Titanium-rich Slag Research Articles

Synthesis of an iron-titanium-carbon composite from slag high in titanium for removing arsenic particles from drinking water

The objective is to develop a novel iron-titanium-carbon composite using titanium-rich slag as a precursor material. This composite should demonstrate efficient arsenic removal capabilities for water-based treatments. The straightforward photochemical method is used to create a microporous iron-titanium/carbon composite by milling titanium-rich slag with activated carbon at room temperature. XRD, SEM, EDX, and N2 adsorption/desorption were used to describe it. This microstructure sorbent has excellent composition, surface area, and pore structure suitable enough to intake As(V) ions from drinking water at pH 6 with the adsorption capability of 86 mg/g. Among the many adsorption isotherm types examined, the Langmuir isotherm had the best fit with R2:0.9879. The intake of As(V) into the produced composite was most aptly stated by the Elovich model (R2:0.9899), according to the kinetic investigations. Given that, the synthesized micro-composite exhibits long-term stability and reproducibility over several regeneration cycles. Our findings displayed that the synthesized iron-titanium/carbon composite is effectively convenient for the elimination of As(V) with the effectiveness of recuperation of 95%.

Electro-deoxidation behavior of Ca4Ti3O10 in molten CaCl2-NaCl

Ca4Ti3O10 is one of the important minerals enriched by titanium-containing blast furnace slag. The electro-deoxidation behavior of Ca4Ti3O10 was investigated, and titanium metal was successfully prepared in molten CaCl2-NaCl by the FFC Cambridge process. Firstly, the band structure and state density of Ca4Ti3O10 were calculated by the first principle, and the bond-breaking trend was analyzed. Then, the reduction process of Ca4Ti3O10 and the preparation mechanism of titanium were carried out by electrochemical methods. Finally, constant voltage electrolysis experiments were conducted at 900 °C and a voltage of 3.2 V for different durations. The electrolytic products were characterized using XRD, SEM-EDS, and XPS. The results revealed that the reduction process of Ca4Ti3O10 proceeded as follows: Ti4+→Ti3+→Ti2+→Ti+→Ti. The deoxidation path of the product after constant voltage electrolysis was observed as Ca4Ti3O10 → TiO2 → CaTiO3→ TiO2→ Ti2O3 → TiO → Ti2O → Ti. The whole deoxidation process can be divided into three stages: (I) the Ti-Ca bond in Ca4Ti3O10 is broken to form CaTiO3 and TiO2; (II) CaTiO3 and TiO2 are reduced from the surface of the cathode sheet inward to form a Ti-O solid solution; (Ⅲ) Ti-O solid solution is further deoxidized to form Ti metal. This method provides a theoretical basis for the subsequent electrolysis of titanium-rich slag, thereby contributing to developing a more sustainable and efficient method for extracting titanium from enriched titanium slag.

Technological research of process for producing titanium rich slag and complex titanium-containing ferroalloy

This paper demonstrates the results on the experimental smelting of the titanium rich slag and complex titanium-containing ferroalloy under the large-scale laboratory conditions that simulate industrial one. The technological researches of the process were performed on an ore-thermal furnace with 200 kVA transformer power. The titanium rich slag was produced from the low-grade ilmenite concentrate, i.e. the low TiO2 content and the high content of impurities. During the production of the high-grade titanium slag (TiO2 content: 75–80%), the impurity elements are transferred into the associated alloyed metal (cast iron). Thus, it can be used to smelt the steel. As a result, samples of titanium slag have been produced with the content of the main components, %: TiO2 – 80.2; Al2O3 – 4.5; SiO2 – 1.97; Cr2O3 – 1.3 and Fe2O3 – 9.87. Then, in metallurgical practice a complex titanium-containing ferroalloy was first smelted from the previously produced titanium rich slag using a carbothermic approach. The high-ash coal was applied as a carbon-bearing reducing agent. The ash was more 45%. As a result of tests, a pilot batch of the alloy was produced with the following chemical composition, %: Ti - 20–25; Si - 35–45; Al - 10–15; C - 0.2–0.5; P - no more than 0.08; and ferrum. The main component content in the produced alloy suggests that it can serve as an alternative to a mechanical mixture (FeSi45, aluminum shavings, low-percentage ferrotitanium) for steel alloying and deoxidation purposes.

Carbothermic Reduction of Ilmenite Concentrate with Sodium Carbonate Additive to Produce Iron Granules and High Titania Containing Slag

The influences of heating pattern and sodium carbonate addition on the carbothermic reduction of ilmenite concentrate have been experimentally studied. The experiments were carried out using isothermal–gradient temperature technique between 1000 °C and 1500 °C with different temperature profiles for a total reduction time between 110 and 160 min. The sodium carbonate was varied between 0 to 60 wt%. It was found that the temperature profile and sodium carbonate addition play an important role on the separation between metallic iron granule and titania rich slag. The optimum condition was achieved at initial and final reduction temperatures of 1300 °C and 1500 °C, respectively, with sodium carbonate addition of 30 wt%. At the optimum condition, the iron recovery was 97.1% and the solidified slag contained titanium pentoxide (Ti3O5), anatase (TiO2), and sodium titanium dioxide.

Replacing Fossil Carbon in the Production of Ferroalloys with a Focus on Bio-Based Carbon: A Review

The production of ferroalloys and alloys like ferronickel, ferrochromium, ferromanganese, silicomanganese, ferrosilicon and silicon is commonly carried out in submerged arc furnaces. Submerged arc furnaces are also used to upgrade ilmenite by producing pig iron and a titania-rich slag. Metal containing resources are smelted in this furnace type using fossil carbon as a reducing agent, which is responsible for a large amount of direct CO2 emissions in those processes. Instead, renewable bio-based carbon could be a viable direct replacement of fossil carbon currently investigated by research institutions and companies to lower the CO2 footprint of produced alloys. A second option could be the usage of hydrogen. However, hydrogen has the disadvantages that current production facilities relying on solid reducing agents need to be adjusted. Furthermore, hydrogen reduction of ignoble metals like chromium, manganese and silicon is only possible at very low H2O/H2 partial pressure ratios. The present article is a comprehensive review of the research carried out regarding the utilization of bio-based carbon for the processing of the mentioned products. Starting with the potential impact of the ferroalloy industry on greenhouse gas emissions, followed by a general description of bio-based reducing agents and unit operations covered by this review, each following chapter presents current research carried out to produce each metal. Most studies focused on pre-reduction or solid-state reduction except the silicon industry, which instead had a strong focus on smelting up to an industrial-scale and the design of bio-based carbon for submerged arc furnace processes. Those results might be transferable to other submerged arc furnace processes as well and could help to accelerate research to produce other metals. Deviations between the amount of research and scale of tests for the same unit operation but different metal resources were identified and closer cooperation could be helpful to transfer knowledge from one area to another. Life cycle assessment to produce ferronickel and silicon already revealed the potential of bio-based reducing agents in terms of greenhouse gas emissions, but was not carried out for other metals until now.

Generation of titania-rich slag and iron from ilmenite concentrate by carbothermic reduction and magnetic separation in the presence of Na2CO3

ABSTRACT The carbothermic reduction of an ilmenite concentrate, followed by wet magnetic separation, was performed with varying additions of Na2CO3 to generate metallic iron and a titanium-rich slag. The size of the metallic iron particles correlated positively with increasing graphite addition up to a C/O (O bound to Fe) molar ratio of 1.4; further increases beyond this level decreased the particle size. The size of these metallic iron particles also increased with greater addition of Na2CO3. The addition of Na2CO3 to the ilmenite concentrate enhances the carbothermic reduction by promoting the gasification of C and fluxing the slag phase, lowering its melting point and increasing fluidity; a 5.97 wt% addition of Na2CO3 decreased the reduction onset temperature from 1020 to 900°C. This fluxing of the slag with Na2CO3 also allows for much lower concentrations of FeO than the 10–12% concentration typically required to ensure adequate fluidity in conventional EAF smelting operations. With the addition of Na2CO3, the recovery of Fe to the magnetic fraction, following magnetic separation, was over 97% and the non-magnetic fraction contained more than 74% TiO2. Within the range of conditions considered in this study, the highest recovery of TiO2 to the non-magnetic fraction (89%) was achieved for material reduced at 1450°C.

Cleaner and effective recovery of metals and synthetic lithium-ion batteries from extracted vanadium residue through selective leaching

A process for recycling steelmaking waste is proposed, and high value-added lithium-ion batteries (LIBs) electrode materials LiFePO4 and Li4Ti5O12 are prepared. The precursor material FePO4·xH2O is prepared from the iron-rich filtrate formed after HCl leaching the waste residue. Using FePO4·xH2O and Li2CO3 as raw materials by the carbothermal reduction method, LiFePO4 containing a small amount of metal doping is prepared. By comparing the XRD patterns, it is found that the purity of the synthesized LiFePO4 material is higher if the precursor whose Fe–P molar ratio is close to the theoretical value of 1 is used as the raw material. The initial discharge capacity of LiFePO4/C at 0.1C is 139.3 mAh·g−1, and after 50 cycles, the capacity retention rate is 94.97%. In sulfuric acid medium, NH3·H2O and H2O2 are used to selectively leaching Ti from the titanium-rich slag. High-purity TiO2 is prepared by calcining the peroxy titanium compound. The spinel-type lithium-ion battery anode material Li4Ti5O12 is prepared with TiO2 as the precursor. The initial discharge capacity of the battery assembled with Li4Ti5O12 at 0.1C is 163.3 mAh·g−1. This study is helpful to solve the environmental pollution problem and the energy crisis.

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.

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.

Dissolution Behavior of Aluminum Titanate Inclusions in Steelmaking Slags

The current work investigates the dissolution path and mechanism of aluminum titanate inclusions in steelmaking slags using a high-temperature confocal scanning laser microscope (CSLM). To study this phenomenon, a single particle of aluminum titanate is dissolved in slag at 1773 K. During the dissolution process, gas bubble evolution is observed. Further, the particle–slag system is rapidly quenched using helium at different stages of dissolution. The quenched samples are examined for distribution of the constituent elements: Al, Ti, Ca, and Si using the scanning electron microscope (SEM). Phases such as alumina, titanium-rich slag, and calcium titanate are detected at the particle–slag interface. The dissolution path of aluminum titanate is proposed in the following steps. First, aluminum titanate dissociates into alumina, titanium oxide, and oxygen while slag penetrates through the particle. In the next step, the alumina and titanium oxide dissolve in slag, and the oxygen leaves the system. The existence of gas bubbles enhances the overall rate of Al2TiO5 dissolution. The dissolution of Al2TiO5 appears to be controlled by mass transfer in the slag. Evidence in support of this finding is the particle–slag interface characterization by line scan analysis and calculated diffusivity values being inversely proportional to the viscosity of slag.

Study of Porosity on Titania Slag Obtained by Conventional Sintering and Thermal Plasma Process

This article investigates the development of porosity in titania-rich slag obtained by sintering via conventional and thermal plasma heating at 1000°C in inert atmosphere. The holder in the plasma reactor acted as the discharge anode confined within a hollow graphite cathode. Quantitative evaluation of the porosity in the conventionally sintered and plasma-sintered titania-rich slag was performed via pycnometry. Specifically, the physical dimension and morphology of the pores were characterized according to the area fraction, mean diameter, shape factor, and elongation factor. Under both conventional and thermal plasma heating conditions, porosity developed on the surface of titania-rich slag. The titania-rich slag obtained by two processes showed different porosity features in terms of the morphology and porosity. A lower porosity was observed in the plasma-sintered sample when compared with that obtained via conventional heating.

An alternate approach to synthesize TiC powder through thermal plasma processing of titania rich slag

This paper reports the preparation of fine titanium carbide (TiC) powder by using titania rich slag as a cheap raw material. The mixture of titania rich slag and activated charcoal was reacted in a thermal plasma reactor for 30min under argon flowing atmosphere. The reaction product, a fused mass of Fe-TiC composite, was milled to fine powder at ambient atmosphere for 10h then chemically leached for the removal of iron and other minor impurities. The obtained TiC powder after leaching was characterized by X-ray diffraction (XRD), Raman spectroscopy, electron probe micro analysis (EPMA), field emission scanning electron microscopy (FESEM) and particle size analysis (PSA). XRD, Raman spectroscopy results confirmed the formation of TiC. EPMA, EDS results indicated the synthesized product obtained after leaching to be free from iron and other minor impurities. Particle size analysis result revealed the average particle size of TiC powder to be 2.54µm.

Gas-Based Direct Reduction of Hongge Vanadium Titanomagnetite-Oxidized Pellet and Melting Separation of the Reduced Pellet

The recovery rates of vanadium, titanium, and chromium are much low in the current process of the vanadium titanomagnetite in Hongge region, China. In order to utilize Hongge vanadium titanomagnetite (HVTM) effectively, a novel clean process is proposed in this study, in which HVTM-oxidized pellets are reduced initially in shaft furnace and then melting separated. The influences of reduction temperature and ratio of φ(H2) and φ(CO) on the reduction process and melting morphology of the reduced pellets are investigated. It is found that the rate and degree of reduction are improved with the increase of temperature and ratio of φ(H2) and φ(CO). The appropriate temperature and ratio of φ(H2) and φ(CO) are 1050 °C and 2.5, respectively. The phase transformations of the valuable elements during the reduction process can be described as follows: Fe2O3 → Fe3O4 → FeO → Fe; Fe9TiO15 → Fe2.75Ti0.25O4 → Fe2TiO4 → FeTiO3 → TiO2; (Fe0.6Cr0.4)2O4, Fe0.7Cr1.3O3 → FeCr2O4; (Cr0.15V0.85)2O3 → Fe2VO4. The recovery rates of iron, vanadium, chromium, and TiO2 are 98.7, 88.27, 91.38, and 92.52%, respectively. The separated iron is a clean raw material for steelmaking; moreover, the titanium-rich slag can be used for further process to recover titanium. This study aims to provide theoretical and technical bases for the comprehensive utilization of HVTM and increase the recovery rates of valuable elements.

Synthesis and Characterization of Titanium Slag from Ilmenite by Thermal Plasma Processing

Titanium rich slag has emerged as a raw material for alternative titanium source. Ilmenite contains 42–50% TiO2 as the mineralogical composition depending on the geographical resources. Application of titanium in paper, plastic, pigment and other various industries is increasing day by day. Due to the scarcity of natural raw mineral rutile (TiO2), ilmenite is considered as precursor for the extraction of TiO2. Ilmenite is reduced at the initial stage for the conversion of complex iron oxide into simpler form. Therefore, pre-reduction of ilmenite concentrate is essential to minimize the energy consumption during thermal plasma process. Thermal plasma processing of ilmenite for the production of titania rich slag is considered to be the direct route to meet the current demand of industrial needs of titanium. Titania rich slag contains 70–80% TiO2 as the major component with some other minor impurities, like oxide phases of Si, Al, Cr, Mg, Mn, Ca, etc. Usually titanium is present in tetravalent forms with globular metallic iron in the slag. Titania rich slag undergoes leaching for the removal of iron and transforming the slag into synthetic rutile having 85–95% of TiO2.

The electrochemical synthesis of TiC reinforced Fe based composite powder from titanium-rich slag

Nano-sized TiC reinforced Fe based composite particles with a multi-core microstructure were synthesized by electrochemical reduction.

The FFC Cambridge process and its relevance to valorisation of ilmenite and titanium-rich slag

The Fray–Farthing–Chen (FFC) Cambridge process was patented in 1998 for low cost and clean electrochemical extraction of metals and synthesis of alloys directly from the mineral precursors, particularly oxides (including slags) and sulfides, with the aid of molten salts. In this paper, the technical success of this unique method is explained from the basic electrode reaction thermodynamics and mechanisms at the compound/metal/electrolyte three-phase interlines (boundaries). Selected recent innovations are then introduced towards more efficient cathode design and practices. Finally, the prospects of the FFC Cambridge process are discussed for processing the ilmenite ore and the so-called titanium-rich slag to produce Fe–Ti alloys and its commercial potential in the future titanium industry.

Morphological Characterization Of Titania Slag Obtained From Red Sediment Placer Ilmenite Using Microwave Energy

This paper deals with the main objective to observe the effect of microwave heat treatment for the production of Titania rich slag and pig iron from placer ilmenite. The experiments carried out in the present investigation on the oxidized ilmenite sample for microwave heat treatment in microwave sintering furnace reveals that a product can be obtained containing Titania rich slag and metalized iron. The in-depth characterisation of these products using SEM–EDAX shows that around 75–85 % of titanium dioxide is formed in terms of titania rich slag by using microwave sintering furnace after reduction of oxidized ilmenite with proper stoichiometric graphitic carbon and silicon carbide (SiC) susceptor. The titania rich slag is considered to be better input material for production of pigment grade titanium dioxide. On the other hand, the pig iron obtained as by product from titania rich slag is also important for automobile and steel industries application.

A novel method to extract iron, titanium, vanadium, and chromium from high-chromium vanadium-bearing titanomagnetite concentrates

A novel process for the extraction of iron, titanium, vanadium, and chromium from high-chromium vanadium-bearing titanomagnetite concentrates is proposed. This process involves several steps: partial reduction of the concentrates, magnetic separation, hydrochloric acid leaching of the titanium-bearing tailing, and alkaline desilication of the HCl leach residue. The partial reduction ensures that the vanadium and chromium are predominantly concentrated in the titanium-bearing tailing. Subsequently, magnetic separation is used to recover an iron concentrate with a total iron content of 94.57%. During acid treatment, 90.8% vanadium leaching and 93.4% chromium leaching were obtained, with titanium losses of less than 0.3%. 96.3% of the silicon was removed by alkaline desilication, and titanium-rich slag with a purity of 93.39% was produced. The total recoveries of iron, titanium, vanadium, and chromium under the experimental conditions were 88.3%, 93.7%, 81.7%, and 84.4%, respectively.

Preliminary investigations on alkali leaching kinetics of red sediment ilmenite slag

The present paper deals with soda ash roasting of red sediment ilmenite (47.03% TiO2) and leaching of obtained titanium rich slag with hydrochloric acid for preparation of synthetic rutile. The experimental conditions used for roasting are Na2CO3 to ilmenite ratio of 1: 1 at 1,223 K for 4 h. This soda ash slag product is subjected to hydrochloric acid leaching to remove the iron content. The optimum conditions for leaching achieved are 6M hydrochloric acid at 398 K for 2.5 h (10/1 liquid/solid mass ratio) at 100 rpm. Shrinking core model is found to be fit for the experimental results. The apparent activation energy is 37.9 kJ/mol. This process of soda ash roasting is one of the best processes for preparation of high purity synthetic rutile assaying about 97.21% TiO2.

Electrolytic Reduction of Titania Slag in Molten Calcium Chloride Bath

Ferro-titanium is prepared by direct electrolytic reduction of titania-rich slag obtained from plasma smelting of ilmenite in molten CaCl2. The product after electro-reduction is characterized by x-ray diffraction, scanning electron microscopy, and electron probe microanalysis. The electrolysis is carried out at a cell voltage of 3.0 V, taking graphite as the electrolysis cell as well as the anode, and a titania-rich slag piece wrapped by a nichrome wire is used as the cathode.