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How to Filter and Recycle Acid Pickle?

Nov. 30, 2022


Acid pickle is produced in the process of nitration, esterification, sulfonation, alkylation, catalysis and gas drying of organic matter. Acid pickle mainly includes waste sulfuric acid, waste nitric acid, waste phosphoric acid, waste hydrofluoric acid, etc. Because direct discharge of waste acid not only wastes resources, but also pollutes the environment, so it is essential to recycle acid waste liquid. There are many ways to purify waste acid. Now we mainly introduce how to use ion exchange resin to filter and recycle waste acid.

The principle of ion exchange resin treatment of acid pickle is to pass the waste acid containing salt (such as metal salt) through the ion exchange resin bed. The free acid is adsorbed and blocked in the resin bed, and the salt will pass through and flow out without adsorption, and then pass into (pure) water to elute the free acid on the resin bed to complete a cycle, and so on, complete the separation of acid and salt.

First, discharge the waste acid that needs to be treated into the grease trap, remove larger solid particles and oily substances, then flow into the waste acid pool, and then further remove smaller impurities through the security filter system. The security filter system is usually composed of two sets of filter housings with different filter fineness in the front and rear in series.

The function of the pre-filter housing is to retain larger particles and protect the service life of the downstream filter consumables. The filter housing generally chooses Plastic (PPH ) Bag Filter Housing or Plastic (PPH) Cartridge Filter Housing, and the filter consumables are generally selected Filter Bag or String Wound Cartridges with a filtration accuracy of 10 micron.

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The role of the rear filter housing is to remove small particles of impurities, protect the downstream resin bed from contamination by impurities, and prolong its service life. The post-filter housings generally use Plastic (PPH) Cartridge Filter Housings or Plastic (PPH) High Flow Filter Housings, and the filter consumables usually choose Melt Blown Cartridges, Pleated Filter Cartridges or High Flow Filters with 1 micron filtration accuracy.

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Store the acid pickle treated by the security filter system in the buffer tank, and then pump it into the acid adsorption tank equipped with ion exchange resin through the booster pump, the free acid in the waste acid is adsorbed by the resin, and the metal salt is discharged from the adsorption tank. Pure water backwash is then used to elute the free acid from the resin bed, resulting in regenerated acid that can be used in the pickling process during production.

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