Purifying recovery method of gallic acid production wastewater

A gallic acid and waste water production technology, applied in chemical instruments and methods, water/sewage treatment, water/sewage multi-stage treatment, etc., can solve problems such as limited use, large environmental pollution, and insufficient purity. Achieve the effects of reducing salt deposition and clogging, improving heat transfer coefficient, and simple process

Inactive Publication Date: 2008-04-16
乐山三江生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These wastewaters are extremely polluting to the environment, and the wastewater treatment process is complex and costly, which has become a major problem in the production of gallic acid
Previously, it was used to directly recycle refined waste water as water for hydrolysis of gallnut or Tara raw materials, but practice found that although

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Example 1: 400kg of wastewater produced by hydrolysis and production of gallic acid, add 15kg of 30% NaOH (weight), stir and neutralize to PH=4.8, send it to the evaporator, evaporate under 0.085KPa vacuum for 2.5h, and concentrate to the original 1 / 3 of the volume, centrifuged to obtain 26.3kg of salt and 115kg of mother liquor; cooled to 10℃, crystallized for 20h, centrifuged and dried to obtain 5.6kg of gallic acid, added 15kg of lime to the mother liquor, adjusted the pH to neutral (PH=7.5), after clarification, Add 7.5kg coal-based charcoal to the supernatant and decolorize at 90°C for 0.5h. The filtered clear liquid is basically colorless. After biochemically in the biochemical tank, it is determined: volatile phenol 0.010mL / L, BOD 5 :28.2mL / L, COD Cr : 88.2mL / L, reaching the first-level discharge standard for second-class waste liquid.

Embodiment 2

[0017] Example 2: Add 10kg of 30% NaOH to the waste water produced by the refined gallic acid of 450kg, PH=5.0, put it in an evaporator, evaporate at 0.009KPa for 2h, distill 320kg of water (discharge), put the concentrated liquid in a crystallization tank, and cool 18h, cooled to 10℃ and centrifuged to dry 6.1kg gallic acid. Add 6.5kg of lime milk to the mother liquor to be neutral. After clarification, add 5kg of coal-based charcoal to the clear liquor, decolorize at 95℃ for 40 minutes, and filter the clear liquor after being biochemically in the biochemical tank. BOD 5 :27.40mL, COD Cr : 91.2mL / L.

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PUM

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Abstract

The invention relates to a method for purifying and recycling the waste water produced in the production of gallic acid, wherein, the waste water is produced during the hydrolyzation or refining process of the production of the gallic acid with nutgall or tala as the raw materials. The concrete process is as follows: the waste water is neutralized with 30 percent NaOH to a PH value between 4.5 and 5 and then is vaporized condensed in vacuum, centrifugated to reclaim salt, cooled to between 10 DEG C and 15 DEG C to precipitate gallic acid crystals, and centrifugally filtered to removel gallic acid crystals and obtain gallic acid; the filtrate is neutralized to the neutralization by adding into milk of lime, after the clarification, the clear liquid is decolored by coal-based activated carbon, then the waste water is subject to biochemical treatment by a biochemical pool to reach the drainage standard. The recycling of the gallic acid can be used to produce products such as pyrogallic acid, gallate and so on, the reclaimed salt can be taken as whitening agent, the boiler softened water and the lime can be used to produce bricks; the invention has less investment, simple process, low cost and good waste water treatment effect.

Description

Technical field [0001] The invention relates to a method for purifying and recycling gallic acid production wastewater. Background technique [0002] The production of gallic acid is made from the forest plant gallnut or tara as raw materials through alkaline hydrolysis and refining processes. It is widely used in anti-corrosion agents, integrated circuit detergents and other applications. It is an important fine organic chemical . [0003] my country is rich in forest resources and is the main producer of gallic acid. However, the hydrolysis and refining process of gallic acid production will produce a lot of waste water. The gallic acid production wastewater mainly comes from the following three channels: 1. Hydrolysis wastewater: the wastewater is brown, the pH is about 1.5, and the content of various harmful substances: BOD 5 About 1000mg / L, COD Cr About 2500mg / L, volatile matter 0.015mg / L, suspended matter 400~450mg / L, salt 20~22% mg / L, and also contains about 2% residual ga...

Claims

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Application Information

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IPC IPC(8): C02F9/14C02F1/66C02F1/58C02F1/28
Inventor 张宗和黄嘉玲王金鍫秦清徐浩陶林仲崇茂
Owner 乐山三江生物科技有限公司
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