Abstract: A method of dehydrating carnallite, residing in that preliminarily enriched carnallite with 39-41 wt. % water is heated up to 205.degree.-230.degree. C. by fuel combustion products having a temperature of 500.degree.-600.degree. C., and a partially dehydrated carnallite with 3-8 wt. % water is obtained. Said dehydrated carnallite is melted in a reaction zone and the melt is subjected to the action of a chlorinating agent. Thereafter the melted carnallite is allowed to settle from solid impurities and, as a result, dehydrated carnallite is obtained with water content less than 0.5 wt. %. The melting of partially dehydrated carnallite with 3-8 wt. % water is performed with the aid of fuel combustion products having a temperature of 700.degree.-1150.degree. C. These products are introduced tangentially to the surface defining the reaction zone at a rate ensuring the formation of an intensive eddy flow of gases, which occupies the whole volume of the reaction zone.