Ferrovanadium Production Research Articles

Upcycling of Slags from Ferrovanadium Production as Low-Carbon Footprint Cement for Refractory Castables

Upcycling of Slags from Ferrovanadium Production as Low-Carbon Footprint Cement for Refractory Castables

Evaluation of a Novel High-Efficiency SHS-EAH Multi-Stage DG-ADP Process for Cleaner Production of High-Quality Ferrovanadium Alloy

A novel high-efficiency industrialized clean production technology based on multi-stage gradient batching and smelting was proposed for the production of high-quality ferrovanadium. The thermodynamic mechanism of aluminothermic reduction equilibrium, alloy settlement and raw material impurity distribution were confirmed, and a multi-stage double-gradient aluminum addition pattern (DG-ADP), the highly efficient separation of molten slag and alloy, and typical impurity control standards of raw materials were achieved on the basis of a self-propagating high-temperature synthesis with an electric auxiliary heating (SHS-EAH) process. The reduction efficiency, separation efficiency and the comprehensive utilization rate of the secondary resources were significantly improved, as the whole total vanadium (T.V) content in the industrially produced residue slag reduced from 2.34 wt.% to 0.60 wt.%, while the corresponding smelting yield increased from 93.7 wt.% to 98.7 wt.% and the aluminum consumption decreased from 510 kg·t−1 to 400 kg·t−1. The multi-stage DG-ADP process enabled the internal circulation of vanadium-bearing materials in the ferrovanadium smelting system, as well as the external circulation of iron and residue slag in the same system, and finally achieved the zero discharge of solid and liquid waste from the ferrovanadium production line, which provides a brand-new perspective for the cleaner production of ferrovanadium alloy.

Clean preparation of V2O3 by one-step molten salt electrochemical reduction of soluble NaVO3

Vanadium oxides, such as V2O5 and V2O3, are important metallurgy products and mainly used to prepare V-based alloys for steelmaking. At present, vanadium oxides are mainly produced by complex sodium salt roasting process. Serious environmental pollution, such as emission of ammonia nitrogen wastewater and NH3, are restrictive problems. Here, a clean and sustainable method for V2O3 preparation is proposed by one-step molten salt electrochemical reduction of soluble NaVO3, i.e. an indispensable intermediate in traditional V metallurgy. The pollution issues are well solved. The theoretical decomposition voltages of different vanadate to various low-valence vanadium oxides were calculated. NaVO3 with a solubility of 14.7 wt% is the most suitable vanadate for the direct preparation of V2O3 by molten salt electrolysis. The effects of cathode structure, NaVO3 content, electrolysis temperature and voltage on current efficiency and electricity consumption were systematically studied. High-purity V2O3 with uniform particle distribution is obtained and the lowest electricity consumption is only 2.86 kWhkg−1. V2O3 is mainly produced by one-step electrochemical reduction of soluble NaVO3 through two-electron transfer process. The economic evaluation for ferrovanadium production is preliminarily carried out. Compared with the traditional process, the cost for ferrovanadium production is lower by the aluminothermic reduction of V2O3 which is prepared by clean one-step electrolysis of soluble NaVO3.

Refining technology for titanomagnetite ores from Suroyamskoe deposit

Explored reserves of titanomagnetite ores of Suroyamskoe deposit in Chelyabinsk region is equaled to 11 billion tons. Construction of a new metallurgical enterprise may be relevant for their production and processing. The most promising is the traditional scheme of metal production: ore mining, its crushing and enrichment, production of agglomerate and pellets from concentrates, smelting of pig iron in blast furnaces and steel production in oxygen converters. To establish basic technological parameters of the new production scheme, pig iron smelting from sinter obtained from titanomagnetite ores of Suroyams-koye deposit and its further devanadation (to produce vanadium slag suitable for the production of ferrovanadium) were studied in laboratory conditions of Nosov Magnitogorsk State Technical University. At the initial stage, a calculation was carried out, than experiments in laboratory conditions were made. As a result, the technology was developed for smelting pig iron from sinter obtained from concentrate of Suroyamskoe deposit and its subsequent devanalization to produce two products: pig iron and vanadium slag. It has been established that it is advisable to obtain vanadium in it at least of 0.22 % when smelting pig iron. Dependences of the main indicator of devanadation effi-cience - the content of vanadium oxide in slag - on the concentration of vanadium in pig iron and the amount of slag were found. The fundamental possibility of de-exploitation of experimental Suroyamskii pig iron was confirmed with the production of vanadium slag containing up to 12 % V 2 O 5 with the use of air blast as an oxidizing agent.

Immune dysregulation in employees of the ferrous metallurgy enterprise under conditions of excessive vanadium contamination

Introduction. Chemical factors in production conditions are sources of constant danger of health disorders, including immunological ones, in employees of a ferrous metallurgy enterprise with a full cycle of ferrovanadium production. The aim of the study was to assess the level of membrane, intracellular and intercellular immunoregulation indicators in employees of the ferrous metallurgy enterprise under conditions of excessive vanadium contamination. Materials and methods . 77 people working in various production conditions at the metallurgical enterprise were examined, including 44 people-employees of the Ferroalloy shop and duplex shop exposed to vanadium; 33 people who do not have professional contact with vanadium (administrative staff). The technology of flow cytometry was used to study and evaluate the immunoregulation parameters of membrane — CD25+, CD95+ and intracellular — p53, as well as the method of enzyme immunoassay of intercellular — TNFa. Results. It was found that those working on exposure to vanadium in the blood are higher than the reference values and the values established for working outside the exposure. For workers exposed to vanadium under the production conditions, the blood vanadium content is statistically significant (p<0.001), 3.2 times higher than the reference level and 5.2 times higher than the values obtained for workers who do not have professional contact with vanadium. It was found that the expression of CD25 + -marker and CD95 + -marker was statistically significantly increased (p<0.001) on average by 1.5 times compared to the values obtained in the subjects who were not exposed to vanadium. It was found that the expression of p53 and TNFa was statistically significantly reduced (p<0.001) (on average by 6 times) in relation to the values obtained in those working outside of contact with vanadium. Conclusions. It was found that immune dysregulation is associated with an increased content of vanadium in the blood of workers exposed to industrial factors. Employees of the ferrous metallurgy enterprise under conditions of excessive vanadium contamination have an imbalance of membrane (CD4 + CD25 + , CD3 + CD95 + ), intracellular (p53) and intercellular (TNFa) immunoregulation indicators. In the process of adaptation of the body to the effects of harmful factors of the industrial environment, an important role belongs to immunoregulatory mechanisms, the study and evaluation of which can be used for early identification of immune system dysfunction in order to form the prevention of negative health effects caused or mediated by chemical factors.

Synthesis of high alumina cement based on metallurgy wastes

In this paper efficient types of binders – high alumina cements are considered. The shortage of industrial alumina and its high cost constrain the development of high-aluminate cements production. Waste from a number of metallurgical industries can be used as raw materials for their production. The aim of the investigation was to study the influence of metallurgical waste on the mineral formation of aluminate clinker and the properties of cement based on it. As a replacement of industrial alumina, dust of gas cleaning plants of aluminum electrolysis and slag of ferroalloys production were used. Aluminate clinkers were obtained in a laboratory furnace at a temperature of 1200-14000 °C. Mineral composition of clinkers was studied using chemical analysis, XRD and optical microscopy. The cements were obtained by grinding clinkers in a laboratory mill, then they tested for strength at the age of 28 days. It was established that the chemical and phase composition of dust allows to use it as a raw component in the production of high alumina cement. The investigations showed that the properties of alumina cement based on slag ferrovanadium production improved. Hydration activity of cement increases especially in the early period of its hydration.

Evaluating Toxicological Properties of Claydite Gravel, Containing Ferrovanadium Production Sludge, by Method of Biotesting with the of Higher Plants

Recycling of sludge wastes, generated at industrial wastewater treatment and containing heavy metals, is a relevant and long-term task in building materials production. At that, the possibility of toxicants emission to the environment should be taken into account. This paper presents the findings of evaluating toxicological properties of artificial porous aggregates (claydite gravel), containing ferrovanadium production sludge, by means of using higher plants (Avena Sativa and Allium cepa) as test objects. It is demonstrated that adding sludge to the raw charge in amount up to 15% in the process of baking intensifies the melt formation with clay minerals, which contributes to the safe binding of heavy metals, reducing their diffusion to water media. Water extracts of the obtained claydite have no phytotoxic effect on higher plants.

Research of the opportunity to use sludge wastes of ferrovanadium production as pigments for silicate paints

The article considers the urgent problem of formation, storage and recycling of sludge materials of various compositions, generated as a result of industrial enterprises wastewater treatment and sanitation. It is pointed out that in spite of a lot of designs concerning the wastewater neutralization sludges recycling, the share of their efficient usage is still negligible. So, one of the most relevant trends of nature protection activity and the rational use of natural resources is developing a technology of these wastes reclamation and applying them for useful products manufacturing. The research of chemical, mineral and grain composition of ferrovanadium production sludge wastes, generated at waste waters neutralization at the «EVRAZ Vanadii Tula», Tula, Russia, has been carried out. A method of obtaining pigments for silicate paints on the basis of these sludges has been considered. The influence of the sludges' thermal treatment conditions on their mineral composition and the properties of paints based on them has been evaluated. The pigments content varies from 1 to 3 %. It has been demonstrated that the most promising is the usage of initial sludges and heat-treated at temperature 1000°С sludges as pigments for high-performance silicate paints.

The Use of Ferrovanadium Production Sludge Wastes in Claydite Gravel Technology

The paper affirms that, despite the number of works in the sludge neutralization of waste water containing heavy metal compounds, the proportion of their use remains marginal. Therefore, one of the important directions of nature protection activities and the natural resources rational use is developing a technology for processing these wastes and their involvement in the production of useful products. The research of chemical, mineralogical and granulometric composition of wastewater slurry waste neutralization in production of vanadium pentoxide and ferrovanadium alloys by OJSC "EVRAZ Vanadium Tula" has been carried out. It is proposed to use a slurry waste in the claydite gravel production technology. The introduction of 1% sludge makes it is possible to obtain the following characteristics of claydite gravel: strength brand P 25, a packed density mark - 250. The 3% increase of the sludge provides a claydite gravel with the strength brand P 15 with the packed density of 250 kg/m3.

Adjustable tuyere for oxygen converters

In ferrous metallurgy, there is a pressing need to increase the proportion of scrap in the metal batch for steel smelting—primarily in oxygen converters. This is of particular concern at OAO Nizhnetagil'skii Metal� lugicheskii Kombinat (NTMK), on account of the shutdown of openhearth shop 1. In the oxygencon� verter shop, hot metal that is naturally alloyed with vanadium undergoes a twostage process. In the first stage, oxygen injection of the vanadium hot metal in the converter generates slag containing 17-21% V2O5, which is used in ferrovanadium production, and a molten metal product, which is converted to steel in the second stage. Thus, in the oxygenconverter shop at OAO NTMK, metal scrap may only be used in the second stage of the process. The complications in the second stage are mainly due to the chemical composition of the molten metal, which is in fact ferrocarbon melt. As a result, slag pro� duction is very slow. This leads, first, to unstable injec� tion, accompanied by splashing and entrainment of metal from the converter; second, to ineffective desphosphorization; third, to unstable oxidation of car� bon; and, fourth, to intense loss of iron, with the forma� tion of a large quantity of brown smoke at the end of smelting. In addition, in the second stage of the process, there is a problematic thermal balance, on account of the insufficient heat liberation in oxidation. This heat will be sufficient if the batch in the converter consists solely of the molten metal product but is far from suffi� cient with even 20% scrap in the batch. Thus, effective processing of metal scrap in 160�t oxygen converters entails the following improvements:

Ferrovanadium production from petroleum fly ash and BOF flue dust

Fly ash is generated as a solid residue in the power plant using crude oil and petroleum coke as fuels, and contains significant amount of vanadium. To utilize the industrial wastes, a better processing route is to convert environmentally hazardous wastes that have no or limited market value into products or intermediate products with added market value. In the present study a recipe-based concept is introduced and metal recovery from a selected waste mixture is investigated in the lab-scale experiments. Two waste ash residues of BOF steelmaking flue dust and petroleum fly ash are used as raw materials, and the residue carbon from the fly ash is used as reducing agent. The ferrovanadium with about 20 wt.% vanadium is obtained. This proves that a recipe-based waste processing can be a sustainable option for the future waste management.

Possibility of Selective Oxidation of Vanadium from Iron and Phosphorus in Fe‐V‐P Melt

AbstractExperiments on a vanadium recovery method from vanadium containing BOF‐slag using both a Tamman furnace (3 kg scale) and an induction furnace (150 kg scale) were conducted. The vanadium was extracted into the slag phase by bubbling oxidation gas into a metal bath consisting mainly of V (1–10 mass%), Si (less than 1 mass%) and P (about 1 mass%). The first experiments revealed that the slag formed during oxidation reaction had considerably high phosphate capacity. High phosphorus content would rule out the possibility of using the slag as a raw material for the production of ferrovanadium of high quality. In order to reduce the P‐content in the slag, addition of slag former to reduce phosphate capacity was necessary. A suitable slag system (having the initial composition 40 mass% Al2O3 ‐ 25 mass% CaO ‐ 35 mass% SiO2) and a suitable atmosphere, by using CO2, that enhanced the oxidation of vanadium, but limit the oxidation of iron and phosphorus was found. However, more efforts should be put forward, e.g. study of the phase diagram, the viscosity of the slag and even oxide activities to gain more insight into the slag formed by selective oxidation.

Electrochemical Behavior of Vanadium Oxides in Chloride-Fluoride Melts

The determination of the oxidation state in which vanadium is in metallurgical slag's is an important factor in choosing the optimal conditions for the production of ferrovanadium by the silicothermal method. On the basis of thermodynamic calculations, electrochemical investigations and UV-Vis spectroscopy it has been shown that in vanadium-contain metallurgical slag's vanadium is in the form of V2O3.

Energy efficiency of alternative coke-free metallurgical technologies

Energy analysis is undertaken for the blast-furnace process, for liquid-phase processes (Corex, Hismelt, Romelt), for solid-phase pellet reduction (Midrex, HYL III, LP-V in a shaft furnace), for steel production in systems consisting of a blast furnace and a converter, a Midrex unit and an arc furnace, or a Romelt unit and an arc furnace, and for scrap processing in an arc furnace or in an LP-V shaft furnace. Three blast-furnace processes with sinter and coke are adopted as the basis of comparison, as in: the standard blast-furnace process used in Russia; the improved blast-furnace process with coal-dust injection; and the production of vanadium hot metal from vanadium-bearing titanomagnetite ore (with a subsequent duplex process, ferrovanadium production, and its use in the arc furnace).

Thermodynamic Calculations of the Production of Ferrovanadium from V-containing Steelworks Slags with a low Content of V2O5. Part 1

The use of low grade vanadium slags from steel works for the production of ferrovanadium is an alternative for the future besides vanadium oxides, slags with high vanadium content, flue ashes or residues from the petrol industry. Thermodynamic calculations show the possibility of pyrometallurgical processing of such a material. On the one hand, a saleable ferrovanadium should be produced and, on the other hand, the produced slag should be used as a raw material in the building or cement industry. The treatment of the slag was done in two different reduction steps. While the first one leads to an enrichment of vanadium oxide in the slag and to a decrease of different elements, especially iron, in the second reduction step ferrovanadium is produced aluminothermically.

Equilibrium slag losses in ferrovanadium production

Ferrovanadium is sometimes produced from V2O3 in electric arc furnaces, using aluminum as a reductant. The CaO fluxes the alumina, which forms during reduction of the vanadium oxide. Incomplete reduction of vanadium oxide from the slag is a significant cause of vanadium losses. To quantify factors that can affect the equilibrium vanadium loss, the vanadium oxide activity coefficient was measured experimentally for different slag compositions. Hydrogen-water mixtures were used to control the partial oxygen pressure (approximately 10−13 atm) ove CaO-Al2O3 slags contained in vanadium crucibles at 1700 °C; gas-phase mass transfer was controlled by jetting the gas mixture onto the slag surface. Manipulation of the redox conditions at a single slag composition and temperature showed that, as expected, the vanadium is present in the trivalent state in the slag. The slag basicity (CaO-Al2O3 ratio) was found to have a very strong effect on the activity coefficient of VO1.5, with clear implications for the effect of plant practice on vanadium loss.

On the aluminothermic reduction of calcium vanadate

In the aluminothermic reduction of m e t a l oxide, calcium oxide is often used as a flux. The calcium oxide instead of forming an extraneous addition can sometimes be present in chemical combination with the m e t a l oxide. A familiar example is the aluminothermic reduction of calcium tungstate for the production of ferrotungsten. It has been stated1 that good coalescence of ferrotungsten is probably due to calcium oxide being an integral part of the tungsten resource, thus being made available essentially on a molecular basis for combining with alumina reaction product and quickly forming a fluid s lag . This can be considered to be a favorable state of affairs in the aluminothermic reduction of metal oxide as tied up with calcium oxide. In this context, reference can also be drawn t o the aluminothermic reduction of calcium molybdate for the production of ferromolybdehum and of molybdenum reported previously from this laboratory.~'3 This communication is an account of the efforts made for the preparation of vanadium and of ferrovanadium from calcium vanadates. The literature has made reference to the precipitation of calcium vanadate from vanadium bearing aqueous solution.4-7 T h e r e is however no information available on any technical use that has been developed for calcium vanadate. Aluminothermic reduction of vanadium pentoxide for the production of ferrovanadium or of vanadium in the industrial practice is known to be c a r r i e d out in presence of lime serving as a flux. This points towards the possibility for calcium vanadate as an alternative starting material for the aluminothermic reduction. For use in the present investigation the calcium vanadates were prepared in the laboratory. The compounds corresponding t o 2 CaO.V205 and to 4 CaO.V2Os were precipitated from alkaline sodium vanadate colution by treatments with CaC12 and lime respectively essentially in accordance with published work.7 The precipitated vanadium salts were dried, calcined at 1123 K and ground predominantly to -100 m e s h . The 2 CaO.V~Os and the 4 CaO.V2Os compounds, as made ready for use, analyzed 59.18 pct VaO5 and 44 pct V2Os respectively. Aluminum powder (grade ' C ' , 1 2 0 mesh) as received from M/s Indian Aluminium Co. was used as the reductant. The proc e d u r e for carrying out the aluminothermic r e d u c tions in refractory lined open vessels was essentially