Titanium oxide, extraction

Titanates and silico-titanates The oxide and hydroxide of titanium are effectively used in applications of removing metal ions from water. Early studies (since 1955) have shown that hydrous titanium oxide is the most appropriate material for extracting uranium from seawater, whereas titanates and hydrous titanium oxide are suitable for removing strontium. 

Titanium cesium alum, 6 50 Titanium (II) chloride from disproportionation of titanium (III) chloride, 6 56, 61 Titanium(III) chloride, 6 52, 57 Titanium (IV) chloride, reduction of, with hydrogen, 6 52, 57 Titanium complex compounds, cations, with acetylacetone, [Ti-(C.H. hTiCl, and [Ti(C6H7-0,),]FeCl , 2 119, 120 Titanium(IV) oxide, extraction of, from ilmenite, 5 79, 81 to titanium powder with calcium, 6 47... 

The chief mined ore of titanium is ilmenite (iron titanium oxide, FeTiC>3) and it occurs as vast deposits of sand in Western Australia, Canada and the Ukraine. Large deposits of rutile (titanium dioxide, TiO ) are known in North America, and South Africa. World production of the metal itself is around 90,000 tonnes per year, small compared to titanium dioxide production which is 4.3 million tonnes per year. Reserves of titanium amount to more than 600 million tonnes and while there is an abundance of this element it is extremely costly because it has to be extracted by a complicated process, and yet it could be so much more useful if it was cheaply available. 

The achievement of an economically viable process for the extraction of uranium fix>m seawater, however, could be achieved only through use of a sorbent with uranium concentrating factors greater than those provided by titanium oxides [181]. Polyacrylamidoxime sorbents, characterized by D value > 10 ( 10 ) (see Table 5) made an appearance at the end of the 1970s to remove this impediment to the economic recovery of uranium fix>m seawater. Their appearance reoriented research in the field of uranium recovery toward highly selective organic resins [188, 189]. 

Titanium is a transition metal used in many alloys because it is extremely strong and lightweight. Titanium tetrachloride (TiC ) is extracted from titanium oxide using chlorine and coke (carbon). 

In the petrochemical industry sulfuric acid is utilized, for example, in the alkylation of isoalkanes with alkenes, in the chemical industry in the manufacture inorganic chemicals (e.g. hydrofluoric acid, chromic acid, aluminum sulfate) and organic products (e.g. dyes, explosives, isocyanates, soaps, detergents, fibers and pharmaceuticals). Sulfuric acid is also utilized in the manufacture of titanium oxide pigments, uranium and copper extraction, in steel pickling and in batteries. 

Although strontium is one of the major metal ion constituents in sea water, its concentration of 8.1 mg/1 is about 50 times lower than that of calcium. No procedures are known for a commercial recovery of strontium from sea water. Strontium can be extracted from sea water along with uranium and other elements by hydrous titanium oxide. However, only 120-fold concentration has been reached... 

Extraction. — Rutile is exceedingly resistant to chemical action. Either rutile or ilmenite may be brought into solution by fusion with alkali, alkali carbonate, or bisulfate and extracting with add. By adding ammonia to this solution a mixture of iron and titanium oxides is thrown down. Another satisfactory method fuses the ore with carbon in an electric furnace, subjects the carbides to the action of chlorine, and distills off the volatile titanium tetrachloride.2... 

In a December 1974 report, Battelle Pacific Northwest Laboratory [B2] summarized the principal processes that had been proposed for extracting uranium from seawater and gave references to more detailed descriptions of these processes. That report concluded that the most promising process was the selective adsorption of uranium from seawater on hydrous titanium oxide (titania). 

Here we show that the polarity of polymer solar cells can be reversed by changing the position of two interfacial layers vanadium oxide (V2O5) layer as hole injection and cesium carbonate (CS2CO3) layer as electron injection, independent of the top and bottom electrodes. ° Since our first demonstration of inverted solar cells, more and more interests have focused on this new architecture. Waldauf et al. demonstrated inverted solar cells with a solution-processed titanium oxide interfacial layer. White et al. developed a solution-processed zinc oxide interlayer as efficient electron extraction contact and achieved 2.58% PCE with silver as a hole-collecting back contact. It is noteworthy to mention that EQE value for inverted solar cells approaches 85% between 500 and 550 nm, which is higher than that of normal polymer solar cells. This is possibly due to (i) the positive effect of vertical phase separation of active layer to increase the selection of electrode and (ii) lower series resistance without the PEDOT PSS layer. 

Cobalt titanium oxide Cocoa (Theobroma cacao) extract Cocodimonium hydroxypropyl silk amino acids Coconut (Cocos nucifera) extract Coffee (Coffea arabica) extract Coneflower (Echinacea angustifolia) extract Coneflower (Echinacea pallida) extract Coneflower (Echinacea purpurea) extract Connective tissue extract Copper acetate (ic) Copper acetylmethionate Copper aspartate Copper gluconate (ic) Cornflower (Centaurea cyanus) extract Com (Zea mays) germ extract... 

Transition metal oxides that do not change their transparency, or color very little, under ion/electron insertion and extraction can also be used as a counter electrode in electrochromic devices anploying tungsten oxide as a cathodic material. There has been particular interest in oxides based on vanadium pentoxide and cerium oxide. Pure V2O5 as well as a mixture of vanadium and titanium oxide are of interest. Cerium-based mixed oxides, in particular cerium-zirconium oxide (Veszelei et al. [1999]), exhibit less optical absorption, but the stability is not sufficient for many applications. 

Coaxial spinning can also be used to form polymer-particle composite nanofibers as discussed in Chapter 6. Li et al. (2005a), in their research on decorating the interior of hoUow nanofibers with nanoparticles, used this technique very effectively. The core fluid used was a ferrofluid of magnetic iron oxide particles and the shell layer was a mixture of poly(vinyl p5u-olhdone)/ titanium isopropoxide. Extraction of the core phase of the core-shell nanofibers with octane yielded hollow, magnetically susceptible nanofibers, with their interiors decorated with oxide nanoparticles. 

Chlorination. In some instances, the extraction of a pure metal is more easily achieved from the chloride than from the oxide. Oxide ores and concentrates react at high temperature with chlorine gas to produce volatile chlorides of the metal. This reaction can be used for common nonferrous metals, but it is particularly useful for refractory metals like titanium (see Titanium and titanium alloys) and 2irconium (see Zirconium and zirconium compounds), and for reactive metals like aluminum. 

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