Originally Posted by BSD_Glass
Because the energy to convert the ingredients to glass is the expensive part of the process and it is gone when the bottles are cool. Silica is plentiful and the primary ingredient in glass.
To "recycle" glass means melting it along with many other bottles and whatnot in a huge furnace and adding fluxes and stirring to get a homogeneous product that can then be run through a processing machine to get more bottles or whatever, but it is much easier, for the same energy to use raw materials and be assured of a clean and consistent product. Or the glass can be crushed when cold and used as gravel or aggregate in concrete or pavement.
If glasses of varying coefficient of expansion are combined in the same melt, products may not be homogenized and the glass may actually pull itself apart due to internal mechanical stresses. It is also much harder to get clean, pristine product from recycled glass than from raw glass.
Roadbed aggregate is a great way to recycle glass. Remelting recycled glass is mostly a marketing gimmick and the work is often aesthetically or even structually inferior to the same work produced from batch (raw) glass.
This is not true--glass has infinite recycling capabilities (any impurities are easily removed) and virtually all glass includes ground recycled glass as one of the ingredients by default.
It also requires half the energy to recycle a pound of glass as it does to create it from raw materials, and while the raw materials are plentiful, open pit mining is devastating to the environment.http://earth911.com/recycling/glass/
Some states do have redemption values on wine bottles.