Titanium Metals from

Alternatively, the TiCl may be reduced using hydrogen, sodium, or magnesium. It follows that TiCl2 is the first stage in the KroU process for the production of titanium metal from titanium tetrachloride. A process for recovery of scrap titanium involving the reaction of scrap metal with titanium tetrachloride at >800° C to form titanium dichloride, collected in a molten salt system, and followed by reaction of the dichloride with magnesium to produce pure titanium metal, has been patented (122,123). 

Figure 4.23 Vacuum distillation assembly for separation of zirconium/titanium metals from reduction products.

PROBLEM 20.17 How many liters of Cl2 at 20°C and 740 mm Hg pressure would be needed to produce 1.00 X 105 tons of titanium metal from Ti02 if the overall yield is 93.5% ... 

Airplane parts with high strength and low weight are sometimes made from materials containing the metal titanium. One step in the process of purifying titanium metal from its ore is ... 

Fig. 290. Preparation of titanium metal from titanium (IV) chloride and magnesiiun. a) chrome-nickel alloy outer container (Inconel, Nichrome, or other similar alloys may be used) h) iron crucible c) molybdenum lining d) iron-plate lid e) adapter cover /) cooling chambers g) cooling coils (lead) h) vacuum line i) rubber balloon for Ar k) rubber connections and seals 1) iron inlet tube for TiCU in) dropping funnel with TiCU n) electrodes o) calcium rods p) glass adapter for a sight glass

We can obtain titanium metal from its oxide according to the following balanced equation TiOaW + 2C(i) Ti(5) + 2CO(g)... 

The U.S. titanium market distribution is shown in Table 18. Before 1970, more than 90% of the titanium produced was used for aerospace, which feU to ca 70—80% by 1982. Mihtary use has continually decreased from nearly 100% in the early 1950s to 20% in the 1990s. In contrast to the United States, aerospace uses in Western Europe and Japan account for only 40—50% of the demand (58). The CIS s consumption of titanium metal prior to the breakup was about one-half of the world consumption. In the 1980s, considerable amounts were used for submarine constmction. Since the breakup of the former Soviet Union, the internal consumption of titanium in the CIS is beheved to be a modest fraction of its former capacity, thus leaving a large capacity available for export. The world production faciUties for titanium metal and extraction are given in Table 19. 

A number of high temperature processes for the production of titanium carbide from ores have been reported (28,29). The aim is to manufacture a titanium carbide that can subsequently be chlorinated to yield titanium tetrachloride. In one process, a titanium-bearing ore is mixed with an alkah-metal chloride and carbonaceous material and heated to 2000°C to yield, ultimately, a highly pure TiC (28). Production of titanium carbide from ores, eg, ilmenite [12168-52-4], EeTiO, and perovskite [12194-71 -7], CaTiO, has been described (30). A mixture of perovskite and carbon was heated in an arc furnace at ca 2100°C, ground, and then leached with water to decompose the calcium carbide to acetjdene. The TiC was then separated from the aqueous slurry by elutriation. Approximately 72% of the titanium was recovered as the purified product. In the case of ilmenite, it was necessary to reduce the ilmenite carbothermaHy in the presence of lime at ca 1260°C. Molten iron was separated and the remaining CaTiO was then processed as perovskite. 

Direct synthesis from nitrogen and finely divided titanium metal can be achieved at temperatures of >ca 1200° C (4). Typically, titanium sponge or powder is heated in an ammonia- or nitrogen-filled furnace and the product is subsequently milled and classified. 

Titanium Monoxide. Titanium monoxide [12137-20-17, TiO, has a rock-salt stmcture but can exist with both oxygen and titanium vacancies. For stoichiometric TiO, the lattice parameter is 417 pm, but varies from ca 418 pm at 46 atom % to 4I62 pm at 54 atom % oxygen. Apparendy, stoichiometric TiO has ca 15% of the Ti and O sites vacant. At high temperatures (>900° C), these vacancies are randomly distributed at low temperatures, they become ordered. Titanium monoxide may be made by heating a stoichiometric mixture of titanium metal and titanium dioxide powders at 1600°C... 

Both anatase and mtile are broad band gap semiconductors iu which a fiUed valence band, derived from the O 2p orbitals, is separated from an empty conduction band, derived from the Ti >d orbitals, by a band gap of ca 3 eV. Consequendy the electrical conductivity depends critically on the presence of impurities and defects such as oxygen vacancies (7). For very pure thin films, prepared by vacuum evaporation of titanium metal and then oxidation, conductivities of 10 S/cm have been reported. For both siugle-crystal and ceramic samples, the electrical conductivity depends on both the state of reduction of the and on dopant levels. At 300 K, a maximum conductivity of 1 S/cm has been reported at an oxygen deficiency of... 

Titanium tetraiodide can be prepared by direct combination of the elements at 150—200°C it can be made by reaction of gaseous hydrogen iodide with a solution of titanium tetrachloride in a suitable solvent and it can be purified by vacuum sublimation at 200°C. In the van Arkel method for the preparation of pure titanium metal, the sublimed tetraiodide is decomposed on a tungsten or titanium filament held at ca 1300°C (152). There are frequent hterature references to its use as a catalyst, eg, for the production of ethylene glycol from acetylene (153). 

Titanium disulfide can also be made by pyrolysis of titanium trisulfide at 550°C. A continuous process based on the reaction between titanium tetrachloride vapor and dry, oxygen-free hydrogen sulfide has been developed at pilot scale (173). The preheated reactants ate fed iato a tubular reactor at approximately 500°C. The product particles comprise orthogonally intersecting hexagonal plates or plate segments and have a relatively high surface area (>4 /g), quite different from the flat platelets produced from the reaction between titanium metal and sulfur vapor. The powder, reported to be stable to... 

A remarkable change in reaction course is notable when changing the metal from aluminum to titanium for cydoaddition reactions using BINOL as the chiral ligand. When the chiral aluminum(III) catalyst is applied the cydoaddition product is the major product, whereas for the chiral titanium(IV) catalyst, the ene product is the major product. The reason for this significant change in reaction course is not fully understood. Maybe the glyoxylate coordinates to the former Le-... 

Titanium has an unusually high ratio of strength to weight. It is considerably stronger than either aluminum or steel, two metals with which it competes (for special purposes). Its density (4.5 g/cm3) is intermediate between that of Al (2.7 g/cm3) and that of Fe (7.9 g/cm3). Titanium is extremely resistant to corrosion by air, soil, seawater, and even such reactive chemicals as nitric acid and chlorine gas. Like aluminum, it forms a thin, tightly adherent oxide layer that protects the metal from further attack. 

Lest you suppose that titanium is a metal for all purposes, we should point out one of its limitations. It is far more expensive than aluminum or steel, selling for about 50 a kilogram in 2007. The high cost of extracting the metal from ilmenite ore makes it very, very unlikely that you will ever see lawnmowers or kitchen sinks made out of titanium. 

Hydrogen reduction has a major advantage in that the reaction generally takes place at lower temperature than the equivalent decomposition reaction. It is used extensively in the deposition of transition metals from their halides, particularly the metals of Groups Va, (vanadium, niobium, and tantalum) and Via (chromium, molybdenum, and tungsten). The halide reduction of Group IVa metals (titanium, zirconium, and hafnium) is more difficult because their halides are more stable. 

C04-0111. The element titanium is commonly found as the ore ilmenite, F eTi03. Much of the world reserves of titanium is found in Canada. At a particular mine, a sample of earth was found to contain 15% ilmenite by mass. What mass of pure titanium metal can be isolated from 1.00 x 10 metric tons of earth, if the extraction process is 95% efficient ... 

Figure 1 shows AES data for the oxidized titanium surface before and after deposition of 30 X of platinum with the substrate held at 130 K. The platinum thickness was calculated from the attenuation of the oxygen AES signal assuming layered growth of the metal. From the spectra It Is clear that the platinum was sufficient to completely attenuate the underlaying features of the titanium oxide. 

For preparative purposes, titanium metal can be used in place of sodium or lithium in liquid ammonia for both the vinyl phosphate231 and aryl phosphate232 cleavages. The titanium metal is generated in situ from TiCl3 by reduction with potassium metal in tetrahydrofuran. 

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