Method for preparing aluminum oxide by circularly and continuously electrolyzing sodium aluminate solution

A technology for electrolysis of sodium aluminate and sodium aluminate, applied in electrolysis components, electrolysis process and other directions, can solve the problems of increased energy consumption and material circulation pressure, increased energy consumption, and high system energy consumption, and achieve the effect of increasing alkalinity

Active Publication Date: 2017-01-04
内蒙古瑞达泰丰化工有限责任公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] 1. The tank voltage in the electrolysis process is as high as 3V, which exceeds the economical electrolysis level of 1.7V, resulting in higher power consumption costs
[0007] 2. During the electrolysis process, the oxygen evolution of the anode and the continuous acidification will cause part of the aluminum hydroxide to flocculate directly on the cation exchange membrane, blocking the ion channel of the cation exchange membrane, making the life of the ion membrane prematurely terminated, and aggravating the resistance of ion diffusion during the electrolysis process. Further increase energy consumption
[0009] 1. It is necessary to add additional sodium carbona

Method used

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  • Method for preparing aluminum oxide by circularly and continuously electrolyzing sodium aluminate solution
  • Method for preparing aluminum oxide by circularly and continuously electrolyzing sodium aluminate solution
  • Method for preparing aluminum oxide by circularly and continuously electrolyzing sodium aluminate solution

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Effect test

Embodiment 1

[0085] Prepare a certain concentration of sodium aluminate solution, centrifuge to obtain the supernatant, and measure the content of each component of the sodium aluminate solution: where [Na 2 O]=308g / L, [Al 2 o 3 ]=253g / L, the caustic ratio is 2.0. Keep the sodium aluminate solution at a constant temperature to 85°C, and slowly drop 0.01M HCl solution into the sodium aluminate solution with a peristaltic pump at a speed of 6r / min. In order to prevent coagulation due to local acidification, add hydrochloric acid At the same time vigorous stirring is required. Due to the low concentration of hydrochloric acid solution, it takes a long time to observe the phenomenon of the solution continuously. Considering the volume change when adding hydrochloric acid, and because the aqueous solution will also volatilize at a constant temperature of 85°C, so in the process of adding acid Attention should be paid to the volume change. Distilled water at the same temperature can be added ...

Embodiment 2

[0088] Ti / NiCo 2 o 4 is the anode, the oxygen electrode is the cathode, and the oxygen circulation device is used for electrolysis, and the anolyte is [Na 2 O]=189g / L, [Al 2 o 3 ]=193g / L sodium aluminate solution, volume is 200mL, catholyte is 10% sodium hydroxide solution, electrolysis temperature is 65 ℃, and current density is 50mA cm -2 During the electrolysis process, the caustic ratio is measured every 30 minutes to 1 hour, and the electrolysis is stopped when fine particles of aluminum hydroxide appear. The electrolysis time is 6 hours. The relationship between the tank pressure and time during the electrolysis process is as follows: image 3 , the first electrolysis 6h reaches the critical point K 0 1.45, the tank pressure is 1.43V, the seeds are naturally lowered to room temperature and stirred, and 19.96g of aluminum hydroxide can be obtained, and the alumina content after roasting reaches 99.64%; the caustic ratio of the sodium aluminate solution after solid-liq...

Embodiment 3

[0090] With nickel foam as anode and oxygen electrode as cathode, the effective use area of ​​the electrode is 2.4*3.4cm 2 , using an oxygen cycle electrolysis device for electrolysis, the anolyte is [Na 2 O]=189g / L, [Al 2 o 3 ]=149g / L, caustic ratio is the sodium aluminate solution of 2.0, and volume is 100mL, and catholyte is 10% sodium hydroxide solution. The electrolyte temperature is 55°C, and the critical point value K is determined by chemical method 0 is 1.46, the current density of constant current electrolysis in the electrolysis process is 50mA cm -2 , the time obtained by calculation is about 10h, the current efficiency is 85%, and 8.19g aluminum hydroxide is obtained after the seed separation, and its electron microscope picture is as follows Figure 4 As shown, it can be seen that the sample has good dispersion, and the particle size is 2-8 μm. The alumina content of the product obtained after roasting is 99.7%. The caustic ratio of the mother liquor after ...

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Abstract

The invention provides a method for preparing aluminum oxide by circularly and continuously electrolyzing a sodium aluminate solution, and belongs to the technical field of production of aluminum oxide. The method for preparing the aluminum oxide by circularly and continuously electrolyzing the sodium aluminate solution comprises the steps that the sodium aluminate solution and a diluted NaOH solution are guided into an anode chamber and a cathode chamber separated by an ion exchange membrane correspondingly, the NaOH solution is subjected to reductive electrolysis on the cathode while the sodium aluminate solution is oxidized on the anode, and seed precipitation is conducted on an electrolyte, obtained after electrolysis, in the anode chamber, so that aluminum hydroxide is separated out, and electrolysis can be conducted again after solid-liquid separation; and the high-concentration NaoH solution, obtained through electrolysis, in the cathode chamber can be used for the leaching process of the aluminum oxide. According to the method for preparing the aluminum oxide by circularly and continuously electrolyzing the sodium aluminate solution, a hug seed precipitation tank is not needed, seed crystals do not need to be added, the decomposition rate is increased while energy is saved, and meanwhile, the high-concentration alkaline solution which can be used for leaching of the aluminum oxide is obtained.

Description

technical field [0001] The invention belongs to the technical field of alumina production, in particular to an oxygen cycle continuous electrolysis of sodium aluminate solution to prepare alumina, and belongs to the fields of nonferrous metal industry and chemical industry. [0002] Background of the invention [0003] Aluminum and its aluminum alloys have many excellent properties in terms of electrical conductivity, thermal conductivity, and antimagnetic properties, and have become the most widely used non-ferrous metals. The production and consumption of aluminum oxide, the raw material for electrolysis, are also increasing year by year. According to statistics, in the first half of 2014, the global alumina production was 53.46 million tons, of which my country's alumina production was 24.9 million tons, accounting for 46.58% of the global total. [0004] At present, the methods of alumina production at home and abroad mainly include Bayer method (Bayer), sintering method ...

Claims

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Application Information

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IPC IPC(8): C25B1/00
Inventor 潘军青马婷孙艳芝
Owner 内蒙古瑞达泰丰化工有限责任公司
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