Method for producing high-purity potassium nitrate from potassium-containing waste liquid produced by synthetic fungicide difenoconazole

Abstract

The invention discloses a method for producing high-purity potassium nitrate from a potassium-containing waste liquid generated from synthesized bactericide difenoconazole. The method comprises the following steps: putting the potassium-containing waste liquid generated from the synthesized bactericide difenoconazole into a neutralization oxidization kettle, adding a proper amount of concentrated nitric acid for neutralization and oxidization, and in the oxidation reaction process, performing temperature increase pressure reduction so as to recycle bromine; after the reaction is completed, adding the mother liquor of potassium nitrate obtained from centrifugation of a former batch of operation into the neutralization oxidization kettle, adding a proper amount of activated carbon to remove color and impurities, and carrying out suction filtration after stirring to obtain a potassium nitrate solution; and carrying out reduced pressure evaporation and concentration on the potassium nitrate solution, cooling and then centrifuging to obtain a crude product of potassium nitrate and the mother liquor, spraying the crude product of potassium nitrate with methanol in the centrifugation process so as to obtain a wet product of potassium nitrate, and performing air flow drying, thereby obtaining a product of potassium nitrate. The waste activated carbon dregs are washed and filtered with hot water and are further treated as solid wastes, and an activated carbon washing liquid is mixed with the mother liquor so as to be fed back to the neutralization oxidization kettle for repeated use. The potassium nitrate methanol spraying liquid is subjected to pressure reduction and distillation to recycle methanol, and a mixture of a residual liquid and the mother liquor of potassium nitrate is fed back to the neutralization oxidization kettle for recycling.

Description

technical field [0001] The invention belongs to the field of chemical environmental protection, and relates to the manufacturing technology of inorganic chemical potassium nitrate, in particular to a method for producing high-purity potassium nitrate by using potassium-containing waste liquid produced in the production process of the synthetic fungicide difenoconazole. Background technique [0002] Difenoconazole, trade name: Cisco, Shigao, is a fungicide developed by Syngenta for fruits, vegetables, grains and South American cotton crops, and is an important part of Syngenta's global plant protection product line , and at the same time, it is also the only one used for the development of seed coating agents among Syngenta's current triazole fungicide products. It has been registered and distributed in important international markets such as the United States, the European Union, and Brazil. The structural formula is as follows: [0003] [0004] Difenoconazole is a tria...

AI Technical Summary

Problems solved by technology

They use secondary acid precipitation to remove impurities by adsorption and precipitation, and then carry out oxidation, decolorization, concentration and salt washing processes. The process is complicated, the treatment cycle is very long, and the operating cost is high.

[0008] Potassium-containing waste liquid is produced during the production of difenoconazole, which is concentrated by evaporation under reduced pressure, cooled and crystallized, and then centrifuged to obtain potassium-containing waste residue. The evaporated condensed water is then discharged up to standard through biochemical treatment, but the disposal of the potassium-containing waste residue is still ineffective deal with

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