Effects of Fe2O3 on Reduction Process of Cr-Containing Solid Waste Self-Reduction Briquette and Relevant Mechanism

Abstract

High-temperature quench method, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), and thermodynamic analysis were adopted to study the effects of Fe2O3 on reduction process of Cr-containing solid waste self-reduction briquette (Cr-RB). Moreover, the relevant mechanism was also studied. The results clearly showed that the addition of Fe2O3 decreased the chromium-iron ratio (Cr/(Fe + Cr)) of Cr-RB itself and promoted the reduction of chrome oxide in the Cr-containing solid wastes such as stainless steel slag and dust. A large number of Fe-C alloy droplets generated in the lower temperature could decrease the activity of reduced chromium by in situ dissolution and the reduction of Cr-oxide was accelerated. Rapid separation of metal and slag could be achieved at a relatively lower temperature, which was very beneficial to the efficient recovery of Cr. Finally, the corresponding mechanism diagram was presented.

Preparation of Black Ceramic Tiles Using Waste Copper Slag and Stainless Steel Slag of Electric Arc Furnace

“…It indicates that the main crystalline phases of copper slag are Fe2SiO4 and Fe3O4. The stainless steel slag mainly consists of spinels, such as FeCr2O4, MgCr2O4, NiCr2O4, and Fe3O4, which is consistent with previous studies [7,9,[13][14][15].…”

“…The main chemical constituents of copper slag used in this study are Fe 2 O 3 and SiO 2 , the content of them are 52.69% and 33.44%, respectively, whereas the main chemical constituents of stainless steel slag are SiO 2 , CaO, and Cr 2 O 3 , which account for about 70 % of the total content. [7,9,[13][14][15]. In this study, the environmental protection industry standard of China HJ/T299-2007 [30] was adopted to carry out the leaching test of toxic substances in ceramic tiles.…”

A computational study on the mixing and reduction of slags from ferrochrome and stainless steel production

“…As the amount of reductant is increased, a molten metal phase containing e.g. iron and carbon (as suggested by Wu et al [18]) is formed and eventually chromium is reduced into elemental Cr which is dissolved into the formed metal phase. It is also seen from Fig.…”

“…Cr 3 C 2 , Cr 7 C 3 and Cr 23 C 6 ) during the carbothermic reduction of Cr 2 O 3 has been detected in the experiments by Mori et al [17], who also concluded that the carbide formation may hinder the conversion of Cr 2 O 3 into metallic chromium [12,17]. To avoid this hindrance caused by the carbide formation, Wu et al [18] studied the effect of Fe 2 O 3 on the chromium reduction and found out that the presence of Fe 2 O 3 in the initial system results in the formation of Fe-C-alloys into which the reducing chromium is dissolved (rather than forming carbide precipitates) [12,18]. Adamczyk et al [13] have also observed the formation of carbides while reducing chromium from stainless steelmaking slags.…”

Ironmaking and Steelmaking

“…Naseri Seftejani and Schenk [31] analysed the thermodynamics of the hydrogen plasma smelting reduction of iron ore in the process of using hydrogen in a plasma state to reduce iron oxides. The other nine papers covered experimental studies (El-Tawil et al [26], Fukushima, and Takizawa [23], Wu et al [5], Zhou et al [6], Zhang et al [7]), modelling predictions (Gao et al [8], Tang et al [9]), and kinetic analysis (Wang et al [10], Chen et al [11]).…”