Around 65 million used tyres are produced every year in Germany alone. Processing them into fine rubber powder or coarser granulate is now an important part of sustainable disposal alongside export, retreading and thermal recycling. The new raw material is used in road construction, but also as a surface for sports fields or children's playgrounds and in the manufacture of elastic adhesives and fillers, shoe soles, roof coverings and many other products. One of the most modern fine grinding plants for used tyres is located in Landau in the Palatinate, on the premises of Kurz Karkassenhandel.
Shredding used tyres to produce rubber powder is a relatively complex and time-consuming process. First, the tyres are pre-shredded into roughly palm-sized pieces or shredded with rotary shears. Only these pieces are then further processed in fine grinding plants to produce rubber flour of the desired grain size. The individual components of the tyre - primarily metal, rubber and textiles - are also separated from each other during this process. Grain sizes of 0.5 to 7 mm are common on the market. There are two common methods of grinding: cold and hot grinding.
Cold and hot grinding
In cold grinding, the tyre pieces are made brittle by adding liquid nitrogen and ground in hammer mills. One grinding stage is sufficient to separate the individual components and achieve different grain sizes. The disadvantage of cold grinding is the high cost of using liquid nitrogen. In addition, the individual grains of the granulate have a small surface area.
Hot grinding, on the other hand, takes place at ambient temperature: the tyre parts are crushed in high-speed mills and gradually ground to the desired particle size by connecting several granulators in series.
Rubber fine grinding of the highest quality
The fine grinding system from Kurz works at room temperature using the ambient grinding process. The special feature: It is specially designed to grind peel strips from truck tyres. The long, approx. 5 cm wide black rubber strips that are produced when the tread of tyres is cut from the carcass for retreading are called peel strips. The new shredder, which was purchased especially for shredding the peelings, measures 3.6 x 2.3 x 2.5 metres and consists of a 2 x 2.1 metre feed chute into which the peelings are fed using a gripper arm. A total of 144 rotor knives and seven stator knives grind the rubber into coarse granulate in just a few minutes and, in a second step, into fine flour, which is packaged in various finenesses after sieving. Every hour, the Kurz Karkassenhandel plant processes up to two tonnes of peeling snakes into rubber flour with a fineness of up to 0.4 mm.
Das Gummimehl ist völlig frei von jeglichen Verunreinigungen und entspricht höchsten Qualitätsstandards. Das ist in dieser Form europaweit einmalig. Zum Versand wird das Mehl gemäß Kundenanforderung verpackt. Um Anlauffehler auszuschließen und Abläufe genau analysieren zu können, wurde die Anlage zunächst auf niedrigem Niveau betrieben und erst nach und nach an ihre volle Kapazität herangeführt. Sie kann jährlich Mengen von bis zu 5000 Tonnen des zukunftsträchtigen Werkstoffs produzieren. Neben Altreifengummi können mit dieser Anlage auch andere Elastomere und Gummiproduktionsabfälle in Contract grinding der Produktion zurückgeführt werden. Die Anlage von Kurz regeneriert 100% Gummiabfälle zu neuen Rohstoffen.
About Kurz Karkassenhandel GmbH:
Kurz Karkassenhandel GmbH is a certified specialist disposal company and has been involved in the professional disposal of all types of used tyres since it was founded in 1955. The company maintains and utilises long-standing national and international contacts. In 2015, the company celebrated its 60th anniversary. All information and contact details about Kurz can be found on the Kurz Karkassenhandel website. Further information: www.kurz-karkassenhandel.de
