Aluminum hydroxide decomposition crystallization temperature control energy-saving device

The utility model belongs to the technical field of aluminum oxide production, and particularly relates to an aluminum hydroxide decomposition crystallization temperature control energy-saving device which comprises a decomposition tank, a high-temperature slurry feeding pipe is fixedly arranged at the upper end of the left side wall of the decomposition tank, and a high-temperature slurry discharging pipe is fixedly arranged on the lower side wall of the decomposition tank. A first annular pipe is arranged at the upper end in the decomposition tank, a second annular pipe is arranged at the lower end of the first annular pipe, vertical pipes which are uniformly distributed are longitudinally arranged between the first annular pipe and the second annular pipe, and the first annular pipe, the second annular pipe and the vertical pipes form a tubular dividing wall heat exchanger; a low-temperature mother liquor feeding pipe is fixedly arranged on the right side wall of the second annular pipe, the right end of t