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Method of preparing chromium oxide using wet reducing potassium bichromate or sodium bichromate

A technology of chromium trioxide and potassium dichromate, applied in the directions of chromium trioxide, chromium oxide/hydrate, chemical instruments and methods, etc., can solve the problems of environmental pollution product quality and high production cost, and achieve the reduction of production cost, Product quality and yield improvement, the effect of cleaner production

Inactive Publication Date: 2003-04-16
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the invention is to overcome defects such as high production cost, environmental pollution and low product quality in the existing production of dichromium trioxide, and provide a method for preparing dichromium trioxide by wet reduction of potassium dichromate or sodium dichromate method, while reducing production costs and simplifying the production process, at the same time, realize no pollutant discharge in any form, and achieve the goal of controlling pollution from the source

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Prepare K at a concentration of 40% 2 Cr 2 o 7 aqueous solution, the 416.67g K 2 Cr 2 o 7 Aqueous solution and 29.05g sucrose (C 12 h 22 o 11 ) into the hot-pressed reaction kettle, according to the stoichiometric ratio, the amount of sucrose is 120 mol% of potassium dichromate, and when heated to 120 ° C, the redox reaction begins to occur, and the reaction continues depending on the heat and pressure released by itself, and the system reaches The highest temperature is 220°C, the highest pressure reached by the system is 2.5 MPa, and the reaction time is about 15 minutes; the obtained slurry is easy to be separated by filtration. The separated filter cake was dried at 110 °C in CO 2 Carry out high-temperature calcination under gas protection, the calcination temperature is 800°C, and the calcination time is 2 hours; the calcined material is washed three times with water, and the product is obtained after drying at 110°C; the primary eluate is causticized with ...

Embodiment 2

[0034] Prepare K at a concentration of 40% 2 Cr 2 o 7 aqueous solution, the 375.34gK 2 Cr 2 o 7 Aqueous solution and 26.85g sucrose (C 12 h 22 o 11 ) and the KHCO obtained in Example 1 3Add 52ml of crystallization mother liquor into the hot-pressed reaction kettle, wherein, the total amount of sucrose in the system is 120 mol% of the total amount of potassium dichromate according to the stoichiometric ratio, and the oxidation-reduction reaction begins to occur when heated to 140°C, and the reaction depends on the heat released by itself And the pressure continues, the highest temperature reached by the system is 210°C, the highest pressure reached by the system is 2.3MPa, and the reaction time is about 17min; the obtained slurry is easy to filter and separate. After the separated filter cake was dried at 110 °C in N 2 Carry out high-temperature calcination under gas protection, the calcination temperature is 900°C, and the calcination time is 2h; the material after ca...

Embodiment 3

[0036] Prepare K at a concentration of 40% 2 Cr 2 o 7 aqueous solution, the 380.85gK 2 Cr 2 o 7 Aqueous solution and 27.42g sucrose (C 12 h 22 o 11 ) and the KHCO obtained in Example 2 3 Add 45ml of crystallization mother liquor into the hot-pressed reaction kettle, wherein the total amount of sucrose in the system is 120 mol% of the total amount of potassium dichromate according to the stoichiometric ratio, and the oxidation-reduction reaction begins to occur when heated to 130°C, and the reaction depends on the heat released by itself And the pressure continues, the highest temperature reached by the system is 210°C, the highest pressure reached by the system is 2.4MPa, and the reaction time is about 15min; the obtained slurry is easy to filter and separate. The separated filter cake was dried at 110 °C in CO 2 Carry out high-temperature calcination under gas protection, the calcination temperature is 1000°C, and the calcination time is 1h; the material after calcin...

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Abstract

A process for preparing Cr2O3 by wet reduction of potassium (or sodium) bichromate includes such steps as preparing the aqueous solution of potassium (or sodium) bichromate, thermal pressure reactionon reducer to obtain hydrate of chromium oxide, filtering, drying filter cake, high-temp. calcining under protection of inertial gas, and cooling. Its advantages are short period, low cost and high output rate (more than 95%).

Description

technical field [0001] The invention relates to a method for producing inorganic materials, in particular to a method for preparing dichromium trioxide by wet reduction of potassium dichromate or sodium dichromate. Background technique [0002] Chromium oxide, also known as chromium trioxide or chromium oxide green, is one of the leading products in the chromium salt industry. It is widely used as a green pigment, a raw material for smelting metal chromium, and a catalyst in organic synthesis. Metal chromium is used in the metallurgical industry to produce high-grade alloys, namely superalloys with high temperature resistance, wear resistance, corrosion resistance, and oxidation resistance. It is widely used in the manufacture of heating furnaces for atomic power stations, gas turbines, aircraft engines, special military equipment, and chemical devices. etc.; corrosion-resistant aluminum alloys and high-strength aluminum alloys produced from chromium a...

Claims

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Application Information

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IPC IPC(8): C01D1/20C01D7/00C01G37/033
Inventor 姚芝茂张懿李佐虎
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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