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Method for separating chromium from iron in electroplating sludge leaching liquid through complexing precipitation

A technology for complexing sedimentation and electroplating sludge, applied in the fields of hydrometallurgy, materials, and chemistry, it can solve the problems of difficult separation of Cr and Fe, and achieve the effect of reducing the concentration

Active Publication Date: 2017-09-26
JIANGXI UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem of difficult separation of Cr and Fe in the electroplating sludge leaching system, the present invention provides a method for complexing precipitation to separate ferrochrome from the electroplating sludge leaching solution. The method has low equipment requirements, simple operation, low cost, and no Pollution, can effectively separate Cr and Fe, so as to meet the requirements of efficient separation and recovery of Cr in electroplating sludge

Method used

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  • Method for separating chromium from iron in electroplating sludge leaching liquid through complexing precipitation

Examples

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Effect test

Embodiment 1

[0028] (1) The electroplating sludge leachate that has been pretreated to remove impurities such as Ni and Zn: iron content Fe 3+ 4g / L, chromium content Cr 3+ 3.8 g / L, solution pH=1.5.

[0029] (2) Pipette 100mL of leaching solution into a 300mL Erlenmeyer flask and put it into a constant temperature water bath with magnetic stirring. Weigh 2.62 g of benzoic acid and dissolve it in 10mL of ethanol, then slowly add it into the Erlenmeyer flask under constant temperature stirring at 30°C, and wait until the addition is complete. After stirring evenly, add 10% NaOH or other alkaline solutions to slowly adjust the pH of the rare earth solution to 2.5, continue to stir for 10 minutes, and then vacuum filter to obtain the filtrate. Through the above operations, Fe in the solution 3+ The content is 0.1g / L, the precipitation rate of iron is 95.43%, the loss of chromium is 3.2%, and the content of iron ions in the filtrate is significantly reduced.

Embodiment 2

[0031] (1) The electroplating sludge leachate that has been pretreated to remove impurities such as Ni and Zn: iron content Fe 3+ 5g / L, chromium content Cr 3+ 6g / L, solution pH=1.5.

[0032](2) Pipette 100mL of leaching solution into a 300mL conical flask and put it into a constant temperature water bath with magnetic stirring. Weigh 3.27 g of benzoic acid and dissolve it in 10mL of ethylene glycol, then slowly add it to the conical flask with constant temperature stirring at 30°C, and wait until Add 10% NaOH or other alkaline solutions to slowly adjust the pH of the rare earth solution to 2.5 after the feeding is completed and stir evenly. Continue to stir for 10 minutes and then vacuum filter to obtain the filtrate. Through the above operations, Fe in the solution 3+ The content is 0.26g / L, the precipitation rate of iron is 97.8%, the loss of chromium is not more than 2.9%, and the content of iron ions in the filtrate is significantly reduced.

Embodiment 3

[0034] (1) The electroplating sludge leachate that has been pretreated to remove impurities such as Ni and Zn: iron content Fe 3+ 5g / L, chromium content Cr 3+ 6g / L, solution pH=1.5.

[0035] (2) Pipette 100mL of leaching solution into a 300mL conical flask and put it into a constant temperature water bath with magnetic stirring. Weigh 4.476 g of p-nitrobenzoic acid and dissolve it in 15mL of methanol, then slowly add it into the conical flask at 30°C with constant temperature stirring. Add 10% NaOH or other alkaline solutions to slowly adjust the pH of the rare earth solution to 2.5 after the feeding is completed and stir evenly, continue to stir for 10 minutes and then vacuum filter to obtain the filtrate. Through the above operations, Fe in the solution 3+ The content is 0.2315g / L, the precipitation rate of iron is 96.37%, the loss of chromium is not more than 4.1%, and the content of iron ions in the filtrate is significantly reduced.

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Abstract

The invention discloses a method for separating chromium from iron in electroplating sludge leaching liquid through complexing precipitation. Benzoic acid or derivatives of the benzoic acid are used as complexing precipitants to separate chromium ions from iron ions in the electroplating sludge leaching liquid where only Fe3+ and Cr3+ are left after Ni, Zn, Cu and other hetero-ions are removed through pretreatment, and the iron ions contained in the leaching liquid are removed in a precipitation mode. By controlling the using amount of the complexing precipitants, the reaction temperature, the solution pH value and the reaction time, the removing rate of the iron ions in the electroplating sludge leaching liquid can reach 95% or above, and the loss of the chromium does not exceed 5%. Compared with the prior art, the method for separating the chromium from the iron through complexing precipitation has the low requirements for equipment and is easy to operate, and an obtained precipitate is easy to filter and has no pollution to the environment.

Description

technical field [0001] The invention relates to a method for complexing precipitation to separate ferrochrome from electroplating sludge leaching solution, and belongs to the technical fields of hydrometallurgy, chemistry, materials and the like. Background technique [0002] Electroplating sludge is heavy metal-containing sludge generated after wastewater treatment in the electroplating industry, and is included in the national hazardous waste list. As the "final state" of electroplating wastewater, although its amount is much less than that of wastewater, since heavy metals such as Cu, Ni, Zn, Fe, Cr in wastewater are transferred to sludge, in a sense The potential harm of electroplating sludge to the environment is far more serious than that of electroplating wastewater. If the electroplating sludge rich in heavy metals is not disposed of, the damage to the ecological environment is self-evident. On the other hand, electroplating sludge usually contains Cu1%~2%, Ni0.5%~1...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B34/32
CPCC22B7/007C22B34/32Y02P10/20
Inventor 李金辉徐志峰罗天贵廖家隆陈志峰
Owner JIANGXI UNIV OF SCI & TECH
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