One of the most modern fine-milling plants for end-of-life tires and technical rubber remains in Europe is located in Landau, south-east of Germany, at the premises of the company Kurz Karkassenhandel GmbH.
Grinding used tires using rubber mills is a rather demanding and complex process. First, tires are pre-shredded or crushed with rotor blades. Then, these pieces are processed with fine-grinding machines and yield rubber powder of desired sizes. Supplementary tire elements – metal and textile – are eventually separated from the output. To produce rubber powder, two methods of grinding are generally used: cold and ambient grinding
Cold grinding utilizes liquid nitrogen to effectively reduce the size of rubber using e.g. jet mills. A disadvantage of the cold grinding is the rather high production cost, which is due to the fair amount liquid nitrogen needed. In contrast, ambient grinding takes place at ambient temperatures. Cracker mills lined up in a row grind up coarser granulates by means of slow-spinning mills to the desired sizes, leading into high quality rubber powder with large surface area.
The fine milling line of Kurz operates at ambient temperatures. A special distinctive feature of the equipment is that it is specifically designed to crush and grind truck tire tread strippings, i.e. long, up to 5 cm wide black rubber tread peelings of a very high quality, which arise in the process of truck tire retreading. According to the company, the equipment of Kurz Karkassenhandel enables to reprocess up to two tons of tuck tire tread strippings into rubber powder of up to 0.4 mm in size.
In the end of the process, the rubber powder becomes completely free from impurities such as steel or textile and corresponds to the highest quality standards. The quality of rubber powder by Kurz is regarded as unique of its kind in Europe. Before sending the material to the customer, Kurz packages it according to specific needs and requirements posed by the buyer. In the very beginning after starting the plant’s operation, the team ran production at low levels and gradually brought it to its full capacity. Currently, it is capable of producing up to 5000 tons of fine rubber powder annually.
Besides truck tread peelings the plant is also capable of custom grind any other elastomeric secondary raw materials. According to statements by Kurz Karkassenhandel, the plant converts 100% of rubber waste into new raw materials.