At the glass recycling plant in Næstved, 70 km from Copenhagen, two “first generation” sorters have just been replaced by the latest STEINERT MSort generation. The so-called fine glass line at this location is now up to the challenge of sorting the 3-10 mm fraction for the coming years. Even after 10 years, the other MSorts running on the 10-60 mm line are in such good condition that they will continue to produce for years to come without any major maintenance.
STEINERT meets Benedikt Heitmann, Technical Managing Director of Reiling Glas Recycling GmbH & Co. KG, on a cold February day at the yard in Næstved. He reports that Reiling basically receives two types of glass: Hollow glass and flat glass. The former is container glass such as drinks bottles and glass packaging for food. The second is for example insulating glass, windows and car windscreens, including replacement glass. Differentiating between the different types of glass is important, he says, because the sorting is different. For hollow glass, recycling in Denmark starts either at the collection container, which everyone knows from the cityscape, or at the deposit return system. In Denmark, there is also a third stream - in some regions, glass and metal are collected together from private households. Reiling processes these material streams at the Næstved site in order to return the cleaned and sorted hollow glass to the cycle in the form of recycled glass cullet. The following is about precisely this material flow.
The threshold values are strict
“No matter how bad the input material of the hollow glass that ends up with us is,” explains Heitmann, ”the sorted product at the end of the entire sorting line is subject to strict limits. Even small quantities of impurities can cause major damage in the manufacture of new glass products. We return more than 90% of the glass that arrives here to the glassworks. One of Heitmann's tasks is to comply with the threshold values by selecting the right technology. The task is not easy, as the requirements for the composition of the cullet quality are high. The threshold values are set out in the T 120 guideline, specifically the “Quality requirements for cullet for use in the container glass industry”. Glassworks and recyclers developed them years ago by mutual agreement so that all recyclers have the same specifications. Two grams of Fe-metals per ton of glass are permitted, which is the weight of a small wire. By comparison, a Fe-lid weighs 10-20 grams. For non-ferrous metals, recyclers are not allowed to exceed three grams per ton. And in the case of the contaminant CSP (ceramics, stones, porcelain) it is 20 grams per ton, which is just the handle of a cup. After sorting in Næstved, the secondary raw material is sent to the Ardagh Group, among others. The world's second largest glass producer is right next door in Holmegaard, just 15 minutes away by car.
Mechanical pre-sorting
The first steps on the way through the recycling plant are crushing and pre-sorting. Without these steps, there is no raw material from the recycling process. A roller crusher crushes the glass and, in this way, exposes the different materials. There are light material extractors that separate the labels and paper as well as magnets and non-ferrous metal separators that remove ferrous and non-ferrous materials from the glass. Plastics are also separated after the pre-sorting process. However, these processes mean that there is a non-negligible residual fraction that still contains a lot of glass.
MSort sorting systems in glass recovery and fine sorting
In order to further increase the recovery of raw materials, Reiling then relies on a Recovery Line in the next step. In this line, the waste material and glass in the 0-10 mm fraction that accumulates in the main processing plant is fed in. These quantities run through optical sorting systems. Here, the materials pass through the optical sensors again, albeit at a slower speed, as absolute accuracy is essential here. But what does optical sorting actually mean? Sensors use transmitted light to “see” whether light gets through the glass. If no light comes through, it must be an interfering material such as ceramics, stones, and porcelain. If it is metal, the metal sensor detects this. Air blasts then separate the sorting material A from material B. The Recovery Line consists of a fine sorting and a coarse sorting line and here there are several MSort sorting systems of different generations. The Fines Line, which sorts 4-10 mm cullet, is now equipped with the latest systems in the yellow STEINERT design: MSort AF (Rougher Stage) and MSort AK (Cleaner Stage). The MSort AX has been in use since 2014 in the line, over which the 10-60 mm cullet run. Once the impurities have been removed, it is the turn of the color sorting. At the very end of the sorting line, the result is brown glass, white glass and green glass in its purest form.
Reiling has been buying MSort since the very beginning
MSort sorting systems, then under the umbrella of Mogensen, have been on the market since 1996. Just one year later, the first MSorts were already sorting at Reiling and today, almost 30 years later, there are many sorting systems spread across Europe. “We have been relying on MSort for a long time and under the STEINERT umbrella we are once again investing in sorting technology. For this reason, we are building on our long-standing supplier and following the path to the new generation of sorting systems in glass recycling. Today's progress is tomorrow's standard,” concludes the Managing Director, who would like to return much more than 90% to the recycling loop in the future. STEINERT MSort is happy to help.