Black glass
The Arc France group is launching new ranges of black glass products. Did you know that this type of glass comes from the recycling of scrap and breakage internal to production factories? Interview.
Tableware is still excluded from national packaging sorting instructions. However, manufacturers are optimizing the recycling of scrap and breakage from their processes in order to reduce their greenhouse gas emissions. With this in mind, the Arc France group is launching new ranges of black glass products on the market. We take this opportunity to take stock of black glass, its manufacturing process and its interest in the circular economy.
The group has four factories dedicated to tableware around the world: in France, the United Arab Emirates, China and the United States. It employs some 7,800 people, including 5,000 in France. The Arques site is designed for a production of 215,000 tonnes. Valentin Singlit is director of strategy and glass methods, in charge of the teams that manage the fusion of the furnaces and of the workshop that prepares the raw materials to be placed in the furnaces. He explains to us the benefit of black glass for recycling scraps and breakages which are commonplace in the glass industry.
Engineering techniques: During glass production, falls and breakages are relatively frequent, why?
Valentin Singlit: Scraps and breakage represent around a third of production. There are rejects due to defects, but above all due to processes. In particular, press-blown is used to make cups or stemware. Some of the glass is used in the process, but is cut and discarded in the final item. Almost all of this waste will be reinjected into the ovens. Black glass makes it possible to recycle the part that cannot be directly put back into the ovens.
To understand, you have to quickly look at the production chain. To put it simply, we melt the glass, then possibly color it and finally shape it. It can also receive a decoration on its exterior surface. In the art of the table, we have a level of quality of glass higher than that of the bottle, whether in color or discoloration. We cannot therefore afford pollution by coloring oxides. Once a colored or decorated glass has been made, it is therefore not put back into the transparent glass furnace, but will be used to make black glass.
How is black glass made?
The black glass consists of 70% crushed colored glass from production, 20% virgin material and 10% colorant. The dye is manganese oxide. This 70/20/10 ratio is the balance between the chemistry of the glass, our deposit and the concentrations of the raw materials. This makes it possible to recycle all the colored glass on the surface or in the mass. This manufacturing process reduces the carbon impact by approximately 10% compared to the production of transparent soda lime glass. Indeed, the cullet has already been pre-melted and therefore requires less energy to melt.