Tube array and remaining tank dissolving-out system and method for gibbsite bauxite

Abstract

The invention discloses a tube array and remaining tank dissolving-out system and a tube array and remaining tank dissolving-out method for gibbsite bauxite and belongs to the technical field of alumina production. The dissolving-out system comprises a circulating mother liquor groove, a heat preservation remaining tank, a flash evaporation device and a dilution device; the circulating mother liquor groove is communicated with a tube array heating device through a mother liquor feed pump; the tube array heating device is formed by connecting a first-level tube array preheater, a second-level tube array preheater and a third-level tube array preheater, a condensed water tube array preheater, and a live steam tube array preheater in series; the method comprises the following steps of: conveying the circulating mother liquor in the circulating mother liquor groove into the tube array heating device by using the mother liquor feed pump, heating to 180 to 190 DEG C, and feeding the circulating mother liquor into the heat preservation remaining tank; and conveying desilicication ore pulp in a desilicication groove into the heat preservation remaining tank, mixing the desilicication ore pulp and the circulating mother liquor, and dissolving out, feeding the pulp obtained after dissolving into the flash evaporation device and performing flash evaporation and then feeding into the dilution device. The system and the method can improve the treatment capacity of pulp, save energy sources, and reduce the production cost and equipment corrosion.

Description

technical field [0001] The invention belongs to the technical field of alumina production, in particular to a stripping system and method for gibbsite-type bauxite with tubes and retention tanks. Background technique [0002] At present, more than 95% of alumina plants in China adopt the Bayer process. The core of the Bayer method production process is the dissolution process of bauxite slurry. The purpose of dissolution is to make bauxite and circulating mother liquor react at a certain temperature to generate sodium aluminate solution. The reaction formula is: [0003] al 2 o 3 (1 / 3)H 2 O+2NaOH+aq→2NaAl(OH) 4 +aq [0004] Due to the different chemical compositions of bauxite ores in various places, the required dissolution temperature varies greatly; domestic ores are mainly diaspore type, and the dissolution method of high temperature and high alkali is generally used; foreign ones are mainly trihydrate aluminum For the mixed type of gibbsite plus boehmite (and boeh...

AI Technical Summary

Problems solved by technology

[0009]1. Theory and production practice have proved that the mother liquor and the desiliconized slurry are mixed first and then preheated and heated by multi-inner tube casings. Due to the limitation of pipeline manufacturing, the largest outer pipe can only be DN=600, which limits the size and quantity of the inner pipes and cannot continue to increase. The maximum is 3 inner pipes of DN200. If the system flow is increased under this condition, As a result, the flow velocity in the casing reaches more than 3m / s, resulting in excessive system resistance loss, large equipment wear, high equipment manufacturing costs, and high operating costs, which are not economically reasonable

[0010]2. When the casing plus residence tank dissolution process slurry is heated in the casing, scarring is easy to occur (mainly caused by kaolinite reaction), The heat transfer coefficient of the casing heat exchanger is at least 1000Kcal / m2.h.℃ without scarring; the heat transfer efficiency drops rapidly in the case of scarring, and the heat transfer coefficient drops to 550 About Kcal / m2.h.℃, affect the heat transfer effect

Images