Vanadium-containing Slag Research Articles

Effects of Spinel Crystallization Characteristics on Leaching Vanadium from Vanadium-Containing Slag

Effects of Spinel Crystallization Characteristics on Leaching Vanadium from Vanadium-Containing Slag

Analysis of the Leaching Stage Effect on the Vanadium Extraction from Technogenic Raw Materials

As a result of titanomagnetite iron ore processing, technogenic waste is formed in the form of vanadium-containing slags. The industrial processing of these slags is important to improve the environmental situation in industrial regions and expand vanadium raw material base. The study purpose was the vanadium extraction from slags of titanomagnetite ore processing (ITmk3 process slag and JSC “EVRAZ NTMK” slag) in the soluble vanadate form. Research tasks: hydrometallurgical vanadium extraction from slags of different chemical composition using soda technology; determination of the leaching mode effect (temperature and duration) on the vanadium extraction degree. Experimental samples in the form of slag and soda Na2CO3 mixture were processed to oxidative roasting and subsequent water leaching at different temperatures from 50 °C to 80 °C for 1, 2 and 3 hours. In the resulting solutions the vanadium content was determined with X-ray fluorescence spectroscopy (XRF). Analysis of the research results showed that the slag chemical composition and the water leaching conditions had a significant effect on vanadium extraction degree. The vanadium extraction degree from the JSC “EVRAZ NTMK” slag was 2 – 2.5 times higher than from the ITmk3 process slag after applying the same leaching modes. The highest degree of vanadium extraction was obtained after leaching at a temperature of 80 °C for 3 hours. These leaching modes increased the vanadium extraction degree from the JSC “EVRAZ NTMK” slag to 65 – 87%, and from the ITmk3 process slag to 31 – 33%.

Comparative study of B4C, Mg2B2O5, and ZrB2 powder additions on the mechanical properties, oxidation, and slag corrosion resistance of MgO–C refractories

Boron-containing additives are used to improve the oxidation resistance of carbon-containing refractories; however, their effects on the mechanical properties and slag corrosion resistance of the refractories have rarely been studied. In this work, B4C, Mg2B2O5, and ZrB2 powders were incorporated into low-carbon MgO–C refractories to study their effects on the mechanical properties, oxidation resistance, and slag corrosion resistance of the refractories. The relationships between these properties and the microstructure and phase evolution were also studied. The results show that the flexural strengths of the MgO–C refractories at high temperatures are closely related to the apparent porosity and formation of an Mg3B2O6 phase. The oxidation resistances are greatly improved after the introduction of boron-containing additives into the MgO–C refractories in terms of both thermodynamical aspects and the filling of voids and pores. The most effective antioxidant is B4C, followed by the ZrB2 and Mg2B2O5 powders. The mechanisms through which the vanadium-containing slag attacks the MgO–C refractories mainly include the dissolution of magnesia to form melting phases, penetration through pores, and redox reaction with carbon.

Addition of V2O5 and V2O3 to the CaO–FeO–Fe2O3–MgO–SiO2 database for vanadium distribution and viscosity calculations

Vanadium oxides were added to the existing GTOx database because of its important role in the ferro-titanium metallurgy as well as in petroleum coke gasification. The CaO–FeO–Fe2O3–MgO–SiO2 system is a part of GTOx database and is chosen because of the existence of experimentally determined vanadium distributions between vanadium ferroalloys and metallurgical slags. The CaO–FeO–Fe2O3–MgO–SiO2–V2O3–V2O5 system including all binary and ternary sub-systems was thermodynamically assessed using all available experimental data. Vanadium was introduced into the thermodynamic description of solid solution phases such as MeO, Spinel, Corundum and Ca2SiO4-α using available experimental information. Particular attention was given to the phase Spinel which forms the wide completely miscible solid solution Fe3O4–FeV2O4–MgV2O4–MgFe2O4. The thermodynamic description of the metallic vanadium containing systems was taken from the SGTE alloy database. With the knowledge about the complex behavior of vanadium in slags as well as in liquid metal alloys it is possible to calculate the vanadium distribution ratios (V)/[V] between iron melts and slags in a wide range of temperatures and compositions, corroborating the validity of the model under reducing conditions. The additionally developed viscosity model shows good agreement between the calculated and experimental values in vanadium-containing slags.

Crystallization Behavior and Growth Mechanisms of Spinel Crystals in Vanadium-Containing Slags

Crystallization Behavior and Growth Mechanisms of Spinel Crystals in Vanadium-Containing Slags

Features of the Microstructure and Chemical Compositions of Vanadium-Containing Slags Including Determination of Vanadium Oxidation Degrees.

Metallurgical vanadium-containing converter slag could be used as an alternative vanadium source. The development of a physico-chemical basis for the comprehensive processing of industrial vanadium-containing debris requires information about their elemental composition as well as the oxidation degrees of the elements and forms of compounds in order to solve two key problems: a better utilization of industrial wastes and a lowering of environment impact. This research was aimed at the development of methods to determine the fractions of elements and their oxidation degrees in vanadium-containing industrial debris exemplified by basic oxygen converter vanadium slags. A set of bulk and surface analysis methods (X-ray fluorescence analysis (XRF), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS)) was used for this purpose: based on results of elemental analysis, SEM detects the oxide phases of metals, while an analysis of the XPS lines’ fine structures provides fractions of corresponding elements with definite oxidation degrees. In this way, one can determine the fractions of vanadium in multiple oxidation degrees in slags and can properly select the chemicals and parameters of chemical processes for its fullest extraction.

Determination of optimum parameters of melting and converting of iron-containing melt with the production of vanadium-containing slag

The development of a comprehensive technology for processing titanomagnetite concentrate at the Masalsky field will enable the production of an iron-containing alloy and a vanadium product.The processing of the titanomagnetite concentrate of the Masalsky deposit includes rework firing, magnetic separation of the cinder, the melting of a large phase of the reduced metal and the magnetic fraction of the cinder, and further conversion of the cast iron to produce vanadium-containing slag and iron-containing alloy. In this paper, the main direction was to determine the optimal melting parameters and convert the iron-containing melt to produce a vanadium-containing slag. Melting of the magnetic fraction and class +0.1 mm of cinder after reduction firing was carried out at temperatures of 1400, 1450 and 1500 °C. It was found that the optimum melting temperature of the class +0.1 mm and the magnetic fraction of the cinder is 1450 ° C for 20 min. Chemical, mineralogical and electron probe analysis of the obtained alloys showed that after melting the phases become more homogeneous, structured and magnetic. The composition of the glandular matrix consists of 88-90 % of reduced iron and manganese inclusions of about 7%. The aggregative structure of the matrix is due to the presence of rounded, oval separations with a cementing mass, detected at relatively high magnifications. Vanadium in all samples is concentrated in the interstices between the rounded ferruginous segregations. Carbon together with iron is in large inclusions. Composition of the obtained cast iron, wt. %: 88.3-90.2 Feсоmm; 0.286-0.354 V; 0.012-0.236 Ti; 3.54-4.06 C. The cast iron was converted into a laboratory unit consisting of a Kejia chamber furnace, an air flow meter, an air supply pump 2FY-1B. The parameters of the conversion of cast iron were determined: a temperature interval of 1200-1450 °C, a duration of 110 minutes with an air supply of 5-10 liters / min. Vanadium-containing slags of the following composition, wt. %: 13.8-16.05 V2O5; 35.9-42.8 Fecomm; 3.5-11.17 TiO2; 3.78-17.66 SiO2; 1.6-2.9 Cr; 5.95-9.5 Mn. The composition of iron-containing alloys, wt. %: 96.8-97.1 Fecomm; 0.11-0.26 Ti; 0.1-0.14 V; 0.78-1.2 C; 0.1-0.13 Si; 0.035-0.40 Cr; 0.3-0.4 Mn. The cast iron and vanadium slag obtained by us correspond to the existing analogues in terms of the content of impuritycomponents.

Process Mechanism of Vanadium-containing Slag Roasting and Alkali Leaching

Process Mechanism of Vanadium-containing Slag Roasting and Alkali Leaching

Interactions of vanadium-rich slags with crucible materials during viscosity measurements

Slag chemistry is important for the assessment of flow behaviour of slags produced during gasification of coal and coal–petroleum coke blends. Slags containing vanadium species react readily with the crucible and spindle materials used for viscosity measurements. Interaction of vanadium-rich slags with various materials has been investigated in order to obtain a better understanding of the impact of containment materials on the resulting slag chemistry and viscosity. The bulk and phase compositions of two petroleum coke slags in Al2O3, Mo, Pt and Ni crucibles produced under different laboratory conditions were analysed, and kinetics of slag composition changes at 1400 °C were determined. Mechanisms of the slag interactions with crucibles are described. They involve exchanging of crucible and slag constituents, formation of interfaces with distinct compositions, and continuously changing phase equilibria in the system. For slag processed in Ni and Pt crucibles, reduction of Fe and Ni from oxide to metallic form occurs and is followed by dissolution into the crucible materials. Viscosity of slags with Mo, Ni and Al2O3 crucibles are determined in the temperature range 1200–1500 °C. Resulting changes in the bulk composition of the processed slag has an impact on the slag viscosity. At given temperatures, viscosities of the slags produced in different crucibles are different. The impact of crucible materials and their applicability in viscosity measurements of high vanadium-containing slags are also discussed in order to define the optimal conditions.

High-temperature mass spectrometric study of the vaporization processes of V2 O3 and vanadium-containing slags

A Knudsen effusion mass spectrometric method was used to study the vaporization processes and thermodynamic properties of pure V(2)O(3) and 14 samples of vanadium-containing slags in the CaO-MgO-Al(2)O(3)-SiO(2) system in the temperature range 1875-2625 K. The system was calibrated using gold in the liquid state as the standard. Vaporization was carried out from double tungsten effusion cells. First it was shown that, in vapor over V(2)O(3) and the vanadium-containing slags in the temperature range 1875-2100 K, the following vapor species were present: VO(2), VO, O, WO(3) and WO(2), with the latter two species being formed as a result of interaction with the tungsten crucibles. The temperature dependencies of the partial pressures of these vapor species were obtained over V(2)O(3) and the slags. The ion current comparison method was used for the determination of the V(2)O(3) activities in slags as a function of temperature with solid V(2)O(3) as a reference state. The V(2)O(3) activity coefficients in the slags under investigation indicated positive deviations from ideality at 1900 K and a tendency to ideal behavior at 2100 K. It was shown that the V(2)O(3) activity as a function of the slag basicity decreased at 1900 K and 2000 K and was practically constant in the slag melts at 2100 K. The results are expected to be valuable in the optimization of slag composition in high-alloy steelmaking processes as well as for their environmental implications.

Activity of VO1.5 in CaO-SiO2-MgO-Al2O3 Slags at Low Vanadium Contents and Low Oxygen Pressures

In the present work, the gas-slag equilibration technique was employed for the measurement of the thermodynamic activity of vanadium oxide. The vanadium-containing slag kept in a platinum crucible ...

98/02349 Treatment of coal ash in blast furnace : Okuyama, Y. Jpn. Kokai Tokkyo Koho JP 10 25,504 [98 25,504] (Cl. C21B5/00), 27 Jan 1998, Appl. 96/200,967, 12 Jul 1996, 4 pp. (In Japanese)

Titanomagnetites represent a valuable raw material for the production of steel, vanadium and titanium. In several countries they are already processed whereby the treatment is adjusted to the content of the components to be recovered.In case of beach sands mining can be effected very easily. Upgrading is also rather simple for all types of titanomagnetites and can mainly be achieved by low-density magnetic separation after suitable grinding.The recovery of iron and vanadium is done by Highveld Steel and Vanadium Corp. in South Africa. Steel and vanadium-containing slag are produced, the latter to be processed by roasting and leaching to achieve V2O5-flakes as marketable product. The overall V-recovery is reparted to be in the magnitude of 60–75%.According to the Otanmäki Process the titanomagnetite concentrate is pelletized with sodium carbonate and the pellets indurated according to a certain pattern in a shaft furnace. Afterwards, the pellets are subjected to leaching and the formed water-soluble Na-vanadates are recovered in a solution, from which the vanadium is precipitated as V2O5. Two plants according to this process are operated in Finland by Messrs. Rautaruukki Oy.In New Zealand beach sands are mined, upgraded and further processed by direct reduction and steel smelting. Together with local, not cokable coal the beach sand represents the basis for the main steel production in this country. The plant is being largely extended and by process modification also a vanadium slag will be produced.Out of ilmenites high-grade TiO2-products can be produced. This is possible by direct reduction and subsequent leaching to separate the iron. The resulting product is an artificial rutile. This process is realized in Australia.Another possibility is to smelt the ilmenite in electrical furnace to produce cast iron of special quality and TiO2-slag. This treatment is well known as Sorel Process. One plant in Canada and another in South Africa use this process successfully. A plant of similar process is under construction in Norway.Advanced processes are under development aiming in recovery of all valuable components of the titanomagnetites.

Effect of sodium and potassium polyvanadates on aluminum-powder oxidation

The effect of polyvanadates and vanadium oxide bronzes of alkali metals on aluminum-powder oxidation has been studied by thermogravimetry and x-ray phase analysis. The macromechanism of promotion of aluminum oxidation in which the catalytically active component is meltedNa2AlxV12O31 has been established. It is shown that the intermediate product of vanadium-containing slag processing can be used as an activator.

The production of vanadium and steel from titanomagnetites

Titanomagnetites represent a valuable raw material for the production of steel, vanadium and titanium. In several countries they are already processed whereby the treatment is adjusted to the content of the components to be recovered. In case of beach sands mining can be effected very easily. Upgrading is also rather simple for all types of titanomagnetites and can mainly be achieved by low-density magnetic separation after suitable grinding. The recovery of iron and vanadium is done by Highveld Steel and Vanadium Corp. in South Africa. Steel and vanadium-containing slag are produced, the latter to be processed by roasting and leaching to achieve V 2O 5-flakes as marketable product. The overall V-recovery is reparted to be in the magnitude of 60–75%. According to the Otanmäki Process the titanomagnetite concentrate is pelletized with sodium carbonate and the pellets indurated according to a certain pattern in a shaft furnace. Afterwards, the pellets are subjected to leaching and the formed water-soluble Na-vanadates are recovered in a solution, from which the vanadium is precipitated as V 2O 5. Two plants according to this process are operated in Finland by Messrs. Rautaruukki Oy. In New Zealand beach sands are mined, upgraded and further processed by direct reduction and steel smelting. Together with local, not cokable coal the beach sand represents the basis for the main steel production in this country. The plant is being largely extended and by process modification also a vanadium slag will be produced. Out of ilmenites high-grade TiO 2-products can be produced. This is possible by direct reduction and subsequent leaching to separate the iron. The resulting product is an artificial rutile. This process is realized in Australia. Another possibility is to smelt the ilmenite in electrical furnace to produce cast iron of special quality and TiO 2-slag. This treatment is well known as Sorel Process. One plant in Canada and another in South Africa use this process successfully. A plant of similar process is under construction in Norway. Advanced processes are under development aiming in recovery of all valuable components of the titanomagnetites.

Complexometric determination of aluminum in vanadium-containing slag

Complexometric determination of aluminum in vanadium-containing slag