A kind of separation method of chromium and iron and aluminum in sulfuric acid system solution containing chromium, iron and aluminum

A sulfuric acid system and separation method technology, applied in the field of hydrometallurgy, can solve the problems of large processing scale, low concentration of chromium ions, and difficulty in large-scale industrial application, and achieve the effects of low cost, short process flow and strong selectivity

Active Publication Date: 2018-05-08
JIANGSU UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method can achieve a chromium recovery rate of more than 98%, the applicable chromium ion concentration is low (0.1-30g / L), resulting in a large scale of treatment and difficult large-scale industrial application

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Example 1: Separation of chromium and iron and aluminum in the sulfuric acid system solution containing chromium, iron and aluminum.

[0031] (1) To the sulfuric acid system solution containing chromium, iron and aluminum (wherein Cr 3+ The mass concentration of Fe is 49.3g / L, Fe 2+ The mass concentration is 2.1g / L, Al 3+ The mass concentration is 2.13g / L) by adding Cr 6+ The waste liquid, through redox reaction Fe 2+ Oxidized to Fe 3+ , while Cr 6+ reduced to Cr 3+ , until the chromium, iron and aluminum elements in the mixed solution are only Cr 3+ , Fe 3+ 、Al 3+ form exists;

[0032] (2) Add saturated sodium hydroxide solution to the mixed solution in step (1), until pH=2.0, according to n(PO 4 3- ):n(Fe 3+ +Al 3+ )=0.5:1 molar ratio, adding sodium phosphate, and insulated and stirred at 5°C for 10min, the stirring line speed was controlled at 150m / min, and filtered to obtain iron-aluminum phosphate composite precipitation and filtrate mainly based on ir...

Embodiment 2

[0035] Example 2: Separation of chromium and iron and aluminum in the sulfuric acid system solution containing chromium, iron and aluminum.

[0036] (1) To the sulfuric acid system solution containing chromium, iron and aluminum (wherein Cr 3+ The mass concentration is 30g / L, Fe 2+ The mass concentration of Al is 1.29g / L, Al 3+ The mass concentration is 1.25g / L) by adding Cr 6+ The waste liquid, through redox reaction Fe 2+ Oxidized to Fe 3+ , while Cr 6+ reduced to Cr 3+ , until the chromium, iron and aluminum elements in the mixed solution are only Cr 3+ , Fe 3+ 、Al 3+ form exists;

[0037] (2) Add saturated sodium hydroxide solution to the mixed solution in step (1), until pH=2.1, according to n(PO 4 3- ):n(Fe 3+ +Al 3+ )=0.53:1 molar ratio, adding sodium phosphate, and insulated and stirred at 10°C for 8min, the stirring line speed was controlled at 200m / min, and filtered to obtain iron-aluminum phosphate composite precipitation and filtrate mainly based on ir...

Embodiment 3

[0040] Example 3: Separation of chromium and iron and aluminum in the sulfuric acid system solution containing chromium, iron and aluminum.

[0041] (1) To the sulfuric acid system solution containing chromium, iron and aluminum (wherein Cr 3+ The mass concentration is 10.5g / L, Fe 2+ The mass concentration is 0.56g / L, Al 3+ The mass concentration is 0.51g / L) containing Cr 6+ The waste liquid, through redox reaction Fe 2+ Oxidized to Fe 3+ , while Cr 6+ reduced to Cr 3+ , until the chromium, iron and aluminum elements in the mixed solution are only Cr 3+ , Fe 3+ 、Al 3+ form exists;

[0042] (2) Add saturated potassium hydroxide solution to the mixed solution in step (1) until pH=1.0, according to n(PO 4 3- ):n(Fe 3+ +Al 3+ )=0.2:1 molar ratio, adding potassium phosphate, and insulated and stirred at 30°C for 20min, the stirring line speed was controlled at 400m / min, and filtered to obtain iron-aluminum phosphate composite precipitation and filtrate mainly based on ...

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PUM

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Abstract

The invention belongs to the technical field of hydrometallurgy and relates to a method for separating chromium and iron and aluminum in a sulfuric acid system solution containing chromium, iron and aluminum. The method comprises the following steps: 1) adding an oxidizing agent for pretreatment; 2) adjusting the solution to a specific pH value, adding phosphate and reacting at a specific temperature to obtain iron-aluminum phosphate composite precipitation and filtrate mainly composed of iron phosphate; 3) Adjust the filtrate to a specific pH value, add phosphate again and react at a specific temperature to obtain iron-aluminum phosphate composite precipitation mainly composed of aluminum phosphate and chromium sulfate solution to complete the separation of chromium and iron-aluminum. The method has short flow, simple operation, and is easy to be applied on a large scale; adopting the step-by-step precipitation method of phosphate has strong selectivity and ideal separation effect; the recovery rate of metal chromium is greater than 98%, and the economic benefit is remarkable; the whole separation process No chemical substances that may cause harm to the environment are used, which meets the requirements of green environmental protection.

Description

technical field [0001] The invention belongs to the technical field of hydrometallurgy. Background technique [0002] In the process of resource utilization of electroplating sludge, sulfuric acid is a commonly used hydrometallurgical leaching solvent, which has high leaching efficiency and good leaching effect, so it is widely used. Sulfuric acid leaching uses PAC (polyaluminum chloride) as a flocculant to form a mixed solution containing chromium sulfate, aluminum sulfate, and ferrous sulfate. Since the atomic radii of chromium, iron, and aluminum are similar and their chemical properties are similar, there is a problem of difficulty in separation. [0003] The separation method of chromium and iron in the sulfuric acid system that has been developed at present mainly comprises the following several: (1) solvent extraction method: this method has characteristics such as equipment is simple, process is easy to control and reagent can be recycled, through phosphine extracti...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B21/00C22B34/32
CPCC22B7/006C22B21/0023C22B34/32Y02P10/20
Inventor 朱炳龙赵世晓周全法岳喜龙汪洋王盼丽陆静蓉梁志强陈科黄继忠周雅雯范雨濛
Owner JIANGSU UNIV OF TECH
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