It works by injecting the material stream to be sorted into a chamber which contains a column of rising air. Inside the separation chamber, air drag on the objects supplies an upward force which counteracts the force of gravity and lifts the material to be sorted up into the air. Due to the dependence of air drag on object size and shape, the objects in the moving air column are sorted vertically and can be separated in this manner.
Air classifiers are commonly employed in industrial processes where a large volume of mixed materials with differing physical characteristics need to be separated quickly and efficiently. Air classifier is helpful for cement, air pollution control, food processing, pigments, pharmaceutical, cosmetics or chemical industries. One such example is in municipal recycling centers, where various types of metal, paper, and plastics arrive mixed together and need to be sorted before further processing can take place.
Air classifiers can also be used as a step in the automotive recycling process. For example, after the crushing and shredding steps, steel is removed by electromagnets, and nonferrous metals are removed by eddy-current separators. Then an air classifier can be used to deal with the remaining dense materials (such as glass) as well as the remaining materials of various densities, most notably plastics, foams, and cloth.
Wang, Xiaoyan; Ge, Xiaoling; Zhao, Xuehua; Wang, Zhiwen (August 1998). "A model for performance of the centrifugal countercurrent air classifier". Powder Technology. 98 (2): 171–176. doi:10.1016/S0032-5910(98)00040-0.
Yang, G.; Zheng, D.; Zhou, J.; Zhao, Y.; Chen, Q. (August 2002). "Air classification of moist raw coal in a vibrated fluidized bed". Minerals Engineering. 15 (8): 623–625. doi:10.1016/S0892-6875(02)00057-2.
Recycling is the process of converting waste materials into new materials and objects. The recovery of energy from waste materials is often included in this concept. The recyclability of a material depends on its ability to reacquire the properties it had in its original state. It is an alternative to "conventional" waste disposal that can save material and help lower greenhouse gas emissions. It can also prevent the waste of potentially useful materials and reduce the consumption of fresh raw materials, reducing energy use, air pollution and water pollution.
Cyclonic separation is a method of removing particulates from an air, gas or liquid stream, without the use of filters, through vortex separation. When removing particulate matter from liquid, a hydrocyclone is used; while from gas, a gas cyclone is used. Rotational effects and gravity are used to separate mixtures of solids and fluids. The method can also be used to separate fine droplets of liquid from a gaseous stream.
Although PET is used in several applications,, as of 2022 only bottles are collected at a substantial scale. The main motivations have been either cost reduction or recycle content of retail goods. An increasing amount is recycled back into bottles, the rest goes into fibres, film, thermoformed packaging and strapping. After sorting, cleaning and grinding, 'bottle flake' is obtained, which is then processed by either:
Fibre-reinforced plastic is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually glass, carbon, aramid, or basalt. Rarely, other fibres such as paper, wood, or asbestos have been used. The polymer is usually an epoxy, vinyl ester, or polyester thermosetting plastic, though phenol formaldehyde resins are still in use.
A materials recovery facility, materials reclamation facility, materials recycling facility or Multi re-use facility is a specialized plant that receives, separates and prepares recyclable materials for marketing to end-user manufacturers. Generally, there are two different types: clean and dirty materials recovery facilities.
In the field of extractive metallurgy, mineral processing, also known as ore dressing, is the process of separating commercially valuable minerals from their ores.
Plastic recycling is the reprocessing of plastic waste into new and useful products. When performed correctly, this can reduce dependence on landfill, conserve resources and protect the environment from plastic pollution and greenhouse gas emissions. Although recycling rates are increasing, they lag behind those of other recoverable materials, such as aluminium, glass and paper. The global recycling rate in 2015 was 19.5%, while 25.5% was incinerated and the remaining 55% disposed of to landfill. Since the beginning of plastic production in the 20th century, until 2015, the world has produced some 6.3 billion tonnes of plastic waste, only 9% of which has been recycled, and only ~1% has been recycled more than once.
Refuse-derived fuel (RDF) is a fuel produced from various types of waste such as municipal solid waste (MSW), industrial waste or commercial waste.
A mechanical biological treatment (MBT) system is a type of waste processing facility that combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion. MBT plants are designed to process mixed household waste as well as commercial and industrial wastes.
Waste sorting is the process by which waste is separated into different elements. Waste sorting can occur manually at the household and collected through curbside collection schemes, or automatically separated in materials recovery facilities or mechanical biological treatment systems. Hand sorting was the first method used in the history of waste sorting.
Single-stream recycling refers to a system in which all paper fibers, plastics, metals, and other containers are mixed in a collection truck, instead of being sorted by the depositor into separate commodities and handled separately throughout the collection process. In single-stream, both the collection and processing systems are designed to handle this fully commingled mixture of recyclables, with materials being separated for reuse at a materials recovery facility.
The term spiral separator can refer to either a device for separating slurry components by density, or for a device for sorting particles by shape.
Optical sorting is the automated process of sorting solid products using cameras and/or lasers.
Magnetic separation is the process of separating components of mixtures by using a magnet to attract magnetic substances. The process that is used for magnetic separation separates non-magnetic substances from those which are magnetic. This technique is useful for the select few minerals which are ferromagnetic and paramagnetic. Most metals, including gold, silver and aluminum, are nonmagnetic.
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives.
Recycling can be carried out on various raw materials. Recycling is an important part of creating more sustainable economies, reducing the cost and environmental impact of raw materials. Not all materials are easily recycled, and processing recyclable into the correct waste stream requires considerable energy. Some particular manufactured goods are not easily separated, unless specially process therefore have unique product-based recycling processes.
Colour sorters or color sorters are machines that are used on the production lines in bulk food processing and other industries. They separate items by their colours, detecting the colours of things that pass before them, and using mechanical or pneumatic ejection devices to divert items whose colours do not fall within the acceptable range or which are desired to form a separate group from the rest.
MBA Polymers is a recycling company with operations globally that recovers plastics from waste electrical and electronic equipment (WEEE) and auto-shredder residue from end-of-life automobiles (ELV).
Appliance recycling is the process of dismantling waste home appliances and scrapping their parts for reuse. Recycling appliances for their original or other purposes, involves disassembly, removal of hazardous components and destruction of the equipment to recover materials, generally by shredding, sorting and grading. The rate at which appliances are discarded has increased with technological advancement. This correlation directly leads to the question of appropriate disposal. The main types of appliances that are recycled are televisions, refrigerators, air conditioners, washing machines, and computers. When appliances are recycled, they can be looked upon as valuable resources. If disposed of improperly, appliances can become environmentally harmful and poison ecosystems.
China's waste import ban, instated at the end of 2017, prevented foreign inflows of waste products. Starting in early 2018, the government of China, under Operation National Sword, banned the import of several types of waste, including plastics. The ban has greatly affected recycling industries worldwide, as China had been the world's largest importer of waste plastics and processed hard-to-recycle plastics for other countries, especially in the West.
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