Ilmenit

Titanium is not a rare element it is the most abundant transition metal after iron, and is widely distributed in the earth s surface, mainly as the dioxide TiOj and ilmenite FeTi03. It has become of commercial importance since World War II mainly because of its high strength-weight ratio (use in aircraft, especially supersonic), its... 

It occurs in the minerals rutile, ilmenite, and sphene, and is present in titanates and in many iron ores. Titanium is present in the ash of coal, in plants, and in the human body. 

Examples MgTi03, magnesium titanium trioxide ilmenite type) FeTi03, iron(II) titanium trioxide (ilmenite). 

The heavy mineral sand concentrates are scmbbed to remove any surface coatings, dried, and separated into magnetic and nonmagnetic fractions (see Separation, magnetic). Each of these fractions is further spHt into conducting and nonconducting fractions in an electrostatic separator to yield individual concentrates of ilmenite, leucoxene, monazite, mtile, xenotime, and zircon. Commercially pure zircon sand typically contains 64% zirconium oxide, 34% siUcon oxide, 1.2% hafnium oxide, and 0.8% other oxides including aluminum, iron, titanium, yttrium, lanthanides, uranium, thorium, phosphoms, scandium, and calcium. 

Minerals. Iron-bearing minerals are numerous and are present in most soils and rocks. However only a few minerals are important sources of iron and thus called ores. Table 2 shows the principle iron-bearing minerals. Hematite is the most plentiful iron mineral mined, followed by magnetite, goethite, siderite, ilmenite, and pyrite. Siderite is unimportant in the United States, but is an important source of iron in Europe. Tlmenite is normally mined for titania with iron as a by-product. Pyrite is roasted to recover sulfur in the form of sulfur dioxide, leaving iron oxide as a by-product. 

Parameter Hematite Magnetite Goethite Siderite Ilmenite Pyrite... 

High intensity magnetic separators are used to upgrade iron ores containing hematite or ilmenite. Dry separators require ore that is finely sized and bone dry. They are dusty, expensive, and have a low capacity. Wet separators have larger capacity, are less dusty and can handle ore sizes up to 1 mm. 

Ilmenite is more abundant than mtile. Ilmenite world suppHes are estimated to meet the requirements of the Ti02 industry into the twenty-second century. The largest sources of ilmenite are in AustraHa, Canada, South Africa, Russia, and the United States. Large, unexplored sources also exist in China. About 9 million metric tons of ilmenite are mined aimuaHy. Long-term atmospheric effects weather ilmenite into leucoxene [1358-95-8], which contains most of its iron as Fe " . The majority of the world s supply of mtile comes from the beach sands of AustraHa, Florida, India, Bra2H, and South Africa. The total worldwide supply is estimated to be about 50 million metric tons. About 0.5 million tons are mined a year. The supply should last at least until the end of the twenty-first century. 

Titanium slag and synthetic mtile are also used as raw materials in the production of titanium whites. Titanium slag results from a metaHurgical process during which iron (qv) is removed from ilmenite by reduction with coke in an electric arc furnace at 1200—1600°C. Under these conditions, iron oxide is reduced to metal, melts, and separates from the formed titanium slag. Titanium slag contains 70—75% Ti02 and only 5—8% iron. 

Synthetic mtile raw material is produced from ilmenite by reducing the iron oxides and leaching out the metallic iron with hydrochloric or sulfuric acids. In both processes, the objective is to increase the amount of Ti02 in the raw materials. 

Under normal conditions about 95—97% of TiOg from ilmenite is solubilized. Most of the iron in the solution is in the Fe " oxidation state. Any Fe " present must be reduced to Fe " because iron can only be removed by crystallization in its divalent form. The reduction is usually done by adding some scrap iron during the digestion step. 

Induced-roU separators have also been used in the concentration and cleaning of heavy minerals found in beach sands. Examples are the mtUe and ilmenite beach sands of Florida and New Jersey. Induced-roU separators are frequently used in combination with high tension or electrostatic separators. 

Paints. Paints account for perhaps 3% of sulfur consumption (see Paint). The main sulfur use is for the production of titanium dioxide pigment by the sulfate process. Sulfuric acid reacts with ilmenite or titanium slag and the sulfur remains as a ferrous sulfate waste product. Difficulties with this process have led to the development of the chloride process (see Pigments, inorganic Titanium compounds). 

Table 1. Ilmenite and Rutile Resourees in the World s Major Deposits ...

Ilmenite includes equivalent titanomagnetite, leucoxene, and perovskite. Rutile does not include anatase from Brazil. 

Includes lecoxene in ilmenite production data for United States are withheld to avoid disclosing proprietary information. 

Slag is also produced in Norway but is not included under slag to avoid dupHcation. Beginning in 1990, about 25% of Norway s ilmenite production was used to produce a slag containing 75% Ti02. 

Ilmenite is also produced in Canada and in South Africa, but this output is not included here because an estimated 90% of it is dupHcated output reported under slag. 

Titanium, Ti, atomic number 22, relative atomic mass 47.90, is the ninth most common element (ca 0.6% by weight) and is widely distributed in the earth s cmst. It is found particularly in the ores mtile, Ti02, and ilmenite, FeTiO. ... 

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. 

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