Method for achieving defluorination and recycling of secondary aluminum ash with series-parallel method

A technology of secondary aluminum and mixed connection method, which is applied in the direction of solid waste removal, etc., can solve problems such as danger, high energy consumption, and acid waste water cannot be recycled, and achieve the effect of reducing equipment corrosion and solving circulation problems

Active Publication Date: 2019-02-22
郑州中科新兴产业技术研究院 +1
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  • Claims
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Problems solved by technology

[0004] At present, there have been some researches on the recovery of alumina in aluminum ash, such as alkaline smelting method, acid dissolution method, alkali dissolution method, etc. Alkaline smelting method can recover the fluorine in aluminum ash in the form of gas, and effectively recover aluminum resources , but its biggest disadvantage is high energy consumption, and the solution obtained by leaching is difficult to treat separately; the disadvantage of the acid-dissolving method is that the acidic wastewater produced cannot be recycled; the only disadvantage of the alkali-dissolving method is that the soluble fluoride contained in the aluminum ash is in the Under the condition of high pressure and strong alkali, it is easy to corrode the reaction equipment for a long time, which is dangerous

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  • Method for achieving defluorination and recycling of secondary aluminum ash with series-parallel method

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Embodiment 1

[0023] The hybrid method of this embodiment realizes the method of secondary aluminum ash defluorination and resource utilization, and the steps are as follows:

[0024] Take 50 g of high-fluorine secondary aluminum ash with a particle size of less than 150 μm as the raw material, see Table 1 for the chemical composition, add 37.65 g of solid sodium hydroxide (soda-ash ratio 0.75:1), mix well and sinter at 800 °C for 2 h , the fluorine in aluminum ash is represented by SiF 4 Volatile form, absorbed by sodium hydroxide solution.

[0025] The sintered clinker was leached with an aqueous solution, the liquid-solid ratio was controlled at 4:1, the leaching temperature was 80 °C, and the leaching time was 2 h. The obtained eluate composition was: Al 2 o 3 =81.73g / L, Na 2 o k =86.49g / L, caustic ratio αk=1.74. After adding calcium oxide and stirring for defluorination, the solution can be used as a seed solution and incorporated into the Bayer system for processing low-fluorine ...

Embodiment 2

[0029] The hybrid method of this embodiment realizes the method of secondary aluminum ash defluorination and resource utilization, and the steps are as follows:

[0030] Take 50 g of high-fluorine secondary aluminum ash with a particle size of less than 150 μm as the raw material. The chemical composition is shown in Table 2. Add 67.37 g of solid sodium carbonate (soda-to-ash ratio 1.347:1), mix well and sinter at 900 °C for 2 h. Fluorine in aluminum ash is SiF 4 Volatile form, absorbed by sodium carbonate solution.

[0031] The sintered clinker is leached with an aqueous solution, the liquid-solid ratio is controlled at 5:1, the leaching temperature is 90 °C, and the leaching time is 2 h. The obtained leaching liquid composition is: Al 2 o 3 =43.38 g / L, Na 2 o k =77.62 g / L, caustic ratio αk=3.83. After adding calcium oxide and stirring for defluorination, the solution can be used as a circulating mother liquor and incorporated into the Bayer system for processing low-flu...

Embodiment 3

[0035] The hybrid method of this embodiment realizes the method of secondary aluminum ash defluorination and resource utilization, and the steps are as follows:

[0036] Take 50 g of high-fluorine secondary aluminum ash with a particle size of less than 150 μm as the raw material. The chemical composition is shown in Table 3. Add 50 g of solid sodium hydroxide (soda-ash ratio 1:1), mix well and sinter at 800 °C for 2 h. Fluorine in aluminum ash is SiF 4 Volatile form, absorbed by sodium hydroxide solution.

[0037] The sintered clinker is leached with an aqueous solution, the liquid-solid ratio is controlled at 5:1, the leaching temperature is 80 °C, and the leaching time is 2 h. The obtained leaching liquid composition is: Al 2 o 3 =77.21 g / L, Na 2 o k =51.13 g / L, caustic ratio αk=1.47. After adding calcium hydroxide and stirring for defluorination, the solution can be used as a seed solution and incorporated into the Bayer system for processing low-fluorine materials to...

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Abstract

The invention discloses a method for achieving defluorination and recycling of secondary aluminum ash with a series-parallel method. The method specifically includes the following steps that (1), theraw material secondary aluminum ash comprises high-fluorine secondary aluminum ash and low-fluorine secondary aluminum ash, and the low-fluorine secondary aluminum ash is treated with a Bayer process;(2), the high-fluorine secondary aluminum ash is treated with an alkali sintering method, volatile silicon fluoride gas is absorbed with alkali liquor, and sintered clinker is obtained; (3), the sintered clinker is immersed in water, a defluorination agent is added into leachate, the materials are stirred, the materials are filtered, purified liquor is obtained, and after leached residues are washed, common solid waste is obtained; and (4), a defluorinated solution is merged into the Bayer process flow for treating the low-fluorine secondary aluminum ash according to the causticity ratio. Thelow-fluorine secondary aluminum ash and the high-fluorine secondary aluminum ash are treated with the series-parallel method, on one hand, the aqueous leachate of the sintered clinker supplements losses of liquid alkali of the Bayer process flow, on the other hand, most of the harmful element fluorine in the raw material can be removed, and it is avoided that soluble fluorine enters a high-temperature high-pressure alkali dissolution system, so that reaction equipment is corroded.

Description

technical field [0001] The invention relates to the field of secondary aluminum ash recovery, in particular to a method for realizing defluorination and resource utilization of secondary aluminum ash by a hybrid method. Background technique [0002] Aluminum ash is mainly solid waste produced in the process of electrolytic aluminum. On the one hand, this type of solid waste contains Al and Al 2 o 3 On the other hand, it also contains fluoride discharged during the electrolytic aluminum process. According to statistics, my country's alumina output in 2017 was about 66.6 million tons, and every 1 ton of primary aluminum produced would produce 30-50 kg of aluminum ash. In addition to the amount of aluminum ash accumulated in history, it is urgent to find a reasonable and effective way to realize aluminum ash resources. harmless and harmless. [0003] At present, the way to deal with aluminum ash in China is generally to extract the high-content aluminum by physical methods, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00B09B5/00
CPCB09B3/00B09B5/00
Inventor 付明波郭强李永利田登超
Owner 郑州中科新兴产业技术研究院
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