扩展阅读 Glass recycling

Glass RecyclingGlass has the least volatile pricing of all the post consumer recycling commodities. Composed of sand and potash; bottle glass is made from readily available and inexpensive raw materials. To be competitive, recycled glass must maintain a price that competes with these abundant raw materials. Traded as flint (clear), amber (brown), emerald (green) or mixed color broken glass. The price depends on the cleanliness and color of the recycled product. Clean flint cullet (another word for broken glass) is usually the most desirable form of recycled glass scrap. Mixed color broken glass with ceramics or stones mixed in it is the least desirable grade of cullet bringing the lowest price. Most Recyclers color sort and break or crush and screen bottles before selling their product. Modern, high production bottle manufacturing requires very clean and uniform feedstock. Over the past decade there has been a growth in the glass benefaction sector. These are intermediate processors that receive glass from recycling programs and run it through a series of steps to remove any contaminants (rocks, ceramics, metal caps, etc.) and provide a uniform feedstock to the bottle manufacturers. These preprocessor provide an excellent market for recycling programs that do not have the volume or ability to produce glass for direct mill delivery. Glass beneficiation plants use sophisticated optical sorting machines to separate the glass into the three color types. They may also x-ray the glass to detect any rocks or ceramics which are then removed. Magnets and eddy current separators are used to removed magnetic and non-magnetic metal contamination from caps and lids. The end product is a uniformly sized load of ground glass that is free of contaminants readily acceptable by bottle manufacturers. Lower grades of recycled glass that are too mixed or contaminated, may be used in concrete or in road paving material called Glass halt. In some areas where there is an overabundance of low grade glass it is used to cover over the rubbish in the land fill in place of sand. This is not truly recycling and it is hoped that better sorting technology will soon make this material usable for new bottles. Glass recycling saves energy because recycled glass can be processed at a lower temperature than blending new glass from raw materials. Also, recycled glass is usually closer to the bottle plants than the sources of potash, the most expensive component in glass bottles and jars. Bout 32% of energy can be saved because of its low melting point. It is easier to manufa