Computer scraps recycling.
 
A lot of computers are somehow recycled this days.
 
Of course computers are made of very many different materials, including steel and other metals, precious materials, thermosets plastics and thermoplastics.
 
The last category is what is of interest to us.
 
The most common materials used in computers and other electronic devices are ABS, PS, some PA, PC and PMMA, plus some PE and PP.
 
Main problems are practically two:
- First is the fact that, even if your supplier swears he will supply only the plastic parts of computers, it just cannot be true.
- Second is the different polymers are not compatible each other and needs to be separated.
 
First problem can be by-passed by a special shredder that can handle metal parts without being damaged.
And this is available.
 
About the second problem, the matter is a little more complicated.
 
Let's give a look to density of the polymers that can be inside:
 
(densities are g/cm3)  for more go to POLYMERS CHARACTERISTICS
 

LDPE-HDPE-PP

range from 0,92 to 0,96

PS (polystyrene)

about 1,05

ABS

from 1,06 to 1,18  (depends on the Butadiene content)

PA

about 1,20

PC

about 1,41

PMMA

about 1,18
 
So, because the material that interest the most is ABS separation is not the simplest thing in the world.
 
Fortunately most of this PA is glass filled and sinks like a stone and a little bit of PMMA and PS are not harmful.
 
Moreover, using an "homogenizer" the final result is a strong defined polymer.
 
Anyway, in this situation, to make some money, quantity of scraps to be recycled should be not less than one ton per hour or so because, if the recycling system itself is not very complicated, and therefore affordable, what goes around it (space and water treatment) comes up to be quite expensive.