Almost all glass waste materials can befurther processed(second processing). Glass disposal is nowadays done in the form of dumping or recycling. Unlike other secondary raw materials, physical and chemical qualities of waste glass are excellent, even idealfor secondary processing. Recycled waste glass as a result of recycling (so called glass sand) enters the production again as secondary raw material, without losing any qualities that would reduce its utility value. This is how glass can circulate over and over again. After being processed, waste shards can be used not only for production of new glass, but also for production of glass fibres in form of isolation, production of foam glass with excellent thermal-insulating qualities, production of hardened stone used as high-quality interior facing and others. As for technology, it is obviously a very demanding process which requires a lot of financial resources.
Glass recycling is generally of the following use in the society:
economical
ecological
In most developed countries, where the extent of glass recycling is higher, these two meanings overlap and are inseparable, as the highly-developed society realizes the importance of the care for the environment. Therefore the extent of recycling is so high, doing over 85 % in proportion to the produced glass waste. The latest researches show that it mainly depends on the knowledge of the environment and educational forwardness of the economics. The extent of recycling is not so sensitive to the price for these services. In the less-developed countries the economical motivation of recycling prevails (to save money on waste disposal), which is its drivingforce. These countries show a lower percentage of glass utilization.
Special glass recycling and disposal
Special glass includes glass processed in any way, differing from mass productionby its qualities and use. Glass made by ordinary mass production can be modified mechanically or chemically in a special way. By chemical modification a substance is added into glass, which is usually bound in the form of oxide to the basic glass raw materials in the process of glass melting. This substance then gives molten glass required qualities (colour, softness, transparency, …). Physical qualities can be changed e.g. by applying these layers, pasting, heating-up… this is how modern glass applications are formed in electrical engineering and aviation.
When recycling special glass, qualities and substances, which have been added in order to achieve its special application, must be removed.We remove them mechanically or chemicallyor at very high temperatures. After the removal of these qualities, standard glass comes as the result, which is fully recyclable and can be used as melting charge by the production of new glass.However, it happens sometimes that some undesirable admixtures cannot be removed economically by means of present-day technologies, and therefore special glass is sometimes dumped.This is such a huge waste of primary raw materials. We must realize that glass recycling is a very noble process, as we can save up to 1/4 of glass raw materials (sand, soda, limestone), 43% of energy and we considerably reduce emissions ofcarbon dioxide (CO2) into the air by glass production from glass shards.
