g/L
range, and the electrolyte temperature is stabilized in the 55-65°C range. This precisely regulated environment
ensures the effective migration of copper ions and inhibits the co-deposition of impurity metals.
Current density is a key parameter affecting production efficiency. Modern factories usually control the current density
at 220-300A/m², which not only ensures a reasonable deposition rate, but also avoids loose copper cathode structure
caused by excessive current. Under the monitoring of intelligent control system, the voltage fluctuation of each
electrolyzer is no more than 0.3V, which creates a stable electrochemical reaction environment.
Modern electrolytic copper production process
The raw material pretreatment link determines the starting point of the quality of the final product. After precise
proportioning, the crude copper raw material is melted into liquid state in the high temperature melting furnace at
1150℃, and cast into standard anode plate with thickness of 100mm and weight of 300kg. In this process, the specific
gravity method of impurity removal device can remove more than 90% of lead, zinc and other heavy metal impurities.
The core electrolysis process is carried out in a 12-meter long large electrolysis tank. 200 anode plates and 201 cathode
plates are arranged in an alternating pattern, with the pole spacing accurately controlled at 90-100mm, and the
electrolytic solution circulates at a flow rate of 1.5m/s to ensure uniform ion distribution. 72 hours of continuous
electrolysis results in a cathode copper plate thickness of 6-8mm, with a single-tank daily production capacity
of up to 2.5 tons.
The post-processing system adopts fully automatic assembly line operation. The mechanical stripping device cuts the
0mm thick copper cathode plate into standard sizes, and the surface treatment unit removes the surface oxides through
three processes of acid washing-washing-drying, and the X-fluorescence analyzer tests the composition of each batch
of products to ensure that the copper content reaches the international standard of 99.997%.
Technological Advantage and Environmental Protection Innovation
Compared with traditional pyrometallurgical smelting, electrolytic purification has significant advantages in energy consumption.
The modern electrolysis system adopts insoluble anode design with pulse current technology, which reduces DC power
consumption to below 2200kWh/t. The waste heat recovery device can convert electrolyte waste heat into heat energy required
for other processes, increasing the overall energy utilization rate by more than 35%.
The environmental protection treatment system builds multiple protection barriers. Copper-containing wastewater is washed
by three-stage countercurrent, with a copper recovery rate of 99.9%, and the purified water reaches the industrial reuse standard.
The acid mist collection tower is made of double-layer glass fiber reinforced plastic, and together with the lye spraying system,
the concentration of acid mist in the workshop is controlled to below 2mg/m³. The gold, silver and other precious metals in the
anode sludge are extracted through a special process, realizing all-element recovery of resources.
Intelligent transformation is reshaping the traditional electrolysis workshop. The digital twin system simulates the operating status
of electrolysis tanks in real time, the big data platform analyzes ten years of production data to optimize process parameters, and
the AGV unmanned vehicle accurately distributes pole plate materials. These innovations have increased labor productivity by
40% and stabilized the product qualification rate at over 99.98%.
Driven by the goal of carbon neutrality, electrolytic copper refining technology is undergoing a green transformation. The new
ion membrane electrolysis technology reduces energy consumption by another 15%, the combined bioleaching-electrolysis
process increases the utilization rate of low-grade ore to 85%, and the photovoltaic direct supply electrolysis system creates a
new mode of clean production. These innovations not only continue the centuries-old vitality of electrolytic copper refining,
but also write a new chapter of modern metallurgical industry in the era of digital economy. When the morning sun lights up
the electrolysis workshop, the rose-red copper crystals growing on the surface of the cathode are witnessing the perfect
transformation of this traditional process into a high-end, intelligent and green one.