Most metals are found combined with other elements, as compounds in ores.Copper froth flotation
There are 2 types of methods:
1. Reduction (Burning ores with carbon & Electrolysis)
2. Froth Flotation
Burning ores with carbon
The ore is being reduced by carbon by removing the oxygen atoms. Carbon not only acts as a reducing agent, but it also acts as the fuel to provide heat for the process.
Eg. PbO + C -> Pb + CO
In this reaction, the carbon removes oxygen from lead oxide.
This occurs because carbon is more reactive than lead.
The addition of oxygen to a substance is called oxidation.
Electrolysis
This is a common extraction process for the more reactive metals. During electrolysis, electrons are being added directly to the metal ions at the cathode (the negative electrode) which will decompose the compound.
Froth flotation
The ore is first crushed and then treated with something which will bind to the particles of the metal compound that you want and make those particles hydrophobic (scared of water). The treated ore is then put in a large bath of water containing a foaming agent and air is blown through the mixture to make a lot of bubbles. The coated particles of the metal compound tend to be picked up by the air bubbles because they are water-repellent and float to the top of the bath.
Iron:
Extracted by Reduction (burning ores with carbon)
Stage 1:
A mixture of three raw materials is added through the top of the blast furnace:
Iron ore, carbon (coke), limestone.
Stage 2:
Hot air is blown in to the bottom of the furnace, providing the oxygen to burn the carbon in the coke. The furnace needs to be at a temperature of 1200-1300 degrees Celsius.
Stage 3:
When carbon-rich coke is burnt in oxygen, carbon dioxide is formed.
The carbon dioxide then reacts with coke to form carbon monoxide.
Stage 4:
Iron oxide in the iron ore is actually reduced by the carbon monoxide to form iron.
The molten iron produced collects at the bottom of the furnace. It is about 89% pure.
Stage 5:
Limestone reacts with sand and other impurities in the iron ore to form slag. This floats on top of the iron. It is drained off and be used to build roads.
Stage 6:
The reactions inside the blast furnace produce carbon dioxide and nitrogen.
These waste gases are removed from the blast furnace for treatment.
Environmental Impacts and Solutions
Workplace
Impacts:
They have a goal for this environment, which is zero significant incidents which means that they want a safe place to work, with a safe work environment. However, minimal incidents are still possible.
Solutions:
They have made sure that each employee is fully equipped and is not vulnerable to any danger. The thing they check for is whether you have all your safety equipment (goggles, boots, gloves etc) and that your health is up to standard. With all of this being checked before you start work it makes it a safer place and a better environment to work in.
Land
Impacts:
The extraction of iron is very close to the land of native aboriginals and in all perspectives, they own this land so it is our duty to return it back to normal after it has been used.
Solutions:
We must rehabilitate the land, which is a re-engineering process that attempts to restore an area of land back to its natural state after it has been damaged as a result of some sort of disruption. The process involves such things as removing all man-made structures, toxins and other dangerous substances, improving the soil conditions and adding new flora. This also prevents erosion in the new future.
Biodiversity
Impacts:
Much of their activities have an impact on the natural environment, including the diversity of flora, fauna and their habitats.
Solutions:
They can choose areas which do not have much diversity which is helping the environment. But for the place they have to mine, they carefully remove the whole habitat to another space which is undisturbed and once finished mining they replace the habitat to the original place. So from this they can have minimal destruction of flora and fauna.
Air emissions
Impacts:
The air that is emitted from the extraction of is totally safe as it is in a remote place. Although the amount of gases emitted is a lot but is not enough to damage the air quality. The only people who faces any real harm are the workers as they are so close to the gases
Solutions:
So as to protect themselves, they have to wear a gas mask.
Waste
Impacts:
Through different activities, their sites generate a variety of wastes. Such wastes are in the form of general waste and hazardous waste.
Solutions:
The chemical byproducts may be toxic but can be commercially useful. These byproducts include ammonia that can be used in a large number of products; pheonol that can be used to make plastics and antiseptics and cresols that can be used in pesticides and photographic chemicals. Slag can be used in road making or sold as a building material.
