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Preparing method of chromium trioxide and chromium trioxide crystal particle obtained through preparing method

A chromic anhydride, crystal technology, applied in the field of chromium chemical industry, can solve problems such as low yield

Active Publication Date: 2017-09-22
HUBEI ZHENHUA CHEMICAL CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The preparation method of the chromic anhydride is green and clean, and the prepared chromic anhydride crystal particles have high purity and uniform particle size, which solves the problem of the generation of highly toxic chromium chloride gas, low yield and trivalent chromium chloride in the existing industrial production of chromic anhydride. chrome problem

Method used

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  • Preparing method of chromium trioxide and chromium trioxide crystal particle obtained through preparing method
  • Preparing method of chromium trioxide and chromium trioxide crystal particle obtained through preparing method

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preparation example Construction

[0073] A clean preparation method for crystalline chromic anhydride, comprising the following steps:

[0074] (1) Add concentrated sulfuric acid dropwise or directly pour it into 10~70°Bé sodium dichromate solution, the molar ratio of sodium dichromate to concentrated sulfuric acid is 3:4~3:6.5, Na 2 Cr 2 o 7 React with acid, the reaction time is 5-50min, to obtain the reaction liquid;

[0075] (2) Add water or chromic anhydride solution to the reaction solution obtained in step (1) to adjust the concentration to the concentration to be crystallized (10-57°Bé), and evaporate at a vacuum degree of 0.05-0.1MPa and a temperature of 40-100°C Crystallization, evaporative crystallization time is 4-12h, and evaporated components are obtained;

[0076] During the evaporative crystallization process, the produced HCl, Cl 2 , CrO 2 Cl 2 Gas is sent to alkaline water for absorption;

[0077] (3) separating the evaporated components obtained in step (2) from solid to liquid;

[00...

Embodiment 1

[0087] (1) Add the concentrated sulfuric acid dropwise to 10 ° Bé sodium dichromate solution, the molar ratio of sodium dichromate and concentrated sulfuric acid is 3:4, Na 2 Cr 2 o 7 React with acid, the reaction time is 5min, obtain reaction solution;

[0088] (2) Add water or chromic anhydride solution to the reaction solution obtained in step (1) to adjust the concentration to 10 ° Bé, and conduct evaporation and crystallization at a vacuum of 0.1 MPa and a temperature of 60 ° C. The evaporation time is 6 hours to obtain the evaporation component ;

[0089] During the evaporative crystallization process, the produced HCl, Cl 2 , CrO 2 Cl 2 Gas is sent to alkaline water for absorption;

[0090] (3) separating the evaporated components obtained in step (2) from solid to liquid;

[0091] Add water to dissolve the solid component to 10°Bé, carry out secondary evaporation and crystallization at a vacuum degree of 0.1MPa and a temperature of 60°C, and evaporate for 6 hour...

Embodiment 2

[0098] (1) Add the concentrated sulfuric acid dropwise to 20°Bé sodium dichromate solution, the mol ratio of sodium dichromate to the concentrated sulfuric acid is 3:4.5, Na 2 Cr 2 o 7 React with acid, the reaction time is 10min, to obtain the reaction solution;

[0099] (2) In the reaction liquid that step (1) obtains, add water or chromic anhydride solution and adjust concentration to be 20 ° of B é, be that 0.09MPa, temperature carry out evaporative crystallization at 50 ℃ in vacuum tightness, add perchloric acid in evaporation process, evaporation time For 7h, the evaporated component was obtained;

[0100] During the evaporative crystallization process, the produced HCl, Cl 2 , CrO 2 Cl 2 Gas is sent to alkaline water for absorption;

[0101](3) separating the evaporated components obtained in step (2) from solid to liquid;

[0102] The solid component was dissolved in water to 20 ° Bé, and the second evaporation crystallization was carried out at a vacuum degree o...

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Abstract

The invention relates to a preparing method of chromium trioxide. The preparing method comprises the first step of adding strong sulphuric acid into a sodium dichromate solution, and conducting a reaction to obtain reaction liquor; the second step of adjusting the concentration of the reaction liquor till the to-be-crystallized concentration reaches, and conducting evaporative crystallization to obtain evaporation components; the third step of conducting soil-liquid separation on the evaporation components, adding water to dissolve solid components again till the to-be-crystallized concentration reaches, and then conducting evaporative crystallization again to obtain secondary evaporation components; the fourth step of conducting solid-liquid separation on the secondary evaporation components obtained in the third step, wherein the solid component is a crude product of chromium trioxide; the fifth step of washing the crude product of chromium trioxide obtained in the fourth step, and drying the washed product to obtain the finished product of chromium trioxide crystal. According to the preparing method of chromium trioxide, the purity of the obtained product of chromium trioxide is larger than 99.9%, the particle sizes are uniform, and the preparing method is green and clean.

Description

technical field [0001] The invention belongs to the technical field of chromium chemical industry. Specifically, the invention relates to a preparation method of chromic anhydride and prepared chromic anhydride crystal particles. The prepared chromic anhydride crystal particles have uniform particle size and high purity. Background technique [0002] Chromic anhydride is one of the main products of chromium chemical industry. It is an important inorganic chemical raw material. It is widely used in electroplating, tanning, metal passivation, production of chromium oxide green, chemical fertilizer, medicine and other industries, and plays an important role in the national economy. There are nearly ten kinds of industrial production methods of chromic anhydride, but in terms of reaction principle, there are only two basic methods, sulfuric acid method and electrolysis method, or a combination of the two. [0003] The electrolysis method uses sodium dichromate or sodium chromate...

Claims

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Application Information

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IPC IPC(8): C01G37/033
CPCC01G37/033
Inventor 徐红彬蔡再华田颖程西川裴丽丽段静张笛刘静文张红玲陈小红
Owner HUBEI ZHENHUA CHEMICAL CO LTD
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