Copper is a purplish red metal with hardness of 2.5 ~ 3 and specific gravity of 8.5 ~ 9. It has strong ductility and thermal conductivity and high conductivity. Due to these properties and the properties of alloys combined with zinc, lead, nickel, aluminum and titanium, copper is widely used in electrical appliances, machinery, vehicles, shipbuilding industry and civil appliances.
There are more than 280 kinds of copper bearing minerals in nature, of which 16 are of industrial significance. Today, Fodamon engineer explained some main copper mines with copper ore dressing significance.
1、 Copper (copper)
The composition is Cu, and the original natural copper sometimes contains silver and gold. Isometric. The crystal is cubic, but rare; It is generally dendritic, flake or dense block aggregate. Copper red, the surface is easy to oxidize into brown black. The streaks are bright copper red. Metallic luster. Hardness 2.5 ~ 3. Strong ductility. The fracture is serrated. It is a good conductor of electricity and heat. Density 8.5 ~ 8.9 g / cm3. Natural copper is common in the oxidation zone of copper sulfide deposits, which is generally the product of the transformation of copper sulfide into oxide. Primary natural copper of hydrothermal origin is often disseminated in some hydrothermal deposits. Natural copper is also often produced in copper bearing sandstone. When Dali accumulates, it can be used as copper ore.
2、 Copper sulfide
- Chalcopyrite
Component CuFeS2, containing cu34 56%。 Tetragonal system. The crystal is tetragonal bipyramid or tetragonal tetrahedron, but it is rare; They are often granular or dense massive aggregates. Brass. The surface is often dark yellow or mottled due to oxidation. Stripes are green and black. Hardness 3 ~ 4. Density 4.1 ~ 4.3 g / cm3. It mainly occurs in copper nickel sulfide deposits, porphyry copper deposits, contact alternating copper deposits and layered copper deposits of some sedimentary origin (including volcanic sedimentary origin). Under weathering, chalcopyrite is transformed into water-soluble copper sulfate, which forms malachite and azurite when it reacts with carbonic acid containing solution. Chalcopyrite is one of the main ore minerals in copper smelting.
- Bornite
The component is cu5fes4, containing cu63 33%。 Isometric. Usually in granular or dense massive aggregates. The fresh fracture is copper red, and the surface is blue purple stain due to oxidation, so it is named. Streaks are grayish black. Hardness 3. Density 4.9 ~ 5.0 g / cm3. Porphyry copper is a widely distributed mineral in many copper deposits. Endogenetic porphyry copper ore often contains inclusions of micro flake chalcopyrite, which is the product of solid solution decomposition. The secondary bornite was formed in the secondary enrichment zone of the copper deposit. It is one of the main ore minerals in copper smelting.
- Chalcocite
Component Cu2S, containing cu79 86%。 Orthorhombic system. Crystals are rare, usually in soot shape, granular or dense block. Lead grey. Streaks of dark gray. Metallic luster. Hardness 2 ~ 3. It is slightly malleable. It is carved with a knife, leaving bright groove marks. Density 5.5 ~ 5.8 G / cm3. It can be of endogenetic hydrothermal origin and exogenetic origin. It is one of the main ore minerals for copper smelting.
- Copper blue
Component cus. Including CU66 5%。 Hexagonal system. Usually lamellar, membranous or soot like aggregates. indigo. Streaks gray to black. Metallic luster. Hardness 1.5 ~ 2. Cleavage parallel to the bottom {0001} completely. Density 4.59 ~ 1.67 g / cm3. The sheet is slightly elastic. Copper blue is mainly of exogenous origin and is the most common mineral in the secondary enrichment zone of copper sulfide deposits. Cerulean Bletilla formed by hydrothermal solution is rare. It is one of the ore minerals for copper smelting.
- Fangchalcopyrite
Cufe2s3 is an orthorhombic system. The crystals are often elongated flat prisms, sometimes forming V-shaped bicrystals or radial hexagonal crystals or flake aggregates, and blocks are rare. Copper yellow, Stripe Black, opaque. Mohs hardness is 3.5 ~ 4, metallic luster, specific gravity is 4.1g/cm3, cleavage is incomplete, fracture is shell like. With longitudinal stripes. It often coexists with chalcopyrite, quartz, natural gold, siderite, calcite, pyrite, pyrrhotite and other copper sulfides. Minor rare copper minerals.
- Tetrahedrite
Component: Cu12Sb4S13, containing cu45 77%。 It forms a isomorphic series with arsenite Cu12As4S13. Generally, tetrahedrite contains a certain amount of arsenic tetrahedrite molecules. Isometric. The crystals are tetrahedral, but usually granular or dense massive aggregates. Steel gray to iron black, fresh fracture is swarthy black. The stripes are the same color. Semi metallic luster. Hardness 3 ~ 4. Density 4.4 ~ 5.1 g / cm3. It is found in various genetic copper bearing hydrothermal deposits. It is often used as copper ore together with other copper bearing minerals.
- Chalcopyrite (enargite)
Component cu3ass4, containing cu48 3%。 Orthorhombic system. Crystals are often columnar, but usually dense massive or granular aggregates. Steel gray to iron black. Streaks are grayish black. Metallic luster. Hardness 3.5. Cleavage parallel orthorhombic column {110} complete. Density 4.4 ~ 4.5 g / cm3. It is mainly found in mesothermal hydrothermal copper deposits and coexists with chalcopyrite and tetrahedrite. When enriched, it can be used as an ore for copper smelting.
3、 Copper oxide
- Cuprite
The component is Cu2O, containing C88 82%。 Isometric. The crystal is a small octahedron, sometimes in needle or hair shape, which is called needle hematite. The aggregate is dense, massive, granular or earthy. Dark red. Streaks maroon. Diamond luster or semi metallic luster. Hardness 3.5 ~ 4. Density 6 g / cm3. Formed under exogenous conditions, it is mainly found in the oxidation zone of copper deposit and is the product of oxidation of copper bearing sulfide. It can be used as copper ore.
- Tenorite
Component Cuo, containing cu79 9%。 Monoclinic system. Black or grayish black. Streaks are grayish black. Semi metallic luster. Brittle. Hardness 3.5. Density 5.8 ~ 6.4 g / cm3. It is mainly found in the oxidation zone of copper deposit and is the product of oxidation of copper bearing sulfide.
- Malachite
The composition is Cu2 CO3 2, cu57 4%。 Monoclinic system. Crystals are acicular, usually radial or bell emulsion aggregates. Green. Glass luster. Hardness 3.5-4. Density 3.9-4 0 g / cm3. Blister in case of hydrochloric acid. It is a secondary mineral formed after the oxidation of primary copper bearing sulfide. It occurs in the oxidation zone of copper bearing sulfide deposit and often coexists with azurite. Their appearance can be used as a sign to search for primary copper deposits. A large and beautiful malachite is the material of craft carving. It is made of powder pigment, which is called stone green. It can also be used as traditional Chinese medicine, called Lvqing. It can be used as copper ore in case of large accumulation.
- Azurite
Component cu3 [CO3] 2 (OH) 2, containing Cu55 2%。 Monoclinic system. The crystals are short columnar or thick plate, usually granular, massive or radial, as well as earthy or crusty aggregates. Dark blue, earthy or crusty, light blue. Glass luster. Hardness 3.5 ~ 4. Density 3.7 ~ 3.9 g / cm3. Blister in case of hydrochloric acid. It is a secondary mineral formed after the oxidation of primary copper sulfide. It occurs in the oxidation zone of copper sulfide deposit and often coexists with malachite. Their appearance can be used as a sign to search for primary copper deposits. Powder is used to make blue pigment, which is called Shiqing. Medicinal, called flat green. It can be used as copper ore in case of large accumulation.
- Chrysocolla
Composition (CA, Al) 2h2si2o5 (OH) 4 · nH2O. Cryptocrystalline or colloidal aggregate, in Bell emulsion, shell and soil shape. Green, light blue-green, brown and black when containing impurities. Waxy luster, with ceramic appearance, glass luster, earthy luster. Hardness 2 ~ 4. Density 2.0 ~ 2.4 g / cm3.
- Blanchardite
Component cu4so4 (OH) 6. The crystal belongs to monoclinic system. The single crystal is a short column to needle shaped transparent to translucent crystal, and sometimes a plate-shaped, renal or fibrous aggregate. The color is emerald green, black green or even all black. Light green streaks. It has glass to pearl luster. Hardness 3.5 ~ 4. Specific gravity 3.5 ~ 4 g / cm3. The fracture is uneven with good cleavage in one direction. It belongs to brittle minerals. Water gall alum is a secondary mineral, which often occurs in the oxidation zone in the upper part of copper deposit.
- Atacamite
Component cu2cl (OH) 3. Including cuo50 4%。 Cubic system. The crystal is short columnar. Green to turquoise. Stripe green. Glass luster. Cleavage parallel whiplash body is complete. Hardness 5. Density 3.28-3.35 g / cm3. It is the oxidation product of copper sulfide, which is found in the oxidation zone of copper deposit. Also known as perspective stone.