Method for preparing color hydrated chromium oxide by using atmospheric pressure reduction process

A technology of hydrated chromium oxide and reduction method, applied in the directions of chromium trioxide, chromium oxide/hydrate, etc., to achieve the effects of cheap and easy-to-obtain raw materials, simple process operation and equipment, and high efficiency

Active Publication Date: 2013-08-28
HUBEI ZHENHUA CHEMICAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] Regarding the method for preparing colored hydrated chromium oxide by reducing dichromate under acidic and normal pressure conditions, there are no bibliographical reports and patented technologies that adopt the same or similar methods as the present invention

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  • Method for preparing color hydrated chromium oxide by using atmospheric pressure reduction process
  • Method for preparing color hydrated chromium oxide by using atmospheric pressure reduction process

Examples

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Embodiment 1

[0028] In the present embodiment, get 500 milliliters of water, adjust to pH value 3 with the mixed solution of 1mol / L sulfuric acid+1mol / L hydrochloric acid (the consumption of mixed acid is about 2~3 milliliters), add 100 grams of potassium dichromate under stirring and completely dissolved, adding 5 ml of 0.5% dodecyltrimethylammonium chloride aqueous solution; stirring and heating to 80° C., slowly adding 74 grams of glucose, reacting for 1 hour, and insulated at 80° C. for 2 hours; filtering to obtain Chromium hydroxide hydrate filter cake and the filtrate containing a small amount of hexavalent chromium, wash the filter cake twice with 50 ml of water, and return the combined filtrate to the batching process for recycling; N 2 Air protection and drying at a temperature of 60° C. for 1.5 hours, and cooling to room temperature gave 62.5 grams of emerald blue hydrated chromium oxide product (yield 98.3%). After testing, the total chromium in the product (as Cr 2 o 3 Count,...

Embodiment 2

[0031] In this embodiment, take 500 milliliters of water, adjust the pH value to 2 with a mixed solution of 1mol / L sulfuric acid+1mol / L boric acid (the amount of mixed acid is about 3-5 milliliters), and add 100 grams of potassium dichromate under stirring And completely dissolved, add 5 milliliters of 0.5% dodecyltrimethylammonium chloride aqueous solution; stir and heat to 60 ℃ and slowly add 74 grams of glucose, react for 1.5 hours, keep warm at 86 ℃ for 2 hours; filter to obtain chromium hydroxide Hydrate filter cake and filtrate containing a small amount of hexavalent chromium, wash the filter cake twice with 50 ml of water, and return the combined filtrate to the batching process for recycling; N 2 Air protection and drying at 65° C. for 1.6 hours, and cooling to room temperature gave 63.1 g of vivid blue hydrated chromium oxide product (yield: 99.26%). After testing, the mass percentage of total chromium in the product is 61.8%, the mass percentage of water is 34.9%, an...

Embodiment 3

[0034] In this embodiment, take 500 milliliters of water, adjust the pH value to 1 with a mixed solution of 1mol / L hydrochloric acid+1mol / L boric acid (the amount of mixed acid is about 6-10 milliliters), and add 100 grams of potassium dichromate under stirring And dissolve completely, add 5 milliliters of 0.5% dodecyltrimethylammonium chloride aqueous solution; stir and heat to 70 ℃ and slowly add 74 grams of glucose, react for 1.5 hours, keep warm at 90 ℃ for 2 hours; filter to obtain chromium hydroxide Hydrate filter cake and filtrate containing a small amount of hexavalent chromium, wash the filter cake twice with 50 ml of water, and return the combined filtrate to the batching process for recycling; N 2 Air protection and drying at 60° C. for 2 hours, and cooling to room temperature gave 61.9 g of bright yellow-green hydrated chromium oxide product (yield: 97.4%). After testing, the mass percentage of total chromium in the product is 61.3%, the mass percentage of moisture...

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Abstract

The invention discloses a method for preparing color hydrated chromium oxide by using an atmospheric pressure reduction process. The method comprises the following steps: dissolving bichromate in an aqueous solution, wherein the pH value of the aqueous solution is adjusted to 1 to 3 by using a proper amount of combined inorganic acid, slowly adding polyhydroxy carbohydrates or alcohols with stirring under normal pressure, wherein a mol ratio of the polyhydroxy carbohydrates or alcohols to bichromate is 1.2 to 1.3, carrying out a reaction with stirring for 1 to 2 h and maintaining a resultant at a temperature in a range of 80 to 100 DEG C for 2 h so as to obtain chrome oxide hydrate slurry; filtering the slurry to obtain a hydrated chromium oxide filter cake and a filtrate containing a small amount of hexavalent chromium, rinsing the filter cake a plurality of times, combining obtained filtrates together and allowing a combined filtrate to be returned to a batching procedure for cycle use; and drying the filter cake at a temperature of 60 to 80 DEG C under the protection of N2 for 1.5 to 2 h and cooling to room temperature so as to obtain a color hydrated chromium oxide product. The method has the characteristics of simple process, short flow, low production cost, high purity and yield, etc.

Description

technical field [0001] The invention belongs to the field of inorganic chemical industry and relates to a method for preparing colored hydrated chromium oxide by reducing dichromate under normal pressure and acidic conditions. Background technique [0002] Hydrated chromium oxide [Cr 2 o 3 · n H 2 O, n=2~5], is one of the main products in the industrial production of chromium salt. Hydrated chromium oxide is a gray-green amorphous substance, insoluble in water but easily soluble in acid and alkali. Chromium oxide hydrate is an amphoteric compound, which is alkaline in strong acid solution and acidic in strong alkali solution. Hydrated chromium oxide is dried at more than 100°C, and begins to dehydrate and transform into anhydrous substances with different water contents, and further burns to become chromium trioxide Cr 2 o 3 (dark green). [0003] As a pigment, hydrated chromium oxide is mainly used for coloring paints and varnishes and making other chromium salt pigm...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/033
Inventor 吕泉赵冰珊陈小红刘静文周飞龙
Owner HUBEI ZHENHUA CHEMICAL CO LTD
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