Monday, May 10, 2010
Glass has been made for over 4000 years, and it basically consists of silica (sand), potassium or soda, lime, and occasionally some other chemicals. They are melted together and cooled at air temperature so that the material is hard, but has a smooth and flowing shape like a liquid. The precise recipe can vary from time to time, however, in most cases glass is made in a basic way. All of the virgin or recycled glass materials are melted in a furnace at a heat of about 1500 degrees Celsius. The ingredients are melted into a liquid or molten form that is then dropped into a mould. Air blowing into the mould creates the shape of a bottle or jar.
Glass has many uses. It is used for beverage bottles, as well as being used for many types of food containers as well as dishes and drinking glasses. It is used for windows in homes and buildings as well as in vehicles. Glass is used in jewelry, ornaments, decorations, lighting, as well as what many people have on their face to read this article. The manufacture of glass uses energy in the extraction and transportation of the raw materials, and during processing, as materials have to be heated together to a very high temperature. Large amounts of fuel are used and the combustion of these fossil fuels produces carbon dioxide, which is a greenhouse gas. Glass containers are 100 percent recyclable, and recovered glass is used as the majority ingredient in new glass. In the United States alone, nearly 13 million glass jars and bottles are recycled every day and the glass container industry has annual revenue of over five billion dollars. Over 41 billion glass containers are produced every year and thirty percent of glass containers in the supermarkets and other retail stores are recyclable, but consumers recycle less than half of these containers.
How Glass is Recycled:
Glass makes up a large component of household and industrial waste due to its weight and density. The glass component in municipal waste is usually made up of bottles, broken glassware, light bulbs and other items. Glass recycling uses less energy than manufacturing glass from sand, lime and soda. Every tonne of waste glass recycled into new items saves over three hundred kg of carbon dioxide. Glass can be recycled indefinitely using a simple process, as its structure does not deteriorate when reprocessed. In the case of bottles and jars, up to eighty percent of the total mixture can be made from reclaimed scrap glass known as cullet. Cullet from a factory has a known composition and is recognized as domestic cullet. Recycling reduces the demand for raw materials. There is no shortage of the materials used, but they do have to be quarried from our landscape, so with this in mind, there are environmental advantages to recovering and recycling glass. Also, there are many bottle depots that accept glass for reuse or to recycle.
After glass is disposed of in a recycling bin it is and taken to a glass treatment plant. The glass is sorted by color and washed to remove any impurities. All glass comes in one of three different colors: clear, green and brown. Glass products need to be sorted by color before recycling. You also need to look for the “G” logo on the product, which means that the product is made from recycled glass and can be recycled again. The glass is then crushed and melted, then molded into new products such as jars and bottles. Cullet is crushed glass, and is created by melting down bottles and jars in a furnace. Any paper labels left on the glass will be burnt off, but metal lids are removed so they do not harm the furnace. Cullet melts at a lower temperature than raw ingredients used to make new glass, such as sand, so significant energy is saved in this process. Cullet serves as the main ingredient in new glass containers, often as high as seventy percent of the content. The melted cullet is molded into the desired shape of a bottle or jars, with the end product soon back on store shelves after being recycled. Recycled glass may be used for alternative purposes such as brick manufacture or decorative uses. A recycled, crushed glass product can also be used successfully as a sand substitute in concrete or into other glass products like fiberglass insulation. Glass does not degrade through the recycling process so it can be recycled again and again. Glass recycling companies are very sensitive regarding glass contamination and will send truckloads of glass to landfills for having any amount of cross-color mixing or inclusion of non-recyclable glass.
Glass can be recycled forever. The same glass can be recycled thousands of times over to produce bottles and jars of the same high quality every time. However minimal amounts of some materials mixed in with the glass can cause contamination. It is very important to know what types of glass can and can’t be recycled.
Types of Glass that can be Recycled:
Most disposable glass food and drink containers are recyclable. Clear, green or brown bottles, including wine, beer, juice, soft drink and sauce bottles can be recycled. Glass jars such as those from jams, spreads and other foods are also recyclable. You need to make sure to empty the containers and take off the lids as they are not recyclable .It is important to sort glass by color for recycling purposes. Clear glass is the most valuable. Although not as common as in past decades, some glass beverage containers are refillable. Refillable glass or plastic bottles can be refilled several times over. Refillable glass bottles normally have a deposit on them at retail level and customers are encouraged to return them for cash refunds.
One important aspect to keep in mind is that it is better to reuse glass as to recycle it. There are many ways you can reuse glass bottles and jars. Some glass bottles, such as beer bottles are refillable. Glass jars and containers are perfect for storing food and last for years. Wine bottles can be used for vases and other decorations. Small glass jars can be used to store spare change, screws and nails, and other household items.
Types of Glass that Can’t be Recycled:
Examples of glass that can’t be recycled include cookware, ceramics, coffee mugs, windowpanes, Pyrex, auto glass, light bulbs and fixtures and mirrors. Medical or laboratory glass is not recyclable. If the recycled glass is being used to make new glass it must be pure and this means you can only use glass and beverage containers. Other types of glass can have a damaging or harmful affect on the quality of the new glass. Light bulbs, mirrors and Pyrex have been treated with contaminants when manufactured.Light bulbs and other electronic equipment, which have glass components, contain many metal elements and a range of heavy metals such as lead and cadmium and should be disposed of by specialist companies. Many of these glass types can actually damage a glass manufacturer's furnace.
Benefits of Glass Recycling:
Everything that you recycle is put to good use. Your recycling prevents needless use of landfill sites or incineration. You are helping to protect and improve the environment when you recycle glass products. The typical glass container is made up of as much as seventy percent-recycled glass. It is estimated that eighty percent of recycled glass as a whole will end up as new glass containers. Unlike other substances such as paper, glass can be recycled infinitely without any loss of purity or quality. A glass bottle can take up to one million years to break down, which is how long it will sit in a landfill and take up space if it is not recycled.
Making new glass from recycled cullet saves energy because recycled glass melts at a lower temperature than virgin raw materials. Because the materials do not need to be heated as much, less energy is required in the manufacturing process. Glass recycling has many benefits. Recycling a glass jar saves enough energy to light a bulb for four hours. Glass can be recycled over again and never lose its quality or quantity. Recycling glass decreases air pollution by twenty percent and reduces water pollution by fifty percent. It also reduces that amount of landfill space that is used. Recycling reduces the amount of waste glass, which needs to be land filled. Although glass is inert and is not directly hazardous to the environment, it will remain there indefinitely.
Taking part in recycling the waste we produce makes us think about the environmental effects we are avoiding. We need to recycle glass, along with other materials such as plastic, paper and metals to ensure we leave a healthier planet for future generations along with combating the threat of global warming and issues associated with climate change.