Aluminum hydroxide roasting furnace waste heat comprehensive recovery system and method

The invention discloses an aluminum hydroxide roasting furnace waste heat comprehensive recovery system and method. The system comprises a first heat exchanger of sandy aluminum oxide and demineralized water, a second heat exchanger of flue gas and demineralized water, a third heat exchanger of demineralized water and mother liquor and a circulating water pump. The method comprises the steps that the circulating water pump is started, and demineralized water circularly flows in the first, second and third heat exchangers; the method comprises the following steps: fluidizing sandy aluminum oxide by using an air blower, enabling the fluidized high-temperature aluminum oxide to flow through a first heat exchanger, realizing heat exchange between the high-temperature aluminum oxide and demineralized water in the first heat exchanger, and heating the demineralized water for the first time; high-temperature flue gas generated by the aluminum hydroxide roasting furnace is introduced into a second heat exchanger, hea