Continuous cleaning system for halogen salts

A process for reducing impurities in a halogen salt or halogen salt mixtures of two, three or more halogen salts, comprising the following steps:

• a) providing a container in which the halogen salt or halogen salt mixture is brought into contact with an active metal,
• b) providing said halogen salt or halogen salt mixture, which is in a liquid form,
• c) providing an active metal,
• d) contacting said halogen salt or halogen salt mixture with said active metal in an inert atmosphere at a temperature that is above the melting temperature of said active metal and above the melting temperature of said halogen salt/halogen salt mixture, whereby impurities in said halogen salt or halogen salt mixture react with said active metal, to obtain a halogen salt or halogen salt mixture having a proportion of impurities of 0.05% by weight or less, especially of 0.01% by weight or less, and
• e) separating the purified halogen salt or halogen salt mixture,
• wherein
• said halogen salt is a halogen salt of an alkali metal, or an alkaline earth metal, or a transition metal, or a metal of group 13 or 14 of the periodic table,
• said inert atmosphere consists of nitrogen and/or noble gas, and
• said active metal is selected to
• be immiscible with the molten halogen salts,
• have an electromotive force (EMF) that is not larger than that of the metals forming the cations of the halogen salt or salts,
• have an electromotive force (EMF) that is larger than that of the corrosive impurities of the halogen salt or salts, and
• have a density different from that of the purified halogen salt.