Method for utilizing circulation water in aluminum hydroxide or aluminum oxide production process

Abstract

The invention relates to a method for utilizing the recycled water during the production process of aluminum hydroxide or aluminum oxide, which comprises the following steps: the recycled water produced from a mother liquor evaporating system is directly sent to a washing heater for heating, when the temperature of the recycled water reaches 95- 100 DEG C, the recycled water can be used for washing red mud. The utilization method of the recycled water has the advantages that: the pressure of a cooling tower is reduced, as the recycled water with a speed of approximately 60 m<3> need not be cooled down to 35-38 DEG C from 50-60 DEG C, but is instead directly conveyed to the washing heater for use; due to the new recycle water line, the pressure of a wastewater treatment system is eased, the wastewater can be treated in a timely manner and all enter the flow path, thus realizing zero discharge and avoiding environmental pollution; the consumption quantity of fresh water is accordingly reduced by avoiding the discharge of sewage; the alkali taken from a water cooler returns to the flow path and gradually enter the flow path, therefore, the alkali consumption is lowered and the cost is accordingly saved; due to the adequate utilization of the heat, the heating of recycled water in the washing heater is facilitated with sufficient heat, no new steam is necessary, thus economizing the use of heat energy and greatly reducing the labor intensity and danger of the working staff.

Description

technical field [0001] The invention relates to a method for producing aluminum hydroxide or aluminum oxide, in particular to a method for utilizing circulating water in the production process of aluminum hydroxide or aluminum oxide. technical background [0002] In the production process of traditional aluminum hydroxide (alumina), the water used for red mud washing (60m 3 / h or so) except for a small part used as white mud washing liquid, it is used for circulating water after cooling (the temperature does not exceed 38°C in summer and 35°C in winter), due to the need for red mud washing and settlement in the settling tank , the temperature needs to be raised to 95°C. Therefore, it has to pass through the wash water heater on the upper part of the dilution tank. Most of the heat source of the wash water heater comes from the steam released by the hot slurry in the dilution tank, and these heat sources cannot meet the needs. It is often necessary to inject new steam to pro...

AI Technical Summary

Problems solved by technology

In fact, while circulating water brings a large amount of non-condensable gas out of the process, it also takes part of the heat and part of the alkali carried by water vapor and non-condensable gas out of the process and enters the circulating water system; often due to insufficient water treatment, often Drained from the sewage outlet, causing the alkalinity of the discharged sewage to exceed the standard, resulting in excessive sewage discharge and polluting the surrounding environment; in addition, due to the reduction of circulating water, a large amount of new water needs to be replenished, which is costly

The disadvantages of the circulating water process in the traditional production method are: ①The circulating water evaporated from the mother liquor needs to be cooled from 50-60°C to 35-38°C, while the cooled circulating water has to be heated from 35-38°C to above 95°C To meet the needs of red mud washing and settling, these two processes need to consume more energy; ② circulating water heating needs to open new steam because the temperature is always insufficient, resulting in increased load on the boiler, difficult to control and frequent operations make the labor of workers The strength is improved; ③The untreated water is discharged, and the slack alkali causes environmental pollution, and it needs to be replenished with new water accordingly

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