A novel method to extract vanadium and chromium from vanadium slag using molten NaOH‐NaNO₃ binary system

Abstract

A new method using NaOH-NaNO 3 binary melts to treat vanadium slag is proposed. Vanadium and chromium can be simultaneously extracted in the leaching processes. Under the optimum reaction conditions, the recovery of vanadium and chromium can reach 93.7% and 88.2% in 6 h, respectively. The kinetics investigation indicates that the decomposition of vanadium slag is controlled by mass transfer in product layer. During the reaction, NaOH is believed to provide basic media and facilitate the dissolution of acidic oxides. NaNO 3 decomposes to produce a large amount of active oxygen species, such as O, O 2À 2 , and O 2À . NaOH intensifies the decomposition of NaNO 3 to NaNO 2 , but inhibits further decomposition of NaNO 2 . NaNO 3 can be regenerated by oxidation of NaNO 2 using oxygen at high temperature. The apparent activation energy of NaNO 2 oxidation in the temperature ranging from 350 to 450 C is 105.5 kJ/mol. Figure 16. Flow sheet for the leaching and recovery of vanadium and chromium.

Viscosity Property and Structure Analysis of FeO–SiO₂–V₂O₃–TiO₂–Cr₂O₃ Slags

“…[1][2][3] Since the blowing smelting time is merely 3 to 5 minutes, the thermodynamics and the dynamics conditions for oxidizing vanadium in hot metal are very important during the blowing smelting process. 4,5) Thus, the properties of the slag, such as melting temperature and viscosity, are very crucial to improve the process conditions.…”

Thermodynamic and kinetic studies of the MgCl2‐NH4Cl‐NH3‐H2O system for the production of high purity MgO from calcined low‐grade magnesite

“…23 To determine the kinetic parameters and the rate-limiting step of the leaching of calcined low-grade magnesite in NH 4 Cl solutions, the experimental data was analyzed on the basis of the shrinking core model. [24][25][26][27] In this model, the dissolution reaction initially takes place on the outer skin of the calcined magnesite particle. However, as the reaction proceeds, the reactive surface of the reaction is progressively shifted into the interior of the solid to leave behind an inert ash layer (e.g., Si-rich layer).…”

Preparation of V2O5 from converter slag containing vanadium

“…Nowadays, about 85 % of the vanadiumbearing products produced worldwide are consumed in the iron and steel industry [1]. The vanadium-titanium magnetite is the most important one of dozens of vanadiumcontaining minerals [2,3]. During the steel production process with vanadium-titanium magnetite as raw materials, vanadium-containing minerals are smelted together with iron-bearing species, finally causing vanadium to be transferred to steel slag.…”

“…The recovery of vanadium from steel slag attracts extensive attention since it can not only enhance economic benefits of steel slag but also avoid environmental impacts due to the presence of heavy metal vanadium [4,5]. The content of V 2 O 5 in steel slag greatly varies in the range of 2 wt%-25 wt% depending on the mineral types and smelting process [1,2,[6][7][8][9][10]. Steel slag becomes the main raw material for the production of vanadium and its compounds [1,11].…”

“…In the last decades, many studies have been conducted to recover vanadium from steel slag [2,6,[8][9][10][12][13][14]. To recover vanadium in the form of metal vanadium or V 2 O 5 , steel slag containing vanadium is usually treated through several processes including roasting, leaching, extracting, and precipitating.…”