Copper can be found in it's element form however, it is usually mined from its ores, such as chalcopyrite or chalcocite or bornite.
Copper ore/Chalcopyrite is treated through the following processes to extract pure copper(99.8%Cu).
1. Pulverization
2. Concentration/ froth floatation
3. Roasting
4. Smelting
5. Besemerisation
6. Electro refining
Explain each extraction process and insert equations where necessary
1. Pulverization:
The first step in the extraction process is pulverizing the copper ore into small particles. This increases the surface area of the ore and makes it easier to separate the copper minerals from the gangue (unwanted rock and minerals).
2. Concentration/Froth Floatation:
The pulverized ore is then mixed with water and chemicals, including frothers and collectors. Frothers help to create a stable foam on the surface of the pulp, while collectors selectively bind to the copper minerals. Air is then blown through the mixture, causing the copper minerals to attach to the air bubbles and float to the surface as a froth. This froth, containing the copper minerals, is skimmed off and collected.
3. Roasting:
The froth obtained from the froth floatation process is subjected to roasting. Roasting involves heating the ore in the presence of excess air or oxygen. This step helps to remove any impurities present in the copper concentrate and convert certain metal sulfides in the ore into oxides. The reactions involved in roasting depend on the specific composition of the copper ore but usually involve the conversion of copper sulfide minerals into copper oxide and sulfur dioxide gas:
2CuFeS2(s) + 3O2(g) -> 2CuO(s) + 2FeO(s) + 2SO2(g)
4. Smelting:
The roasted copper concentrate is mixed with a reducing agent, such as coke (carbon), and heated in a furnace. This process, called smelting, aims to reduce the copper oxides back to metallic copper while removing impurities present in the concentrate. The carbon in the coke reacts with oxygen present in the copper oxides, resulting in the production of carbon dioxide gas and the reduction of copper oxide to metallic copper:
2CuO(s) + C(s) -> 2Cu(s) + CO2(g)
5. Bessemerisation:
The smelted copper metal obtained from the furnace is subjected to a process called bessemerisation, where it is purified further. The molten copper is blown with air or oxygen, which oxidizes any remaining impurities, such as iron and sulfur, that might be present in the metal. The impurities are selectively oxidized and can be removed as slag, leaving behind pure copper metal.
6. Electrorefining:
The final step in the extraction process is electrorefining, where the purified copper obtained from bessemerisation is further purified electrolytically. The impure copper metal is used as the anode, and a pure copper cathode is used. The anode and cathode are placed in an electrolyte solution containing copper sulfate. When an electric current is passed through the electrolyte, copper ions from the anode are oxidized and dissolve in the electrolyte, while copper ions from the electrolyte are reduced and deposited onto the cathode as pure copper. This process ensures that the final copper product is 99.8% pure.
1. Pulverization: The copper ore, such as chalcopyrite or chalcocite or bornite, is first crushed into small pieces to increase the surface area for subsequent processes.
2. Concentration/Froth Floatation: The crushed copper ore is then mixed with water and chemicals, including frothers and collectors. The mixture is agitated to create bubbles, which attach to and float the copper minerals to the surface while the gangue (unwanted material) sinks. The copper concentrate is then collected and further processed.
3. Roasting: The copper concentrate is subjected to high temperatures in a roasting furnace. This process involves heating the concentrate in the presence of air, converting the majority of the remaining sulfide minerals (such as chalcopyrite) into oxides. The reactions that occur during roasting can be represented by the following equations:
2CuFeS2(s) + 4O2(g) → 2FeO(s) + 2CuS(s) + 2SO2(g)
Cu5FeS4(s) + 3O2(g) → 2FeO(s) + 5CuS(s) + SO2(g)
4. Smelting: The roasted copper concentrate, along with fluxes (materials that help remove impurities), is melted in a smelter. The smelting process involves high temperatures and the addition of additional reactants to further separate impurities. The reactions that occur during smelting can be represented by the following equation:
2Cu2S(s) + 3O2(g) → 2Cu2O(s) + 2SO2(g)
5. Bessemerization: The obtained copper matte from smelting is then subjected to the Bessemerization process. This involves blowing air through the molten matte to oxidize impurities like iron and sulfur, which form a slag that can be easily separated. The reactions that occur during Bessemerization can be represented by the following equations:
2Cu2O(s) + O2(g) → 4Cu(s) + 2SO2(g)
2Cu2S(s) + 3O2(g) → 2Cu2O(s) + 2SO2(g)
6. Electrorefining: The final step in the extraction process is electrorefining. The impure copper obtained from the Bessemerization process is used as the anode, while a pure copper cathode is used as the cathode. The anode and cathode are placed in an electrolyte solution, and an electric current is passed through. This causes impurities to dissolve from the anode and deposit on the cathode, resulting in pure copper being deposited on the cathode. The overall reaction during electrorefining can be represented by the following equation:
Cu(s) → Cu2+(aq) + 2e^-
The steps mentioned above are commonly used in the extraction of pure copper from ores. However, it is worth noting that different variations of these steps may be used depending on the specific ore and desired final product.
Sure! Here is an explanation of each extraction process involved in obtaining pure copper (99.8% Cu) from copper ore, specifically chalcopyrite:
1. Pulverization:
The first step in the extraction process is pulverizing the copper ore into small particles. This increases the surface area of the ore, allowing for better reactions during subsequent steps.
2. Concentration/Froth Floatation:
In this step, the pulverized ore is mixed with water and chemicals known as collectors. The mixture is then agitated, creating bubbles that attach to the copper sulfide minerals in the ore. These bubbles rise to the surface and form a froth, which is then collected. This process is called froth flotation or concentration and helps separate the valuable copper minerals from the rest of the ore.
3. Roasting:
The froth containing the copper minerals obtained from the concentration process is subjected to high temperatures in a furnace. This step is called roasting. Roasting converts copper sulfide minerals, such as chalcopyrite (CuFeS2), into copper oxide (Cu2O) and sulfur dioxide (SO2) gas. The reaction is as follows:
2CuFeS2(s) + 3O2(g) → 2Cu2O(s) + 2FeO(s) + 2SO2(g)
4. Smelting:
The copper oxide obtained from roasting is then subjected to smelting, which involves heating the material along with a reducing agent, such as carbon or coke. The purpose of smelting is to remove the oxygen from the copper oxide, resulting in the production of impure molten copper known as blister copper. The reaction is as follows:
2Cu2O(s) + C(s) → 4Cu(s) + CO2(g)
5. Bessemerization:
The blister copper obtained from smelting still contains impurities, such as iron, sulfur, and other elements. To remove these impurities, the blister copper is subjected to the Bessemerization process. In this process, air is blown through the molten copper, which oxidizes impurities like iron and sulfur to form their respective oxides. These oxides can then be removed as slag. The reaction is as follows:
2Fe(s) + 3O2(g) → 2FeO(s)
2Cu2S(s) + 3O2(g) → 2Cu2O(s) + 2SO2(g)
6. Electrorefining:
After Bessemerization, the blister copper is further purified through electrorefining. The blister copper acts as the anode, while a pure copper cathode is placed in an electrolytic cell. The electrolysis process dissolves the anode, and pure copper ions migrate towards the cathode, where they plate onto it. This electrorefining step ensures the production of high-purity copper. The reaction is as follows:
Anode: Cu(s) → Cu2+(aq) + 2e^-
Cathode: Cu2+(aq) + 2e^- → Cu(s)
These extraction processes collectively result in the production of pure copper (99.8% Cu) from copper ore such as chalcopyrite.