At a time when climate change is being felt in almost every area of our lives, the duty of care for air quality and natural resources rests largely on the shoulders of the construction industry, responsible for almost 40% of global carbon emissions.
Today, the sector's biggest players are therefore playing "green" - basing their business models on the principles of sustainability and inspiring others to implement green technologies. On the road to achieving climate neutrality, Saint-Gobain introduced its Grow&Impact strategy last year, the main goal of which is to work extensively to combat global warming and provide comfort to building users without burdening the planet. The overarching goal of "Making The World a Better Home" guides all of the Group's brands, and the pledge to make the world a better home starts as early as at the manufacturing plants - including the use of cullet to produce construction glass (facade glazing, window or interior glass) and automotive glass.
Experts Konrad Brylinski - Glass Recycling Project Manager and Katarzyna Kordus - Environmental Manager at Saint-Gobain Glass talk about the essence of glass recycling and its benefits for the environment.
We are well on our way to decarbonizing our plants.
© Saint Gobain
1 The closed-loop economy is the future of every industry. What is the technological importance of cullet to the glass melting process?
Konrad Brylinski: Cullet in itself is already glass, and therefore our final product. The only thing that needs to be done with it is, in a nutshell, to re-melt it and re-form it. Unlike glass obtained from melting a mixture of glassmaking raw materials, where the appropriate reactions and bonding must take place and the partial losses resulting from these cycles, the process of re-melting cullet itself is much simpler and therefore less energy-intensive and, very importantly, almost loss-free.
2 So in terms of environmental protection, dosing cullet into the production process has a positive impact on the climate?
Katherine Kordus: As Konrad mentioned, recycling cullet is a far less energy-intensive process, as up to 30% less energy is used to melt it than is used to make glass from natural resources. This brings tangible environmental benefits in the form of a significant reduction in greenhouse gas emissions from plants, among other things. Each ton of cullet saves about 300 kg of CO2 due to less fuel burned and no decomposition of carbonate raw materials due to the fact that cullet is already a processed material. Recycling also contributes to reducing the consumption of fossil raw materials such as sand, limestone and dolomite, which are replaced with cullet.
Konrad Brylinski: I would also add that this type of production is practically lossless - from 1 ton of glass waste we get 1 ton of glass again. For comparison - to produce 1 ton of glass from virgin raw materials we need about 1200 kg of glass mixture, including as much as 750 kg of sand.
Katarzyna Kordus
Photo: Saint-Gobain Glass
3 What requirements for the quality of the raw material must be met by cullet used in the production of flat glass?
Konrad Brylinski: The requirements for cullet for flat glass production are very restrictive. As a rule - the raw material that reaches us should be free of any impurities. Actually, it should be only broken flat glass, in addition, segregated by species/color. At present, all of the external cullet is sourced through recyclers, who should be a guarantor of the quality of the goods offered. Polish suppliers of cullet for flat glass production source it for the Float line mainly from the pre-consumer market (glass processing plants), where the risk of contamination is relatively low. We verify the quality of cullet supplied to us by subjecting it to visual inspection during delivery and during loading of the raw material into the day silos, where strong permanent magnets and a metal detector are installed on the conveyor belts, which protects the production process from dangerous metal contamination. In the future, when we source and process glass from the post-consumer market, that is, from demolition or renovation of buildings, the risk of contamination will certainly be higher, if only due to the presence of other renovation waste, such as rubble. In such a case, it will be necessary to expand the detection system with optical detectors that allow the capture of such contaminants, such as the aforementioned stones or ceramics or porcelain, which are just as dangerous in their effects as metal contaminants. The first lines of this type, designed to verify the quality and purification of cullet from the post-consumer market, have already been established in our Group at plants in France and Romania.
Konrad Brylinski
Photo: Saint-Gobain Glass
4 GOZ-based production and recycling of cullet is one of Saint-Gobain's most important steps toward achieving climate neutrality. What is the Group's strategy for increasing cullet consumption?
Katarzyna Kordus: The targets have been specified very clearly - the average share of cullet in melting for the Float line at Saint-Gobain plants should reach at least 50% by 2050, 25% of the raw material is to come from thepre-consumer market (cullet from glass processors), 10% from the post-consumer market (post-consumer cullet), and the remaining percentage will be our own cullet (generated on-site at the plant). In our strategy, we have also set an intermediate target for 2030 of using cullet for glass production at 40%, including 20% of raw material from the pre-consumer market and 5% from the post-consumer market.
Konrad Brylinski: To achieve these goals, we will continue our policy of cooperating with recyclers in the local market, trying to obtain as much high-quality cullet as possible from them. A much more difficult challenge, which will certainly determine our activities in the near future, will be to focus on the post-consumer market, which is only in its infancy in Poland. Forecasts and analyses of available volumes over the next few years are very optimistic.
5. Given the improvements in manufacturing technologies, what is the future of low-waste glass melting at Saint-Gobain plants?
Katherine Kordus: With the environmental challenges facing manufacturers and consumers, the world is changing very rapidly. We are witnessing tremendous technological advances, so by definition we cannot rule out the emergence of a completely new flat glass technology that will dominate the market - just as happened with Float technology, invented in the 1950s. In the perspective of the next few years, based on current production methods and with consistent implementation of the Saint-Gobain Grow&Impact strategy, our main activities will focus on maximizing the share of cullet and obtaining the energy used in the entire manufacturing process from RES. We have already taken the first steps in this direction, including. We have already taken the first steps in this direction, including signing a long-term agreement to obtain electricity from wind farms from Tion Renewables AG, or launching industrial-scale production of ORAÉ base glass, which is a product with a reduced carbon footprint thanks to the use of 70% cullet and energy derived entirely from renewable sources (including the biomethane used for melting). To these achievements should also be added the world's first zero-carbon glass production campaign, which took place this May at Saint-Gobain Glass in Aniche, France. The success was determined precisely by the use of 100% cullet, 100% green energy produced from biogas and decarbonized electricity.
Konrad Brylinski: In the medium term, we will certainly see a hybridization of glass furnaces and tubs. In the new types, the share of electricity in the glass melting process will increase significantly - but this will be largely from RES. Although it is difficult to imagine for the moment the complete elimination of gas in the production process, it will certainly be possible to replace it with another eco-gas or hydrogen in the future. Our R&D teams are already working on the concept of modern, "green" furnaces, and we hope that this type of innovation will soon take hold at the Dabrowa Gornicza glassworks. Our recent investments and successes in the field of sustainable production have shown that we are well on our way to decarbonizing our plants for the benefit of the planet and people.
We are well on our way to decarbonizing our plants.
© Saint Gobain
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