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A deep purification method for organized tail gas discharge during aluminum electrolysis production process

A production process and deep purification technology, applied in chemical instruments and methods, separation methods, products, etc., to reduce carbon emissions, have considerable economic value, and improve the effect of defluorination

Active Publication Date: 2020-09-08
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem of organized flue gas discharge in the existing aluminum electrolysis production process, the present invention provides a deep purification method for organized exhaust gas discharge in the aluminum electrolysis production process. Firstly, HF is deeply removed, and then zinc oxide slurry is used to absorb SO 2 , and forced oxidation to get ZnSO 4 Solution, separated from zinc oxide and concentrated to produce ZnSO 4 ·7H 2 O, while capturing CO 2 Obtain light calcium carbonate, comprehensively utilize various beneficial elements while reducing pollution

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  • A deep purification method for organized tail gas discharge during aluminum electrolysis production process
  • A deep purification method for organized tail gas discharge during aluminum electrolysis production process

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Experimental program
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Effect test

Embodiment 1

[0044] The concentration of HF in the organized exhaust gas is 1.2mg / Nm 3 , SO 2 The concentration is 1000mg / Nm 3 , CO 2 The concentration is 8000mg / Nm 3 ;

[0045] The organized exhaust gas is passed into the moving bed equipped with γ-alumina, and the deep defluorination is carried out through the γ-alumina, and the defluorinated tail gas is formed after the deep defluorination; the organized exhaust gas enters from the lower part of the moving bed and flows upward , γ-alumina moves from top to bottom in the moving bed, the flow rate of the exhaust gas is controlled to be 3m / s, the moving speed of γ-alumina is 0.04m / h, and the solid-gas ratio is 25g / m 3 ; The solid-gas ratio refers to the weight of γ-alumina to the volume ratio of the organized exhaust gas;

[0046] HF concentration in defluorinated tail gas 3 ;

[0047] Inject the defluorinated tail gas and ozone into the desulfurization reactor equipped with zinc oxide slurry at the same time. The zinc oxide slurry i...

Embodiment 2

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

[0056] (1) The concentration of HF in the organized exhaust exhaust gas is 2.1mg / Nm 3 , SO 2 The concentration is 780mg / Nm 3 , CO 2 The concentration is 9000mg / Nm 3 ;

[0057] (2) γ-alumina moves from top to bottom in the moving bed, the flow rate of the exhaust gas is controlled to be 2m / s, the moving speed of γ-alumina is 0.03m / h, and the solid-gas ratio is 28g / m 3 ;

[0058] (3) Desulfurization reactor initial condition Zinc oxide accounts for 18% of water gross weight; When the concentration of the zinc sulfate solution in the reaction tank reaches 260g / L, 1 / 3 of all zinc sulfate solution in the reactor is discharged;

[0059] (4) SO in desulfurization tail gas 2 The concentration of 12mg / Nm 3 ;

[0060] (5) Lower the temperature to 25±1°C for 20 minutes in a water bath, and dry the crystalline solid phase obtained by filtration at 45°C;

[0061] (6) The calcium ion concentration of the calcium ion-containi...

Embodiment 3

[0063] Method is with embodiment 1, and difference is:

[0064] (1) The concentration of HF in the organized exhaust gas is 3.3mg / Nm 3 , SO 2 The concentration is 590mg / Nm 3 , CO 2 The concentration is 10000mg / Nm 3 ;

[0065] (2) γ-alumina moves from top to bottom in the moving bed, the flow rate of the exhaust gas is controlled to be 1m / s, the moving speed of γ-alumina is 0.02m / h, and the solid-gas ratio is 32g / m 3 ;

[0066] (3) Desulfurization reactor initial condition Zinc oxide accounts for 15% of water gross weight; When the concentration of the zinc sulfate solution in the reaction tank reaches 220g / L, 1 / 3 of all zinc sulfate solution in the reactor is discharged;

[0067] (4) SO in desulfurization tail gas 2 The concentration of 10mg / Nm 3 ;

[0068] (5) Lower the temperature to 25±1°C for 30 minutes in a water bath, and dry the crystalline solid phase obtained by filtration at 45°C;

[0069] (6) The calcium ion concentration of the calcium ion-containing solu...

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Abstract

The invention discloses a deep purification method for organically discharged tail gas in an aluminum electrolysis production process. The deep purification method comprises the following steps: (1) feeding the organically discharged tail gas into a moving bed with gamma-aluminum oxide, and carrying out deep defluorination through the gamma-aluminum oxide; (2) simultaneously blowing defluorinationtail gas and ozone into a desulphurization reactor with zinc oxide slurry, wherein under the action of the ozone and a stirring condition, SO2 in the defluorination tail gas and zinc oxide react witheach other to generate zinc sulfate for desulphurization reaction, and the zinc sulfate forms a zinc sulfate solution in water; (3) heating the discharged zinc sulfate solution for evaporative concentration, and carrying out filtering and drying, thus obtaining a heptahydrate product; (4) feeding a calcium ion-containing solution into a water inlet of a Venturi jet reactor, then feeding desulphurization tail gas at the same time for mineralization reaction, and discharging decarbonization tail gas from a gas outlet. According to the method disclosed by the invention, heptahydrate and calciumcarbonate products are prepared, and SO2 and CO2 resources in aluminum electrolysis tail gas are recycled; meanwhile, the problem on pollution caused by waste calcium carbide slurry is solved, and theflue gas treatment cost is greatly reduced.

Description

technical field [0001] The invention belongs to the fields of metallurgical technology and environmental protection technology, and in particular relates to a method for deep purification of exhaust tail gas organized in the production process of aluminum electrolysis. Background technique [0002] In the process of aluminum electrolysis, the carbon anode and alumina react electrochemically in the cryolite melt to produce a certain amount of SO 2 , CO 2 And containing fluorine, containing Al 2 o 3 Dust flue gas, the flue gas is collected by the gas collecting hood on the upper part of the aluminum electrolytic cell and then discharged from the chimney after being purified by the exhaust system and equipment. This kind of aluminum electrolysis flue gas is usually called primary flue gas, also known as organized flue gas ; At present, dry purification is mainly used in my country to remove fluoride in the organized emission of aluminum electrolysis, but for SO in flue gas 2...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/75B01D53/83B01D53/68B01D53/80B01D53/76B01D53/50B01D53/73B01D53/78B01D53/62C01F11/18C01G9/06
CPCB01D53/507B01D53/62B01D53/685B01D53/73B01D53/75B01D53/78B01D53/83C01F11/181C01G9/06C01P2006/80Y02C20/40Y02P20/151
Inventor 张廷安刘燕张伟光曹雪娇豆志河吕国志
Owner NORTHEASTERN UNIV LIAONING
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