Bühlmann Recycling improves recovery with Steinert sorters

Beginning work at Steinert’s Test Centre in Cologne, Germany, in May 2015, Swiss company Bühlmann Recycling prepared a demanding sorting task for the equipment company’s applications specialists. The challenge was to use a flexible facility (i.e., one that could be adapted to future input materials) to manufacture a variety of products. The feed bunker contained electronic scrap. Today, almost two years later, the facility is being operated by Steinert partner MWN in Lyss, Switzerland, where it produces the desired results.

This flexibility is mainly because of the Steinert KSS and UniSort Black sorting systems. The former is equipped with color, X-ray and metal sensors and with a laser-based 3D recognition system. The overlap of sensors and signals enables the system to perform a wide variety of sorting tasks. A touch panel allows users to select and preset several different programs.

The second machine uses an HSI (hyperspectral imaging) NIR (near-infrared) sensor to sort materials. This high-resolution camera technology even enables the machine to recognize black plastics, which are otherwise undetectable.

These two Steinert machines at the end of the Bühlmann processing chain enhance product quality to the level that purchasers need, the company says. The system’s 11 conveyor belts and reversible discharge belts make it flexible. The machines can run either in parallel or in series to perform different sorting tasks. The process is simple, and the preset recipes enable it to be used to produce a variety of products. In this way, Bühlmann is adapting to new legislation, new designs for electrical devices and fluctuating stock market prices. Moreover, it enables the company to sort the materials that maximize its profits, Steinert says.

In the past, the sorting process was finished once the material was shredded and iron was separated from nonferrous materials. The residual fraction wasn’t processed any further unless it was specifically paid for. This is no longer the case.

The drop of the upstream magnetic separators for iron and nonferrous now go directly to the Steinert KSS. In the first step of the process for the 12-to-30-millimeter electronic scrap, the Steinert KSS produces a circuit-board/cable product. Flame-retardant plastics (including black plastic) are separated during this step as well. The rest of the sorting is performed by the UniSort Black, which uses a NIR sensor to detect and sort out visible acrylonitrile butadiene styrene (ABS), polyethylene (PE), polystyrene (PS) and polypropylene (PP) plastics. The UniSort Black produces a fraction of mixed black plastics that are purchased by the downstream recycling industry.

At the same time, the Steinert KSS sorts the nonferrous metals. The X-ray sensor ensures a pure aluminum product and separates heavy metals, Steinert says. Color sorting is used to separate the heavy metal product into copper, brass and grey metals.

Bühlmann generates up to seven different products using only two machines. Additional combinations of sensors will be added for future sorting tasks.

To increase the depth of the value added, black plastics also could be sorted by polymer class. Steinert also supplies the next solution for this purpose: UniSort BlackEye.

More information is available from Karl Hoffmann at karl.hoffmann@steinert.de.