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Clean regeneration method for chromium-containing waste acid

A chromium waste and clean technology, applied in chemical instruments and methods, chromium sulfate, sulfur trioxide/sulfuric acid, etc., can solve the problems of complex equipment, short process, difficult process control, etc., achieve clean treatment, eliminate emission pollution, Simple effect of process equipment

Inactive Publication Date: 2022-03-01
INST OF PROCESS ENG CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the method is mainly aimed at iron ions in waste acid, and the recovery efficiency of chromium ions is not high, and the metal precipitate obtained after solid-liquid separation cannot be directly reused, which to a certain extent has caused the complexity of the process.
[0008] At present, there are research reports that the diffusion dialysis method is used to separate sulfuric acid and hexavalent Cr ions from chromium-containing waste acid, and the appropriate membrane materials and process conditions have been determined through experimental research. This method can recover acid and metals in the washing waste liquid. Short, but the equipment is complicated, the membrane life is limited, the process control is difficult, the recovered acid cannot be directly recycled, and the problem of waste residue and waste liquid discharge is not solved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] This embodiment provides a method for cleaning and regenerating waste acid containing chromium, and the method for cleaning and regenerating waste acid containing chromium includes the following steps:

[0051] (1) Mix the chromium-containing waste acid of 500mL and the oxalic acid of 110g with the frequency of 450rpm for 10min, so that the oxidation-reduction potential is 200mV; the H of the chromium-containing waste acid + Concentration is 6mol / L, and sulfuric acid concentration is 2.75mol / L, and hydrochloric acid concentration is 0.5mol / L; The total concentration of metal ion in described chromium-containing waste acid is 75g / L, and wherein hexavalent chromium ion concentration is 43g / L, The trivalent chromium ion concentration is 22g / L, the nickel ion concentration is 5g / L, and the manganese ion concentration is 5g / L;

[0052] (2) The mixed solution obtained in step (1) is subjected to a hydrolysis reaction in a stainless steel reactor, the temperature of the hydrol...

Embodiment 2

[0055] This embodiment provides a method for cleaning and regenerating waste acid containing chromium, and the method for cleaning and regenerating waste acid containing chromium includes the following steps:

[0056] (1) Mix 500mL of chromium-containing waste acid and 50g of sodium sulfite with stirring for 25min at a frequency of 100rpm, so that the oxidation-reduction potential is 225mV; the H of the chromium-containing waste acid + Concentration is 8.5mol / L, and sulfuric acid concentration is 3.88mol / L, and nitric acid concentration is 0.8mol / L; The total concentration of metal ion in described chromium-containing waste acid is 95g / L, and wherein hexavalent chromium ion concentration is 27.5g / L L, the trivalent chromium ion concentration is 55g / L, the manganese ion concentration is 6.25g / L, and the iron ion concentration is 6.25g / L;

[0057] (2) The mixed solution obtained in step (1) is subjected to a hydrolysis reaction in a stainless steel reactor, the temperature of th...

Embodiment 3

[0060] This embodiment provides a method for cleaning and regenerating waste acid containing chromium, and the method for cleaning and regenerating waste acid containing chromium includes the following steps:

[0061] (1) Mix 500mL of chromium-containing waste acid and 10g of ferrous sulfate with 15min stirring at a frequency of 200rpm, so that the oxidation-reduction potential is 175mV; the H of the chromium-containing waste acid + The concentration is 2.5mol / L, the concentration of sulfuric acid is 1.2mol / L, and the concentration of oxalic acid is 0.1mol / L; the total concentration of metal ions in the chromium-containing waste acid is 55g / L, and the concentration of hexavalent chromium ions is 12g / L , the trivalent chromium ion concentration is 35.5g / L, the iron ion concentration is 4g / L, and the copper ion concentration is 3.5g / L;

[0062] (2) The mixed solution obtained in step (1) is subjected to a hydrolysis reaction in a stainless steel reactor, the temperature of the h...

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Abstract

The invention relates to a clean regeneration method of chromium-containing waste acid, which comprises the following steps: (1) mixing chromium-containing waste acid and an additive to enable the oxidation-reduction potential to be less than or equal to 250mV; (2) carrying out hydrolysis reaction on the mixed solution obtained in the step (1); and (3) carrying out solid-liquid separation on the product obtained in the step (2) to obtain regenerated sulfuric acid and basic chromium sulfate. According to the method, the process flow is simplified while the chromium-containing waste acid is efficiently treated, the treatment cost is reduced, the regeneration cycle of the acid liquor and the reutilization of metal precipitates are realized, and the emission pollution of waste residues and waste liquor is eliminated.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and relates to a method for cleaning and regenerating waste acid, in particular to a method for cleaning and regenerating waste acid containing chromium. Background technique [0002] Metal chromium and its compounds are widely used in electroplating, leather, chemical, pigment, metallurgy, refractory and other industries due to their excellent physical and chemical properties. For example, metal chromium is used in the production process of stainless steel and various alloy steels in the form of iron alloys (such as ferrochrome); chromium oxide is used as light-resistant and heat-resistant coatings, as well as colorants for glass and ceramics, and catalysts for chemical synthesis; Chromium plating and chromizing can make steel, copper, aluminum and other metals form a corrosion-resistant surface layer, which is bright and beautiful, and is widely used in industries such as furni...

Claims

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Application Information

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IPC IPC(8): C01B17/90C01G37/08
CPCC01B17/901C01G37/08
Inventor 齐涛张健尚广浩朱兆武王丽娜
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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