Lead and ceramic in glass industry


The lead content in recycled glass no longer poses a problem in the glass industry. Cullet recycled by REDWAVE-XRF provides superior results according to glass plants. The lead content in glass is even below the quality limits required by law.

Experiences of glass plants and plant operators:

The REDWAVE-XRF sorting system by BT-Wolfgang Binder GmbH for separation of leaded pieces of glass and glass ceramics has been used worldwide for a couple of years

Mr. Wolfgang Cieleback, Head of the department of glass technology at ArdaghGlass in Nienburg reports: “Cullet recycled by REDWAVE XRF (supplied by Reiling Glas Recycling & Co. KG, Glasrecycling Leeseringen GmbH & Co. KG, Rhenus Hannover GmbH Hannover) achieves definitely the best values with respect to the lead content. They fall below the European threshold values for lead even with 70 per cent of cullet in white glass, for example at the location in Nienburg.”

One of the main initiators of the development of this technique was the geologist Mr. Roland Pohl, Head of quality management at Reiling. At that time he did not focus on the lead content but on glass ceramics which frequently caused considerable damage (machine failures and machine downtime, work time loss, material loss, etc.). In 2004 Mr. Pohl was already looking for a suitable technique for identification of glass ceramics. Firstly, Reiling gained experience with x-ray fluorescence handheld devices, but soon after there was a demand for an online-machine in its processing plant. The company recognized a high demand for such a sorting machine as the cullet percentiles in the glass plants increased and at the same time more and more glass ceramics (fireplace glasses, hobs, etc.) were found in the in-feed materials.

Mr. Marc Uphoff, Managing Director of the Reiling group: “Over the past several years we have gained practical knowledge with the REDWAVE XRF. By now we use it at all our locations due to the very positive results. The identification of leaded and heat resistant glass is exceptional and even dirty cullet does not pose a problem for the REDWAVE XRF. By utilizing the x-ray fluorescence technique also leaded and zirconium-based ‘normal’ ceramics are removed.”

Current situation

Since the 1970s of the last century waste glass has been collected in many countries worldwide to be processed in glass recycling plants. Thus on the one hand the primary raw material quartz sand can be saved, and on the other hand the high energy demand for the primary glass production is minimized. Today up to ninety per cent of glass cullet is added to the process of glass production, depending on color and availability. Due to impurities in the collection it is necessary to process the cullet before the recycling process. Besides magnetic separation, crushing and screening it is important to ensure the purity of the single glass colors by optical sorting.

Besides the CSP (ceramics, stones and porcelain) typical impurities include various glasses which do not belong to the collecting container for waste glass. Such glasses include for example heat resistant, glass ceramics and lead crystal glasses. Glass ceramics lead to manufacturing concerns during glass manufacture and therefore to manufacturing defects in the final product. Lead is an element that is toxic and dangerous for the environment and which is regulated by European legislation taking into account the precautionary levels (in Germany 250 ppm).


By using the x-ray fluorescence, as in the case of the REDWAVE-XRF, it is possible to analyze and evaluate leaded glass, glass ceramics and other impurities on the basis of their chemical composition and to separate them effectively from the glass flow.

Thereby legal requirements can be met in the most accurate and cost effective way and quality issues due to glass ceramics can be almost alleviated.

The separation of impurities in terms of color and CSP can be undertaken by both IR transmission and RGB color detection methods.


REDWAVE-XRF provides excellent results, as contrary to other methods, it also ensures a very good detection with dirty glass and other impurities. The sorting machine scans the glass flow and identifies the chemical composition of the material, and not its visible optical effects. For this reason, it is not important how the material looks like but simply its chemical composition.

This is also a unique sorting technology as both glass ceramics and leaded glass can be separated reliably with only one sorting machine and in only one sorting step. Specific elements such as titan, zinc or lead are searched for, detected and undesirable parts are reliably ejected.

This sorting system is highly flexible and can be individually adapted to changing situations or new requirements at anytime.

Flexibility with future legal provisions:

Since legal provisions concerning glass purity will probably become more and more stringent in the foreseeable future it is important to stay flexible with investments like this. If future regulations regarding the content of other heavy metals such as strontium, chrome, etc. will come into effect, it is possible to promptly react to them with the REDWAVE-XRF, since this sorting system works with an x-ray-fluorescence-method which analyzes and evaluates glass by means of its chemical composition. The identification of further elements can be adapted individually at anytime.

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