Black plastic doesn't get recycled because it doesn't reflect light well enough when passing the laser sorting systems. Therefore it can't be detected.
The other thing about black plastic, is that it's the only plastic that can't be dyed a different colour when using the plastic to make a new product. What I'm perhaps more interested in, is why so many companies insist in making black plastic? For example, the tomato trays that I buy are nearly always black.
I think there's only one recycling center in Ireland that now has the technology capable recycling black plastic. Also, I recently read, that it's possible to use a detectable black colourant that enables polymers to be detected by laser sorting systems enabling black plastic packaging to be recycled into plastic for the manufacture of new items.
Puts man on the moon using radars and satellites.
Can't detect black plastic in a garbage bin.