Method for recycling iron and aluminum by particle size grading pretreatment of Bayer process red mud
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A technology of Bayer process red mud and recovery method, which is applied in the field of resource utilization of industrial waste residues, and achieves the effects of good economy, good promotion prospects, and reduced energy consumption
Inactive Publication Date: 2010-01-13
HUAZHONG UNIV OF SCI & TECH
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[0010] To sum up, the existing patented technology generally recovers iron, aluminum and other resources separately, and the existing red mud particle size classification technology only uses iron recovery
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Embodiment 1
[0029] (1) Classification of red mud
[0030] The Bayer process red mud used in the present invention comes from an alumina plant in Shandong. After classification, the red mud is divided into parts with a particle size of 1.2mm. Among them, the red mud with a particle size of 0.075mm accounts for 25.69% (called coarse red mud) (see Table 1 for details).
[0031] Table 1 Mass specific gravity of red mud with different particle sizes
[0032]
[0033] The chemical composition of red mud with various particle sizes is shown in Table 2. The chemical composition of red mud with a particle size greater than 1.2mm is mainly CaO, and the red mud with a particle size between 0.075mm and 1.2mm contains Fe 2 o 3 , SiO 2 High content, Al 2 o 3 The content of the red mud is lower; the red mud with a particle size of less than 0.075mm is compared with the original red mud SiO 2 The content of Al / Si has decreased significantly, and the Al / Si has increased from 1.0 of the original...
Embodiment 2
[0042] (1) Classification of red mud
[0043] The red mud is classified into coarse red mud with a particle size of >0.075mm and fine red mud with a particle size of <0.075mm through particle size separation. Among them, coarse red mud accounts for 25.91%, and fine red mud accounts for 74.09%. The chemical composition analysis of the two kinds of red mud is shown in Table 3 below.
[0044] Table 3 Chemical composition analysis of coarse and fine red mud after classification
[0045]
[0046] (2) Separation and utilization of iron concentrate and coarse sand in coarse red mud
[0047] Using the method of Example 1, iron ore and sand with an iron grade of 58.13% were separated from the coarse red mud.
[0048] (3) Fine red mud iron and aluminum recovery
[0049] Dried fine red mud and a certain amount of NaCO 3 , CaO and carbon powder are finely ground and mixed, among which NaCO 3 Add according to Na / Al=1.3 (molar ratio), CaO according to Ca / Si=2.3 (molar ratio), add c...
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Abstract
The invention relates to a method for recycling iron and aluminum by particle size grading pretreatment of Bayer process red mud, belonging to the technology for recycling red mud resources. The method comprises the following steps: firstly, Bayer process red mud is graded in terms of the particle size by using a physical method into coarse red mud and refined red mud; the coarse red mud is processed using physical mineral dressing processes, such as magnetic separation, gravity separation and the like, in order to obtain iron ore having high iron quality and coarse-grained sand, which are made use of respectively; the refined red mud is mixed with sodium carbonate, limestone and carbon power and is then subjected to reduction sintering, and two processes of magnetizing reduction roasting of iron and soda lime sintering of aluminum are implemented synchronously by means of the control of sintering conditions; sodium aluminate is dissolved out of clinker through dilute alkali solution, dissolved slag is subjected to magnetic separation to recover iron ore concentrate, and after being subjected to dealkalized cleaning, the residual calcium silicon slag is applied to building material industry. The method realizes combined recovery of iron, aluminum and other elements, magnificently achieves the comprehensive utilization of the Bayer process red mud, is capable of effectively relieving environment pollution resulting from the accumulation of the Bayer process red mud, and has excellent economic and social benefits.
Description
technical field [0001] The invention belongs to the technical field of resource utilization of industrial waste residues, and in particular relates to a method for resource recovery and utilization of Bayer process red mud after classification. The method is especially suitable for iron content of not less than 30% 2 o 3 High-iron Bayer process red mud based on the total iron content in total. Background technique [0002] Red mud is an industrial solid waste produced after alumina is extracted from bauxite. Every ton of alumina produced will produce 0.6-2.0 tons of red mud. According to different alumina production processes, red mud is divided into sintering red mud and Bayer red mud. 90% of the world's alumina is produced by Bayer process. The Bayer process for smelting alumina uses strong alkali NaOH to dissolve bauxite. Bayer process red mud contains a variety of valuable elements (such as high iron and aluminum content), and a large amount of accumulation will not o...
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