Aluminum nitrate-containing nitric acid wastewater treatment system and treatment method thereof

Abstract

The invention discloses an aluminum nitrate-containing nitric acid wastewater treatment system which comprises a two-stage column chromatography separation system and further comprises an aluminum sulfate purification system. The aluminum sulfate purification system comprises an aluminum sulfate feeding tank, a preheater, a two-effect three-stage falling film evaporator used for repeatedly evaporating and concentrating an aluminum sulfate solution, a cooling crystallization tank, a crystallization transfer tank, a filter press, a high-level tank used for receiving solids obtained after filterpressing and a scraper which are connected in sequence, and the aluminum sulfate feeding tank is connected with an aluminum sulfate solution tank. An aluminum nitrate-containing nitric acid wastewatertreatment method based on the wastewater treatment system is small in evaporation capacity and relatively low in production risk; replacement is thorough, the content of nitric acid in the obtained aluminum sulfate solution is low, and aluminum sulfate superior to the national standard can be further produced; and the process is more energy-saving, the obtained aluminum sulfate product is higherin quality, the overall temperature is not too high, and long-time stable operation is facilitated.

Description

technical field [0001] The invention relates to the technical field of waste acid treatment, in particular to a nitric acid waste water treatment system containing aluminum nitrate and a treatment method thereof. Background technique [0002] The corrosion process in the production process of electrode foil requires a large amount of mixed acid, which produces a large amount of wastewater containing strong acid. One of the main wastewater is aluminum-containing nitric acid wastewater. The general treatment method is to discharge it directly after neutralization. Although it can greatly reduce the acidity, but which has a lot of NO 3 - 、Al 3+ It still exists in an ion state, which will cause total nitrogen, serious excess and waste of resources, which does not meet environmental protection requirements. Chinese patent literature (application number 201711286050.0) discloses a treatment method for aluminum-containing nitric acid wastewater, including the steps of: performin...

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Problems solved by technology

[0004] The amount of evaporation needs to be large, and the hydrated aluminum nitrate decomposes at 135 degrees. Three-effect evaporation is used. Since the solubility of aluminum nitrate changes greatly with temperature, the final effect temperature should not be too low, so the first effect temperature is relatively high, and the production is more dangerous. Big;

[0005] The separated aluminum nitrate can be replaced by adding sulfuric acid, but the replacement is not complete. The obtained aluminum sulfate contains more nitric acid, and the residual sulfuric acid is not treated, resulting in waste of nitric acid and impurity of aluminum sulfate

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