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Production method of potassium dichromate

A technology of potassium dichromate and production method, applied in directions such as chromate/dichromate, can solve the problems of low utilization rate of chromium in chromite, environmental pollution, unreusable by-products, etc., and achieve the utilization rate of chromium High, the effect of avoiding chromium mist pollution and eliminating Cl pollution

Inactive Publication Date: 2005-01-19
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Abstract
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Problems solved by technology

[0021] The purpose of the present invention is to overcome the defects of serious environmental pollution, low chromium utilization rate in chromite ore and non-reusable by-products in the existing potassium dichromate production method, thereby providing a kind of dichromic acid with industrial operability Potassium cleaner production methods

Method used

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  • Production method of potassium dichromate
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Effect test

Embodiment 1

[0041] The reaction process is as figure 1 As shown, the potassium chromate used is an analytical reagent produced by Beijing Hongxing Chemical Factory, and potassium dichromate is an analytical reagent produced by Beijing Hongxing Chemical Factory, CO 2 It is cylinder gas (content ≥99%), and a 1.2-liter autoclave is used for carbonization reaction.

[0042] 1) Prepare 800ml of 550g / L potassium chromate slurry solution. Continuous access to CO 2 The gas is heated to 0.3MPa, and the slurry carbonation reaction is carried out with stirring at a speed of 900 rpm / min. The initial temperature of the reaction is 50°C. The temperature is lowered slowly by indirect cooling with conventional cooling water. After the reaction is controlled for 2 hours, the temperature is lowered to 15°C after the reaction is completed. , The carbonization rate reaches 81.7%. Filter the mixed solution at a pressure of 0.2 MPa to obtain potassium dichromate crystals and potassium bicarbonate solutions, respec...

Embodiment 2

[0046] The reaction process is as figure 1 As shown, the potassium chromate used is an industrial grade potassium chromate product of Henan Zhenxing Chemical Group, and potassium dichromate is an analytical reagent produced by Beijing Hongxing Chemical Plant. CO 2 It is cylinder gas (content ≥99%), and a 1.2-liter autoclave is used for carbonization reaction.

[0047] 1) Prepare 800ml of 700g / L potassium chromate slurry solution. Continuous access to CO 2 Gas to 0.8MPa, stirring at a speed of 1100 revolutions per minute for slurry carbonation reaction. The initial temperature of the reaction is 60°C. Use conventional cooling water to cool down slowly and react for 4 hours. After the reaction is completed, the temperature is reduced to 20°C. , The carbonization rate reaches 84.4%. The mixed solution was filtered at a pressure of 0.4MPa to obtain potassium dichromate crystals and potassium bicarbonate solutions, respectively.

[0048] Item

[0049] 3) The potassium bicarbo...

Embodiment 3

[0051] The reaction process is as figure 1 As shown, the potassium chromate used is an industrial grade potassium chromate product of Henan Zhenxing Chemical Group, and chromic anhydride is an industrial grade product of Henan Zhenxing Chemical Group, CO 2 It is cylinder gas (content ≥99%), and a 1.2-liter autoclave is used for carbonization reaction.

[0052] 1) Prepare 800ml of 650g / L potassium chromate slurry solution. Continuous access to CO 2 The gas is heated to 0.5MPa, and the slurry carbonation reaction is carried out with stirring at a speed of 1000 revolutions per minute. The initial temperature of the reaction is 55°C. Use conventional cooling water to cool down slowly and react for 3 hours. After the reaction is completed, the temperature is reduced to 18°C. , The carbonization rate is 83.1%. The mixed solution was filtered at a pressure of 0.3MPa to obtain potassium dichromate crystals and potassium bicarbonate solutions, respectively.

[0053] Item

[0054]...

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Abstract

The invention relates to a production method of potassium dichromate for preparing potassium bichromate K2Cr2O7 from potassium chromate crystal K2CrO4 which comprises, acidifying the potassium chromate slurry, refining through iron and aluminium impurity substance removal, cooling the obtained potassium hydrogen carbonate solution, and recovering potassium chromate. The invention realizes the reuse of potassium carbonate.

Description

Technical field [0001] The invention relates to a method for producing dichromate, in particular to a method for cleanly producing potassium dichromate from potassium chromate. technical background [0002] Potassium dichromate is also known as potassium red alum, and its molecular formula is K 2 Cr 2 O 7 , Is an important chromium chemical product. Mainly used in the preparation of chromium salt products such as chromium trioxide, chromium potassium sulfate and chrome yellow pigment, and also used in the manufacture of matches, explosives, electroplating additives, mordants, tanning agents, medicines, oxidants, synthetic fragrances, enamel glaze powder, metals Products such as passivating agent, printing ink and welding rod. [0003] The traditional production method of potassium dichromate is as described in "Chromium Salt Production Process" (Beijing: Chemical Industry Press, 1988) edited by Cheng Siwei et al. The main methods are: sodium dichromate and potassium chloride doub...

Claims

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Application Information

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IPC IPC(8): C01G37/14
Inventor 李会泉李佐虎张懿徐红彬杨仁春
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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