The Heating Characteristics of CaO–SiO₂–Fe_tO System Slags under Microwave Irradiation

Abstract

In order to develop an efficient heating process for the waste slag treatment, the heating behavior of the synthetic CaO–SiO₂–Fe_tO slag under microwave irradiation was investigated. The heating rate of the slags was found to vary with the ratio of Fe³⁺/(Fe²⁺+Fe³⁺) in the slags and the microwave energy was most efficiently absorbed when the value of Fe³⁺/(Fe²⁺+Fe³⁺) was around 0.16 with the largest dielectric loss of the slag. Also the heating rate was benefited considerably from the presence of CaFe₃O₅ and magnetite phases in slags that have high value of dielectric loss. When the graphite powder was added to the slags, heating rate was drastically increased and the larger amount of carbon addition brought the higher value of heating rate.