Composite red mud depositing separating washing method and tank

Abstract

An integrated red mud settling, separating and washing method includes such steps as settling the diluted slurry, separating the solution of sodium aluminate from red mud, washing with hot water for removing alkali, and stacking the red mud. The flat-bottom settling bath is used for settling and separation. The efficient settling bathes are used for hot-water washing. Its advantage is very low cost.

Description

Technical field: [0001] The invention relates to a process and a tank for sedimentation, separation and washing of red mud in alumina production. Background technique: [0002] In the production project of alumina, after the slurry after dissolution is diluted, it needs to be separated by sedimentation in a settling tank, and the red mud and sodium aluminate solution are separated, and the overflowed sodium aluminate solution passes through the subsequent section to obtain alumina. Products, the separated red mud should be reverse washed with hot water to reduce the alkali content, and discharged to the red mud dam after meeting the environmental protection standard. The existing red mud washing process uses 3 to 5 washing and settling tanks to wash the red mud, and one or more separating and settling tanks are used to separate the materials. , and then set up a settling tank as a public settling tank, which can be used as a separation settling tank or as a washing settling...

AI Technical Summary

Problems solved by technology

[0003] The flat-bottomed settling tank has a large diameter, occupies a large area, and requires a large investment. Its advantages are large volume, easy cleaning, and less flocculant addition (less than 25g / t dry red mud). Larger fluctuations or discharge in the dissolution section can be well buffered to ensure continuous and stable production of the whole plant; the disadvantage is that the material stays for a long time and the hydrolysis loss is large, and red mud needs to be used for dry storage. The filter needs to be filtered and washed once before it can meet the discharge standard.

[0004] The diameter of the high-efficiency settling tank is small, the land occupation is small, and the corresponding investment is also small. Its advantages are short material residence time, small hydrolysis loss, and the washed red mud can be discharged directly without filtering and washing, so a large number of operators can be reduced. , which greatly reduces the operating cost; the disadvantage is that the volume is small, the amount of flocculant added (more than 50g / t dry red mud), the operation and maintenance are more complicated, and there are large fluctuations in the production process or the discharge cannot be dissolved. Good buffering to ensure continuous and stable operation of production

Images