Metals and Recycling of Metals

Cutting or recycling of metals

Metal is one of the most important materials available to us. What makes metals so valuable is that metals are highly versatile. They are lustrous in appearance, they can be made into sheets and wires and their high melting and boiling point makes them able to withstand high temperatures. These along with other various properties allow them to be used in a vast array of products. There are different types of metals at our disposal such as gold, aluminum, iron and metals can be combined with other different metals to produce various alloys which can be used in different products.

Metals are not available to us directly and need to be extracted from their ores to obtain their pure form. Pure metals are achieved through reduction only. Extraction is carried out to obtain pure forms of metals so they can be used accordingly. Metals can be converted to various types of alloys by melting them until they become molten and are then mixed with other molten metals to produce alloys of different metals and compositions.

Metals like many other substances are available to us in finite amount, thus, it is very important for us to use them efficiently and prevent their depletion. Hence, people have adapted recycling of metals to deal with the increasing demand of metals and alloys and to prevent the excessive depletion of metals.

Various uses of different metals:

  • Gold is used in watches, jewelry and electronic devices.
  • Carbon and iron are used to make steel and stainless steel which are used in the construction industry.
  • Aluminum is heavily used in the automotive industry and to make parts of airplanes.
  • In medicine, Aluminum is used to make antacids, and to treat other medical conditions.
  • Mercury is used in to make thermometers and also used as to make filling materials used in dentistry.
  • Copper is used in wires to transmit electricity.
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The process of metal recycling

Here’s a bit of introduction to metals. Metals can be classified as non-ferrous and ferrous;

Non-ferrous metals are those that don’t contain carbon and iron and are mostly precious metals such as gold, silver, copper, zinc, tin and lead.

Ferrous metals are those that contain carbon and iron such as cast iron, wrought iron, steel and stainless steel.

The main stages of recycling are as follows;

1. Collection

Metals are usually collected as scrap materials. Metals have a high scrap value unlike other materials and are collected from places such as railroad tracks, construction sites, ships and car junkyards. Most of the iron in scrap form is collected from scrap vehicles in the junkyard. Third world countries have these ‘pickers’ that scan the city for scarp materials with high scrap value like metals and bring them to the junkyard. However, the sad part is that these pickers are very young kids being exposed to all forms of trash and harsh environments.

2. Sorting

Once the metals have been collected, they are transported to recycling facilities. Here they are sorted out from different metals and other waste materials. Magnets and sensors are used to extract metals from the pile of garbage. Metals can be sorted on the basis of their weight, color and other specific properties.

3. Processing

In this step metals are shredded into smaller sizes. The reason for doing this is to increase the surface area and reduce the energy required to melt these metals which will be the next step after the processing of metals is completed.

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4. Melting

After processing, the metals are now ready to be melted. The process of melting requires a large furnace. The metals are placed inside the furnace and are heated to high temperatures until they melt completely. Although, this process requires extremely high amount of energy, it is significantly less for recycled metals compared to the initially produced metals and is also reduced by the previous process of shredding.

Melting of metals may take minutes to hours depending on:

  • The size of the furnace
  • The type of metal
  • The amount of metal

5. Purification

Metals then need to be purified. The purification of metals is done through the process of electrolysis. Electrolysis is a process in which a metal is converted from its ionic form to its proper atomic uncharged form. Metals have a tendency to react with other elements to form various compounds of oxides, halides and carbonates and thus must be purified through electrolysis to obtain them in their purest form with its pure-metal properties as well as to increase their value.

6. Solidification

The metals after being purified are allowed to be cooled and solidified. Sometimes water is used to expedite the process. It is here that the metals may be converted to different sizes and shapes and then cooled after to solidify it. They are usually shaped into bars.

Forging of metal prick with hammer to give it shape before it solidifies.

7. Transportation

After solidification, recycled metals are then transferred from the facility to different factories. In those factories they are usually used as raw materials to form new products. These products made from recycled metals are then used by us once again. Once those products are no longer useful for us, they may be thrown away and can then be recycled again through the various stages mentioned above.

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Advantages of Recycling Metals:

  1. Metals are only available in a finite amount to us and must be used with caution so they may not run out. Metal recycling thereby saves the reserves of metal on earth and protects from over-mining.
  2. Recycling helps to preserve the life of these metals by constantly being purified and used to form new products and thereby increase the longevity of the metal.
  3. Metals are extracted and that process requires high amounts of energy and is very expensive. Recycling allows the metals to be used once again with reduced energy usage and lower cost of production.
  4. The products formed using recycled metal can reduce the price of the product available to the consumer which also increases the potential demand and sale of the product.
  5. The extraction of metals produces a lot of pollution and damage to habitats; recycling of metals however, like other materials being recycled, is a very eco-friendly process.

Before you leave this page let me show you a few facts on Metal Recycling as well.

Facts on Metal Recycling

  1. If the recycling process is fast and efficient, aluminum can be recycled and available to us in markets as a new product within 2 months!
  2. Steel is the most recycled material in the world.
  3. 40% of steel being produced is made from recycling nowadays.
  4. Recycled metals take 17 times less energy for manufacturing than newly mined metals.
  5. 98% of lead that is being used in batteries is recycled.
  6. The highest rate of recycling of metal is of copper.
  7. The most recycled consumer product are aluminum cans.
  8. Nearly 400 Million tons of metal are recycled worldwide.
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