Separation of composite materials
Composite materials such as fiber- or metal-reinforced thermoplastics, galvanized plastic parts, such as sanitary facilities or used tires, can be decomposed by the cryogenic milling technique with relatively little energy input into their constituents or cleaned from impurities. Basis of these cryogenic techniques are the different coefficients of linear expansion and the embrittlement capability of the various materials.
This cryogenic technology must be adapted to the respective requirements and material properties. For example rubber shrinks 7.5 times more than iron during cooling (see diagram below). With a subsequent shock stress the composite material can be separated.
The goals of the cryogenic composite separation are:
- a high degree of separation of the composites, because a clean individual material has a higher market value
- a high throughput capacity to achieve low production costs
- avoid thermal damage of the ground products
- to prevent the risk of dust explosions and fires during grinding
Messer operates a highly specialized test facility, which offers the opportunity to profit from process developments, to estimate production costs or to produce sample batches. Here separation tests can be made using liquid nitrogen. All relevant parameters, such as the degree of separation, electricity and nitrogen requirements and throughput are measured, evaluated and made available to the customer.
Even existing mills at the customer’s site can be optimized. Granulate coolers, nitrogen control valves and temperature control can be provided for carrying out tests on these plants on site.