Method for electrochemical synthesis of chromic anhydride from sodium chromate

An electrochemical and sodium chromate technology, applied in the electrolysis process, electrolysis components, etc., can solve problems such as cumbersome operation, complicated equipment, and long process flow

Inactive Publication Date: 2009-09-16
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

Minority with Na 2 CrO 4 Electrochemical synthesis technology as raw m

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] The anode chamber of the two-chamber electrochemical synthesis reactor is made of pure titanium, and the cathode chamber is made of stainless steel. Perfluorosulfonic acid membrane, the anode is Ti / TiO 2 -RuO 2 -IrO 2 , the cathode is stainless steel, the electrode spacing is 0.5 mm, and the reaction pressure is normal pressure.

[0045] Continuously introduce Na at a concentration of 500 g / L into the anode compartment of the primary electrochemical synthesis reactor 2 CrO 4 The initial anode solution, the initial cathode solution of NaOH with a concentration of 10g / L is continuously introduced into the cathode chamber, and the current density is 2.05KA / m 2 , The reaction temperature is 50 ℃ for electrochemical synthesis reaction, control the anode Na 2 CrO 4 The rate at which the solution is added to the primary anode chamber makes the Na in the anode solution leaving the outlet of the anode chamber + with Cr 6+ The mol ratio is 1.50, and the NaOH solution spe...

Embodiment 2

[0047] The anode chamber of the two-chamber electrochemical synthesis reactor is made of pure tantalum, and the cathode chamber is made of refined steel. Perfluorosulfonic acid / sulfonic acid reinforced composite membrane, the anode is Ta / Ta 2 o 5 -IrO 2 , the cathode is stainless steel coated with nickel, the electrode spacing is 1mm, and the reaction pressure is 0.05MPa.

[0048] Continuously introduce Na at a concentration of 610 g / L into the anode compartment of the primary electrochemical synthesis reactor 2 CrO 4 The initial anode solution, the initial cathode solution of NaOH with a concentration of 50g / L is continuously introduced into the cathode chamber, and the current density is 2.68KA / m 2 , The electrochemical synthesis reaction is carried out under the condition that the reaction temperature is 80°C, and the anode Na is controlled 2 CrO 4 The rate at which the solution is added to the primary anode chamber makes the Na in the anode solution leaving the outl...

Embodiment 3

[0050]The anode chamber of the two-chamber electrochemical synthesis reactor is made of pure titanium, and the cathode chamber is made of refined steel. Perfluorosulfonic acid / carboxylic acid reinforced composite membrane, the anode is Ti / TiO 2 -RuO 2 , the cathode is refined steel coated with Ni-Co-Ce ternary alloy composite coating, the electrode spacing is 2mm, and the reaction pressure is normal pressure.

[0051] Continuously introduce Na at a concentration of 700 g / L into the anode compartment of the primary electrochemical synthesis reactor 2 CrO 4 The initial anode solution, the initial cathode solution of NaOH with a concentration of 150g / L is continuously introduced into the cathode chamber, and the current density is 3.00KA / m 2 , The electrochemical synthesis reaction is carried out at a reaction temperature of 90 ° C, and the anode Na is controlled 2 CrO 4 The rate at which the solution is added to the primary anode chamber makes the Na in the anode solution ...

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Abstract

The invention belongs to the fields of chromium chemical industry and production of chromium salts, more particularly relates to a method for electrochemical synthesis of chromic anhydride from sodium chromate. The method takes a sodium chromate solution as raw material, carries out secondary electrochemical synthesis reaction in a dual-chamber electrochemical synthesis reactor containing an anode chamber and a cathode chamber and carries out the electrochemical synthesis of a sodium bichromate solution in a primary electrochemical synthesis reactor, a cathode solution and an anode solution after the primary electrolysis are controllably transferred to the cathode chamber and the anode chamber of the secondary electrochemical synthesis reactor for carrying out the electrochemical synthesis reaction after dilution or concentration, the cathode chamber generates a sodium hydroxide solution and the anode chamber generates a chromic acid solution. Concentration, crystallization, separation, washing and drying are executed to the chromic acid solution obtained by an anode to prepare a chromic anhydride product (CrO3). The method has the advantages of short process flow, mild reaction conditions, good product quality, no side reactions, no pollution, strong operability, easy industrialization and the like.

Description

technical field [0001] The invention belongs to the field of chromium chemical industry and chromium salt production, and in particular relates to a method for electrochemically synthesizing chromic anhydride from sodium chromate. technical background [0002] Chromic anhydride is referred to as chromic anhydride or chromic acid, and its molecular formula is: CrO 3 , is an important chromium chemical product, a strong oxidizing agent, easily deliquescent, soluble in water, highly corrosive, and toxic. Among the chromium salt products, chromic anhydride accounts for 60% of the total output, which is mainly used for the preparation of water-soluble wood preservative chromium copper arsenate, followed by metal finishing, catalyst preparation, chromium trioxide and magnetic material chromium dioxide And used as oxidant, mordant, etc. [0003] Industrialized chromic anhydride production technology, such as Na 2 Cr 2 o 7 -H 2 SO 4 Batch melting method, Na 2 Cr 2 o 7 -H ...

Claims

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Application Information

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IPC IPC(8): C25B1/00
Inventor 齐涛李成未余志辉初景龙曲景奎张懿王世君李兆业
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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