8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

Abstract: According to the coexistence theory of slag structure, a calculation model of concentration of SiO2-CaO-Al2O3-FeO of depleted copper slag was established. The model was used to calculate and analyze the effects of slag composition, temperature (T) and basicity (B) on the activity of FeO (NFeO). The results show that NFeO tends to increase and then decrease with the increase of basicity, due to the fact that CaO is easier to combine with SiO2 than FeO to form calcium silicate, which replaces FeO in 2FeO·SiO2 and increases NFeO. However, an increase of CaO content leds to the formation of high-viscosity silicate 2CaO·SiO2, which increases the difficulty of combining CaO with 2FeO·SiO2 and decreases the NFeO. In the temperature range of 1523-1773K, NFeO decreases with an increase of temperature. In addition, the activity of FeO decreases with the increase of Al2O3 content. By comparing with the measured values, it is found that the calculated results of this model are close to the actual values, and therefore, it can be used as a theoretical basis to guide the carbon carbothermal reduction of copper slag. Keywords: Quaternary slag system of SiO2-CaO-Al2O3-FeO; Calculation model of concentration; Activity of FeO