Contaminants in recycled aggregates? There is a solution.
In the recycling of concrete and rubble aggregates, the quality of the end product is crucial. That is why removing contaminants such as wood, plastic, textiles and iron is an essential step in the process. And one rule is clear: the earlier contamination is removed, the better.
In practice, however, this is not always easy. At fixed processing sites, there is often more control over the incoming material. Mobile installations are a different story. Large volumes of rubble from different phases of a project are often processed together, with varying composition and levels of contamination.
Fortunately, there are efficient solutions for both fixed and mobile installations. Larger contaminants can still be removed manually or with an excavator, but once the material becomes finer, mechanical techniques are far more effective.
A commonly used solution is the wind sifter, which removes light materials such as wood, plastic and textiles from the aggregate stream. For optimal performance, the fine sand fraction must first be removed. This prevents additional dust problems and significantly improves separation. This technique can also be successfully applied in mobile installations.
When a wind sifter is less suitable, a float-sink system using a water bath can be an effective alternative. In this process, light materials float to the surface, while heavier fractions sink to the bottom and are discharged separately.
Iron also requires attention. Although it is less often seen as a contaminant, it can still cause significant damage to machines and conveyor belts. That is why magnets such as overband magnets and magnetic head pulleys are often used in recycling processes to remove metal particles efficiently from the material flow.
The right solution always depends on the installation, the material and the required capacity. But one thing is certain: a well-designed contaminant removal process leads to better analysis results, a higher-quality end product and a stronger circular value chain.
Curious which solution best fits your installation? Van Der Spek is happy to help!