Titanium slags

Titanium silicalite Titanium silicates Titanium-silicon alloy Titanium slag Titanium suboxides... 

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. 

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). 

Both processes also use up-graded ilmenite (slags). About 30% of the world s titanium feedstocks are suppHed by titanium slag producers in Canada, South Africa, and Norway. Slags are formed by the high temperature reduction of ilmenites in electric furnaces. Much of the iron oxide content is reduced to metallic iron and separated as a saleable by-product. Magnesium and other impurities may also be incorporated in the following equations. 

Alternatives to the fluidized-bed method process include the chlorination of titanium slags in chloride melts, chlorination with hydrogen chloride, and flash chlorination. The last is claimed to be particularly advantageous for minerals having a high impurity content (133—135,140). The option of chlorinating titanium carbide has also been considered (30). 

Production TiClj Using Combined Fluidized Bed by Titanium Slag Containing High-Level CaO and MgO... 

Titanium pyrophosphate, 25 57 Titanium sesquioxide, 25 14 Titanium sesquisulfide, 25 58 Titanium silicates, 25 56, 102 Titanium silicides, 25 55—56 Titanium—silicon alloy, 22 520 Titanium silicon compounds, 25 55—56 Titanium slag, 19 388, 389 Titanium sponge... 

With both ilmenite and titanium slag, mixed digestion can be carried out in which the Ti3+ content of the slag reduces all the Fe3+ to Fe2 +. The dissolved products obtained from the separate digestion of ilmenite and titanium slag can also be mixed [2.28], [2.29],... 

Enhancing -> passivation of iron and steel and dissolving refractory substances such as titanium slag, copper-yttrium oxide, and metal fluorides. 

In the chloride process, the titanium-containing raw materials ilmenite, leucoxene, rutile, titanium slag, or anatase are chlorinated at 700-1200 °C. The TiCU is oxidized at temperatures of900-1400 °C to form Ti02. This raw pigment is ground and coated with inorganic compounds. 

The starting materials for Ti02 production are ilmenite and titanium slag in the case of the sulfate process (see Section 5.9.2.2.3) and leucoxene, rutile, synthetic rutile, titanium slag and in the future possibly also anatase for the chloride process (see Section 5.9.2.2.3). 

Production of titanium slags by reduction of ilmenite at 1200 to 1600°C and separation of the liquid iron... 

Titanium slags from ilmenite are important raw materials for the sulfate and chloride processes, due to their high Ti02-content. The iron contained in ilmenite is largely reduced with carbon to the metal in an arc furnace at 1200 to 1600°C and is separated off. The slags formed have a Ti02-content of 70 to more than 85%, depending upon the ilmenite used. The main producers are the Quebec Iron and Titanium Corp. (QIT) in Canada and Richards Bay Minerals Ltd. (RBM) in South Africa. The capacity of QIT is 800 103 t/a, that of RBM also 800 I O t/a. 

Synthetic rutile has a Ti02-content of 85 to 90%. In all these processes iron is either removed in the form of a salt solution which has to be worked up or as valueless oxide. In the process for the production of titanium slag, on the other hand, metallic iron is obtained, which makes this process more interesting both ecologically and economically. As a result, a large proportion of the synthetic rutile manufacture plants has been closed down. 

The sulfate process (see Figure 5.9-1) utilizes ilmenite or titanium slag. 

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