2021 Volume 61 Issue 6 Pages 2002-2008
The Sn-bearing iron concentrate had a great influence on the pyrolysis of waste tire rubbers, and simultaneously the Sn in this concentrate could be removed efficiently during the pyrolysis process. With the additive of Sn-bearing iron concentrates, the gas yield from the pyrolysis of waste tire rubbers increased while the solid yield decreased. This was mainly due to the reduction of Fe3O4 by the pyrolysis char. A CaO–MgO containing complex was formed during the pyrolysis of waste tire rubbers with Sn-bearing iron concentrates, which could prevent the formation of stable chemical structures in hydrocarbons and decrease the activation energy of degradation reactions. The derived-oil yield was increased with it. The ‘S’ in the waste tire rubber could be transformed into Sn-bearing iron concentrates through the formation of FeS and ZnS, and then be oxidized to SO2 (g) by Fe3O4 or reduced to COS (g) by CO (g), causing the sulfur content in the derived-oil to be decreased. Simultaneously, in the presence of these generated SO2 (g) and COS (g), the Sn in the Sn-bearing iron concentrate could be sulfurized and removed. The Sn residual content in this Sn-bearing iron concentrate was decreased to 0.062 wt.% at pyrolysis temperature of 1000°C for 60 min in a high purity N2 flow rate of 100 ml/min.