Recycling Waste CDs as a Carbon Resource: Dissolution of Carbon into Molten Iron at 1550°C

Carbon dissolution investigations were carried out at 1550°C on chars from waste CDs as an alternative resource for ironmaking. Waste CDs/DVDs consist of polycarbonate material (thermoplastics polymer) and these produced a significant volume of residual char (~19 wt%) during heat treatment at 1550°C for 15 minutes. The carbon content of chars was determined to be 89% C. XRD and RAMAN analysis were used for the structural characterization of chars. Carbon dissolution investigations using the sessile drop method showed a very rapid carbon pickup reaching 4.12%C within 2 minutes (overall rate constant K: 19.2 × 10–3 s–1). SEM investigations confirmed the absence of oxides and other ash impurities in the interfacial region. The contact angle was seen to change from 79° to 100° after 3 minutes and 105° after 15 minutes of contact. These studies have shown that carbon from waste material could prove to be a valuable carbon resource and be used to partially replace coal and coke during iron making for carburization.