© GRI Glasrecycling GmbH   
Business Services Glass Recycling Contact Glass Impressions GRI Glasrecycling GmbH

Hollow and Flat Glass

Glass is...

… an amorphous material and is mostly produced from the natural raw materials sand,             sodium carbonate and lime. … inert and neutral in its effect i.e. no mutual reactions exist between the glass container             and the respective content. … entirely tasteless. Glass is used in various fields of application depending on its chemical composition. Different kinds are, amongst others, soda-lime glass, fused quartz, borosilicate glass, float glass and lead glass. Primarily, glass is put into use as hollow or flat glass. Both the respectively used production processes as well as the products' application range itself may be many-sided.

Hollow Glass

Container glass, also generally called “hollow glass”, is used as packaging in all aspects of everyday life, e.g. for food, beverages, perfumes, medicine, etc. Glass packaging can be produced in almost all colors in order to achieve additional features. amber glass, for instance, is used to pack light/ UV sensitive contents, such as medicine, juice or beverages containing beer to prolong shelf life. Choosing the glass color for a product, a company's marketing department should, however, always take into consideration the recycling possibilities, e.g. red glass is not a reasonable choice in the sense of recycling. Classifying the glass while trying to correctly separate it at the bottle banks becomes disproportionately more difficult for the consumer which thereby leads to a decline in the recycling results. Hollow glass is predominantly soda-lime glass. Glass packaging can be found at retailers as disposable (mostly food) or reusable containers (mostly beverages). Reusable packaging makes it possible to reach a countless number of circuits concerning the bottling of beverages. In contrast, disposable glass containers are taken to a waste glass treatment plant, provided a functioning recycling system. After reducing impurities at the facility, the glass can be reused in the glass industry. Evidently, container glass is thereby introduced to a closed and infinite circuit. Fundamental for a functioning system are a clean and color-pure waste glass collection (container glass collection close to households) as well as an innovative and continuously improved recycling process. This is a requirement absolutely necessary to guarantee high recycling rates of the resource glass. Compared to other materials, glass is a perfectly recyclable material which can be kept infinitely in the circuit without any quality loss: Glass is inherently stable and especially suitable for bottling processes because of its temperature compatibility. Glass packaging is airtight and therefore capable of keeping even carbonated drinks “fresh”/enjoyable. Glass can be entirely cleaned and reused and is suited ideally for reusable container system. In hollow glass production, the Owens machine (introduced by Michael Joseph Owens in 1903) was revolutionary as it was the world's first fully automatic bottle machine. Today's industrial container glass production is still based on this invention: By creating a vacuum inside a riser which has been immersed into the melt, the precisely needed amount of melted glass is drawn into the raiser's inside. The raiser pushes the drop into a metal shape and and then completely blows the liquid glass into the shape by using compressed air. Through this, the glass gains its final form and appearance. This technique is called “suction blow molding” and allows the automatic production of a great number of containers in a short time. A lot of emphasis is put on a cautious cooling process to ensure that the container is not exposed to any tension and not prone to breaking. Finally, various tests make sure that the bursting of the container during transport, while being filled under high pressure or due to changes in temperature is prevented. In Germany, Saint-Gobain Oberland AG (verallia Deutschland), the Ardagh Glass Group, O-I GLASSPACK, Wiegand- Glas GmbH, Noelle + von Campe Glashütte GmbH, Weck Glaswerk GmbH, Gerresheimer Gruppe, HNG global GmbH and many others are the main producers of container glass and therefore customers for recycled cullet. Flat Glass / Float Glass Float glass, also generally called flat glass, is used in many different fields of application, e.g. in construction and in the automobile industry as window segments, in architecture, in solar thermal energy and photovoltaics, in manufacturing furniture as mirrors, display cases, shelves as well as for TV and computer screens and smartphone displays, etc. The most common production methods for flat glass are the so-called float glass procedure as well as the casting or the rolling of flat glass. The production of float glass is an infinitely continuous process: Under approximately 1100 degrees Celsius, the glass is cleaned of bubbles and the glass melt is directed into an oblong vat filled with liquid tin (300 – 800 m) in which the lighter glass “floats”. Because of the surface tension of the tin and of the liquid glass, smooth surfaces form. A failure-free look is achieved without the need for prior grinding or polishing. The cooling down glass is drawn out with a certain speed through an attached annealing lehr to eliminate any tensions in the glass and therefore ensure an optimal life span. After visual and technical quality inspections, the cutting of the glass takes place. This process was perfected by Sir Alastair Pilkington at the end of the 1950s to make it industrially applicable. The float glass procedure allows the production of glass starting at 0,4 mm thickness. Worldwide standard seizes are 2, 3, 4, 5, 6, 8, 10, 12, 15, 19 and 24 mm which are optionally produced as demanded. Typical products in the flat glass production are toughened glass, laminated glass, safety glass, insulated glass, fire resistant glass, solar control glass, solar glass, bulletproof glass, heat protection glass, wired glass made from cast glass, etc. In Germany, the main flat glass manufacturers are Saint-Gobain Glass, Pilkington Group (Nippon Sheet Glass), AGC Glass Europe (Asahi Glass Co. Ltd.), etc. The production processes for container and flat glass products are very energy-intensive which is why the energy- saving effects of using recycling cullet play such an important role in the glass industry. Waste glass will always be an important raw material in the container glass industry. Given the cooperation of waste glass treatment plants and the glass industry, it can be recycled infinitely without any quality loss and melted again and again so that new high-quality glass containers can be created. By using waste glass, primary raw materials and energy can be saved sustainably. Therefore, waste glass contributes to an extensive reduction of CO² emission. Preserving resources and a sustainable ecology are the main goals of the product recycling glass.
Privacy Policy Imprint Sitemap