Copper scrap: classification, recycling and applications

Copper scrap refers to end-of-life products, production and consumption waste containing copper and its alloys, which are used as secondary raw materials for producing refined copper and alloys. Due to copper's ability to be recycled repeatedly without loss of properties, copper scrap is a strategically important resource that reduces the burden on primary mining, lowers energy consumption and minimises environmental impact. Secondary copper accounts for a significant share of global metal consumption and plays a key role in balancing the market.

Classification and Categories of Copper Scrap

The classification of copper scrap in Russia and CIS countries is regulated by GOST 1639 and GOST R 54564 standards (the current version reflects modern requirements for accounting and sorting). Scrap is divided by chemical composition, degree of contamination, presence of coatings and origin. The main categories used in industry and trade:

• Copper without coatings and soldering (group M1, M2, M3): the purest category, represented by conductive products — wire, busbars, cables without insulation, as well as lump waste. Copper content is at least 99.5% for the highest categories. This scrap is a priority feedstock for the production of wire rod and electrical products.

• Coated copper (tinned, soldered): contains tin, lead or other metals that require removal during processing. It is used for producing alloys or refining with preliminary preparation.

• Copper alloys (brass, bronze): scrap and waste from double and special brasses, tin, lead, silicon, manganese and aluminium bronzes. It is sorted by alloy grades and alloying element content for remelting into corresponding alloys.

• Low-grade scrap and waste: slimes, skimmings, dust-like waste, heavily contaminated scrap requiring complex preparation or hydrometallurgical processing.

Scrap quality is assessed by the content of the base metal, contamination, moisture and the presence of harmful impurities. The higher the category, the lower the processing costs and the higher the economic efficiency.

Chemical Composition and Impurities

Copper scrap, especially low-grade, contains a wide range of impurities that must be removed to obtain metal suitable for electrical and structural applications. Key impurities are iron, nickel, lead, tin, antimony, zinc, as well as non-metallic inclusions — insulation, plastics, oils, paints. The presence of coatings (tin, lead, nickel) requires special technological techniques, since these elements affect the electrical conductivity and mechanical properties of the finished copper.

Recycling Technology

Copper scrap recycling includes several successive stages, the choice of which depends on the scrap category and the required quality of the final product.

Sorting and preparation. Scrap is sorted by category, cleaned of non-metallic inclusions, and separated into copper and alloy fractions. For cable scrap, mechanical shredding, air separation and magnetic cleaning are used to separate copper granules from insulation and achieve copper content above 99%. Modern air classification technologies ensure high purity of copper granules.

Fire refining. High-grade scrap and pre-prepared charge are subjected to fire refining in melting furnaces at a temperature of about 1200–1250 °C. During melting and oxidation, many impurities are removed, and then the melt is reduced (deoxidised) to remove excess oxygen. The result is blister copper or anode copper with a purity of about 99.5%. Fire refining is an effective method for removing iron, zinc, lead and tin, but antimony and nickel are more difficult to remove and require adjustment of the slag composition.

Electrolytic refining. To achieve the purity required for electrical applications (99.99%), anode copper is subjected to electrolysis in a solution of sulfuric acid and copper sulfate. When direct current is passed, copper deposits on the cathode, while impurities concentrate in the anode slime or pass into the electrolyte. Electrolysis ensures the production of high-grade copper cathode suitable for wire rod and wire production.

Hydrometallurgical methods. For low-grade scrap, slimes and dust-like waste, leaching methods followed by electrowinning or precipitation are used. These technologies allow copper to be extracted from complex raw materials that are inefficient to process by pyrometallurgical methods.

Applications

The main consumers of copper scrap are metallurgical enterprises producing copper cathode, wire rod, ingots and alloys. Secondary copper is used for the production of electrical products, cables, wires, pipes, brasses and bronzes. Significant volumes of scrap are consumed by foundries to produce castings from copper alloys. In addition, copper scrap is exported and imported as an exchange-traded commodity, and its price serves as an important indicator of the non-ferrous metals market.

Safety and Storage

Copper scrap is in most cases not chemically hazardous, but during storage and processing, the presence of oils, paints, plastic insulation and other combustible materials must be taken into account. During mechanical processing (cutting, shredding), dust is generated, which can be fire-hazardous. During melting, metal and oxide vapours may be released, so effective ventilation and personal protective equipment are required. Scrap storage is carried out on equipped areas with hard surfacing, separately by category, in compliance with fire safety measures and protection from contamination.

Market and Trends

The copper scrap market is an important part of the global copper market. Secondary raw materials provide a significant share of global metal consumption, and demand for them is growing steadily due to the development of the power industry, electric vehicles and renewable energy. Key trends include tightening requirements for scrap purity and traceability of its origin, the development of sorting and recycling technologies, and growing competition for quality secondary raw materials among refined copper producers. The Asia-Pacific region remains the largest consumer of copper scrap, and export flows are shaped by customs regulation and price conditions.

Conclusion

Copper scrap remains a key element of sustainable copper supply for global industry. The development of sorting, refining and hydrometallurgy technologies allows increasingly complex types of raw materials to be involved in processing, increasing metal recovery and reducing environmental impact. Organising supplies of copper scrap, including category assessment, quality confirmation and logistics, requires an individual approach that takes into account the requirements of processing enterprises and regulatory restrictions.