Abstract:
Waste Tyre disposal is one of the most crucial environmental challenges in the world
and Pyrolysis has been recognised as a sustainable solution to reduce the accumulation
of waste tyres. Pyrolytic oil, gas, and char are the three primary by-products generates
from the pyrolysis of waste tyres. The economic value of the pyrolytic char (PT-char)
is low, and solid char disposal is difficult. Waste char could be given an economic
value by being transformed to carbon black. The current study outlines a cost-effective
method for producing commercial grade carbon black from low-grade PT-char. Prior to
size reduction by ball milling and/or sieving, the pyrolytic carbon black was initially
passed over a magnetic separator to remove metallic particles. These particles were
demineralized at 60–80 ◦C for 1–2 hours with diluted acids and/or bases (2M HCl and
2M NaOH). CHN, XRD, SEM, and TGA were used to study the purity and surface
properties of modified carbon char. Carbon content of char was improved after treating
with two times in 2M HCl and once in 2M NaOH to ∼91 wt% (initial value of 67 wt%)
while the ash content was decreased from 17.65% (w/w) to 3.59% (w/w). The removal
of Zn from PT-char was confirmed by XRD and surface modification was confirmed by
SEM images. The upgraded PT-char was used as reinforcing filler for the preparation of
solid tyre cushion compounds. The rheological and physico-mechanical properties of the
PT-char compounds were evaluated and compared with commercial grades of carbon
black; N330, and N660. It was found that the rubber compounds prepared using purified
PT-char do not significantly differ in their tensile strength, tear strength, and hardness
from samples prepared using commercial carbon black grades. However, compression
set shows the little lower values compared to commercial grade carbon black. Due to
the effectiveness and efficiency of the upgrading procedure, it can be concluded that the
upgraded PT char has a high potential to be used as cost-effective reinforcement filler
in the rubber industry and solid tyre sector.
