Recovery Of Ti Research Articles

Recovery of Ti and Li from spent lithium titanate cathodes by a hydrometallurgical process

Despite the potential application of lithium titanate (Li4Ti5O12) battery, recovering Ti and Li from the spent batteries remains a largely unexplored but important topic. In this contribution, a process including leaching, extraction for the separation of titanium from leaching liquor and synthesizing TiO2 nano-particles by a homogeneous precipitation method is presented as a successful strategy. Various operating parameters were optimized, affording more than 97% leaching efficiency of both Ti and Li at a sulfuric acid solution of 4M, H2O2 of 20vol.%, solid-to-liquid ratio of 0.025gmL−1, leaching temperature of 80°C and leaching time of 4h. In the case of the extraction, the solvent extraction efficiency of titanium about 99% can be achieved with 30vol.% primary amine N1923 as an extractant and kerosene as a diluent at highly acidic condition, organic phase/aqueous phase (O/A) ratio 2:1 within 10min of contact time in ambient temperature, while the solvent extraction efficiency of lithium is only 1.4%. The raffinate was concentrated from 0.74gL−1 to 1.11gL−1 by evaporation, then lithium carbonate was precipitated by adding saturated solution of sodium carbonate affording 85% recovery. Finally, the stripping was fast with equilibrium time of 10min with 2M H2SO4 and titanium stripping of 98%. The results of XRD and SEM show that the size of as-prepared TiO2 powders is 100–200nm from the stripped solution by the homogeneous precipitation method.

Preparation of high-value TiO2 nanowires by leaching of hydrolyzed titania residue from natural ilmenite

In this work, a simple and efficient process is developed to synthesize high-value TiO2 nanowires from natural ilmenite, combining acid and alkali leaching together. Valuable Fe and Ti were selectively divided from ilmenite by hydrochloric acid leaching, and then the obtained hydrolyzed titania residue with mainly precipitated hydrated TiO2 was leached by sodium hydroxide and hydrogen peroxide. Ti and Si were monitored by ICP and EDS during the process. The effects of NaOH to-hydrolyzed titania residue (Na+/Ti4+) molar ratio, H2O2 to-hydrolyzed titania residue (O22−/Ti4+) molar ratio, leaching temperature and leaching time on leaching of hydrolyzed titania residue were investigated. Results indicated that the recovery of Ti was 96.39% and dissolution of Si was 67.9% under the optimal conditions: Na+/Ti4+ molar ratio of 8/1, O22−/Ti4+ molar ratio of 6/1, leaching temperature of 30°C and leaching time of 30min. And then simple boiling divided the Ti and Si very efficiently resulting in high-purity of synthetic TiO2 within 0.47% of SiO2. Meanwhile, the high-value TiO2 exhibited echinus-like structure with aggregations of nanowires and well-crystallized anatase phase at 400°C.

Mineralogical characterization and leaching behavior of Nigerian ilmenite ore

The characterization and H2SO4 leaching behavior of a Nigerian ilmenite ore following mechanical activation and alkali roasting were investigated. The effects of NaOH/ore ratio, H2SO4 concentration, leaching and roasting temperature on the Ti recovery from the milled ore were examined. The results show that mechanical activation significantly enhances the dissolution of ilmenite ore. Under the leaching conditions of 90 °C, 60% (v/v) H2SO4 and 4 h, about 72% Ti extraction was obtained from a milled ore roasted at 850 °C with 60% NaOH. X-ray diffraction (XRD) phase analysis of the roasted mass, water treated residue and leach residue supports the reaction mechanism and experimental results.

Sensitive Voltammetric Determination of Titanium(IV) in Catalytic Adsorptive Mandelic Acid‐Chlorate(V) System on Renewable Silver Amalgam Film Electrode

AbstractThe renewable mercury film electrode, applied for the determination of titanium(IV) ultratraces using differential pulse catalytic adsorptive cathodic stripping voltammetry (DP CAdSV) in the presence of mandelic acid as a ligand and chlorate(V) as an oxidant is represented. The calibration graph obtained for Ti(IV) is linear from 0.05 nM (2.39 ng L−1) to 95 nM (4.55 µg L−1) for a preconcentration time of 30 s, with correlation coefficient of 0.9995. For the renewable mercury electrode (Hg(Ag)FE) with a surface area of 8.6 mm2 the detection limit for a preconcentration time of 180 s is as low as 0.006 nM (0.29 ng L−1). The repeatability of the method at a concentration level of the analyte as low as 23.9 ng L−1, expressed as RSD is 1.8 % (n=5). The proposed method was successfully applied and validated by studying the certified reference material NWTM‐26.3 and simultaneously recovery of Ti(IV) from spiked samples.

Leaching of ilmenite ores by acidic chloride solutions

The direct leaching of Australian ilmenite ore samples with HCl was found to be much more effective with high chloride (Cl−) concentration (~500g/L) in the feed solution. The presence of CaCl2 was more effective for leaching than that of MgCl2 and NaCl due to its higher solubility. The effects of pulp density, retention time, HCl concentration, CaCl2 concentration and temperature were examined to optimise the leaching conditions. The optimum conditions for leaching ilmenite in this study were found to be 5–7.5M HCl solution with a total Cl− concentration of ~500g/L, 3.3% (w/w) pulp density, 70–80°C and 4–6h of retention time. Under these conditions, the optimum leaching efficiencies were ~98–99% Ti and 96% Fe for ilmenite ore A and 94% Ti and 93% Fe for ilmenite ore B. One of the advantages of the HCl–CaCl2 direct leach process is that the HCl–CaCl2 solution can be recycled back to leaching after Ti recovery. The leach residue containing mainly unleached rutile and pseudorutile can be used as a feed for synthetic rutile production.

Study on Utilization Technology of Vanadium Titanium Magnetite Based on the Rotary Hearth Furnace Direct Reduction Process

Through carrying out large scale of experiments, the process of ‘rotary harth furnace direct reduction—deep reduction electric arc furnace—extracting vanadium from vanadium bearing slag—extracting titanium from titanium bearing slag gets through and the recovery of Fe, V and Ti reached 90.77%, 43.82% and 72.65% respectively. With the study on the laboratory experiments and industrial tests, the bottlenecks of this technology such as low metallization rate of vanadium-titanium magnetite in direct reduction process, low reduction rate of vanadium in EAF, vanadium-recovery of hot metal with high silicon content, titanium-recovery of high –Mg &Al slag with titanium, and so on, have been solved. Based on this, the metallization rate of vanadium-titanium magnetite in direct reduction process is more than 90%, reduction rate of vanadium in EAF deep reduction process is more than 80%, vanadium-recovery rate in slag is more than 65%, and titanium-recovery rate in slag is more than 75%. That means good study results have been gotten. Furthermore, low-carbon pig iron with good quality in EAF steelmaking are gotten. Otherwise, V2O5 sheet and titanium products can meet the requirements of GB3283-87 and PTA121, respectively.

Preparation of TiO2 from ilmenite using sulfuric acid decomposition of the titania residue combined with separation of Fe3+ with EDTA during hydrolysis

A new process of “mechanical activation–hydrochloric acid leaching–concentrated sulfuric acid decomposition–water leaching–separation of Fe3+ with EDTA during hydrolysis” was proposed to prepare high-purity TiO2 from Panzhihua ilmenite. The hydrolyzed titania residue prepared from mechanically activated Panzhihua ilmenite leached by hydrochloric acid was decomposed by concentrated sulfuric acid and subsequently dissolved in water yielding titanium sulfate solution. In order to improve the purity of the precursor during the hydrolysis of TiO2+, EDTA was investigated as an additive to restrain the hydrolysis of Fe3+. The effects of sulfuric acid concentration, acid-to-titania residue mass ratio in the process of acid digestion and the significant effects of water leaching time, leaching temperature and liquid-to-solid mass ratios on the recovery of Ti from the residue were studied in this paper. The recovery of Ti was above 98% under optimal conditions. Well-crystallized anatase TiO2 and rutile TiO2 could be obtained through calcining at different temperatures and no impurity can be detected by EDS in titanium dioxide. The results demonstrated that the process is inexpensive, environment friendly and promising in preparing high-purity TiO2 from ilmenite with a high content of gangues like Panzhihua ilmenite.

A novel approach for determining total titanium from titanium dioxide nanoparticles suspended in water and biosolids by digestion with ammonium persulfate

Titanium dioxide (i.e. TiO 2) in nano-form is a constituent of many nanomaterials that are used in sunscreens, cosmetics, industrial products and in biomedical applications. Quantification of TiO 2 nanoparticles in various matrixes is a topic of great interest for researchers studying the potential health and environmental impacts of nanoparticles. However, analysis of TiO 2 as Ti 4+ is difficult because current digestion techniques require use of strong acids that may be a health and safety risk in the laboratory. To overcome this problem, we developed a new method to digest TiO 2 nanoparticles using ammonium persulfate as a fusing reagent. The digestion technique requires short times to completion and optimally requires only 1 g of fusing reagent. The fusion method showed >95% recovery of Ti 4+ from 6 μg mL −1 aqueous suspensions prepared from 10 μg mL −1 suspension of different forms of TiO 2, including anatase, rutile and mixed nanosized crystals, and amorphous particles. These recoveries were greater than open hot-plate digestion with a tri-acid solution and comparable to microwave digestion with a tri-acid solution. Cations and anions commonly found in natural waters showed no significant interferences when added to samples in amounts of 10 ng to 110 mg, which is a much broader range of these ions than expected in environmental samples. Using ICP-MS for analysis, the method detection limit (MDL) was determined to be 0.06 ng mL −1, and the limit of quantification (LOQ) was 0.20 ng mL −1. Analysis of samples of untreated and treated wastewater and biosolids collected from wastewater treatment plants yielded concentrations of TiO 2 of 1.8 and 1.6 ng mL −1 for the wastewater samples, respectively, and 317.4 ng mg −1 dry weights for the biosolids. The reactions between persulfate ions and TiO 2 were evaluated using stoichiometric methods and FTIR and XRD analysis. A formula for the fusing reaction is proposed that involves the formation of sulfate radicals.

Hydrogen peroxide leaching of hydrolyzed titania residue prepared from mechanically activated Panzhihua ilmenite leached by hydrochloric acid

The hydrolyzed titania residue with mainly precipitated hydrated TiO2 is prepared from mechanically activated Panzhihua ilmenite leached by hydrochloric acid. We use H2O2 as a coordination agent to leach Ti from the hydrolyzed titania residue. The effects of H2O2 to-hydrolyzed titania residue mass ratio, leaching pH value, leaching temperature, leaching time, and H2O2 concentration on leaching of hydrolyzed titania residue by H2O2 are investigated. The recovery of Ti is above 98% under the optimal conditions. XRD shows that the peroxo-titania powder prepared by boiling the aqueous titanium peroxide solution is crystalline anatase phase. A well-crystallized anatase TiO2 and rutile TiO2 can be obtained through calcining at the temperature of 800 and 1000°C, respectively. EDS shows that the impurities including silicon are enriched in the leaching slag. Little Si is detected as the only impurity in the synthetic TiO2 due to the weak alkaline condition of leaching.

Study on leaching Ti from Ti bearing blast furnace slag by sulphuric acid

The treatment for leaching Ti using sulphuric acid was investigated in order to utilise Ti bearing blast furnace slag including water quenched slag (WQS) and naturally cooled slag (NCS). Ti bearing blast furnace slag was subjected to direct agitation leaching with dilute sulphuric acid. Variables such as acid concentration, temperature, leaching time, liquid/solid ratio, particle size and stirring speed were studied. It was shown that, when WQS material (size range, 0–0·5 mm) was reacted with sulphuric acid of 50% concentration at a stirring speed of 400 rev min–1 with a liquid to solid weight ratio of 10 at 100°C for 1 h, Ti recovery from leaching was up to 72·3%. However, for NCS, Ti recovery was only ∼45% under comparative leaching conditions. A possible leaching mechanism and the difference of leaching effect between WQS and NCS are discussed. Unlike NCS, WQS is a type of activated slag, making it more favourable for extraction of Ti.

Production of Al–Ti–B grain refining master alloys from Na 2B 4O 7 and K 2TiF 6

It is very desirable to replace the KBF 4 salt in the popular “halide salt” process to reduce the volume of fluoride salts to be added to molten aluminium in the production of Al–Ti–B grain refiners. Being over 2 times richer in B, Na 2B 4O 7 is a promising replacement for KBF 4, and is used in the present work to produce Al–Ti–B grain refiner master alloys. A fraction of the aluminide particles were entrapped in the spent salt giving a relatively lower Ti recovery when KBF 4 was replaced by Na 2B 4O 7. The grain refining performance of the Al–Ti–B grain refiner alloy thus produced was nevertheless acceptable. The spent salt became too viscous with the oxides, aluminides and borides to be removed by decanting when Na 2B 4O 7·5H 2O was used to supply boron. The viscous spent salt, entrained in the grain refiner alloy, did not only impair its performance, but also hurt the fluidity of the molten alloy and made pouring difficult.

Difficulties with Ti-Ni Powder Metallurgy Process and Multi-Stage Sintering Technique for TiNi SMA

A study of the exothermic behavior of reactions that occur within Ni and Ti elemental powder mixtures during heating in medium vacuum (4 x 10 -3 Pa) has been conducted. In comparison with several other ordered intermetallic compound mixes, a much more violently released exothermic heat was observed in the Ti-50Ni mixture. It indicates that the difficulties associated with a common powder metallurgy process for TiNi shape memory alloy (SMA) include the possible oxygen interaction in a low vacuum condition and the large and rapidly generated exothermic heat in a medium or high vacuum condition. Therefore, a multi-stage sintering process is proposed to fabricate the TiNi SMA powder metallurgy (P/M) specimens and their composites. In order to prevent the violently released exothermic heat, the sintering process was divided into several repeated cycles with intermediate cold deformation, and a relatively low sintering temperature, 1030°C (or 1080°C), was employed. Further study of the SMA composites, Ti 50 Ni 50 + 5vol%TiC and Ti 50 Ni 50 + 10vol%TiC, with this technique was presented in this article. The obtained sintering density is above 85%. In the meantime, 94.5% (50%) recovery of Ti 50 Ni 50 + 5vol%TiC (Ti 50 Ni 50 + 10vol%TiC) after 1.0% tensile strain then heated to 80°C were observed. The results of phase transformation and microstructure examination will also be discussed.

A New Process for the Production of Ferrotitanium from Titania Slag

In this research, ferrotitanium was produced from titania slag by an aluminothermic process in an Electro Slag Crucible Melting (ESCM) furnace. The effect of Al and flux additions on titanium recovery, ferrotitanium yield and Ti/Al ratio were studied. It was found that an increase in Al amount led to a decrease in Ti recovery and Ti/Al ratio, in addition to an increase in ferrotitanium yield. Furthermore, increasing the flux amount led to an increase in ferrotitanium yield and Ti/Al ratio. X-ray diffraction (XRD) patterns of the ferrotitanium slag showed that the titanium recovery declined due to the formation of titanium suboxides and tialite in slag. Analysis of ferrotitanium samples, prepared in various conditions, were 45-54.5% Ti, 6-11% Al, 9-11% Si, 0.7-0.9% C, 1.6-2 % Mn, 0.07-0.08 % P and 0.004-0.009% S.

Production of Al–Ti–B grain refining master alloys from B 2O 3 and K 2TiF 6

It is very desirable to replace the KBF 4 salt in the popular “halide salt” process to reduce the volume of fluoride-bearing particulate material to be added to molten aluminium. Several practices all relying on B 2O 3 to supply B, were employed in the present work to produce Al–5Ti–1B grain refiners. Replacing the KBF 4 salt in the halide salt process entirely with B 2O 3, has not only impaired the grain refining performance, but, with the dross generated, has also hurt the fluidity of the melt making pouring difficult. A significant improvement was noted both in the microstructural features and in the grain refining efficiency when B 2O 3 was pre-mixed with a drossing flux to promote the seperation of oxides from the molten alloy. However, this practice has almost completely negated the particulate material savings offered by B 2O 3. The Ti recovery and the grain refining efficiency achieved when B 2O 3 and KBF 4 were used together to supply B, was nearly as good as when the latter was used alone. It is thus concluded that KBF 4 can be replaced with B 2O 3, only partially, to take advantage of lower fluoride emissions and particulate material savings without a penalty in grain refining efficiency.

Martensitic transformation and shape memory effect of Ti–49 at.%Ni alloys

For binary TiNi shape memory alloys, most research work has been devoted to the equiatomic or Ni-rich TiNi alloys, while very few systematical researches are reported on Ti-rich TiNi alloys. In this paper, the martensitic transformation and shape memory effect of Ti-rich Ti–49 at.%Ni alloy were investigated by differential scanning calorimetry, optical microscopy, X-ray diffraction and testing of shape memory in a self-fabricated device. Ti–49 at.%Ni alloy specimens were annealed at 850 °C for 2 h and then cooled in a furnace or in water. The results show that the microstructure of Ti–49 at.%Ni alloys at room temperature consists of three phases, martensite phase B19′ and precipitate phase Ti 2Ni, as well as a small amount of retained parent phase B2. The difference of cooling conditions from annealing temperature 850 °C does not affect the martensitic transformation temperatures and microstructure of Ti–49 at.%Ni alloy. However, furnace cooling contributes to better shape recovery of Ti–49 at.%Ni alloy compared with water quenching. With increasing pre-strain, both one-way and two-way shape recovery of Ti–49 at.%Ni alloy decreases gradually. After 0.38% pre-strain deformation at −30 °C, the Ti–49 at.%Ni specimen exhibits 100% one-way shape recovery upon heating to 180 °C.

Transit time and digestibility of two experimental diets in the maned wolf (Chrysocyon brachyurus) and domestic dog (Canis lupus)

AbstractRecent research involving nutritional management of clinical disease secondary to cystinuria in captive maned wolves (Chrysocyon brachyurus) in the United States resulted in the production of a commercially manufactured maintenance diet and subsequently, a further modified experimental diet. These two diets differed only in their protein sources and sodium concentrations. The purpose of this study was to further investigate these diets by determining their digestibility and transit time in maned wolves, and also to compare these results to the digestibility and transit time of the diets in domestic dogs. The experiment consisted of two diets (maned wolf commercial maintenance diet and experimental diet) and two species (maned wolf and domestic dog [beagle]) arranged as a 2 × 2 factorial design. For the transit time study, titanium dioxide (TiO2, 5 g/kg diet) was administered as a pulse dose and total collection of feces was carried out for 50 hr. There was no effect of diet or species on initial Ti recovery time (IRT), the amount of Ti recovered at IRT, or the time to reach 50% of Ti excretion in the feces. Maned wolves had lower total percent recovery (P<0.01) of Ti than dogs and shorter time to last recovery of Ti in the feces (P<0.05), however, marker excretion in the maned wolves may not have been complete. For the digestibility study, in which chromic oxide was used as a marker, fecal samples were collected on 2 consecutive days immediately after 12 days of being fed the diets and then analyzed for dry matter, energy, protein, and minerals. Crude protein, calcium, phosphorus, and zinc apparent digestibilities were unaffected by species or diet (P>0.05). Apparent digestibility of dry matter (P<0.05) and energy (P<0.01) were higher in the experimental diet and in the dogs. Both dogs and maned wolves fed the maintenance diet exhibited a greater apparent retention of copper, iron, and magnesium (P<0.01). Dogs had a higher apparent retention of magnesium and sodium than the maned wolves. Zoo Biol 0:1–13, 2006. © 2006 Wiley‐Liss, Inc.

Influence of Chelating Agents on the Recovery of Al(III), Fe(III), Ti(IV) and Na(I) from Red Mud by Cation Exchange Membranes

The metal recovery from red mud solution containing chelating agents such as nitriloacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), citric acid, and phosphoric acid were studied by using the Neosepta CMX and CMB cation exchange membranes in Donnan dialysis process. The stripping solution was 1.0 M HCl solution and no external potential field is applied. The efficiency of chelating agents on the recovery of metal ions through membranes was correlated with the flux data. It was observed that the removal and fluxes of metals were enhanced with citrate, EDTA and NTA chelating agents in contrast were decreased with phosphate complexing agent.

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The direct leaching of Australian ilmenite ore samples with HCl was found to be much more effective with high chloride (Cl−) concentration (~ 500 g/L) in the feed solution. The presence of CaCl2 was more effective for leaching than that of MgCl2 and NaCl due to its higher solubility. The effects of pulp density, retention time, HCl concentration, CaCl2 concentration and temperature were examined to optimise the leaching conditions. The optimum conditions for leaching ilmenite in this study were found to be 5–7.5 M HCl solution with a total Cl− concentration of ~ 500 g/L, 3.3% (w/w) pulp density, 70–80 °C and 4–6 h of retention time. Under these conditions, the optimum leaching efficiencies were ~ 98–99% Ti and 96% Fe for ilmenite ore A and 94% Ti and 93% Fe for ilmenite ore B. One of the advantages of the HCl–CaCl2 direct leach process is that the HCl–CaCl2 solution can be recycled back to leaching after Ti recovery. The leach residue containing mainly unleached rutile and pseudorutile can be used as a feed for synthetic rutile production.

Recovery and Concentration of Al(III), Fe(III), Ti(IV), and Na(I) from Red Mud

The transport of Al(III), Fe(III), Ti(IV), and Na(I) ions through charged polysulfonated membrane under Donnan dialysis conditions has been studied as a function of HCl concentration at room temperature. In this process, the membrane is separated by two electrolyte solutions: one side (donor phase) is initially red mud aqueous solution containing Al(III), Fe(III), Ti(IV), and Na(I) ions and the other side is HCl solution at different concentrations with no external potential field applied. The transport of metal ions through membranes was correlated with the flux data, as well as with estimated diffusion coefficients. It was observed that the transport of metals is influenced by the HCl concentration and the flux of ions increased with H+ ion concentration in the receiver phase.

Production of Aluminum-Titanium-Boron Master Alloy by Aluminothermic Process

Al-Ti-B alloys are used as commercial alloys in the aluminum and steel industry. Reacting chemical salts of titanium and boron with molten aluminum produces alloys that are used in the aluminum industry, while Al-Ti-B alloys for the steel industry are produced by metallothermic reactions. In this study, pre-alloys with high titanium and boron contents that may be used for the production of aluminum alloys are produced by a metallothermic reduction process. The effect of the addition of the thermite mixture, which consists of potassium chlorate and aluminum, on the Ti, Al and B content of the alloy and Ti and B recovery, was investigated at the stoichiometric aluminum addition and by varying B 2 O 3 /TiO 2 ratio. An alloy containing 49.8% Ti, 5.7% B, 24.7% Al in metallic and 4.6% Al in oxide form was obtained by 46.9% Ti and 47.7% B recovery at a B 2 O 3 /TiO 2 ratio of 0.22 and by adding a thermite mixture which is 50% of the charged amount. At the same B 2 O 3 /TiO 2 ratio, the effect of CaO addition on the Ti, Al and B contents of the alloy and on Ti and B recoveries was also studied. CaO addition had no beneficial effect on metal recoveries. By varying the B 2 O 3 /TiO 2 to 0.33 and thermite mixture/charge ratio to 60%, Ti, B and metallic Al content of the alloy changed to 63.1%, 7.7% and 25.0% respectively, and recovery of Ti and B was 66.5% and 47.7% respectively. In this alloy, Al in oxide form was determined as 2.0%.