Method for producing lithium hydroxide anhydride and rotary kiln to be used therefor

1. A method for producing lithium hydroxide anhydride from lithium hydroxide hydrate by using a rotary kiln which has a furnace core tube and a heating furnace surrounding a certain part of the furnace core tube in the axial direction, wherein the method comprises the steps of:

supplying the lithium hydroxide hydrate to a region between a heating part which is the part of the furnace core tube surrounded by the heating furnace and one end of the furnace core tube;

delivering the supplied lithium hydroxide hydrate toward the other end of the furnace core tube;

feeding a drying gas with a temperature of 100° C. or higher to the region between the one end and the heating part of the furnace core tube, when the lithium hydroxide hydrate is supplied; and

heating and dehydrating the lithium hydroxide hydrate by the heating furnace which is set to 230-450° C. during the lithium hydroxide delivering step, to form lithium hydroxide anhydride.

2. The method according to claim 1 , wherein the amount of the supplied lithium hydroxide hydrate is from 5 to 15% by volume, based on the volume of the furnace core tube.

3. The method according to claim 1 , wherein the time for heating the lithium hydroxide in the heating part of the furnace core tube is from 30 min to 2 hours.

4. The method according to claim 1 , wherein an insulating material is provided on the outside surface of a region between the one end and the heating part of the furnace core tube.

5. The method according to claim 1 , wherein the rotary kiln comprises an exhaust pipe for discharging the heated drying gas to the outside of the furnace core tube,

wherein the method further comprises a step of discharging the heated drying gas to the outside of the furnace core tube via the exhaust pipe.