Recycling involves using waste, worn out elements (e.g. parts of machines) to make new products, e.g. waste paper to produce paper, worn out tyres to produce fuel used in cement plants. Waste includes all objects and solids as wells as liquid substances which are not sewage and which come from human economic and living activity. Types of waste include: agricultural, industrial and municipal.
Recycling is significant to environmental protection. Some car companies strive for the possibility of recycling above 90% of steel and coloured metals they use for the production of cars; they also use plastics which can be recycled.
Large amounts of paper, metal, plastic and glass waste are used again in the process of recycling (utilization). In western countries the majority of these materials are gathered in special containers at homes or in factories. However, the rest of rubbish also contains many valuable materials which can be separated in various stages of their processing before they land in dump. Dried rubbish is burnt in anaerobic conditions in order to get such useful substances as carbon oxide, methane, hydrogen, mineral oils, tar or charcoal. Ferromagnetic metals (including iron or nickel) are taken from a conveyor belt which transports rubbish by strong magnets which hang above it. Also glass, aluminum and other non-ferrous metals are separated in order to take advantage of their various physical characteristics.
The process of separating materials is often based on the difference in their density, namely specific gravity. One of the separators works in this way that powdered rubbish falls on a conveyor band which goes upwards; the material with higher density falls down and the lighter material goes up. If we burn rubbish, metals and glass melt and they fall on the bottom of a stove from where they can be easily gathered.
Later glass separated from rubbish can be sorted into coloured and white. In order to do that, ground glass goes through strong magnetic field. Pieces of white glass do not interact with the field whereas coloured glass does and it is separated. The pieces of glass go through streams of light and the changes in their colour are recorded by photosensitive elements. On the basis of the signal they send, machines sort the glass - each colour separately.
Recycling is significant to environmental protection. Some car companies strive for the possibility of recycling above 90% of steel and coloured metals they use for the production of cars; they also use plastics which can be recycled.
Large amounts of paper, metal, plastic and glass waste are used again in the process of recycling (utilization). In western countries the majority of these materials are gathered in special containers at homes or in factories. However, the rest of rubbish also contains many valuable materials which can be separated in various stages of their processing before they land in dump. Dried rubbish is burnt in anaerobic conditions in order to get such useful substances as carbon oxide, methane, hydrogen, mineral oils, tar or charcoal. Ferromagnetic metals (including iron or nickel) are taken from a conveyor belt which transports rubbish by strong magnets which hang above it. Also glass, aluminum and other non-ferrous metals are separated in order to take advantage of their various physical characteristics.
The process of separating materials is often based on the difference in their density, namely specific gravity. One of the separators works in this way that powdered rubbish falls on a conveyor band which goes upwards; the material with higher density falls down and the lighter material goes up. If we burn rubbish, metals and glass melt and they fall on the bottom of a stove from where they can be easily gathered.
Later glass separated from rubbish can be sorted into coloured and white. In order to do that, ground glass goes through strong magnetic field. Pieces of white glass do not interact with the field whereas coloured glass does and it is separated. The pieces of glass go through streams of light and the changes in their colour are recorded by photosensitive elements. On the basis of the signal they send, machines sort the glass - each colour separately.
http://ourecology.org/recycling.html
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