Steinert’s MSort AP technology is helping a German recycler achieve new levels of purity and efficiency in processing mineral construction and demolition waste. Otto Dörner Recyclinganlage in Hittfeld operates a wet processing plant that produces clean sand and stones from material legally classified as waste. The facility accepts demolition waste, excavated soil, and mineral material from contractors and construction firms, turning it into products that must hold their own against gravel from traditional gravel pits.
Sorting by size and colour
The incoming material undergoes pre-treatment to remove steel, films, and light materials before water separates the sand from coarser aggregates. A density separation removes remaining light particles while the wash water carries away chemicals and other substances picked up during the material’s previous life. The plant maintains a closed water circuit, with half of the facility dedicated to water treatment.
After washing, a screen arranges the grains by size, but this only knows dimensions, not material type. Two Steinert MSort AP units are now at work, one handling particles between 8 and 16 millimetres and the other covering 16 to 32 millimetres. The particle size ranges are narrow to reduce overlap in detection. The camera detects surface colour and compressed air nozzles direct each grain into the correct stream based on that colour. Because the grains have been washed, the camera sees differences that would be invisible under a layer of soil, and the MSort AP is built to handle moist material without artificial drying.
The camera identifies basalt, red brick, glass, asphalt, and concrete within basalt streams, separating them from the dark rock. The target product depends on the sorting programme, and changing the programme allows the plant to produce different material mixes with properties suited to specific uses. This flexibility enables the removal of red rock, the production of black aggregate, or the separation of glass and asphalt based on their characteristic colours.
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Concrete plants can receive a continuous supply of this material, ensuring stability in their production schedules. The facility delivers quantities sufficient to meet the needs of a concrete plant without interruptions.
Before the machines were purchased, the team tested the plant’s main sorting tasks at the Steinert Test Center in Wedel. Commissioning has been underway since last autumn, and the plant has reached normal operation. Performance is measured by throughput, product quality, and the range of products. He advises others facing similar projects to begin without losing heart, as the results can be fine in the end.
Operational Results and Future Outlook
The plant has met the standards for impurity content. The share of impurities in the product is below 1% for glass. He wants to enhance the output quality even further. This requires fine-tuning the equipment with the technicians from Steinert. They work on the practical details that cannot be planned on paper. This includes belt transfers, bearings, and areas where dirt collects.