How Is Glass Recycled: 5 Things to Know

Did you ever wonder how is glass recycled? Today we will focus on this topic, as it is very important in any discussion about recycling, reusing, and repurposing. Limiting the quantities of waste product ending up in landfills is one of the biggest priorities these days, and recycling is, for the most part, the right solution. However, when it comes to efficient recycling, glass is recycling plants’ favorite material. Glass takes about tens or hundreds years to decompose and break down naturally. When it comes to repurposing, recycling and reusing, few other materials beat glass. Today, you will learn how glass is recycled and other information to help you embrace the glass recycling ideology. This will contribute to making the world a better, cleaner place.

1. The Glass is a Valuable Commodity

The glass is among the few, if not only, 100% recyclable material that can go through a recycling process endlessly without losing its quality, purity, durability, physical properties, and so on. Moreover, recycling glass is cheaper and more environmentally friendly than making new glass. Every 1,000 tons of recycled glass can save up to 350,000 kWh of energy, more than 300 tons of CO2, 1,200 tons of raw material and about 1,000 tons of landfill. Recycling 1,000 tons of glass can create slightly over eight jobs if not more. Imagine recycling a few glass jars and bottles and knowing that somebody just got a job.

In the composition of glass, we find readily available domestic materials. This includes sand, soda ash, limestone and “cullet,” the industry term for crushed, furnace-ready recycled glass. We can substitute recycled glass for up to 95% of raw materials. However, the only material used in greater volumes than cullet is sand.

2. Glass Should Be Clean

When you decide to recycle glass, make sure you clean your jars and bottles or glasses. The glass recycling plant will clean them, but it is a sensible thing to do to spare them the trouble. Jars with food scraps on them can interfere with the recycling process, causing disturbances.

3. Sort Glass Depending on its Color

The next thing you should do is sort the glass depending on its color: green, brown, and clear. To date, glass manufacturers are limited in their use of color-cullet (called the “3 mix”) to manufacture new containers. The standard colors are Flint (clear), Amber (Brown) & Green. When you separate recycled glass by color, the industry can ensure that new bottles match the color standards required by glass container customers.

When it comes to recycling glass containers into new containers, the recycling approach that the industry favors is any recycling program that results in a contaminant-free recycled glass. However, not all glass items make it into this recycling process. Glass containers for food and beverages are 100% recyclable, but not other types of glass. Windows, ovenware, microwave glass plates, light bulbs, Pyrex, crystal glasses or ornaments etc. are manufactured through a different process. If manufacturers introduce such items into the glass container manufacturing process, they can cause production problems and defective containers.

4. Glass Secondary Products are Just as Important

You should not worry about special glass items, however. These kinds of materials end up in secondary recycling products such as fiberglass, tile, ceramic sanitary ware, water filtration media, sandblasting, concrete pavements and parking lots, agriculture and landscaping applications, root zone material or golf bunker sand, the flux in the brick manufacture, and more.

5. The Glass Recycling Process is an Infinite Loop

Now that you know how to collect your glass items, let us talk about the actual glass recycling process. It involves several steps:

  • You wash the glass containers and put them into the recycle bin;
  • The glass items arrive at the glass recycling plant;
  • The cleaning process begins: the manufacturers begin removing all contaminants, impurities, and dirt. As we said before, the contaminant-free glass is the goal at this point in the process. The glass goes through some other processes, the most important one being the removal of all metal scraps. Manufacturers use industrial magnets to remove metallic steel cans and bottle caps. Then, the cullet goes into an enclosed chamber where powerfully blown air removes large lightweight objects. These include paper, plastic bottles, plastic jar lids and plastic bottle caps, and so on. Afterward, this material goes through a manual sorting process. The goal is to remove any objects that may cause issues during the recycling process.
  • A vertical dryer draws hot air up through the cullet as it enters the dryer to remove the moisture from the cullet as well as glass dust and paper labels. The dry and clean cullet passes over an Eddy Current separator to remove aluminum before it is transported to the sorting machines. The first stage of sorting is the removal of contamination. This includes ceramics, stones, metals, lead crystal glass and heat resistant glass.
  • The now clean material goes to color sorting. People and machines (vibrating feeders and conveyors, high definition cameras, scanners, and computers) sort it by color. Manufacturers prefer to recycle together similarly colored glass so that the recycled products are as pure and strong as possible to maximize their utility and prevent breakings.
  • After this is over, the recyclers crush the glass items. This type of cullet is cheaper than the raw materials used to manufacture new glass. Cullet also melts at lower temperatures, so the plants use less energy during the recycling process. Energy costs drop about 2-3% for every 10% cullet used in the manufacturing process.
  • Glass and jar manufacturers receive the pure, clean, high-quality cullet from the recycling plants in order to make new glass containers.
  • The manufacturers mix the cullet with materials such as limestone, sand, and soda ash, and heat it to over 2600 degrees F to make liquid glass.
  • The liquid glass goes into molds. Then the molds sit to cool down and turn into a finished glass product.

Specialists call this type of recycling a “Closed Loop” system, where waste material ends up back into its original form. In the case of glass bottles and jars, recycling plants and manufacturers can repeat this loop infinitely.


Glass container manufacturers benefit from recycling in several ways – it reduces emissions and consumption of raw materials, extends the life of plant equipment, such as furnaces, and saves energy. We, as consumers, should embrace and advocate for more glass recycling, as it does save energy, creates jobs, spares us from too much waste polluting the planet, and offers us the same glass quality we are used to, without disrupting our comfort and lifestyles. Now that we learned how is glass recycled, we can only hope that we could all enhance our efforts, together, to make sure we recycle as much glass as possible.

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William E. Eubanks

I'm one of the main writers on the site; mostly dealing with environmental news and ways to live green. My goal is to educate others about this great planet, and the ways we can help to protect it.

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