Ilmenite properties

Titanium, Ti, a light, strong metal, is used where these properties are critical— in widely diverse applications such as jet engines and dental fixtures such as partial plates. Although titanium is relatively reactive, unlike scandium it is resistant to corrosion because it is passivated by a protective skin of oxide on its surface. The principal sources of the metal are the ores ilmenite, FeTiO , and rutile, Ti02. 

Titanium dioxide (E171, Cl white 6) is a white, opaque mineral occurring naturally in three main forms rutile, anatase, and brookite. More than 4 million tons of titanium dioxide are produced per year and it is widely used for industrial applications (paints, inks, plastics, textiles) and in small amounts as a food colorant. ° "° Production and properties — Titanium oxide is mainly produced from ilmenite, a titaniferous ore (FeTiOj). Rutile and anatase are relatively pure titanium dioxide (Ti02) forms. Titanium oxide pigment is produced via chloride or sulfate processes via the treatment of the titanium oxide ore with chlorine gas or sulfuric acid, followed by a series of purification steps. High-purity anatase is preferred for utilization in the food industry. It may be coated with small amounts of alumina or silica to improve technological properties. 

The electrostatic separation method is the exclusive choice in some specific situations, for example in the cases of rutile and ilmenite deposits. These deposits generally contain minerals of similar specific gravities and similar surface properties so that processes such as flotation are unsuitable for concentration. The major application of electrostatic separation is in the processing of beach sands and alluvial deposits containing titanium minerals. Almost all the beach sand plants in the world use electrostatic separation to separate rutile and ilmenite from zircon and monazite. In this context the flowsheet given later (see Figure 2.35 A) may be referred to. Electrostatic separation is also used with regard to a number of other minerals. Some reported commercial separations include those of cassiterite from scheelite, wolframite from quartz, cassiterite from columbite, feldspar from quartz and mica, and diamond from heavy associated minerals. Electrostatic separation is also used in industrial waste recovery. 

Ta/Nb minerals often occur as impurities in ilmenite, rutile, cassiterite, wolframite and perovskite, most of which contain REE. Because tantalite and columbite have similar chemical properties, they often replace each other, and are usually found as isomorph mixtures. Tantalum and niobium can also be found as separate minerals. Tantalite and microlite are primary sources of tantalum. 

It was a known fact that flotation properties of both chromite and ilmenite are similar and they float equally well using either tall oil or amine collectors. Development testwork involved the examination of different ilmenite depressants and different chromium collectors. Depressants examined in this study included com starch, NaF and H2SiF6 at a low pH. Good ilmenite depression was achieved using H2SiF6, while the chromium was not affected. Similar results were achieved using NaF. 

Titanium - the atomic number is 22 and the chemical symbol is Ti. The name derives from the Latin titans, who were the mythological first sons of the earth . It was originally discovered by the English clergyman William Gregor in the mineral ilmenite (FeTiOj) in 1791. He called this iron titanite menachanite for the Menachan parish where it was found and the element menachin. It was rediscovered in 1795 by the German chemist Martin Heinrich Klaproth, who called it titanium because it had no characteristic properties to use as a name. Titanium metal was first isolated by the Swedish chemists Sven Otto Pettersson and Lars Fredrik Nilson. 

Various well-known industrial and municipal waste products particularly those from the base metal industry, contain appreciable amounts of Fe oxides which may make them suitable for remediation purposes. Two examples from industry are the residues from the alumina and the titanium industries. The extraction of either Al or Ti from the natural ores (bauxite and ilmenite/rutile, respectively) leaves behind an alkaline and acidic (sulphuric) residue, respectively, in which Fe oxides are enriched, as indicated by their names Red Mud and Red Gypsum . A sample of Red gypsum is reported to contain ca. 35% of Fe oxide consisting of goethite and hematite, half of which was oxalate soluble (Fauziah et al., 1996). As expected, this material had an appreciable adsorption capacity for phosphate and heavy metals and, if added to soils, could confer these properties on them (Peacock Rimmer, 2000),... 

Titanium is relatively abundant in the earth s crust (0.6%). The main ores are ilmenite (FeTi03) and rutile, one of the several crystalline varieties of Ti02. It is not possible to obtain the metal by the common method of reduction with carbon because a very stable carbide is produced moreover, the metal is rather reactive toward oxygen and nitrogen at elevated temperatures. Because the metal has uniquely useful properties, however, expensive methods for its purification are justified. In addition to a proprietary electrolytic method, there is the older Kroll... 

Fig. 4.30. Molecular-orbital/band models to illustrate the electronic structures of hematite and ilmenite and based on MS-SCF-Za calculations on FeO , FeOs", and TiO/ clusters. The double arrows labeled (a), (b), (c) refer to electronic transitions giving rise to optical properties (after Vaughan and Tossell, 1978).

Matsui, M., M. Akaogi, and T. Matsumoto (1987). Computational model of the structural and elastic properties of the ilmenite and perovskite phases of MgSiO,. Phys. Chem. Mineral. 14, 101-6. 

Brown, N.E., Navrotsky, A., Nord, G.L., Baneijee, S.K. (1993) Hematite (Fe203)-ilmenite (FeTiOs) solid solutions Determinations of FeTi order from magnetic properties. Am Mineral 78 941-951 Burton, B.P. (1987) Theoretical analysis of cation ordering in binary rhombohedral carbonate systems. Am Mineral 72 329-336... 

Ishikawa Y (1962) Magnetic properties of the ilmenite-hematite system at low temperature. J Phys Soc Japan 17 1835-1844... 

Nord GL, Lawson CA (1989) Order-disorder transition-induced twin domains and magnetic properties in ilmenite-hematite. Am Mineral 74 160... 

Ilmenite from Alfa Aesar Properties 99.9% pure, specific surface area 1.3 m /g [2387]. 

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