Waste tyre recycling
Source: https://www.environmental-expert.com/news/waste-tyre-recycling-790283
In the world, lots of waste tyres are produced annually, and most are used as Refuse Derived Fuel in cement factories and power stations.
Material Recycling of Waste Tyres
In order to recycle the tyre materials, the tyres must be crushed and then separated completely into their components rubber, steel and textile fibres. Normally, the tyres are pre-crushed in slowly running two-shaft shredders or rotor-cutters and afterwards processed to crumb and powder of different granular sizes in a single- or multi-stage grinding process.
After grinding, magnets separate the uncovered steel wires and steel/rubber compounds. In a first screening phase, fines smaller than 8 mm are separated and conveyed to the crumb cleaning system. The coarse fraction and the steel/rubber compounds are returned to the granulation press, the quantity of the returned material depending on the particle size spectrum of the requested product.
After granulation, the ground product is classified according to customer requirement and cleaned in fractions in a multi-stage sorting and sifting system. Metal separation is effected in magnetic drums, classification by means of screens. Final sifting for separation of textiles and minerals is realized by means of zigzag sifters and table separators. Depending on the requirements of the customer, the cleaned crumb can be packed in small or big bags. As alternative, it can also be stored in silos for bulk loading in tank trucks or containers.
Wide Range of Application for Products
Apart from the high purity degree of the rubber crumb and meal, the process also excels by the very pure steel fraction obtained as final product. With a maximum residual impurity of three percent rubber and textiles in the steel, for the first time prices of clearly more than 100 Euro/t can be reached with the steel fraction. These high-quality steels are used in blast furnaces for steel production or recently as additional concrete reinforcement for the construction of buildings.
The rubber crumb obtained by warm grinding has a much larger specific surface than the cold-ground crumb. Rubber crumb and meal are used in different fields of application. They are used as filler in the caoutchouc industry, for example. Thus material costs can be reduced and the production process simplified. With the addition of PU binders, the material can also be pressed to protection mats for playgrounds and sport venues surfaces. Another possibility is the addition to topsoil which improves the compaction and drainage behaviour of heavily trampled lawns. When adding plastic crumb, such as recycled thermoplastics, instead of PU binders, elastomer compounds can be produced in special extrusion processes. By means of extrusion or injection moulding, a large number of products can be produced from these materials. Warm-ground rubber meal is particularly appropriate for this purpose.
When added to asphalt, the asphalt properties for road construction are improved, as the rubber asphalt reduces noise emissions by up to nine decibel. Besides, the temperature stability of the road surface increases, so that the formation of lane grooves in summer and frost cracks in winter is reduced.The application possibilities, particularly for warm-ground crumb, are numerous. But they are only efficient when using an economic granulation process.
For wasted tyre recycling, you may need double shaft shredder knife and granulator knife or pelletizer knife. If you are doing wasted tyre recycling, please email waixiao6@shungji.com.
