Glass recycling “closes the loop,” turning recycled glass containers into new bottles and jars. Glass goes through a series of steps before it becomes new products.
1. Glass Collection
Haulers collect glass from consumers and take it to materials recovery facilities.
Consumers place recyclables in curbside bins or at glass drop-off collection sites, or return glass bottles through a container deposit program. Glass is more valuable if it’s kept color separated, but in many curbside programs all recyclables are collected mixed. Haulers typically take these mixed recyclables to a materials recovery facility (MRF) where the recyclables are sorted by commodity type. Recovered glass is then sent to a cullet processor for further sorting and cleaning. Recovered glass might also be sent from the MRF directly to a business for a use other than manufacture into a new glass bottle.
At drop-off sites, clear, brown and green glass may be collected in separate containers and collected separately from other recyclables. Before being made in to new glass containers, recycled glass must be separated by color. The color of glass containers is created by adding a coloring agent that cannot be removed. This means that colored glass, such as green and brown glass, are required to produce new green and brown glass, respectively. So, sorting makes the recycled glass more valuable to the end market. Deposit programs also yield high-quality container glass. Recycled glass collected at these locations will typically go directly to a cullet processor.
2. Glass Processing
Cullet processors clean and sort glass to make cullet that is sold to manufacturers.
At the cullet processor, the recovered glass first goes through a process of removing contaminants, such as ceramics and other non-container glass, metals, gravel and other dirt. Glass is then sorted by color, and it is sized so that it meets specifications to be “furnace-ready” cullet. The finished cullet is then sold to container manufacturers to be made into new glass bottles and jars or in some cases fiberglass. Glass that does not meet glass manufacturer specifications may be used for a secondary application or product.
3. Glass Bottle Manufacturing
Manufacturers use recovered glass to make new glass products.
Glass bottles are made from readily-available domestic materials, including sand, soda ash, limestone and “cullet” – the industry term for furnace-ready recycled glass. Recycled glass, or cullet, can make up to 70 percent of the raw material mix for new glass containers. These materials are mixed, or “batched,” heated to a temperature of 2600 to 2800 degrees Fahrenheit and molded into the desired shape.
Using recycled glass in the manufacture of new glass containers reduces emissions and consumption of raw materials, extends the life of plant equipment, such as furnaces, and saves energy. A glass container can go from a recycling bin to a store shelf in as little as 30 days
