I throw away a lot of incandescent light bulbs. The thought occured to me that there’s a lot of glass that gets thrown away. Is there some reason it’s not usual to recycle them, as opposed to glass bottles and such where they usually are recyclable?
I ran several searches and this one is the predominant theme.
LIghtbulbs are far too fragile for the automated machinery used by modern recycling facilities. Also, they contain inseparable bits of metal (two different types of metal, no less) and paint. They’d have to be handled separately from the other glass and required specalized machinery to separate the glass and metal bits
Glass bottles are actually pretty easy to process. They’re relatively durable, generally come in one of three colors (clear, brown or green), and include a limited array of contaminants, most easily sprayed off with hot water.
I guess it isn’t practical to separate the materials for the small amount of glass they contain, although I suppose you could break the bulb and collect the glass (the base is usually aluminum and could be recycled too, also a bit of glass insulating the bottom contact from the base, note that the center contact has lead solder).
Incidentally, the EPA calls incandescents “hazardous waste” (PDF) due to the use of lead solder (in the center contact) and leaded glass, which could be problematic for recycling (not sure what is done with leaded glass):
(the same PDF suggests setting up a special recycling system for them)
Kind of interesting actually - CFLs may actually be less toxic overall, depending on the relative toxicities of lead and mercury (of course, they can also have lead in solder, aside from the glass, which may or may not have lead in it, although lead-free solder is common now, and indeed banned/restricted in areas like the EU with many products sold elsewhere being lead free due to global commerce/concern for the environment/etc).