Abstract
The aim of this paper is to determine the heat of combustion of plastic wastes resulted from municipal solid waste, automotive
shredder facility waste and building and construction waste. The plastic wastes have been separated by flotation technique using
as flotation media: water, ethanol, their mixtures and magnetic fluid. Resulted fractions have been analyzed aiming to determine
the most effective fraction from the heat of combustion point of view. The obtained results have been compared to those reported
in the literature, with those calculated by oxygen consumption method and those proposed in this paper and calculated by
weighted sum of combustion heat of components, aiming to allow its approximation for different fractions of polymeric wastes
with known composition, avoiding the experimental measurements. Deviations of measured values of the heat of combustion
from those obtained by theoretical calculation have been explained by the polymer degradation during their life cycle. The most
effective fraction from calorific point of view is that containing polyolefins, but this fraction could be mechanically recycled. The
present study evidenced that the heat of combustion of the plastic waste decreases after polyolefin extraction and the remaining
density fractions can be effectively used for energy recovery of the plastic waste by incineration.