A kind of recovery method and recovery device of waste sulfuric acid and waste aluminum sulfate when producing electrode foil

Abstract

The invention discloses a recovery method and a recovery device for waste sulfuric acid and waste aluminum sulfate in the production of electrode foils. The recovery method is characterized in that sulfuric acid waste liquid and waste nitric acid Perform heat exchange to preheat the sulfuric acid waste liquid, and further evaporate and separate the sulfuric acid waste liquid into sulfuric acid and aluminum sulfate crystals under low temperature conditions through a low-temperature evaporation combined membrane.

Description

technical field [0001] The invention relates to the field of electrode production, in particular to a recovery method and recovery device for waste sulfuric acid and waste aluminum sulfate in the production of electrode foils. Background technique [0002] In the production process of electrode foil (aluminum foil), sulfuric acid waste liquid is mainly produced by the primary electric corrosion process in the corrosion foil process, and its main components include sulfuric acid, aluminum ions, water, and trace metal ions. The chemical reaction equation between sulfuric acid and aluminum foil: 2AL+3H 2 SO 4 =Al 2 (SO 4 ) 3 +3H 2 ↑ [0003] The process principle of primary electro-etching of corroded foil is to dilute concentrated sulfuric acid into low-concentration dilute sulfuric acid. As a corrosion solution, aluminum foil is uniformly electrochemically corroded as an anode under the condition of direct current, and the elemental aluminum in the anode will become Al....

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Problems solved by technology

[0004] (1) The generated waste residue needs to be treated as solid waste, and the treatment cost is high; due to the use of lime milk to neutralize the waste sulfuric acid generated by the system, a large amount of CaSO will be generated 4 Waste residue, and in the neutralization process, it is necessary to purchase the raw material lime for neutralization, and also need to purchase the flocculant for auxiliary sedimentation, and also need to use centrifuge equipment to separate the slurry, the operating cost and supporting equipment and facilities high input cost

at 15m 3 / h waste sulfuric acid treatment design calculation, the cost of gypsum waste slag treatment equipment alone will increase by 800,000 yuan, and the annual cost of lime purchase will be 2.6 million yuan, the cost of waste slag treatment will be 1.2 million yuan per year, the cost of auxiliary materials will be 450,000 yuan per year, and the operating power consumption The cost needs to be 660,000 yuan per year. Calculated according to one year, the cost will increase by 5.8 million yuan per year

[0005] (2) Waste sulfuric acid cannot be reused; due to the use of gypsum neutralization treatment, all waste sulfuric acid will participate in the neutralization reaction to generate waste residue, no recycling

[0006] (3) Aluminum sulfate is not recycled; the waste residue produced by neutralization reaction with lime is not only gypsum (CaSO 4 ) waste residue, and Al(OH) in the alkali neutralization process 3 Produced and shipped out as waste slag; a large amount of recyclable aluminum sulfate is lost

[0007] (4) The working environment is poor; the waste residue generated by the neutralization reaction with lime is separated by centrifugation, and then transported to the external solid waste site by car, and the neutralized and separated sewage is directly discharged

During this process, there will be leakage of slurry, which will pollute the working environment on site, and there will also be overflow of neutralized sewage blocking pipes, resulting in poor working environment

[0008] (5) The cost of operation and operation is high; the neutralization reaction between lime and waste sulfuric acid needs to be equipped with a large number of equipment and facilities, and corresponding operators of various equipment are equipped. The waste slag generated often leaks during the transportation operation. It needs to be cleaned and cleaned regularly and regularly, which consumes a lot of manpower and material resources. The method of neutralization with lime water is used for treatment. More than 30,000 tons of lime powder are produced every year to neutralize the precipitated calcium salt and aluminum salt sludge, and there are also a large amount of sulfate. Coexist with waste residue and discharge, the treatment cost is high, and it also wastes a lot of water and electricity resources

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