Copper smelting is the core process of transforming copper-containing minerals into high-purity
metals, and 80% of the world's copper products are produced through pyrometallurgy. This
technique, which has been passed down for thousands of years, has developed into a complex
system that combines high-temperature reaction, electrolytic purification, and environmental
protection. This article will deconstruct the nature of copper smelting process, technological
innovation and industrial value.
Copper smelting technology principles and process framework
1. Raw material treatment system
Ore pretreatment: 0.5-2% copper-containing raw ore is crushed and ground to -200 mesh, accounting for more than 90%.
Flotation enrichment: the yellow drug trapping agent makes the grade of copper concentrate increase to 20-30%.
Drying and pelletizing: rotary kiln reduces the moisture of concentrate to <8%, and makes 80-120mm sintered lumps.
2. Main smelting process
Modern copper smelting has formed two major technical routes:
Pyrometallurgy: accounts for 76% of the global production capacity, adapted to the treatment of sulfide ores.
Hydrometallurgy: mainly processing oxidized ore and low-grade ore
Pyrometallurgy core process analysis
1. Smelting process technology breakthroughs
Oxygen-enriched smelting technology:
Oxygen concentration increased to 50-85%, melting temperature of 1250-1300℃.
The grade of ice copper is increased from 45% to 65-70%.
The amount of flue gas is reduced by 40%, sulfur capture rate> 99.5%.
Core equipment evolution:
Flash Melting Furnace: capacity up to 4000t/d, thermal efficiency 85
Top-blowing rotary furnace: slag content of copper <0.6%
2. Blowing process process control
PS rotary furnace operation points:
Add quartz flux to regulate Fe/SiO₂ ratio to 1.8-2.0 in stages.
Crude copper grade 98.5-99.5%, sulphur content 0.02-0.05%.
Flue gas waste heat power generation up to 30kWh/ton of copper
3. Refining process quality improvement program
Three stages of refining in anode furnace:
Oxidizing period: Blast air removing impurities (As, Sb, Bi)
Reduction period: natural gas plug wood reduction, oxygen content down to 200ppm
Casting period: vertical mold casting anode plate, qualification rate>99.8%
Wet smelting technology route details
1. Heap leaching-extraction-electrowinning process (SX-EW)
Process parameters:
Leaching cycle of 60-180 days, leaching rate of 70-85%
Extractant (LIX series) copper loading 3-5g/L
Electrowinning DC power consumption 2000-2200kWh/ton copper
Technical Advantage:
Applicable to 0.15-0.8% low grade oxide ore
No sulfur dioxide emission
The cost per ton of copper is 25-30% lower than the thermal method.
2. Biometallurgy innovative application
Thiobacillus oxidans leaching:
pH 1.5-2.5, temperature 30-50℃.
Leaching cycle shortened to 5-10 days
Copper recovery rate is increased to 88-92%.
Electrolytic refining technology upgrade
1. Permanent cathode process (ISA method)
Stainless steel cathode life>10 years
Current density increased to 330A/m².
The purity of copper cathode reaches 99.997%.
2. Intelligent electrolysis system
Automatic stripping unit efficiency 120 pieces/hour
Online monitoring of electrolyte (Cu²+±2g/L, acidity±5g/L)
Pole distance automatic adjustment precision ±0.5mm
Environmental protection governance and resource technology
1. Flue gas purification system
Acid process by double contact method, conversion rate of 99.95
Electrodusting + activated coke desulfurization, emission concentration <50mg/Nm³
Arsenic filter cake curing treatment, leaching toxicity <1mg/L
2. Circular economy practice
Smelting slag preparation of cement mixing material, blending amount 30-40%
Extraction of gold, silver, selenium and tellurium from anode sludge, recovery rate of precious metals＞98%.
Waste heat boiler steam power generation meets 60% of the demand of the plant.
Trend of industry technology evolution
1. Low-carbon smelting technology breakthrough
Hydrogen-based smelting replaces carbonaceous reductant.
Oxygen-enriched concentration increased to 95
Carbon capture rate of metallurgical process >90%.
2. Intelligent factory construction
Digital twin system realizes dynamic optimization of process parameters
AGV unmanned transportation vehicle replaces traditional logistics
Machine vision detects copper cathode defects
3. Transformation of raw material structure
Increase the proportion of recycled copper to 40
Synergistic smelting of complex polymetallic ores
Deep-sea nodule smelting technology reserves
The copper smelting industry is undergoing a transition from “high energy consumption” to “high technology”.
The new process has reduced the comprehensive energy consumption of tons of copper to 380kgce, and the
sulfur dioxide emission has dropped by 78% compared with ten years ago. As the demand for copper in
the field of new energy vehicles and renewable energy surges, efficient and clean smelting technology
will continue to promote the reshaping of the industry's value.