Recovery Of Vanadium Research Articles

Recovery of vanadium from vanadium slag with high phosphorus content via recyclable microemulsion extraction

Because of the interference from phosphorus, it is practically challenging to efficiently recover vanadium from vanadium slag with high phosphorus contents (VS-HPC). We propose to separate vanadium and phosphorus in aqueous medium via microemulsion extraction, which enables the recovery of vanadium from the leach solution obtained by conventional calcification roasting and acid leaching process of VS-HPC. The influences of various factors on the separation of vanadium and phosphorus have been investigated. Under the most suitable conditions, the extraction efficiency of vanadium can reach as high as 99.9% while that of phosphorus has been impressively lowered to 5.5%. After establishing the microemulsion-based separation method of vanadium and phosphorus, the vanadium element in VS-HPC was extracted to leach solution. The extraction and recovery of vanadium and phosphorus has further enabled, the production of V2O5 with a high purity of 99.7%; the high purity has made the products much more economically appealing than the commonly manufactured V2O5 with a purity of 98.0%. This work has provided new pathways of promoting sustainability in the non-ferrous metal resource utilization.

Electrochemical synthesis of EuVO4 for the adsorption of U(VI): Performance and mechanism

The efficient removal of uranium from aqueous solution remains of great challenge in securing water environment safety. In this paper, we reported a high temperature electrochemical method for the preparation of EuVO4 with different morphologies from rare earth oxides and vanadate, which solved the problems of rare earth and vanadium recovery. The effects of pH, ionic strength, contact time, initial concentration and reaction temperature on the adsorption of U(VI) by prepared adsorbent were studied by static batch experiments. When the concentration of U(VI) standard is 100 mg g−1, the maximum adsorption capacity of EuVO4 is 276.16 mg g−1. The adsorption mechanism was elucidated with zeta potential and XPS: 1) negatively charged EuVO4 attracted UO22+ by electrostatic attraction; 2) exposed Eu, V, and O atoms complexed with U(VI) through coordination; 3) the hybrid of Eu was complex, which accommodated different electrons to interact. In the multi-ion system with Al3+, Zn2+, Cu2+, Ni2+, Cr2+ and Mn2+, EuVO4 also showed good selective adsorption properties for U(VI). Five adsorption and desorption cycle experiments demonstrated that EuVO4 possessed good renewable performance.

Selective leaching of vanadium from vanadium-chromium slag using sodium bicarbonate solution and subsequent in-situ preparation of flower-like VS2

A novel leaching method for selectively separating vanadium from calcification roasted vanadium‑chromium slag (VCr slag) was proposed, using sodium bicarbonate (NaHCO3) as the leaching medium. Vanadium disulfide (VS2), which can be used as an energy storage material, was prepared in-situ by a hydrothermal reaction from the vanadium-containing leaching solution, without purification. VS2 was characterized by XRD, SEM, XPS, and BET. Results show that the leaching extent of vanadium was 92.98% when the calcification roasted materials were treated with 80 g/L NaHCO3 solution and leached at 100 °C for 120 min. Additionally, only 1.84% silicon, 0.05% chromium, 0.06% iron, and 0.05% manganese were co-leached along vanadium, meaning that an effective selective vanadium extraction was achieved. The leaching solution was treated with thioacetamide (TAA) in a hydrothermal reaction at 140 °C for 16 h, which resulted in a vanadium recovery of 96.00%. The reaction generated flower-like VS2, with vanadium and sulfur in the form of V4+ and S2−. The BET specific surface area of the flower-like VS2 was 21.63 m2/g. As an anode material for Li-ion batteries, the initial discharge capacity of the flower-like VS2 reached 1119.83 mAh/g at current density of 100 mA/g, which was favorable for ion storage. This process not only achieved the selective extraction of vanadium, but also provided a new mechanism to shorten the preparation process of VS2 while generating a product with added value.

Process design for the Ivana uranium-vanadium mill

ABSTRACT Blue Sky Uranium Corporation’s Amarillo Grande Project in Rio Negro Province, Argentina, features the Ivana near-surface uranium deposit, which has significant vanadium credits. This article begins by reviewing the project location and the specific qualities of the Ivana deposit that led to decisions on the Ivana mining and mineral processing methods. The bulk of the article describes the thought process that resulted in the innovative and unique conceptual milling process for uranium and vanadium recovery. The deposit mineralogy is described in detail. The milling process begins with attrition scrubbing of the mined material to reject coarser barren material and increase mill feed grade by four times. Alkaline carbonate leaching is followed by pressure filtration. The pregnant leach solution is concentrated with concomitant reagent and water recovery using membrane filtration. Activated carbon columns remove the organic impurities from the concentrated leach solution, which then feeds the unique solvent extraction circuit. The solvent extraction process separates uranium and vanadium. Uranium is precipitated as uranium peroxide, which is calcined to U3O8. Vanadium is precipitated as ammonium vanadate, which is calcined to V2O5. The process releases no liquid effluents to the environment.

Characterization of vanadium of biological origin for possible applications in physics experiments

For the first time, vanadium of biological origin, extracted from centrifugal fraction of vanadium-storing blood cells of the Ascidia sydneiensis samea species, was characterized as regards its isotopic composition and content of natural radioactive elements potassium (K), thorium (Th) and uranium (U). The natural abundance of vanadium isotopes has been confirmed with high accuracy, thus excluding a possible selectivity within bio-chemical reactions of vanadium concentration in blood cells from seawater. A large potassium concentration (up to 5500 × 10−6 g g−1) was found in the blood cell samples. The concentration of thorium was determined to be about 30 × 10−9 g g−1, while the uranium concentration was about 150 × 10−9 g g−1. Hence, a highly efficient two-stage purification approach with a total vanadium recovery of better than 70% was developed and applied. The final concentrations of K < 100 × 10−6 g g−1 and of U/Th < 0.5 × 10−9 g g−1 in the purified vanadium-containing samples were achieved. Vanadium extracted from centrifugal fraction of vanadium-storing blood cells after two-stage purification approach could be utilized in various applications, where a high chemical purity compound is required. However, to be used as a source of radiopure vanadium in ultra-low-background experiment aimed to search for 50V beta decay, it should be further purified by Electron Beam Melting against residual potassium.

Recovery of pure molybdenum and vanadium compounds from spent petroleum catalysts by treatment with ionic liquid solution in the presence of oxidizing agent

Nonaqueous solutions were employed to investigate the selective recovery of vanadium and molybdenum from the spent petroleum catalysts. In this work, commercial extractants such as D2EHPA, Alamine336 and Aliquat336, and an ionic liquid synthesized from Aliquat336 and D2EHPA, ALi-D2, were employed as a lixiviant and extractant for the target metal ions in the presence of oxidizing agent, H2O2. Among the 4 nonaqueous systems, ALi-D2 showed the best performance for the selective and effective leaching of vanadium and molybdenum over alumina, nickel and iron. The effect of several parameters on the leaching efficiency was also studied. Under the optimum conditions, the leaching percentage of vanadium and molybdenum was 74.6 and 89.6% in the first stage and 26.0 and 66.9% in the second stage by ALi-D2 system. Vanadium and molybdenum from the ALi-D2 loaded phase can be sequentially precipitated by NH4Cl and BaCl2 solutions in alkaline media. Precipitation percentage of vanadium were 94.2% and its purity was 99.5%, whereas that of molybdenum was 99.4% with 84.1% purity. A process was proposed for recovery of vanadium and molybdenum from the spent petroleum catalysts. Pure vanadium and molybdenum compounds can be recovered by this process with less burden to the environment.

Selective Recovery of Vanadium by Oxy-carbochlorination of Basic Oxygen Furnace Slag: Experimental Study

Vanadium is considered as a critical raw metal in EU whose industry consumes about 13% of the global vanadium production. This metal is mainly used for production of high strength and special steels, and advanced alloys for aerospace application. The vanadium raw material supply is today predominated by China, South Africa, and Russia. This work deals with the development of a chlorination process for vanadium extraction. In order to optimize the selective recovery of vanadium, various parameters (temperature, chlorine partial pressure, carbon content) were investigated. Two approaches for the selective recovery of vanadium are presented in this paper: the first approach consists of selective chlorination and vaporization of vanadium-chlorinated species, which can be then collected in condensates, while the second approach consists in the selective chlorination of vanadium contained in slag in a temperature range avoiding vaporization of vanadium-chlorinated species. Results show that under specific operating conditions, more than 95% of the vanadium content of the slag is recovered. Such specific conditions involve heat-treatment at 900 °C during 90 min of a slag/carbon mixture including less than 20% of carbon under air/chlorine atmosphere at a 0.45 partial pressure value. These promising results highlight the potential of the oxy-carbochlorination treatment for the selective recovery of vanadium from basic oxygen furnace (BOF) slags.

Evaluation of Titania-Rich Slag Produced from Titaniferous Magnetite Under Fluxless Smelting Conditions

Titanium-bearing magnetite ore is generically defined as magnetite with > 1% titanium dioxide (TiO2) and is usually vanadium-bearing. The iron and titanium occur as a mixture of magnetite (Fe3O4) and ilmenite (FeTiO3) with vanadium oxide usually occurring within the solid solution of the titanium-bearing magnetite phase. These ores are currently widely processed in blast furnaces via modified ironmaking processes. Typically, vanadium is recovered as a by-product from the ironmaking process, while the diluted titania slag is stockpiled. Fluxless smelting in a direct-current open-arc furnace is proposed as an opportunity to improve iron and vanadium recovery and potentially unlock the titanium as a slag product. Slags produced from a pilot study are compared to industrial slags produced from ilmenite. The findings from the pilot test show that slag produced under fluxless smelting conditions in an open-arc electric furnace is remarkably similar to industrial ilmenite slags. The test conditions were varied to evaluate the slag and metal composition, and furnace operation, under increasing reducing conditions. The study showed that the slag and metal product was remarkably similar to industrial slag produced from ilmenite.

Recovery of chromium, copper and vanadium combined with electricity generation in two-chambered microbial fuel cells.

Microbial fuel cells (MFCs) offer a promising solution towards recovery and treatment of heavy metal pollutants. In this study, two-chambered MFCs were employed for recovery of chromium, copper and vanadium (Cr (VI), Cu (II) and V (V)). One g/L concentrations of K2Cr2O7, CuCl2 and NaVO3 served as catholytes, while a mixed culture was used as anolyte. Cr (VI), Cu (II) and V (V) were reduced biologically into less toxic forms of Cr (III), Cu and V (IV) respectively. Power density and cathodic efficiency were calculated for each of the catholytes. Cr (VI) gave the maximum power density and cathodic efficiency due to its high redox potential. Current produced depended on the concentration of the catholyte. Over a period of time, biological reduction of catholytes lead to decrease in the metal concentrations, which demonstrated the application of MFC technology towards heavy metal treatment and recovery in a reasonably cost-effective manner.

Analysis of hot metal desulfurization methods efficiency during titanomagnetite processing

To make high-quality steel, it is necessary to ensure low sulfur content in the hot metal entering a steelmaking shop. The task to obtain low sulfur metal can be solved either during blast furnace smelting or its ladle desulfurization immediately after tapping out of blast furnace. Under conditions of JSC EVRAZ NTMK, the ladle desulfurization of vanadium hot metal is not applied, since it leads to a loss of vanadium. Is explained by the fat, that calcium oxide forms with V2O5 a strong calcium vanadate (3СаО·V2O5), which makes the process of vanadium recovery during further slag processing more complicated. Therefore the ladle desulfurization is accomplished after devanadation of hot metal. After the devanadation the semi-product has ions of oxygen, which makes it impossible to arrange an effective desulfurization and males it necessary to smelt the hot metal with limited sulfur content. The factors, effecting the process of hot metal desulfurization in a blast furnace, including slag basicity, MgO content in it, temperature of smelting products and slag viscosity, are presented. Dependence of distribution coefficient of sulfur on slag basicity has been shown. Research goal is pig iron desulphurization efficiency estimation by means of MgO increasing in slag. Data analysis findings about smelting products composition over 500 tappings for each of two investigated JSC EVRAZ NTMK blast furnaces have been reported. The aim of the study was comparison of hot metal desulphurization efficiency due to both slag basicity increase and MgO increase in slag. Results of data analysis on smelting products composition of over 500 heats for each of two investigated JSC EVRAZ NTMK blast furnaces have been presented. It was established that a sulfur content decrease in hot metal is achieved more effectively by MgO increase in slag. It has been shown that MgO has better desulfurizing properties, and with an increase of its content in the blast furnace slag, the overall technology for running the blast furnace process improves. It was recommended to increase the consumption of materials containing MgO while maintaining basicity at a constant level. Such a technology will allow to decrease sulfur content in hot metal, as well as will result in the process stabilization providing other conditions being equal.

Recovery of vanadium(V) from synthetic and real leach solutions of spent catalyst by solvent extraction using Cyphos IL 104

This study addresses the extraction and recovery of vanadium(V) from synthetic and real leach solution of spent V2O5 catalyst using Cyphos IL 104. Vanadium(V) is extracted as [(R3R′P+)4H2V10O284−]org in Cyphos IL 104 and stripped from the loaded organic phase as VO2+ using HNO3 as a stripping agent. The extractant is recyclable up to several cycles and shows high loading capacity. Vanadium(V) was separated from aluminium(III), titanium(IV), chromium(III), manganese(II), iron(II)/(III), molybdenum(VI) and tungsten(VI) with good separation factors. Metals were leached from spent catalyst using alkaline leaching. McCabe-Thiele plots indicated two stages for both extraction and stripping at A/O and O/A = 3/1. Vanadium is finally recovered as V2O5 from the strip liquor and characterized by XRD, FE-SEM and EDX techniques.

Vanadium Recovery from the Waste Sludge of the Lime–Sulfuric Acid Processing of Converter Slag

The results of studying the vanadium recovery from the waste sludge of the manufacture of vanadium pentoxide V2O5 using the lime–sulfuric acid technology are discussed. Vanadium mainly exists in the sludge in three following forms: acid-soluble as manganese vanadate, unrecoverable in calcium silicates, and unrecovered as incompletely oxidized vanadium spinelides in the coarse fraction of the sludge. Low-temperature (20–40°C) sulfuric acid leaching of the sludge for complete recovery of acid-soluble vanadium, which is achieved at pH 0.75–0.8, is studied. Various variants of vanadium precipitation from a sulfuric acid solution are examined. The preliminary purification of the solution from impurities makes it possible to produce pure (≥99.4%) vanadium pentoxide during the precipitation of vanadium in the form of ammonium polyvanadate.

Electrochemical Selective Recovery of Heavy Metal Vanadium Oxyanion from Continuously Flowing Aqueous Streams.

An electrochemical flow cell with redox-active electrodes was used for selective removal and recovery of vanadium(V) oxyanions from aqueous streams. The cell relies on intrinsic affinity of the redox-active polymer poly(vinyl)ferrocene (PVFc) and demonstrates selectivity of >10 towards vanadium compared to a background electrolyte in 40-fold abundance. We demonstrate highly selective vanadium removal in the presence of various competing anions (i.e., fluoride, bromide, nitrate, and sulfate). Surface elemental analysis reveals significant correlation between PVFc moieties and vanadium-rich regions after adsorption, corroborating the central role of PVFc modulation on vanadium separation. We further propose a vanadium speciation mechanism in which high and low pH environments during adsorption and desorption steps favor formation of, respectively, H2 VO3 - / HVO4 2- and H2 VO3 - / H3 VO4 / VO2 + . Results have implications for the development and optimization of flow devices, as per our observations, excessively low pH environments during desorption can lead to subsequent re-adsorption of cationic vanadium(V).

Recovery of vanadium from acid leaching solutions of spent oil hydrotreating catalyst using solvent extraction with D2EHPA (P204)

In this paper, a process of selective extraction and separation of vanadium (IV) from acid leaching solution of spent oil hydrotreating catalyst by a solvent extraction method with P204 as an extractant was proposed. Because the leaching solution contained a large amount of elements such as nickel, aluminium and iron, the effects of various conditions on the separation of vanadium from nickel, aluminium and iron were investigated and the optimum conditions were determined. At the same time, the thermodynamic discussion on the extraction process of vanadium in the system was carried out. Using kerosene as a diluent and 20% (v/v) P204 as an extractant, the single-stage maximum extraction ratio of 93.47% for vanadium was obtained under the optimum extraction conditions of O/A ratio of 2, oscillation time of 8 min, extraction temperature of 298 k(25 °C) and pH value of initial aqueous phase of 2. After three stages of countercurrent extraction experiments, the concentration of vanadium, iron, nickel and aluminium in the loaded organic phase were 0.377, 0.001, 0.005 and 0.02 g/L, respectively, and their extraction ratios were determined to be 99.21%, 1.02%, 2.857% and 1.942%, respectively, realizing the selective extraction and separation of vanadium. With 2 mol/L of sulfuric acid as a stripping reagent, the complete removal of vanadium from the loaded organic phase could be achieved at O/A ratio of 2 by three stages of countercurrent experiments of vanadium removal. The thermodynamic calculation showed that the enthalpy change of the vanadium extraction in the system was −20.37 kJ.mol−1. This demonstrated that the extraction of vanadium from acid leaching solution of spent oil hydrotreating catalyst with P204 as the extractant was an exothermic reaction.

Successive recovery of vanadium and uranium from carnotite-bearing kaolinite sample, Southwestern Sinai, Egypt

In this work; the carnotite sample assaying 3.063%U and 2.142%V was subjected to a roasting step before successive vanadium and uranium leaching. The sample was roasted firstly with Na2SO4 followed by quenching the clinker with water for vanadium dissolution. Under the optimized roasting conditions the vanadium dissolution efficiency attained 89.5%. The obtained solution was then treated with NH4Cl to precipitate the vanadium species as NH4VO3. Secondly, the remained residue was treated with carbonate-bicarbonate solution in presence of H2O2 to leach the uranium content. The resultant solution was subjected to uranium precipitation. The precipitate was gently washed with water and dried.

Phase Transformation and Dissolution Behavior of Pyrite in the Roasting-Sulfuric Acid Leaching Process of Vanadium-Bearing Stone Coal

The selective leaching of vanadium and iron has been one of the main concerns in the field of vanadium recovery from stone coal, but the source of iron ions and their release characteristics were still unclear. In this work, the dissolution of pyrite and its roasted product, under conditions in accordance with the vanadium leaching process from stone coal by blank roasting-acid leaching, were studied. The results indicated that the leaching performances of V and Fe in stone coal were significantly correlated, with both depending on the leaching parameters of the H2SO4 concentration, the leaching temperature, the leaching time and the solid to liquid ratio. Under air conditions, with a roasting temperature of 700 °C, the roasted product of pyrite was hematite. Approximately 45% of the roasted product dissolved at its optimal leaching condition—35% higher than that of the raw pyrite. However, any further improvement was difficult, due to the difference in texture between its outer sphere and inner core. The results demonstrated that the roasting treatment led to a significant increase in the release of iron ions during the vanadium leaching process. The pre-removal of pyrite from the raw ore was necessary to reduce the concentration of iron ions in the leachate.

Direct Leaching of Vanadium from Vanadium-bearing Steel Slag Using NaOH Solutions: A Case Study

ABSTRACT Vanadium-bearing steel slag is a typical solid waste in the steel industry and a valuable secondary resource for vanadium production. In this paper, a direct alkaline leaching process was proposed to extract valuable vanadium and achieve comprehensive utilization of the residue by incorporating the new process into the conventional Bayer alumina production process. The leaching mechanism showed the feasibility of alkaline leaching. The effects of alkaline concentration, temperature, particle size, liquid-solid ratio (mass ratio), and stirring speed on the process were investigated, and the recovery of vanadium was found to achieve 68.4% under optimal conditions. Both the internal diffusion and the interface reaction were found by kinetic analysis to be the controlling steps of the leaching reaction, and the apparent reaction activation energy value of 26.67 kJ/mol was calculated. The valence state of the vanadium in the steel slag was analyzed in detail, finding that low-valent (V3+) and high-valent (V4+ and V5+) vanadium were both present in the steel slag. By introducing oxygen into the reaction system, the recovery could be improved to 85.6%, which was 17.2% higher than that of non-oxidative leaching.

Separation and recovery of vanadium and aluminum from oxalic acid leachate of shale by solvent extraction with Aliquat 336

The solvent extraction of vanadium has been widely studied in inorganic acid systems; but less in organic acid systems. In this study, the separation and recovery of vanadium and aluminum from oxalic acid leachate of shale by solvent extraction with Aliquat 336 was investigated. The results indicated that 99.06% of vanadium was extracted and only 7.95% of aluminum was co-extracted in a counter-current extraction comprising five stages under the optimal conditions; the separation factor (β) of vanadium and aluminum was 1221. 99.32% of vanadium stripped by 8 mol/L HCl in a counter-current stripping comprising four stages, and V2O5 with a purity of 98.4% was obtained by ammonium precipitation method from the stripped vanadium solution. The speciation and extraction mechanism of vanadium were revealed. Vanadium mainly existed as a complex anion, VO(C2O4)22−, and aluminum mainly existed in the forms of Al(C2O4)2− and Al(C2O4)33− in the oxalic acid leachate of shale. The extraction mechanism of vanadium by Aliquat 336 was an anionic exchange mechanism, and the structure of the extractable complex for vanadium could be determined as [(R4N)2·VO(C2O4)2]. A process flowsheet for the separation and recovery of vanadium and aluminum from the oxalic acid leachate of shale using solvent extraction was developed, which has the advantages of rapid extraction speed and without adjusting the initial pH of solution.

Effect of Unstable Tapping of Smelting Products on the Performances of the Evraz Ntmk Blast Furnaces

Timely and full tapping of liquid smelting products is an important condition for forcing the blast-furnace process. Unstable tapping of iron and slag leads to fluctuations of the liquid level in the hearth, changes in the charging rate, and fluctuations in the time the burden stays in the blast furnace. This, in turn, affects the thermal state and the composition of the liquid products. The ratio of tapped slag weight to the hot metal weight is determined by the physical properties of slag and the length and diameter of the taphole. An analysis of the operation of the EVRAZ NTMK blast furnaces revealed substantial fluctuations of this ratio. When the volume of tapped slag is 340 to 360 kg per ton of pig iron, the slag/metal weight ratio is between 200 and 850 kg per ton of pig iron. The objective is to analyze the causes of unstable tapping and the effect of the instability on the furnace performances using the laws of fluid mechanics. It is assumed that the melt flow in the taphole is stratified. The effect of the slag properties and the dimensions of the taphole on the velocity of the melt and, hence, on the slag/metal weight ratio in the taphole is studied. Since the velocity of the melt depends on its physical properties, a mathematical model was developed to assess the slag/metal weight ratio from the viscosity of the slag and the dimensions of the taphole. The results of modeling are validated against the industrial data acquired by the EVRAZ NTMK. It was established that an increase in the tapped slag/metal weight ratio leads to worse performance and lower vanadium recovery from pig iron.

Step-Adsorption of Vanadium (V) and Chromium (VI) in the Leaching Solution with Melamine

The vanadium (V) and chromium (VI) was hard to separate directly due to the similar nature. In this paper, separation and recovery of vanadium (V) and chromium (VI) from a leaching solution was investigated by adsorption of vanadium (V) with melamine, followed by electro-reduction of chromium (VI) and adsorption of chromium (III) with melamine, respectively. The effects of experimental parameters including dosage of melamine, reaction temperature and reaction time on the adsorption process were investigated. The results showed that melamine was a good sorbent for adsorption of vanadium (V) and chromium (III). 99.89% of vanadium (V) was adsorbed by melamine at the optimal conditions, the adsorption kinetic was followed the pseudo-second-order model and the adsorption isotherm conformed to the Langmuir model. While the adsorption of chromium (III) was followed the pseudo-first-order model and the adsorption isotherm was conformed to the Freundlich model as the adsorption efficiency was 98.63% under optimal conditions.