The Kroll process is the main method that is used to isolate titanium on a large scale for industrial purposes. During this process, the ores rutile or ilmenite are reduced by heating them with coke that has been derived from petroleum sources; this reaction takes place in a fluid bed reactor at a temperature of 1832 °F. The next step involves treating the resulting liquid compound to produce titanium tetrachloride in addition to other chloride compounds; the titanium tetrachloride is separated out through fractional distillation. After this step, titanium chloride is reduced by reacting it with liquid magnesium in a stainless steel container at a temperature of approximately 1562 °F.
While pure titanium is isolated from this process, there is a problem with titanium being reduced to its lower chloride form. Magnesium and magnesium dichloride that present problems with reduction are taken out through reactions with water and hydrochloric acid; the resulting titanium sponge has to undergo repeated additional melting and crushing processes to be completely isolated.