Copper
Copper (symbol Cu, atomic number 29) is a reddish-orange metal known for its excellent thermal and electrical conductivity. It is a ductile and malleable element, meaning it can be easily drawn into wires and hammered into thin sheets without breaking. Copper is a relatively unreactive metal, resisting corrosion in many environments.
Occurrence and Extraction
Copper is found in various minerals, including chalcopyrite (CuFeS₂), chalcocite (Cu₂S), bornite (Cu₅FeS₄), and malachite (Cu₂CO₃(OH)₂). Significant copper deposits are located in Chile, Peru, the United States, and China, among other countries.
The extraction of copper from its ores typically involves a combination of mining, concentrating, smelting, and refining processes. Sulfide ores, like chalcopyrite, often undergo froth flotation to concentrate the copper-bearing minerals. The concentrate is then smelted to produce a copper matte, which is further processed to remove impurities like iron and sulfur. The final stage, electrolytic refining, purifies the copper to a high degree (typically 99.99% purity) for electrical applications. Oxide ores, like malachite, can be leached with sulfuric acid to dissolve the copper, which is then recovered by electrowinning.
Properties
- Atomic Number: 29
- Atomic Mass: 63.546 u
- Density: 8.96 g/cm³
- Melting Point: 1085 °C (1985 °F)
- Boiling Point: 2562 °C (4644 °F)
- Electrical Conductivity: Very high
- Thermal Conductivity: Very high
- Ductility: High
- Malleability: High
- Color: Reddish-orange (metallic)
Uses
Copper's high electrical and thermal conductivity, ductility, and corrosion resistance make it a versatile metal with a wide range of applications, including:
- Electrical Wiring: Used extensively in electrical wiring, cables, and electronic components.
- Plumbing: Employed in plumbing pipes and fittings due to its corrosion resistance and workability.
- Heat Exchangers: Used in heat exchangers, radiators, and other heat transfer applications.
- Alloys: Alloyed with other metals to form brass (copper and zinc) and bronze (copper and tin), which are used in a variety of applications requiring strength, corrosion resistance, and machinability.
- Roofing and Building Materials: Used in roofing, gutters, and other building materials due to its durability and aesthetic appeal.
- Coins: Historically and currently used in the production of coinage.
- Antimicrobial Applications: Copper and copper alloys exhibit antimicrobial properties and are used in applications where reducing the spread of bacteria is desirable, such as in hospitals and public transportation.
Biological Role
Copper is an essential trace element for all known living organisms. It plays a crucial role in various enzymes and proteins involved in processes such as respiration, iron metabolism, and antioxidant defense. Copper deficiency can lead to a range of health problems. However, excessive copper intake can also be toxic.
Compounds
Copper forms a variety of compounds, including:
- Copper(I) Oxide (Cu₂O): A red solid used as a pigment and in some antifouling paints.
- Copper(II) Oxide (CuO): A black solid used as a pigment, in catalysts, and in the production of other copper compounds.
- Copper Sulfate (CuSO₄): A blue crystalline solid used as a fungicide, algaecide, and in various industrial processes.
- Copper Chloride (CuCl₂): A green or blue-green solid used in pigments, wood preservatives, and in the petroleum industry.
Environmental Considerations
Copper mining and processing can have environmental impacts, including air and water pollution. Responsible mining practices, pollution control measures, and recycling efforts are important to minimize these impacts. Copper is recyclable, and recycling significantly reduces the energy required to produce new copper from ore.