A kind of method for preparing chromium trichloride hexahydrate with sodium chromate

A technology of chromium trichloride hexahydrate and chromium trichloride, applied in the chemical field, can solve the problems of producing toxic and harmful gases, hindering the occupational health of operators, long process flow, etc., so as to reduce the harm of hexavalent chromium to the human body. , broad market prospects and value profits, the effect of reducing environmental pollution

Active Publication Date: 2016-02-10
SICHUAN YINHE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has a long process flow, high energy consumption, large discharge of three wastes, and high chromium belt loss. Toxic and harmful gases will be generated during the production process, which will hinder the occupational health of operators.

Method used

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  • A kind of method for preparing chromium trichloride hexahydrate with sodium chromate
  • A kind of method for preparing chromium trichloride hexahydrate with sodium chromate
  • A kind of method for preparing chromium trichloride hexahydrate with sodium chromate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Add 0.78L of sodium chromate aqueous solution with a mass concentration of 300g / L and 20.25mL of methanol with a concentration of 99% (1 times the theoretical amount) into the reaction vessel with condensing reflux, and control the temperature to rise to 118°C. Slowly add 174.66mL of hydrochloric acid with a concentration of 37% (1 times the theoretical amount) dropwise within 15 minutes; after adding hydrochloric acid, control the temperature at 120°C for 1 hour, mature at 100°C for 1 hour, add alkaline solution to neutralize the reaction solution to pH =6.8, filter to obtain the intermediate product with chromium hydroxide as the main component; the intermediate product is washed and added with a concentration of 36% hydrochloric acid 281.13mL to react, evaporated and concentrated until the concentration of chromium trichloride reaches 42 Baume degrees, Natural cooling and crystallization, centrifugation and drying at 67°C to obtain chromium trichloride hexahydrate.

...

Embodiment 2

[0051] Add 0.78L of sodium chromate aqueous solution with a mass concentration of 300g / L and 60.75mL of methanol with a concentration of 99% (3 times the theoretical amount) into a reaction vessel with condensing reflux, and control the temperature to rise to 120°C. Slowly add 349.33mL of hydrochloric acid (twice the theoretical amount) with a concentration of 37% dropwise within 20 minutes; after adding hydrochloric acid, control the temperature at 110°C for 2h, mature at 90°C for 1h, add alkaline solution to neutralize the reaction solution to pH =7, filter to obtain an intermediate product with chromium hydroxide as the main component; add 295.24mL of hydrochloric acid with a concentration of 36% to react after the intermediate product is washed, evaporate and concentrate until the concentration of chromium trichloride reaches 45 Baume degrees, Natural cooling and crystallization, centrifugation and drying at 65°C to obtain chromium trichloride hexahydrate.

[0052] Table t...

Embodiment 3

[0057] Add 0.78L of sodium chromate aqueous solution with a mass concentration of 300g / L and 40.5mL of methanol with a concentration of 99% (twice the theoretical amount) into the reaction vessel with condensing reflux, and control the temperature to rise to 120°C, with stirring Slowly add 262mL of hydrochloric acid with a concentration of 37% (1.5 times the theoretical amount) dropwise within 25 minutes; after adding hydrochloric acid, control the temperature at 120°C for 4 hours, mature at 100°C for 4 hours, add alkaline solution to neutralize the reaction solution to pH =7, filter to obtain an intermediate product with chromium hydroxide as the main component; the intermediate product is washed and added with a concentration of 36% hydrochloric acid 288.68mL to react, evaporated and concentrated until the concentration of chromium trichloride reaches 45 Baume degrees, Natural cooling and crystallization, centrifugation and drying at 65°C to obtain chromium trichloride hexahy...

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Abstract

The invention discloses a method for preparing chromium trichloride hexahydrate by utilizing sodium chromate. The method for preparing chromium trichloride hexahydrate by utilizing sodium chromate comprises the following steps: putting a sodium chromate aqueous solution and a reducing agent in a reaction vessel, controlling temperature to be 115-125 DEG C and slowly dropwise adding hydrochloric acid while stirring; after hydrochloric acid is added, firstly controlling temperature of a reaction solution to be 110-140 DEG C, carrying out reaction on sodium chromate, the reducing agent and hydrochloric acid for a first preset time period while stirring, then controlling the temperature of the reaction solution to be 80-100 DEG C, and curing the reaction solution reacted for the first time period for a second time period while stirring; adding the cured reaction solution into an alkali solution, regulating pH value of the reaction solution to be 6.5-7.5, then filtering to obtain an intermediate product, washing the intermediate product, then adding hydrochloric acid, and carrying out reaction; sequentially carrying out evaporation and concentration, crystallization at room temperature and crystal centrifugal drying on the reaction solution obtained in step three, so that chromium trichloride hexahydrate is obtained. The method for preparing chromium trichloride hexahydrate by utilizing sodium chromate is simple in technology and low in raw material cost and can replace a production method of chromium trichloride hexahydrate by virtue of chromic anhydride.

Description

technical field [0001] The invention belongs to the field of chemistry, and relates to a method for preparing chromium trichloride hexahydrate, in particular to a method for directly preparing chromium trichloride hexahydrate from sodium chromate. Background technique [0002] Chromium trichloride hexahydrate is a dark green crystalline powder, easily soluble in water, soluble in ethanol, insoluble in ether, and decomposed by heating. Mainly used in chrome plating, mordant dyeing, catalyst and other industries. This product is a trivalent chromium salt, so it is a general chemical and not regulated. [0003] At present, the main production method of chromium trichloride hexahydrate adopts the chromic anhydride production method, that is, sodium chromate is prepared into sodium dichromate at first, and sodium dichromate prepares chromic anhydride through reaction, and chromic anhydride is passed through adding hydrochloric acid, Ethanol reduction, evaporation concentration,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G37/04
Inventor 李先荣陈宁董明甫王方兵黄玉西袁小超李逢彬
Owner SICHUAN YINHE CHEM
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