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A kind of separation method of chromium and iron in pickling waste liquid

A separation method and a technology for pickling waste liquid, which are applied in the direction of chemical instruments and methods, chromium compounds, process efficiency improvement, etc., can solve problems such as difficult separation, poor separation effect of iron ions and chromium ions, and achieve cost saving Effect

Active Publication Date: 2021-08-06
CHANGZHOU WUJIN YOUBANG WATER PURIFICATION MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defects and deficiencies that the separation effect of iron ions and chromium ions in the existing pickling waste liquid is not good, and it is difficult to completely separate them, and provide a method for separating chromium and iron in the pickling waste liquid. Two-step separation extraction and stripping of valence iron and chromium ions, using the selective extraction of different extractants to achieve a complete separation of chromium and iron

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The raw material of this embodiment is 400 kilograms of stainless steel pickling wastewater, and its acidity (acidity of sulfuric acid) is measured to be 5.3%, the content of chromium ion is 4.5 g / L, the content of ferric iron is 2.8 g / L, and the content of ferrous iron is 75 g / L .

[0036] A method for separating chromium and iron in pickling waste liquid, comprising the steps of:

[0037] S1. Extraction of ferric iron: Add ferric organic extractant to the pickling waste liquid, carry out continuous centrifugal extraction at room temperature to separate ferric ions, and obtain ferric organic phase and aqueous phase of ferrous ions and chromium ions, of which three Valence iron extractant contains 20% trioctyl tertiary amine, 20% dodecyl dimethyl tertiary amine, 10% tributyl phosphate, 50% sulfonated kerosene, and the amount added is 0.5 times the mass of pickling waste liquid ;

[0038] S2. Back extraction of ferric iron: use sulfuric acid solution to back extract fe...

Embodiment 2

[0046] The raw material of this embodiment is 500 kg of stainless steel pickling waste water, and its acidity (acidity of sulfuric acid) is 4.1%, the content of chromium ion is 2.1 g / L, the content of ferric iron is 7.8 g / L, and the content of ferrous iron is 71 g / L .

[0047] A method for separating chromium and iron in pickling waste liquid, comprising the steps of:

[0048] S1. Extraction of ferric iron: Add ferric organic extractant to the pickling waste liquid, carry out continuous centrifugal extraction at room temperature to separate ferric ions, and obtain ferric organic phase and aqueous phase of ferrous ions and chromium ions, of which three Valence iron extractant contains 15% dodecyl tertiary amine, 20% N,N-dimethylhexadecyl tertiary amine, 5% tributyl phosphate, 60% sulfonated kerosene, the amount added is pickling waste liquid 1.6 times the mass;

[0049] S2. Back extraction of ferric iron: use sulfuric acid solution to back extract ferric iron in the organic p...

Embodiment 3

[0057] The raw material of this embodiment is 1000 kg of stainless steel pickling waste water, and its acidity (acidity of sulfuric acid) is 3.8%, the content of chromium ion is 4.8g / L, the content of ferric iron is 7.0 g / L, and the content of ferrous iron is 65 g / L .

[0058] A method for separating chromium and iron in pickling waste liquid, comprising the steps of:

[0059] S1. Extraction of ferric iron: Add ferric organic extractant to the pickling waste liquid, carry out continuous centrifugal extraction at room temperature to separate ferric ions, and obtain ferric organic phase and aqueous phase of ferrous ions and chromium ions, of which three The valent iron extractant contains 30% trioctyl tertiary amine, 10% dodecyl tertiary amine, 10% tributyl phosphate, and 50% sulfonated kerosene, and the amount added is 1.4 times the quality of the pickling waste liquid;

[0060] S2. Back extraction of ferric iron: use sulfuric acid solution to back extract ferric iron in the o...

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Abstract

The invention discloses a method for separating chromium and iron in pickling waste liquid. The method comprises the following steps: extracting ferric iron; back-extracting ferric iron; extracting chromium ions; back-extracting chromium ions. The method of the present invention first obtains ferric ions through organic extraction and sulfuric acid back extraction separation, avoids the incomplete reduction of ferric iron in the reduction method, and avoids the influence of ferric iron on the extraction and separation of chromium ions, and then through specific The extraction-reextraction system separates and obtains chromium ion and ferrous solution, and high-priced chromium salt products can be obtained through concentrated crystallization treatment, and the ferrous acid solution containing ferrous after chromium removal can be used for the preparation of iron-based water purifiers. The present invention After the extraction agent is recovered, the iron ion content is below 25ppm, and the chromium ion content is below 28ppm, which can be recycled, which saves the cost of the extraction agent and realizes a circular economy.

Description

technical field [0001] The invention relates to the technical field of waste water recovery, in particular to a method for separating chromium and iron in pickling waste liquid. Background technique [0002] Pickling is an essential process in the production of stainless steel, which not only ensures the good quality of the steel surface, but also prepares it for further processing. With the process of pickling, metal oxides are continuously dissolved and enter the pickling solution. The hydrogen ions in the original pickling solution are gradually replaced by metal salts, the concentration of acid gradually decreases, and the concentration of metal salts increases accordingly, so the speed of dissolving oxides in the pickling solution gradually slows down, and it is necessary to continuously discharge waste liquid and replenish new pickling solution. This used waste liquid with poor pickling effect is the pickling waste liquid. The components of these waste liquids are c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B3/40C22B7/00C22B34/32C01G37/00
CPCC01G37/00C22B7/006C22B34/32C22B3/402C22B3/409Y02P10/20
Inventor 朱松锋蒋银峰居银栋蒋浩李萍
Owner CHANGZHOU WUJIN YOUBANG WATER PURIFICATION MATERIALS