Chromic oxide and preparation method thereof

A chromium oxide, seed crystal technology, applied in the direction of chromium oxide/hydrate, can solve the problems of reaction temperature, high pressure, long process, difficult to control the reaction process, etc., to shorten the reaction time, reduce the reaction temperature, and improve the nucleation. effect of speed

Active Publication Date: 2019-02-22
青海省博鸿化工科技股份有限公司 +1
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Problems solved by technology

The thermal decomposition method of chromic anhydride uses chromic anhydride as raw material and calcines at high temperature to prepare Cr 2 o 3 , this method is expensive and pollutes seriously
The hexavalent chromium salt reduction method uses sulfur or sulfide as a reducing agent to prepare Cr through wet or dry reduction of hexavalent chromium salt. 2 o 3 , mainly include sodium chromate alkaline liquid sulfur or sodium sulfide reduction method, potassium dichromate sulfur roasting reduction method, sodium dichr

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  • Chromic oxide and preparation method thereof

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[0061] The specific embodiment part of the present invention provides a kind of preparation method of chromium oxide, described method comprises the following steps:

[0062] (1) Adding the hexavalent chromium salt solution containing the crystal seed into the reaction device, feeding the protective gas and raising the temperature in an airtight manner, after reaching the target temperature, continuously feeding the reducing gas to react, and obtaining the mixed slurry;

[0063] (2) separating the mixed slurry obtained in step (1) from solid to liquid to obtain chromium oxyhydroxide powder;

[0064] (3) Calcining the chromium oxyhydroxide powder obtained in step (2) to obtain chromium oxide.

Embodiment 1

[0067] The present embodiment provides a kind of preparation method of chromium oxide, described method comprises the following steps:

[0068] (1) Put 200mL of sodium chromate solution with a concentration of 0.2mol / L in a vertical reactor with a volume of 500mL, add 0.1g of chromium oxyhydroxide seed crystals, feed nitrogen to discharge the air in the reactor and pipeline, and seal Afterwards, the temperature was raised by program, the stirring rate was 200r / min, and after reaching the target reaction temperature of 240°C, hydrogen gas was introduced to react, and the partial pressure of hydrogen gas was maintained at 2MPa. After 1 hour of reaction, the temperature was rapidly cooled by water cooling, and the cooling rate was 10°C / min, and a mixed slurry was obtained. material;

[0069] (2) suction-filtering the mixed slurry obtained in step (1) to obtain a solid and a filtrate, the gained solid is washed and dried to obtain a chromium oxyhydroxide powder;

[0070] (3) Calc...

Embodiment 2

[0074] The present embodiment provides a kind of preparation method of chromium oxide, described method comprises the following steps:

[0075] (1) The potassium chromate solution that 200mL concentration is 0.6mol / L is placed in the horizontal reaction kettle that volume is 500mL, adds 0.05g chromium oxyhydroxide seed crystal, feeds helium gas and discharges the air in the reaction kettle and pipeline, After sealing, the temperature was programmed and the stirring rate was 100r / min. After reaching the target reaction temperature of 200°C, hydrogen gas was introduced to react, and the partial pressure of hydrogen gas was maintained at 8MPa. After 3 hours of reaction, the temperature was rapidly cooled by water cooling at a cooling rate of 5°C / min, and a mixture was obtained. slurry;

[0076](2) suction-filtering the mixed slurry obtained in step (1) to obtain a solid and a filtrate, the gained solid is washed and dried to obtain a chromium oxyhydroxide powder;

[0077] (3) Ca...

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Abstract

The invention provides chromic oxide and a preparation method thereof. The method comprises the following steps: feeding a hexavalent chromium salt solution containing seed crystal into a reaction device, feeding protective gas, sealing the device and rising the temperature, and continuously feeding reducing gas to perform reaction after target temperature is achieved, so as to obtain mixed slurry; performing solid-liquid separation on the obtained mixed slurry, and performing calcination on obtained hydroxyl chromic oxide powder, so as to obtain chromic oxide. The method has the advantages that hexavalent chromium salt is adopted to prepare chromic oxide through a hydrothermal reduction method, the reduction reaction rate is improved through adding of the seed crystal, and regulation of the reducing gas and reaction conditions, the controllability of a reaction process is enhanced, the percent reduction can reach greater than 99.2 percent, reduction products are uniform in phase, sizedistribution is narrow, and the quality of obtained chromic oxide is high and can reach the standard of pigment grade chromic oxide; the method is short in flow, and low in energy consumption and cost, does not produce pollutant emission, belongs to a clean production technology, and has significant economic benefit.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and relates to a chromium oxide and a preparation method thereof, in particular to a method for preparing pigment grade chromium oxide by hydrothermal reduction. Background technique [0002] Chromium oxide (Cr 2 o 3 ) is an important industrial raw material, which is widely used in the fields of metallurgy, pigments, ceramics, coatings, green polishing, and organic catalytic synthesis. Currently, the industrial production of Cr 2 o 3 The methods mainly include chromic anhydride thermal decomposition method and hexavalent chromium salt reduction method. The thermal decomposition method of chromic anhydride uses chromic anhydride as raw material and calcines at high temperature to prepare Cr 2 o 3 , this method is expensive and pollutes seriously. The hexavalent chromium salt reduction method uses sulfur or sulfide as a reducing agent to prepare Cr through wet or dry reduction ...

Claims

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Application Information

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IPC IPC(8): C01G37/02
CPCC01G37/02C01P2002/72C01P2006/80
Inventor 徐红彬史建斌王劲松张红玲史海琴梅海军刘宏辉杨海王爱山雒敏婷
Owner 青海省博鸿化工科技股份有限公司
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