What does “cullet” mean?
Cullet is broken glass used as a feedstock in glassmaking or processed for another material use. It may be collected from manufacturing or after consumer use; those sources have different histories and quality characteristics.
Can every glass item be recycled with bottles?
No. Window glass, ovenware, drinking glasses, borosilicate laboratory glass and specialty glass can have different compositions or attached materials. Follow the local collection instructions and the receiving processor's specification.
Why separate glass by color?
Colorants affect the finished glass appearance. Separating clear, amber and green cullet can help manufacturers maintain color control. Mixed-color material may have other destinations, but suitability depends on a defined product and process.
What are CSP contaminants?
CSP commonly refers to ceramics, stones and porcelain. They do not melt and behave like ordinary container glass under the same conditions and can cause defects or process issues. Sorting and inspection aim to reduce them.
Does using cullet always lower environmental impacts?
Not automatically. The answer depends on feedstock quality, transport, processing, furnace or product performance, energy supply, substitution and the study boundary. Compare equivalent services using transparent life-cycle evidence.
What is foam glass made from?
Foam glass is typically formed by heating prepared glass with a foaming formulation so gas creates a cellular structure. Product properties depend on the feed, recipe and process; check declarations and tests for the intended use.
Can ground glass replace cement?
Some glass powders are assessed for cementitious applications, but not all glass powder qualifies or performs alike. Composition, fineness, testing, mix design, applicable standards and project requirements determine suitability.
What should a recycled-content claim explain?
It should define which material sources count, the calculation method, the product or facility scope, and the reporting period. Ask whether the claim includes post-consumer material, manufacturing scrap, or both.
Where can I ask a materials question?
Use the enquiry sheet to draft a message. Copy or download it locally; this website does not transmit the form contents.
Further reading
Reference points include the US EPA, European Commission, European Environment Agency, ASTM International, ISO, CEN, British Standards Institution, FEVE, Glass for Europe, British Glass, WRAP, Glass Packaging Institute, US Geological Survey, FHWA, UK Environment Agency, BRE, EPD International, ecoinvent, International Energy Agency and Ellen MacArthur Foundation. See our editorial method for source handling.