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Alkali deweighting wastewater processing method and device

A technology for alkali reduction wastewater and treatment methods, which is applied in textile industry wastewater treatment, water/sewage treatment, neutralized water/sewage treatment, etc., and can solve problems such as inability to be directly and effectively removed, many precipitated impurities, and limited recycling

Inactive Publication Date: 2008-08-20
SHAOXING COUNTY JINGSHENG RESIN TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Chinese patent 97106539.x discloses a "treatment method for alkali-reduction wastewater", which is to add ferric salt to alkali-reduction wastewater, and adjust the pH with acid, so that terephthalic acid is precipitated in a solid state, thereby reducing waste water. COD cr value, this method can generally reduce COD cr The value is more than 75%, but the simple precipitation of terephthalic acid has many impurities, which cannot be recycled, and contains secondary pollution caused by solid waste
In addition, the cost of acid precipitation is also high
[0004] Chinese patent (99124266.1) discloses a method for recovering terephthalic acid from alkali reduction wastewater, which can obtain relatively high-purity terephthalic acid, and its resource regeneration can make up for operating costs. However, this type of simple precipitation Terephthalic acid cannot directly and effectively remove residues such as ethylene glycol and sodium sulfate adsorbed by terephthalic acid (acid analysis with sulfuric acid), so its recycling is limited to a certain extent
[0006] In summary, this area lacks an effective method to process alkali reduction waste water

Method used

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  • Alkali deweighting wastewater processing method and device
  • Alkali deweighting wastewater processing method and device

Examples

Experimental program
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Effect test

Embodiment 1

[0127] Take 0.5m of alkali reduction wastewater from polyester warp knitted fabric 3 , The measured pH is 14, COD cr At 25000mg / L. Sulfuric acid with a concentration of 98% by weight was added to adjust the pH of the wastewater to 7, and the amount of acid added was determined by the acid drop of the filter liquid without terephthalic acid precipitation. Collect the precipitated solid terephthalic acid, weigh 100 g after drying, add 50 ml of 98% sulfuric acid and 500 ml of methanol, and react at 70° C. for 10 hours to obtain DMT crystals. After drying, take 50g crude DMT into 200ml ethanol solution and heat to 60°C. DMT is dissolved to obtain a turbid ethanol mixture. This solution is filtered through activated carbon to obtain a clear solution. The resulting clear solution was frozen to 10°C under ice cooling. At this time, DMT crystals precipitated.

Embodiment 2

[0129] Take the alkali reduction wastewater 0.3m of the artificial silk polyester fabric 3 , The pH value is 12.1. Spent sulfuric acid with a concentration of 31 wt% is added, and the pH drops to 6.5. Collect the precipitated solid terephthalic acid and weigh 200 g after drying. Add 58ml of 98% sulfuric acid and 600ml of methanol. At 110℃, 4kgf / cm 2 Under the conditions, react for 3 hours to obtain DMT crystals. Weigh 50g, add 200ml of analytically pure ethanol, all crystals are dissolved at 50°C, add pottery clay, stir and filter through a ceramic microporous tube to obtain a pure clear liquid, condense to 10°C, and all DMT crystals are precipitated.

Embodiment 3

[0131] Using 200ml of waste sulfuric acid with a concentration of 65% in the above test, the pH14 alkaline reduction wastewater of ponge to obtain 80 grams of terephthalic acid was obtained. After esterification reaction (70℃ normal pressure) for 12 hours, DMT crystals were obtained and dissolved in hot ethanol. After adding barium carbonate and stirring, there will be CO2 bubbles and white barium sulfate precipitation. Then add walnut shell filter material, filter through dense filter cloth, and obtain recrystallization at room temperature of 25°C. After the crystals are dried, the purity of DMT is distilled once to reach 99.6%.

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Abstract

The invention provides a processing method for alkali-minimization wastewater, comprising a plurality of steps: (a) adjusting the PH value of alkali-minimization wastewater into 6.5 to 7, using the method of acid precipitation to obtain liquid phase and the solid phase with terephthalic acid; (b) carrying out esterification reaction for the solid phase from the procedure (a) in the presence of methanol to obtain a crude dimethyl terephthalate product. The method recovering terephthalic acid from alkali-minimization wastewater makes CODcr value of the wastewater removal of more than 75% and modifies the wastewater into Biodegradable industrial wastewater and at the same time changes the phthalic acid into dimethyl terephthalate.

Description

Technical field [0001] The invention relates to a treatment method of dyeing and finishing wastewater, in particular to a treatment method of alkali reduction wastewater. Background technique [0002] The alkali weight reduction process is to treat polyester fabric with alkali (NaOH), and hydrolyze the polyethylene terephthalate (PET) on the surface of the fabric at a higher temperature, so that the fabric becomes soft after weight reduction. . The alkali reduction wastewater produced in the alkali reduction treatment process mainly contains the hydrolysate of PET, sodium terephthalate, ethylene glycol, titanium dioxide, and some of the auxiliary agents brought by the spinning and spinning process, and its COD cr The value is generally 8000~30000mg / l (combined value of reduction and washing wastewater). Because the benzene ring structure molecule of sodium terephthalate is extremely difficult to deal with with low-cost biodegradation process. [0003] Chinese patent 97106539.x di...

Claims

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Application Information

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IPC IPC(8): C02F1/58C02F1/66C02F101/34C02F103/30C07C69/82
Inventor 陈定良
Owner SHAOXING COUNTY JINGSHENG RESIN TECH CO LTD
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