Viscosity prediction on iron-bearing slags during pyrometallurgical recycling: structure-based modeling of CaO-‘FeO’-MgO-Al_(2)O_(3)-SiO_(2) system and its subsystems

A structure-based modeling of the CaO-‘FeO’-MgO-Al_(2)O_(3)-SiO_(2) system and its subsystems was investigated based on iron extraction nickel slagaluminum dross.Parameters optimization in the present model indicated that the coefficient of free O^(2-)in FeO,a_(O_(FeO)^(2-)),on the lengths of network linkage had the largest value and O_(FeO)^(2-)(free O^(2)-in FeO)had the largest mobility.The coefficients of bridging oxygen(a_(Si-O-Al) and a_(Al-O-Al))were lower than those of nonbridging oxygen and free oxygen(O^(2-)).Viscosity prediction for the CaO-‘FeO’-(8 wt.%)MgO-Al_(2)O_(3)-SiO_(2) system was conducted at a fixed slag basicity,which indicated that the predicted viscosity changed monotonously with the FeO content.However,the non-monotonous evolution with Al2O3 content reflected the amphoteric behavior of Al2O3.In addition,the performances of the present model in predicting viscosity binary(‘FeO’-SiO_(2))to quinary(CaO-‘FeO’-MgO-Al_(2)O_(3)-SiO_(2))system were analyzed and a comparison with the established models was made.

Effect of Scale Formation on Copper Enrichment Behavior in Continuously Cast Slab

Copper enrichment behavior in continuously cast slab induced by scale formation during continuous cooling was experimentally investigated,and the effects of initial slab surface temperature and oxygen potential in atmosphere were discussed.The results showed that a loose scale adhered to the substrate was formed in H2O-N2 atmosphere at higher slab surface temperature compared to a gap formed between the scale and the steel substrate after continuous cooling in H2O-O2-N2 atmosphere.Under the condition of continuous cooling in H2O-N2 atmosphere,the copper enrichment occurred both within the loose scale and at the scale/steel interface with simultaneous Ni enrichment near the interface at higher slab surface temperature.The combined effects of the loose scale and nickel enrichment were thought to promote the back-migration of Cu-rich phase from the interface and occlusion within the scale layer.While in H2O-O2-N2 atmosphere,the Cu enrichment was found on the steel side and the formed gap prevented the migration of Cu to the scale.