Copper, one of humanity's earliest metals, continues to play an indispensable role in power, electronics,
construction, transportation, and other fields due to its exceptional electrical conductivity, thermal conductivity,
and corrosion resistance. However, transforming ore from deep underground into high-purity cathode copper
requires a series of complex and precise smelting processes. This article systematically outlines the core
processes of modern copper smelting, illustrating how industrial technology transforms raw minerals into
essential foundational materials for contemporary civilization.
Step One: Raw Material Preparation and Mineral Processing
Copper smelting begins with ore extraction. Copper ores typically exist as sulfide minerals (such as chalcopyrite
or bornite) or oxide minerals. After extraction, the ore undergoes physical processing like crushing and grinding
to achieve the required particle size for smelting. Mineral separation then employs flotation techniques, leveraging
differences in surface properties to separate copper minerals from gangue, yielding copper concentrate. This step
significantly enhances copper grade, reducing energy consumption and costs in subsequent smelting stages.
Step 2: Smelting—From Concentrate to Blister Copper
Smelting is a core process in copper metallurgy, aimed at separating impurities like sulfur and iron from the
concentrate to produce the copper-rich intermediate product “blister copper” (Cu₂S·FeS). Modern smelters widely
adopt efficient processes like flash smelting or molten pool smelting. Flash smelting involves injecting dry copper
concentrate, flux, and oxygen-enriched air into a reaction tower, where oxidation occurs instantaneously at high
temperatures to produce blister copper and slag. During smelting, iron and sulfur oxidize into slag and sulfur dioxide
gas, while copper concentrates in the blister copper as cupric sulfide.
Step 3: Blowing – Converting Blister Copper to Blister Copper
Blister copper still contains significant amounts of iron and sulfur, requiring further purification through blowing.
This process occurs in converters or continuous blowing furnaces, where oxygen-enriched air is injected into
molten blister copper. This oxidizes residual ferrous sulfide into ferric oxide, which forms slag with silica, while copper(I)
sulfide gradually oxidizes into blister copper. This process generates high-concentration sulfur dioxide fumes,
necessitating a flue gas treatment system to recover sulfuric acid, thereby achieving the recycling of sulfur resources.
Step 4: Pyrometallurgical Refining and Electrolytic Refining
Blister copper typically achieves 98%–99% purity but still contains trace impurities like gold, silver, nickel, and arsenic,
necessitating further purification through refining. Pyrometallurgical refining occurs in anode furnaces, where
oxidation-reduction reactions remove some impurities before casting into anode plates. Subsequently, the anode plates
enter the electrolytic refining process. When electricity is applied in a copper sulfate electrolyte, pure copper precipitates
at the cathode, while impurities settle as anode slime (from which precious metals like gold and silver can be recovered).
The cathode copper obtained after electrolysis achieves a purity exceeding 99.99%, suitable for direct use in copper
material production or further processing.
Environmental Protection and Resource Utilization
Modern copper smelting prioritizes not only high-efficiency production but also green, low-carbon practices and
resource recycling. Sulfur dioxide fumes generated during smelting are captured for sulfuric acid production, while
treated slag serves as raw material for construction materials. Purified wastewater is recycled. Furthermore, technologies
like oxygen-enriched smelting and waste heat power generation significantly reduce energy consumption and carbon
emissions, driving the industry toward sustainable development.
Conclusion
Copper smelting is a complex process integrating metallurgy, chemical engineering, and materials science. From
ore crushing to electrolytic refining, each step embodies humanity's profound understanding of natural resources
and technological innovation. With the continuous advancement of intelligent control and low-carbon processes,
copper smelting will continue to supply this irreplaceable foundational material to the global industrial system in
increasingly efficient and environmentally responsible ways.