what is van Arkel method?

 Van Arkel method : In this process metals are converted into other metal-compounds like metal-iodides. Metal-iodides are decomposed easily and highly pure metals are then obtained. For example in a pure block of Ti, Fe can be an impurity. This block is heated in iodine at a temperature of 250°C. Ti converts into TiI₄ but the impurities do not. TiI₄ is passed over hot tungsten filament so that TiI₄ is decomposed and ultra pure Ti is obtained.