Titanium sponge reactor

The reactor is removed from the furnace, cooled to room temperature, and stored for 24 hr under a small positive pressure of inert gas, before opening in the dry room . Here, the mixture of titanium sponge, residual magnesium chloride, and excess magnesium metal is drilled out on a lathe in the form of to 1 in. turnings. A jet of helium is available as a precaution against the finely divided metal catching fire. 

The reactor is cooled for a period of several days before opening and removal of the titanium sponge and sodium chloride mixture. The removal operation, as in the magnesium process, is carried out rapidly by means of large horizontal boring machines of the type shown in Fig. 6.13, operated in a dry room . 

The process is operated in heated, batch reactors under an inert atmosphere. Two companies (Deeside Titanium, North Wales, and New Metals Industries, Nihongi, Japan) operate a one-stage process. Reactive Metals Industries Company, Ashtabula, OH, operates a two-stage process in the first stage, at 230°C, the trichloride and dichloride are formed. In the second, more sodium is added and the temperature is raised to 1,000°C. The sponge product is mixed with sodium chloride, which is leached out with dilute hydrochloric acid. Based on the work by M. A. Hunter at Rensselaer Polytechnic, New York in 1910. See also Kroll. 

The mechanism of the sodium reduction reaction is principally via the vapour phase, since the sodium tends to be volatile (b.p. 883°C) and to be boiling xmder reflux during the reaction. This reflux action of the sodium tends to wash the reactor walls free of titanium metal and sodium chloride, so that the disposition of sponge, after completion of a reaction, is different from that in the magnesium process. 

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