Red mud separating washing technology with self circulation and its device

Abstract

A red mud washing-separating process and apparatus with self circulation features that a solution outlet is additionally made at the upper-middle part of each separating settling bath and each washing settling bath, each settling bath has a circulating pump at its bottom for circulating 10-60% of the solution in the bath itself, all the washing settling baths are cascaded for serially transferring te bottom flow from this one to next one, and final red mud is filtered.

Description

Technical field: [0001] The invention relates to a red mud separation and washing process for alumina production and a device thereof. Background technique: [0002] Red mud sedimentation, separation and washing is an important production process in the alumina production process. The purpose is to recover useful components such as alumina and alkali in the red mud bottom flow attached liquid into the process. The washed red mud requires its attached alkali content Na 2 O≤5kg / t- dry red mud, sent to the red mud yard for stockpiling. [0003] The red mud separation and washing process of the existing alumina plant is: the slurry from the dissolution process enters the separation and settling tank, the bottom of the separation and settling tank flows into the washing and settling tank for 3 to 4 times of reverse washing, and the red mud is removed from the red mud filtration process after washing Or send it to the red mud yard. The red mud washing water used comes from the h...

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Problems solved by technology

[0006] For the comprehensive utilization of low-grade bauxite, due to the low grade of ore and the small amount of alumina in the ore, the amount of red mud is particularly large. For example, if Guangxi high-speed iron bauxite is used to produce alumina, the amount of red mud per ton of product can reach 3-4 tons, 0.9-1.3t / t-AL than current alumina plant 2 o 3 The amount of red mud is more than 2 times higher. According to the conventional red mud treatment method, it is difficult to pass the red mud separation and washing process. If the amount of red mud washing water is large, the production system will run at a very low concentration and evaporate. The workshop will also be built very large, which is not economically feasible. If the amount of washing water is greatly reduced, the settling tank will not achieve the effect of settling and washing due to the low liquid-solid ratio of the feed

[0007] The present invention mainly aims at processing low-grade bauxite, the amount of red mud is large, and the red mud separation and washing process is difficult to operate, and proposes a new red mud washing process and its device to solve the problem of large washing water addition and sedimentation. Slots not functioning properly

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