Wednesday 21 September 2011

Recycling of metals

What will happen to the world if there are no more metals?
A metals is a chemical element that is a good conduct of both electricity and heat and forms cations and ionic bonds with non-metals
Each metal has its especial uses and it will depend largely on what you are going to make as to the kind of metal you should make it of.
Metals are present in minute quantities in all living organisms. Na and K are major metals that that are used for transmission of electrical signals from the brain to the entire nervous system. Iron is an important component of hemoglobin in the blood of warm-blooded animals. Iron transports oxygen to issues by forming oxides. In cold-blooded animals, blood contains copper. Chlorophyll in plants contains magnesium. Other metals like copper, zinc etc. are needed by different tissues in a human body for functioning properly. So that if no more metals in the earth, living organisms will not be as right now, even do not exist.
Metals play a different part of living life. For example, the use of aluminium is drinks can, cooking pots, overhead power cables. We use copper for water pipes, electrical wires; iron for bridge construction, building construction… If in the earth there are no more metals all thing are made of it would not exist. So that the earth could not be develop like right now


What is the reason to recycling metals:
It is easy and cost-effective to recycle metal, and metal can be recycled continuously without losing its properties. In addition, recycling metal reduces the environmental impacts associated with metal mining and production. According to Waste Online:
Recycling aluminium requires only 5% of the energy and produces only 5% of the CO2 emissions as compared with primary production and reduces the waste going to landfill. Aluminium can be recycled indefinitely, as reprocessing does not damage its structure. Aluminium is also the most cost-effective material to recycle.
Recycling one tonne of steel cans saves 1.5 tonnes of iron ore, 0.5 tonnes of coal & 40% water usage.
Recycling 1 tonne of steel scrap saves 80% of the CO2 emissions produced when making steel from iron ore.


Isn’t it easier to obtain metals through it s original form through extraction of metals?
It is very hard to extraction metals. There are a number of different methods of metal extraction, including:
• by heating with carbon (in the form of coke)
• by heating with a more reactive metal (active metal)
• by electrolysis of melts
• by reduction with hydrogen gas
• Which method is used depends on:
1) the energy requirements extraction uses large amounts of energy (electricity and / or heat)
2) the cost of the reductant carbon (in the form of coke), which is cheap, is widely used, but sometimes more reactive metals are required which are very costly
3) the metal purity required the higher the required purity, the greater the cost in obtaining that purity





The effect to environment in the recycling of metals:
a) Recycling metals
• We need to recycle metals as supplied will not last forever (for some metals this would happen in our lifetimes).
• Recycling metals:
• saves resources (e.g. metal ores)
• creates less waste (e.g. mining waste)
• saves energy resources (less energy to re-cycle than make from ore, e.g. recycling Al uses 5% of energy used to extract)
• reduces air pollution (e.g. CO2 – greenhouse effect, SO2 – acid rain, CO - toxic)
• However, there are costs associated with sorting and transporting metals to be recycled that have to be factored into the overall financial and energy costs.

b) Recycling copper
• One way to recycle copper is to react scrap copper with sulphuric acid or a specific enzyme to form solutions containing Cu2+(aq).
• The copper can be extracted by reaction with scrap iron: Cu2+(aq) + Fe(s) → Cu(s) + Fe2+(aq)
• This method can also be used to extract copper from low grade ores.

Think of reactive ways, that we can also play a part in recycling metals:
- We can stop use drink cans install of that we use polycarbonate bottle.
- We reuse wires
- We made windows and door frames as wood
- Collect the metals for recycling

Recycled metals products:


Source:
http://www.zerowastesg.com/2008/12/08/metal-recycling/
http://www.educationalelectronicsusa.com/c/metals-XV.htm

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