Ferrotitanium Alloy Research Articles

Improved slag resistance of ferrotitanium slag based Al2O3-SiC-C castables: The effect of reaction between SiC and TiO2

Ferrotitanium slag is a kind of waste slag produced by smelting ferrotitanium alloy. It has high refractoriness (>1790 ℃) and Al2O3 content (≥70 wt%), which can be used to replace bauxite to prepare Al2O3-SiC-C castables. However, excessive substitution will lead to the decrease of slag resistance of Al2O3-SiC-C castables because of impurities in the ferrotitanium slag. In this paper, the slag resistance of ferrotitanium slag based Al2O3-SiC-C castables was improved by increasing the SiC content. The results showed that the castables with 13 wt% SiC had good mechanical properties. Increasing the amount of SiC was beneficial to improve the slag resistance. SiC content increased from 5 wt% to 22 wt%, the erosion index of dynamic slag resistance decreased from 17.05 % to 11.18 %. During the dynamic slag resistance, the TiO2 in the ferrotitanium slag dissolved in the slag, then the SiC reacted with TiO2 in the slag to form TiC coating on the surface of SiC particles. SiC particles wrapped by TiC widely existed in the reaction layer, which prevented further erosion of the slag. Further, the reaction of SiC with TiO2 to consume TiO2 and generate SiO2 increased the viscosity of the slag in the reaction layer, thus hindering slag penetration.

Preparation of ferrotitanium alloy by aluminothermic reduction of perovskite

Titanium-bearing blast-furnace slag is an important secondary resource. Artificial perovskite, with CaTiO3 as the main crystal phase, can be obtained after settling of the slag. Preparation of ferrotitanium alloy using perovskite as the titanium-containing material and aluminum as the reducing agent was studied. X-ray diffraction, scanning electron microscopy with energy-dispersive spectroscopy, and elemental chemical analysis were used to determine the composition and microstructure of the products. The results show that FeTi50 alloy can be prepared by aluminothermic reduction of perovskite. Reduction temperature has a strong influence on the separation of alloy and slag: when the reduction temperature increased from 1500 ℃ to 1600 ℃, the ferrotitanium alloy and slag effectively separated and Ti recovery exceeded 80%. The Al and O contents in the alloy decreased with decreasing aluminum addition, but also reduced Ti recovery. An alloy conforming to the industrial standard for FeTi50-A was obtained when the aluminum addition was 90 mass% of the stoichiometric value regarding reduction of perovskite.

Thermodynamics of Aluminothermic Processes for Ferrotitanium Alloy Production from Bauxite Residue and Ilmenite

Titanium oxide is a major component of bauxite residue (BR) with a high value, but it is often an unwanted element in common BR reuse options such as cement or iron production. Conventional carbothermic reduction smelting of BR produces a slag still containing a large amount of Ti. This study investigates an aluminothermic process for producing an FeTi alloy by combining BR, ilmenite ore, and fluxes. Based on thermodynamic calculations and batch experiments, the amounts of aluminum (reductant) and fluxes were investigated to achieve the optimum alloy production in parallel with a slag that could be further valorized in the cement industry. The mineralogical and chemical analysis of the metallic and slag phase agreed with the thermodynamic calculations. The results obtained by this study can lead to the development of a new process for the complete valorization of BR, paving the way for scaling up aluminothermic processes for producing ferroalloys from all iron-rich residues.

Novel Ti2O3–Al2O3 raw materials with controllable Ti2O3 content from the aluminothermic reduction of ilmenite

Titanium-containing refractories have excellent performance, but the high cost limits their application. A series of Ti2O3–Al2O3 raw materials with different Ti2O3 contents were prepared by aluminothermic reduction of ilmenite, while the generated ferrotitanium alloy can be used as raw materials for special steels. Regulating the amount of aluminum added in the system regulates the degree of titanium reduction, and the formed ferrotitanium alloy can achieve separation from the oxides. With decreasing aluminum content of, the Ti2O3 content increased, and the continuous distribution of the corundum area decreased, resulting in a continuously distributed Ti2O3 area. Our results indicated that the molar ratio of aluminum to ilmenite should be higher than 1.4 to achieve slag iron separation. The reaction model for the aluminothermic reduction was established, and the formation mechanism of Al2O3 and Ti2O3 in the system was discussed.

Formation mechanism of the TiN containing coating on the Al2O3-Ti2O3 composite at 1400°C nitrogen-blowing

The Al2O3-Ti2O3 composite is a byproduct of smelting ferrotitanium alloy, and a gold coating material was successfully obtained by nitriding this raw material at 1400 °C for 3h. The material was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, thermal gravimetry and differential scanning calorimetry (TG-DSC) and vibrating sample magnetometry (VSM). The formation of TiN containing coating layer on the surface of the material was confirmed by XRD and Raman spectroscopy analysis. The golden surface disappeared after polishing by cross-section polishing, and the titanium compounds in the material after nitriding showed a gradient distribution from the surface to the inside as TiN→Ti3O5→Ti2O3. From SEM analysis, titanium nitride was observed to be obtained by a gas-solid reaction with cluster growth, and the thickness of titanium nitride was approximately 10 μm. The main reaction in the nitridation process was determined by TG-DSC as well as thermodynamic analysis. The sample maintained a uniform mass increase from 665 °C to 1430 °C, and the Ti2O3 on the surface of the sample underwent both nitridation and oxidation. The hysteresis of the sample as a composite was complex before nitriding, and behaved as a soft magnetic material after nitriding, indicating the macroscopic scale coating uniformity of the samples.

Phase stability and enhanced mechanical properties of ferro-titanium slag to aluminum titanate ceramics

• The addition of ferro-titanium slag improves the strength of the material. • Impurities in ferrotitanium slag form solid solution with aluminum titanate. • The formation of solid solution inhibits the decomposition of aluminum titanate. • Recycling and harmless utilization of metallurgical waste slag. Ferro-titanium slag is a waste slag from ferro-titanium alloy smelting. It has high strength and has been observed to act as a reinforcing phase in multiphase materials, of which ferro-titanium slag powders were chosen to inhibit the thermal decomposition of AT ceramic in 800–1300 °C temperature range and improve its mechanical strength. It was shown that Si 4 + , Fe 3 + and Ti 4 + ions in ferro-titanium slag can partially replace Al 3 + ion in AT to form an ATFS (the AT ceramic doped with SiO 2 and Fe 2 O 3 ) solid solution, which inhibited the decomposition of AT. In addition, the formation of CA 6 phase contained from phase reconstruction of ferro-titanium slag further reinforced the mechanical properties of the AT ceramic. When 50 wt% ferro-titanium slag was added, the CA 6 enhanced AT multiphase ceramic improved phase stability and reaches mechanical properties (≈14 MPa).

A novel dense Al2O3-Ti2O3 slag synthesized while ferro-titanium alloy making

ABSTRACT This paper describes the preparation route and formation mechanism of a Al2O3–Ti2O3 composite. During the fabrication of a ferro-titanium alloy from titanium concentrate via a thermite method, CaO is generally added to reduce the viscosity of the liquid and promote the separation of the ferro-titanium alloy and Al2O3–CaO–TiO2 slag. The latter represents a multi-oxide system mainly composed of CaAl12O19, CaAl4O7, and CaTiO3 species with poor high-temperature performance, which considerably limits its practical application. The performance optimization and high value-added application of this slag involve the elimination of the CaO phase and replacement of TiO2 with Ti2O3 particles to prevent the formation of a multi-oxide system due to the low solubility of Ti2O3 in Al2O3. The Al2O3–Ti2O3 composite material was successfully prepared via industrial experiments, and its synthesis mechanism and corresponding reaction model are established.

Reaction mechanism and kinetics of ferrotitanium preparation by aluminothermic reduction of CaTiO3

A ferrotitanium alloy production process by aluminothermic reduction and using perovskite as materials was studied in laboratory. The thermodynamics of the Al-CaO, Al-CaO-CaTiO3, Al-CaO-Fe-CaTiO3 system was calculated and the reduction process of CaTiO3 to prepare ferrotitanium was investigated. The Freeman-Carroll method was used to analyze the kinetics of aluminothermic reduction process. The results show that ferrotitanium alloys can be produced by aluminothermic reduction using perovskite as material. In the reduction process, the reduction reaction of TiO2 in CaTiO3 by aluminum proceeds at 1000–1100 ℃, and the formation temperature of ferrotitanium alloy is between 1400 ℃ and 1500 ℃. CaO not only acts as a slag-forming agent in the reaction process, but also participates in the reduction reaction process. The apparent activation energy and the reaction order at the reduction peak decrease with the increasing of heating rate which indicates that the reaction is easier with the increase of heating rate.

STUDYING THE COST AND BENIFIT TO INCREASE THE ADDED VALUE OF THE ILEMENIT MINERAL EXTRACTED FROM THE EGYPTIAN BLACK SAND USING A SHREDDER

The researchers aim to shed light on the economic importance of the Egyptian black sands and the economic minerals extracted from them, and to determine the global and Egyptian reserves from them. The study also deals with raising the added value of ilmenite extracted from Egyptian black sand in order to produce ferotitanium alloy, and prepare an integrated vision to determine the possibility of establishing industrial projects to raise the economic value of ilmenite through the application of methods used in rationalizing costs, using the descriptive analytical method in order to increase the national product accordingly. This study was applied to the black sands of the Rosetta site in the North Delta, which is one of the field work sites of the Nuclear Materials Authority. Ferrotitanium alloy is one of the most widely used alloys in the steel and stainless steel industries, the paint industry, and the missile and aircraft industry. The study concluded that it is possible to increase the revenue generated from the production of ferotitanium alloy and raise the economic added value of ilmenite by using raw materials in different mixing methods that lead to rationalization of costs, achieving sustainable development goals and increasing national income. The researchers recommend expanding the application of the proposal to use the shredder machine in extracting the aluminite metal due to the rationalization of costs, an increase in the revenue, and raising the added value of the aluminite mineral, the need to maintain the quality of production and the introduction of continuous improvements to rationalize the indirect costs, as well as the necessity to supply the Nuclear Materials Authority with supplies, tools and devices used in the exploration of black sand areas throughout Egypt, and the use of fuel derived from solid waste plastic (RDF) instead of natural gas to save energy costs.

Direct Electrochemical Reduction of Natural Ilmenite into Ferrotitanium Alloys in a Molten Salt of LiCl-Li2O

This paper reports a promising method to decrease the operating temperature during electrolysis of natural ilmenite to produce a porous and laminar flake-type intermetallic ferrotitanium (FexTi, x = 1, 2) with a thickness of less than 1 μm by choosing a LiCl-Li2O electrolyte with a lower operating temperature (625 °C) under an inert atmosphere. Results indicate that the Li2O content in the electrolyte has a key effect on the phase transformation of natural ilmenite occurring in the electrochemical reduction process. Full conversion of natural ilmenite into ferrotitanium products can be achieved when the Li2O amount in the electrolyte and the cell voltage are approximately 1 wt.% and −2.5 V, respectively. In addition, the electrochemical reduction mechanism of natural ilmenite is proposed and discussed based on our experimental results and thermodynamic analysis.

Investigating the impact of structure of ferrotita-nium bars obtained by the electroslag remelting method on their crushing capacity

The structure and grinding ability of ferrotitanium ingots of different production methods have been researched. It has been found that the partial decay of primary TiFe2 grains with the formation of TiFe. in the structure of ingots of ferrotitanium ESR at a concentration of Ti 38–4 % improves the ability to crushing. Problem. Electrodes of the basic (fluoride-calcium) type, in particular, the UONI 13/55 brand are used for production of welded products of responsible function. They provide the highest plastic properties of the weld metal at a low content of non-metallic inclusions and gases, which is achieved by deoxidation of metal Mn, Si and Ti, introduced into the coating of the electrodes in the form of ferroalloys. However, in the ferrotitanium FeTi35A of the aluminothermic production method used in the production of welding electrodes, the volumetric part of inclusions reaches 0.3%. In this case, most (up to 70%) are refractory due to aluminum oxides, which contaminate the weld metal. The use of ferrotitanium produced by the electroslag remelting method, with a much lower content of non-metallic inclusions and impurities of non-ferrous metals, allows to improve the quality of the weld metal by reducing the number of exogenous inclusions. However, ingots of ferrotitanium obtained by the method of ESR with a similar content of Ti = 28,5 %–30,0 %, had a fairly low crushing point with the formation of a heterogeneous fraction. Goal. The purpose is to research the structure of ingots of ferrotitanium alloys with different titanium content, and to establish the dependence of the ability to crush on the structure and composition of ingots. Methodology. Ingots of ferrotitanium were obtained by electroslag remelting of combined electrodes composed of strips of low-carbon steel St3 and titanium W1-0 in copper water-cooled crystallizer with a cross section of 80–90 mm. The structure and ability of crushing for ingots with titanium content of 15, 20, 25, 30, 40, 45, 50 and 60 % have been tested. The ingots have been examined in the cast state after cooling in the air. A mixture of hydrofluoric, nitric acid and water in the ratio (1: 1: 3) has been used to researching the microstructure that has been determined using a MIM 8-M metallographic microscope. Crushing ability has been determined by a non-standard method on copra with a vertically falling cylindrical striker. It was found that the ability to crushing was the highest for the production of welding electrodes, ferrotitanium electroslag remelting with a concentration of Ti 38–48 % should be used. Originality. It was discovered that provided a Ti content of 45 % partial decay of primary TiFe2 grains with TiFe formation is observed. Upon cooling, the alloy becomes more balanced. The presence of the TiFe decay phase in the middle of the TiFe2 grain due to the difference in structure creates additional internal stresses and facilitates the destruction of the alloy. Practical value. The grinding coefficient of ferrotitanium ESR with a titanium content of 38–48 % and aluminum-thermal production are almost the same, which facilitates their use in the manufacture of welding electrodes.

Investigating the Aluminothermic Process for Producing Ferrotitanium Alloy from Ilmenite Concentrate

The aluminothermic process is used for producing ferrotitanium alloy (FeTi) from an ilmenite concentrate. In this study, based on thermodynamic calculations and experiments, we investigated the effects of adding varying amounts of exothermal agent (NaClO3), slag-forming agent (CaO), and reducing agent (Al) on the recovery ratio of Ti in the aluminothermic process. The thermodynamic calculations suggested that the exothermal agent plays a crucial role in producing the FeTi alloy from the ilmenite concentrate and the maximum Ti grade in the FeTi alloy was approximately 30 wt %. Experimentally, it was verified that the FeTi alloy obtained under the optimum mixing conditions contained 30.2–30.8 wt % Ti, 1.1–1.3 wt % Si, 9.5–11.2 wt % Al, and 56.9–58.0 wt % Fe, along with trace impurities and small amounts of gases such as oxygen (0.35–0.66 wt %) and nitrogen (0.01–0.02 wt %). At the optimum mixing conditions, the recovery ratio of Ti into the obtained FeTi alloy phase was 60.6–68.9%. These results matched closely with the thermodynamic calculations. Therefore, the thermodynamic calculations performed herein are expected to significantly contribute toward the development of new processes and improvement in conventional processes for producing various ferroalloys including the FeTi alloy through the aluminothermic process.

Extraction of titanium resources from the titanium-containing waste slag: Thermodynamic analysis and experimental verification

Compared with the ilmenite ore, the titanium resources in vanadium titanomagnetite (VTM) have not been effectively recovered yet due to the relatively low grade of titanium oxides. Therefore, after the extraction process of Fe and V from VTM, a large amount of titania slag is currently discarded and landfilled, leading to the environment problems. For the purpose of addressing this problem, the titania slag that is formed after pre-reduction and melt separation of VTM is used as the titanium-containing raw materials in this work. Moreover, the aluminothermic reduction is adopted and the ferrotitanium alloy is chosen as the enrichment end-product of titanium resources. The effects of additive amounts of Al, Fe2O3, and CaO on the reaction process and alloy quality are explored by the thermodynamic analysis. Furthermore, the ferrotitanium alloy that satisfies the standard requirements is successfully prepared and the grade is improved.

Carboaluminothermic Production of Ferrotitanium from Ilmenite Through Thermal Plasma

Ilmenite is the prime mineral used for the production of titania-rich slag and ferrotitanium alloy throughout the globe. In the current research, a 30 kW DC extended arc plasma reactor is employed for the aluminothermic reduction of ilmenite into ferrotitanium. For low-temperature operation, flux is added targeting low melting slag where CaO/Al2O3 ratio is varied from 0.8 to 1.6. Further, to lower down the Al consumption, carboaluminothermic reduction tests are carried out in stages without interruption. The effect of stage-wise reductant addition and CaO/Al2O3 ratio on ferrotitanium yield and titanium recovery is studied, corroborated to the slag chemistry. FeTi26 alloy is obtained through the carboaluminothermic smelting route with 25% excess stoichiometric Al in charge composition. The formation of calcium titanate and calcium aluminates governs slag chemistry and reduction kinetics.

Control of TiN precipitation behavior in titanium-containing micro-alloyed steel

As a kind of high-strength steel, low-carbon titanium-containing micro-alloyed steel has been widely used in the industry recently. Fine TiN precipitates can refine the austenite grains, improve the toughness of the steel, strengthen the good formability and weldability of the steel, and reduce the production costs of the process. However, due to the improper technical operations or steps, a large amount of TiN will precipitate in the billet, which will affect the crack sensitivity of the steel. According to the thermodynamic calculation results, when the nitrogen content is reduced from 50 ppm to 20 ppm, the precipitation temperature of TiN can be reduced to 1400 °C, whilst the amount of TiN precipitate quantity will be significantly reduced. This article conducted the Oxygen and Nitrogen Analysis towards the samples throughout the entire steelmaking process. The results indicated an abnormal increase in nitrogen content during the Ladle Furnace (LF) process. In addition to the reaction between air and molten steel, the raw and auxiliary materials for steelmaking may also be the reasons which caused the increase of nitrogen content in the molten steel, as they contain nitrogen as well. However, there are only a small number of studies that had explored the impact of raw and auxiliary materials on steel quality. This article investigated the cleanliness of ferrotitanium alloys. The results showed that the cleanliness (inclusions and nitrogen content) of TiFe-30 is much higher than that of TiFe-70. When TiFe-70 was replaced by TiFe-30 for steelmaking, the content of nitrogen in the molten steel as well as the content of TiN were reduced, whilst the size of TiN was correspondingly decreased. In this experiment, not only was the performance of steel improved, the cost of steelmaking was also reduced. At last, this work could also awaken the judgment standards for steelmaking alloys.

An Innovative Approach of Recycling Aluminium Scrap for Ferrotitanium Production

The recycling of household aluminium waste metals will be very effective and efficient only when a proper process of recycling is chosen. This paper is an attempt to provide a non-traditional method of utilising the exothermic heat of different Al sources (from automobiles, appliances, windows and doors and other products) for recycling and producing ferrotitanium alloy. Titania slag (75% TiO2) produced from carbothermic reduction of low-grade ilmenite (50% TiO2) and its produced fine dust from top dome are taken as a feed material. Aluminothermic processing of fine dust gives a possibility in the direction of ferrotitanium, followed by the successful execution with titania slag, which include smelting of titania slag with household Al scrap chips and lime in a thermal plasma reactor. The alloy formation is supported with characteristic properties of XRD and FESEM.

Production of ferrotitanium alloy from titania slag based on aluminothermic reduction

At present, the titanium resource from vanadium-titanium magnetite (VTM) has not been used very effectively. With the aim of addressing this urgent problem, the titania slag with over 40 wt% TiO2 was obtained from VTM through gaseous reduction and melting separation in the previous work. In this study, the aluminothermic reduction for the ferrotitanium alloy production was conducted in order to develop a new utilization way for the titanium resource from VTM. CaO and Fe2O3 are extra added to ensure the slag fluidity, alloy quality, and sufficient physical heat. And the addition ratios of Al are optimized by the thermodynamic calculation. At last, the ferrotitanium alloy with 30.5 wt% Ti, 8.4 wt% Al, 3.2 wt% Si content is successfully prepared. However, the macro analysis indicates that some alloy particles with different contents are dispersedly distributed among the slag, and the slag consists of three different phases. It is mainly associated with the reaction intensity and thermodynamic stability, which is detailedly discussed in this paper as well.

Studying the physicochemical regularities in the color- and phase formation processes of clinker ceramic materials

The paper reports results of a comprehensive study, aimed at developing formulation-technological parameters for obtaining volumetrically dyed clinker ceramic materials with a wide range of colors. A possibility has been proven to obtain a ceramic clinker when using the polymineral clay raw materials at a temperature of 1,100 °C. The expediency has been shown to replace expensive ceramic pigments in the composition of masses with anthropogenic materials containing the oxides of metals with variable valency: wastes from alkaline earth syenite extraction, pegmatite enrichment, and production of ferrotitanium alloys. This shows possibilities for reducing the production cost of clinker ceramic articles. The influence of the formulation of raw materials compositions on the processes of color- and phase-formation of ceramic clinker has been investigated, depending on the character of furnace atmosphere. It was established that the brown coloration of clinker ceramics under conditions of oxidative annealing is predetermined by the presence of phases of hematite α-Fe 2 O 3 and Mn 2 O 3 . At annealing in a reducing medium, products acquire color in the range from dark brown to black at the expense of formation of magnetite Fe 3 O 4 and gaussmanite Mn 3 O 4 . The products' terracotta color is due to the presence of phases of hematite and hedenbergitis CaFeSi 2 O 6 . The condition for obtaining clinker ceramics of yellow color is to limit the formulation's content of Fe 2 O 3 to 3 % by weight, as well as the presence of the SiO 2 rutile phase. The paper illustrates the effect of the overall content of oxides of metals with a variable valence S(Fe 2 O 3 +FeO+MnO+Mn 3 O 4 ) on the coloration characteristics of clinker ceramics. The ratios have been derived between the phase-forming oxides Fe 2 O 3 /(Al 2 O 3 +CaO), (Fe 2 O 3 +Mn 2 O 3 )/(FeO+Mn 3 O 4 ) and TiO 2 /(Al 2 O 3 +CaO), as well as the limits in their variation, providing for the formation of color-carrying phases responsible for obtaining products of the desired color under conditions of oxidative and reductive annealing

Preparation of Ferrotitanium Alloys by Electrolysis-Assisted Calciothermic Reduction of Ilmenite in Equimolar CaCl2-NaCl Electrolyte: Effect of Calcium Oxide

The effect of CaO content on the preparation of ferrotitanium alloys from ilmenite with the method of the electrolysis-assisted calciothermic reduction has been investigated by use of ilmenite powders as raw materials that positions them next to the cathodic molybdenum plate, equimolar CaCl2-NaCl molten salt with 2–7 mol.% CaO as electrolyte and graphite as anode at 700°C with cell voltage of 2.8 V under argon atmosphere. It is demonstrated that increasing the reactant CaO content is beneficial to the calciothermic reduction of ilmenite and the intermediate CaTiO3. Experimental results also show that after 14 h of calciothermic reduction process, the products are ferrotitanium alloys and the specific energy consumption is only about 10.21 kWh kg−1 when adding 5 mol.% CaO into equimolar CaCl2-NaCl molten salt and approximately 14.40 kWh kg−1 when CaO content is increased to 7 mol.%.

Synthesis of micro-FeTi powders by direct electrochemical reduction of ilmenite in CaCl2-NaCl molten salt

Micro-ferrotitanium powders have been prepared by molten salt electrolysis via directly electrochemical reduction of solid ilmenite in eutectic CaCl2-NaCl melt at 973 K. In the direct electrochemical reduction process, the reduction of FeTiO3 first gives rise to the formation of Fe and CaTiO3, which as intermediates will be further deoxidized at the interface of iron metals, solid CaTiO3 matrix, and electrolyte to directly form ferrotitanium alloy powders in porous structure. Furthering the electrolytic time can promote the dense structure of ilmenite pellet turn to be more porous, indicating pores inside the pellet are sufficient for the diffusion of oxygen ions. Based on the reduction behavior of partially reduced powders in metallic cavity electrode during the cathodic potentiostatic electrolysis, it shows that the slow deoxidization rate is mainly caused by the more and more difficult reduction of CaTiO3 than that of FeTiO3.