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Treatment method of trivalent chromium passivation wastewater containing aminoacetic acid complexing agent

A treatment method, trivalent chromium technology, applied in water/sewage treatment, chemical instruments and methods, water/sludge/sewage treatment, etc., can solve short production time, low efficiency of aminoacetic acid, waste of trivalent chromium passivation To solve the problem of excessive liquid and so on, to solve the effect of increasing COD and avoiding residue

Active Publication Date: 2022-02-01
GUANGZHOU ULTRA UNION CHEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The composition of the trivalent chromium passivation solution changes rapidly during use and needs to be replaced frequently, resulting in a large amount of trivalent chromium passivation waste liquid, so the treatment volume of trivalent chromium passivation wastewater is relatively large
However, the time for trivalent chromium passivation to be put into large-scale production is relatively short, and its wastewater treatment technology is still immature.
[0005] Some trivalent chromium passivation solutions contain aminoacetic acid, which has strong oxidation resistance. The efficiency of destroying aminoacetic acid by traditional oxidation methods is low. Generally, a large amount of oxidant is required, and the treatment cost is high. It is difficult to be effective in winter when the temperature is low. Removal of complexing agents such as aminoacetic acid
Therefore, if the trivalent chromium passivation wastewater containing aminoacetic acid is treated by the traditional oxidation-hydroxide precipitation method, the content of heavy metal ions such as trivalent chromium in the treated wastewater often does not meet the GB 21900-2008 "Electroplating Pollutant Discharge Standard" "Requirements

Method used

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  • Treatment method of trivalent chromium passivation wastewater containing aminoacetic acid complexing agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Embodiment 1: process the trivalent chromium passivation waste water containing aminoacetic acid of trivalent chromium ion 30mg / L

[0047] Step 1. Precipitate heavy metal ions and complexing agents

[0048] Transport the trivalent chromium passivation wastewater from the wastewater regulating tank to the primary sedimentation tank, stir the tank liquid with a mixer, add lime emulsion to adjust the pH of the wastewater to 10-12, add 10L heavy metal scavenger to each ton of wastewater, and obtain heavy metal ions and The precipitate generated by sodium dimethyl dithiocarbamate and the precipitate generated by complexing agent and calcium ion.

[0049] Step 2. Precipitate the remaining heavy metal scavenger

[0050] The wastewater flows from the primary sedimentation tank into the secondary sedimentation tank, stir the pool liquid with a mixer, add lime emulsion to keep the pH of the wastewater to 10-12, add 8L of ferrous chloride solution to each ton of wastewater, and pre...

Embodiment 2

[0057] Embodiment 2: process the trivalent chromium passivation waste water containing aminoacetic acid of trivalent chromium ion 80mg / L

[0058] Step 1. Precipitate heavy metal ions and complexing agents

[0059] The trivalent chromium passivation wastewater is input from the wastewater adjustment tank to the primary sedimentation tank, the pool liquid is stirred with a mixer, the pH of the wastewater is adjusted to 10-12 by adding lime emulsion, and 30L of heavy metal scavenger is added to each ton of wastewater to obtain heavy metal ions and The precipitate generated by sodium dimethyl dithiocarbamate and the precipitate generated by complexing agent and calcium ion.

[0060] Step 2. Precipitate the remaining heavy metal scavenger

[0061] Wastewater flows from the primary sedimentation tank into the secondary sedimentation tank, stir the pool liquid with a mixer, add lime emulsion to maintain the pH of the wastewater to 10-12, add 20L of ferrous chloride solution to each ...

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Abstract

The invention discloses a treatment method for trivalent chromium passivation waste water containing aminoacetic acid complexing agent, adding a heavy metal catching agent to a waste water treatment pool, then adding lime emulsion to make the pH of the waste water reach 10-12, and using the heavy metal catching agent to precipitate the waste water Heavy metal ions in the medium, and calcium ions are used to precipitate carboxyl-containing organic acid complexing agents. Precipitate the remaining heavy metal scavenger in the wastewater with ferrous ions, add flocculants to aggregate the precipitated particles, filter and separate the precipitates, and adjust the pH of the wastewater to 6-9. The treatment results meet the requirements of Table 3 of GB 21900-2008 "Electroplating Pollutant Discharge Standard". The invention creates a new method for removing heavy metal ions and carboxyl-containing organic acid complexing agents in waste water by using the heavy metal scavenger and calcium ions together. The process is simple and easy, the treatment cost is low, and the method has good market application prospects.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment, in particular to a treatment method for trivalent chromium passivation wastewater containing aminoacetic acid complexing agent. Background technique [0002] Replacing the highly toxic hexavalent chromium passivation with trivalent chromium passivation has been widely used and achieved good environmental and social benefits. [0003] Trivalent chromium passivation solution includes trivalent chromium passivation rinsing water, trivalent chromium passivation waste solution, which contains trivalent chromium and cobalt metal ions, and a carboxyl-containing organic acid complexing agent that forms a complex with it , Some three-price passivation solutions also contain a small amount of rare earth salts. Trivalent chromium passivation is generally used for passivation treatment of zinc coating and zinc-nickel alloy coating. Passivation wastewater contains zinc ions, nickel io...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/52C02F1/56C02F101/22
CPCC02F1/56C02F1/5245C02F2101/22
Inventor 郭崇武黎小阳赖奂汶
Owner GUANGZHOU ULTRA UNION CHEM LTD
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