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Keywords:

  • Bakelite;
  • Carbon dissolution;
  • Steelmaking;
  • Recycling

Abstract

Bakelite is a thermoset plastic commonly found in electronic and automobile components. CaCO3 is generally found in the polymer as a filler material. Since it cannot be remelted, the disposal of this material has become an environmental issue. The present study investigates a new route to utilize waste bakelite as a source of carbon in EAF steelmaking process. This paper reports the carbon dissolution behaviour of bakelite/coke blends into liquid steel at 1550 °C. The carbon pick up in the liquid steel after reaction with varying blends of bakelite/coke for 30 minutes ranged between 0.13 wt% to 0.17 wt%; these were generally higher than that observed from coke alone (0.1 wt%). The dissolution rate (K) was also found to improve and the observed trend was BK2 (0.045 × 10−3 s−1) > BK3 (0.023 × 10−3 s−1) > BK1 (0.005 × 10−3 s−1) > coke (0.003 × 10−3 s−1). The reaction products formed at the interface after 30 minutes of contact between liquid steel and bakelite/coke blends were observed to be a CaS-Al2O3 complex. The presence of CaS in the interfacial layer due to the CaO in the ash, lowered melting temperature of the layer, thereby allowing for increased removal of the ash layer and greater carbon pick-up. The CaO is formed from the decomposition of CaCO3, and its presence was found to have a positive effect on modifying the properties of the coke, and thereby enhancing the carbon dissolution behaviour.