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Two-stage vacuum reduction treatment method for red mud

A two-stage vacuum and red mud technology, applied in chemical instruments and methods, improvement of process efficiency, solid separation, etc., can solve the problem of sodium removal, rare metal elements not being rationally utilized, and the inability to realize the harmlessness of red mud Use other problems to achieve the effect of complete separation

Active Publication Date: 2018-08-24
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition to these two methods, there are many other treatment methods, no matter what kind of treatment method, they have not fully realized the comprehensive utilization or harmless treatment of red mud
The most harmful substance in red mud is mainly alkali (that is, sodium oxide). The existing technology basically revolves around the recovery of alumina in red mud and the utilization of iron oxide. It is difficult to completely remove the sodium in red mud. Realize the complete harmless utilization of red mud
In addition, red mud contains scandium, niobium, vanadium and other rare metal elements, and some rare metal elements have reached the extraction standard, but the production methods of these elements are basically acid leaching, and there are a lot of alkali in red mud At the same time, it also contains a large amount of iron oxide, which increases the amount of acid used in acid leaching, and also increases the difficulty of subsequent leachate treatment, resulting in the traces of rare metal elements in red mud have not been rationally utilized.

Method used

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  • Two-stage vacuum reduction treatment method for red mud

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Grind red mud and carbonaceous reducing agent to particle size ≤ 100 mesh, then mix with sodium sulfate evenly, and press into agglomerates; in the agglomerates, the mass ratio of carbonaceous reducing agent: sodium sulfate: red mud = 15:10: 100; wherein the carbonaceous reducing agent is coal;

[0049] Place the agglomerate in a vacuum furnace, and carry out a reduction reaction under vacuum and a temperature of 700°C for 10 hours. The iron and iron sulfide generated during the reduction process combine to form Fe-FeS alloy balls, and other components exist in the form of melt , Fe-FeS alloy balls precipitate to the bottom of the melt; after the reduction reaction is completed, cool to room temperature with the furnace to obtain a section of reduced slag;

[0050] The reduction slag of the first stage is crushed and ground to a particle size of ≤100 mesh, and then subjected to magnetic separation to obtain Fe-FeS alloy ball products and magnetic separation tailings; th...

Embodiment 2

[0055] Method is with embodiment 1, and difference is:

[0056] (1) Carbonaceous reducing agent by mass ratio in the agglomerate: sodium sulfate: red mud=20: 3: 100; Carbonaceous reducing agent is petroleum coke;

[0057] (2) The reduction reaction temperature is 1200°C and the time is 2h;

[0058] (3) aluminum powder by mass ratio in the secondary agglomerate: additive: magnetic separation tailings=3: 100: 100; additive is calcium carbonate;

[0059] (4) The temperature of the second-stage reduction reaction is 1200°C, and the time is 2h;

[0060] (5) The Fe-FeS alloy ball product contains Fe91% by mass percentage, and the purity of solid metal sodium is 99%; the metallization rate of iron is 75%, and the recovery rate is 71%; the reduction rate of sodium oxide is 48%, and the recovery rate of sodium is 39%. .

Embodiment 3

[0062] Method is with embodiment 1, and difference is:

[0063] (1) carbonaceous reductant in the mass ratio: sodium sulfate: red mud=18:9:100; carbonaceous reductant is anthracite after calcining;

[0064] (2) The reduction reaction temperature is 1100°C and the time is 3h;

[0065] (3) Aluminum powder by mass ratio in the secondary agglomerate: additive: magnetic separation tailings=10: 30: 100; additive is silica;

[0066] (4) The temperature of the second-stage reduction reaction is 1100°C, and the time is 3h;

[0067] (5) The Fe-FeS alloy ball product contains Fe91% by mass percentage, and the purity of solid metal sodium is 99%; the metallization rate of iron is 78%, and the recovery rate is 74%; the reduction rate of sodium oxide is 55%, and the recovery rate of sodium is 42%. .

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Abstract

A two-stage vacuum reduction treatment method for red mud is performed according to the following steps that firstly, after being ground fine separately, the red mud and a carbonaceous reducing agentare mixed with additive sodium sulfate to be prepared into block masses; secondly, under the vacuum condition with the temperature being 700-1200 DEG C, a reduction reaction is performed; thirdly, after fine grinding, Fe-FeS alloy ball products and magnetic separation tailings are obtained through magnetic separation; fourthly, after being mixed, the magnetic separation tailings, aluminum powder and additives are pressed into secondary block masses; and fifthly, under the vacuum condition with the temperature being 700-1200 DEG C, a second-stage reduction reaction is performed, and steam is crystallized into solid metal sodium. The method achieves thorough separation of a sodium element in the red mud, and favorable conditions are created for utilizing of subsequent residues and extractingof rare elements in the subsequent residues.

Description

technical field [0001] The invention belongs to the technical field of vacuum metallurgy, in particular to a method for two-stage vacuum reduction treatment of red mud. Background technique [0002] Red mud is an industrial waste produced by the alumina industry. In the Bayer process, 1.5-2.5t of red mud is discharged for every 1t of alumina produced. For the sintering method and combined method, 1.5-2.5 tons of red mud is discharged for every 1 ton of alumina produced. According to the "Hazardous Waste Identification Standard", red mud is a strong alkali waste residue, which is a serious source of alkaline pollution. Red mud has the characteristics of high moisture content, small particle size and high alkali content. At present, the main treatment methods of red mud are damming and stockpiling, direct reclamation or reclamation after neutralization. The red mud stockyard must use expensive anti-seepage membrane materials, which require a large amount of construction an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00B03C1/30C21B13/00C22B1/245C22B26/10
CPCB03C1/30C21B13/006C22B1/245C22B7/001C22B26/10Y02P10/20
Inventor 李博王耀武马占山
Owner NORTHEASTERN UNIV