Dispose of a glass bottle and you may see it again one day as a new bottle. Because glass is 100 percent recyclable, glass makers can use it repeatedly to make new glass products. The glass manufacturing process uses a mixture of sand and other raw materials as well as recovered glass. The melting point of glass for recycling varies depending on the type of glass you melt.
Cullet in Your Glass
When glass gets to a recycling plant, machines sort and clean the glass before turning it into cullet — small pieces of crushed glass. The plants sell approximately 90 percent of the cullet to glass manufacturers, who mix it with limestone, soda ash and other raw materials. They then melt the mixture by heating it to temperatures of between 1,427 and 1,538 degrees Celsius (2,600 and 2,800 degrees Fahrenheit).
Why Use Cullet
Mixing cullet with other materials reduces the amount of energy it takes to make glass because cullet melts at a lower temperature than glass’s other components. If glass makers mix 9 parts of raw materials with 1 part of cullet, their manufacturing processes use energy 2.5 percent more efficiently. Cullet also helps furnaces last longer, and it’s cheaper to purchase than other raw materials.
Separation Is Important
When you take glass items to a recycling center, package them in separate containers. Jars and bottles, for example, don’t melt at the same temperature as other types of glass, such as light bulbs and mirrors. If you mix jars and bottles with other glass, the recycling process could create new jars and bottles that aren’t as strong as they could be. The new products could explode or crack when people try to open them.
Colors Matter Too
Some recycling centers may also ask people to separate glass by color. This is important because the amount of soda and silica in glass can vary depending on the type of glass you’re recycling. Melting points for various types of glass could vary as well. Recycling centers can produce cullet that has higher economic value if they separate glass by color.
Additional Benefits of Glass Recycling
Five percent of the trash that Americans produce is glass. When you recycle glass, you help reduce the amount of landfill space communities must allocate to store waste. You also help conserve other natural limestone and other natural resources since glass makers don’t have to use as much to make new products.