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Method for treating wastewater containing hexavalent chromium

A hexavalent chromium and wastewater technology, applied in chemical instruments and methods, water pollutants, water/sewage treatment, etc., can solve the problems of complicated equipment, large land occupation, and high cost, and achieve low cost, good effect, and reduced dosage. Effect

Active Publication Date: 2015-09-23
HUNAN ZHONGDA CONSTR ENG TESTING TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to solve the problems of high cost, complicated equipment and large land occupation in the treatment of wastewater containing hexavalent chromium, and to provide a method for treating wastewater containing hexavalent chromium

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0030] Cr content in the electroplating workshop of Beijing Qingyun Aviation Instrument Factory 6+ Wastewater is treated, its Cr 6+ The concentration was 125.5 mg / l. Pyrite ore (commercially available) is pulverized and passed through a 150-mesh sieve to obtain pyrite ore powder; modifier polycarboxylic acid (commercially available) is added to the pyrite ore powder in an amount of pyrite ore 1.5% of the weight of the ore powder, and stirred evenly to obtain the improved pyrite ore powder. Add the improved pyrite ore powder into the waste water containing hexavalent chromium according to the addition amount of 25g / l waste water, the pH value of the waste water containing hexavalent chromium is 2, fully stir, the reaction time is 50 minutes, and the reaction forms Cr 2 S 3 and Cr 3 S 4 Insoluble sulfides. After static precipitation, the turbid solution of the reaction product was allowed to stand for 1 hour, and the precipitate was recovered. The effluent water quality h...

Embodiment 2

[0032] Containing Cr in the electroplating workshop of Fujian Putian Mold Factory 6+ Wastewater is treated, its Cr 6+ The concentration was 175.6 mg / l. The pyrite ore is pulverized and passed through a 200-mesh sieve to obtain the pyrite ore powder; the modifier polycarboxylic acid is added to the pyrite ore powder in an amount of 2.5% of the weight of the pyrite ore powder, and the mixture is evenly stirred. Obtain improved pyrite ore powder. Add the improved pyrite ore powder into the waste water containing hexavalent chromium according to the addition amount of 40g / l waste water, the pH value of the waste water containing hexavalent chromium is 3, fully stir, the reaction time is 1 hour, and the reaction forms Cr 2 S 3 and Cr 3 S 4 Insoluble sulfides. After static precipitation, the turbid solution of the reaction product was allowed to stand for 2 hours, and the precipitate was recovered. Cr after treatment 6+ When the concentration is below 0.002mg / l, the effluent...

Embodiment 3

[0034] Cr content of Changsha Chromium Salt Plant 6+ Wastewater is treated, its Cr 6+ The concentration is 148mg / l. Pyrrhotite ore (commercially available) is pulverized and passed through a 300-mesh sieve to obtain pyrrhotite ore powder; the modifier polycarboxylic acid is added to the pyrrhotite ore powder in an amount of 2.0% of the weight of the powder, and stir evenly to obtain the improved pyrrhotite ore powder. Add the improved pyrrhotite ore powder into the waste water containing hexavalent chromium according to the addition amount of 30g / l waste water, the pH value of the waste water containing hexavalent chromium is 4, fully stir, the reaction time is 1.5 hours, and the reaction forms Cr 2 S 3 and Cr 3 S 4 Insoluble sulfides. After standing still for precipitation, the cloudy solution of the reaction product was left standing for 2.5 hours, and the precipitate was recovered. Cr after treatment 6+ Concentration below 0.017mg / l, except Cr 6+ The rate reached ...

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Abstract

The invention discloses a method for treating wastewater containing hexavalent chromium. The method comprises the following steps: crushing pyrite ores, separating the crushed pyrite ores and screening the separated pyrite ores through a 100-300-mesh screen to obtain pyrite ore powder; adding a modifying agent, namely polycarboxylic acid into the pyrite ore powder to obtain modified pyrite ore powder; adding the modified pyrite ore powder into the wastewater containing hexavalent chromium, fully stirring and reacting for 10 minutes to 2 hours to form sulfide insoluble materials of Cr2S3 and Cr3S4; standing and precipitating; recycling precipitates and enabling the treated wastewater to reach or be below the specified emission standard. The method is simple in equipment, low in cost, small in occupied area and free of secondary pollution; the removal rate of Cr<6+> reaches over 98%; the quality of the discharged water can reach or be below the specified emission standard; the great economic and social benefits can be realized.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a method for treating wastewater containing hexavalent chromium. Background technique [0002] In the prevention and control of heavy metal pollutants to ensure environmental quality, people pay special attention to the treatment of chromium-containing wastewater, which has become a priority control project for environmental protection circles around the world. In my country's sustainable development strategy, it is also clearly stated that the pollutants of chromium, lead, cadmium, mercury and arsenic need to be treated first, and the treatment of hexavalent chromium is particularly emphasized as the top priority for the treatment of heavy metal pollutants in my country at the turn of the century. . [0003] The current treatment method of chromium-containing wastewater mainly adopts the chemical reduction method with complicated equipment and high cost. my country...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/52C02F1/70C02F1/62C02F1/28C02F101/22
Inventor 鲁安怀尹小波王泉黄娟娟
Owner HUNAN ZHONGDA CONSTR ENG TESTING TECH
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