The oxidation of FeV2O4 by oxygen in a sodium carbonate mixture

Effect of Reduction Degree on Characteristics of Slag Formed by Melting Hydrogen‐Reduced DRI and Partitions of P and V between Slag and Metal

“…[ 7,10,35,37 ] The types of phases present in the slag have great impact on the roast‐leach route, because their thermodynamic properties determine, for example, at which temperatures the roasting reactions take place depending on the added roasting reagent(s). [ 38,39 ] In the DRI slag studied in this work, vanadium occurs in both spinel and magnesiowüstite phases. Hence, the development of a process for hydrometallurgical extraction of vanadium from this slag would include finding a way to recover vanadium from both the spinel and magnesiowüstite phases, without negative interference from the matrix phase.…”

Asynchronous extraction of vanadium and chromium from vanadium slag by stepwise sodium roasting–water leaching

“…The optimal temperature is 800°C, at which the V extraction reaches a maximum of 88.6%. Further increase in the roasting temperature leads to decrease in the V extraction, due to that large amount of newly-formed NaVO 3 (melting point: 630°C) melts at high temperatures and flows on the surface of unreacted spinels, which thus hinders further oxidation of spinels (Slobodin et al, 1979;Van Vuuren and Stander, 2001). At all roasting temperatures, Cr extraction is stable and remains lower than 10%, due to minor distribution of Cr-spinels in the outer shell layer of the spinel grain.…”

“…In common sodium roasting technique, V(III) in vanadium slag is oxidized by oxygen to maximal extent and transforms into sodium vanadates in the presence of sodium salts (Na 2 CO 3 , Na 2 SO 4 or NaCl) during roasting. The produced sodium vanadates are leached by water and vanadium products are obtained from the vanadium-containing leaching liquor by precipitation and/or calcination (Barolin, 1982;He et al, 2007;Tavakoli and Dreisinger, 2014b;Van Vuuren and Stander, 2001). However, this process suffers from the emission of corrosive gases such as Cl 2 , SO 2 and HCl due to the addition of Na 2 SO 4 or NaCl (Barolin, 1982;Zhang et al, 2011).…”

Atomic atmosphere: a way to understand phase evolution during vanadium slag roasting at the atomic level

“…In consideration of saving resource and sustainability, the vanadium recovery should be increased during the sodium roasting-water leaching process. To increase the vanadium recovery, the key point is to understand in depth the evolution mechanism of the vanadium-containing phase during the sodium roasting process (Van Vuuren & Stander, 2001). Only when this evolution mechanism has been profoundly understood will it be possible to control the evolution of the vanadiumcontaining phase during sodium roasting and achieve higher vanadium recovery.…”