dd Flashcards
(26 cards)
Where has copper been found to occur in its native state?
Canada, Mexico, Russia, Chile, Zambia, USA, and China
Traces of copper are also found in many plants, in animal blood, and in the feathers of certain birds like peacocks.
What are the main ores of copper?
- Copper pyrites or chalcopyrites (CuFeS2)
- Cuprite or ruby ore (Cu2O)
- Copper glance or chalcolite (Cu2S)
- Malachite (Cu(OH)2.CuCO3)
- Azurite (2CuCO3.Cu(OH)2)
- Tenorite (CuO)
- Bornite (2Cu2S.CuS.FeS)
These ores are primarily used for copper extraction.
What is the molecular formula of copper pyrites?
CuFeS2
What is gangue?
Unwanted material or impurities in the form of sand, rock, etc. that surrounds the mineral in an ore deposit.
What is the Froth Floatation Process used for?
To concentrate sulphide ores.
What happens during the concentration of copper ores?
The ore is powdered, a suspension is created in water, and pine or eucalyptus oil is added, followed by stirring with compressed air.
What is the purpose of roasting in copper extraction?
To remove arsenic and antimony impurities and convert pyrite ore into a mixture of cuprous sulphide, iron sulphide, and ferrous oxide.
What is the chemical reaction for roasting copper pyrites?
2CuFeS2 + O2 → Cu2S + 2FeS + SO2
What is smelting in the context of copper extraction?
Mixing roasted ore with sand and coke in a blast furnace to produce matte.
What is copper matte?
A mixture of sulphides of copper and iron along with SiO2.
What impurities are removed during the Bessemerisation process?
Iron is oxidized to ferrous oxide, which combines with silica to form slag.
What is blister copper?
Copper containing about 2% impurities.
What two methods are primarily used to refine blister copper?
- Furnace/Thermal Refining
- Electro-refining
What happens during the thermal refining of blister copper?
Impurities oxidize and escape, forming volatile oxides, while non-volatile oxides form slag.
What is the process of poling in copper refining?
Stirring molten copper with a pole of green wood to reduce copper oxide to copper.
What is the result of electro-refining of copper?
Copper metal obtained is 99.9% pure.
Copper pyrites are concentrated by which method?
Froth floatation method.
What additional substance is added during smelting to form slag?
Flux
What is the chemical reaction for copper reacting with moist air?
2Cu + H2O + CO2 + O2 → CuCO3.Cu(OH)2
What oxide of copper is formed when heated with air below 1100°C?
CuO (Black oxide)
What oxide of copper is formed when heated with air above 1100°C?
Cu2O (Red oxide)
How does copper react with concentrated H2SO4?
Produces CuSO4, H2O, and SO2.
How does copper react with warm dilute H2SO4?
Produces CuSO4 and H2O.
What is the result when copper reacts with concentrated HNO3?
Produces Cu(NO3)2, H2O, and various nitrogen oxides.
