Method for producing chromium oxide green through sodium circulation

A technology of chromium oxide green and chromium oxide, applied in the directions of chromium trioxide, chromium oxide/hydrate, etc., can solve the problems of long production process, high cost and high energy consumption, and achieve short production process, low production cost, The effect of simplifying the process

Active Publication Date: 2016-03-02
绵阳市安剑皮革化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above disclosed patents have the following disadvantages: the production process is too long, the energy consumption is high, and the cost is high. The crushing of chromium oxide green will produce a large amount of dust, causing serious environmental pollution and human health damage.
At present, as the situation of domestic safety and environmental protection becomes more and more serious, high energy consumption and high pollution enterprises will be gradually eliminated, and the current domestic production cost of chromium oxide green is high.
The above shortcomings will restrict the competitiveness of the domestic chromium oxide green industry for a long time

Method used

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  • Method for producing chromium oxide green through sodium circulation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Step 1: Grind chromite to obtain chromite powder with a particle size of less than 80um;

[0029] Step two, 2.50t chromite powder, 3.50t sodium hydroxide and 5.85m 3 Water is added to the oxidation reaction kettle, oxygen is introduced, and the reaction is heated to 300°C for 3 hours. After the reaction is completed, the temperature is cooled and separated to obtain an alkaline solution of sodium chromate;

[0030] Step 3. Add 1.35t of starch to the alkaline solution of sodium chromate, heat it to 193℃ in the reduction kettle, keep the temperature for 0.6 hours, cool to 20℃, and separate by filtration to obtain chromium oxide hydrate and 4.71m 3 Alkaline filtrate, the alkaline filtrate is Na + Ion concentration 16.56mol / L;

[0031] Step 4. Wash the chromium oxide hydrate countercurrently for 5 times, and recover the washing liquid; then calcinate the washed chromium oxide hydrate in a high-temperature furnace at 1000℃ for 2 hours to obtain 0.96t of chromium oxide green; detect ...

Embodiment 2

[0034] Step 1: Grind chromite to obtain chromite powder with a particle size of less than 80um;

[0035] Step 2. Mix the alkaline filtrate and washing liquid in Example 1 and adjust the alkali as alkaline solution, take 2.40t chromite powder, 3.65m 3 Alkaline solution (Na + Ion concentration 23.63mol / L) was added to the oxidation reactor, oxygen was introduced, and the reaction was heated to 275°C for 1 hour. After the reaction was completed, the temperature was lowered and separated to obtain an alkaline solution of sodium chromate;

[0036] Step 3. Add 1.28t of starch to the alkaline solution of sodium chromate, heat it to 152℃ in the reduction kettle, keep the temperature for 1.8 hours, cool to room temperature, and separate by filtration to obtain chromium oxide hydrate and 2.92m 3 Alkaline filtrate, the alkaline filtrate is Na + The ion concentration is 28.56mol / L;

[0037] Step 4. Wash the chromium oxide hydrate countercurrently for 5 times, and recover the washing liquid; then ...

Embodiment 3

[0040] Step 1: Grind the ferrochrome to obtain ferrochrome powder with a particle size of less than 80um;

[0041] Step 2. Mix the alkaline filtrate and washing liquid in Example 2 to adjust the alkaline solution as alkaline solution, take 1.85t ferrochrome powder, 5.32m 3 Alkaline solution (Na + Ion concentration 7.35mol / L) was added to the oxidation reaction vessel, oxygen was introduced, and the reaction was heated to 285°C for 1.3 hours. After the reaction was completed, the temperature was lowered and separated to obtain sodium chromate alkaline solution;

[0042] Step 3. Add 1.86t of starch to the alkaline solution of sodium chromate, heat it to 178℃ in the reduction kettle, keep the temperature for 1.2 hours, cool to room temperature, and separate by filtration to obtain chromium oxide hydrate and 4.78m 3 Alkaline filtrate, the alkaline filtrate is Na + Ion concentration 8.08mol / L;

[0043] Step 4. Wash the chromium oxide hydrate countercurrently for 3 times, and recover the wa...

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Abstract

The invention discloses a method for producing chromium oxide green through sodium circulation. The method comprises the following steps: adding powdery chromite ores or ferrochromium powder into an alkali solution and introducing oxidation materials for reaction, and separating to obtain a sodium chromate alkali solution after full reaction; adding organic reducing substances into the sodium chromate alkali solution, after hydrothermal reaction, filtering and separating to obtain chromic oxide hydrate and alkali filter liquor; performing countercurrent washing on the chromic oxide hydrate and recycling the washing liquid; calcining the chromic oxide hydrate after washing in a high temperature furnace to obtain chromium oxide green; concentrating and performing alkali modulation on the alkali filter liquor and the washing liquid, and further returning the alkali filter liquor and the washing liquid after concentration and alkali modulation, so as to serve as the alkali solution to realize cyclic utilization of sodium resource in the technological process. Compared with the conventional preparation process of chromium oxide green, the method for producing chromium oxide green, provided by the invention, has the advantages that the production technical process is short, the operation is simple, and the prepared chromium oxide green is high in quality; besides, cyclic utilization of sodium resources in the production technology process is realized, and zero emission of the three wastes is also realized, so that the method is an environment-friendly and clean novel method for producing chromium oxide green.

Description

Technical field [0001] The invention relates to a method for producing chromium oxide green by recycling sodium, more specifically, a method for preparing chromium oxide green with short flow, low cost and high environmental protection. Background technique [0002] Chrome oxide green is one of the four major products in the chromium salt industry. It has excellent chemical properties and thermal stability. It is mainly used in coatings, metallurgy, refractory materials, spraying, ceramics, art paints and camouflage materials. The industrial production of chromium oxide green often uses ammonium sulfate-sodium alum thermal decomposition method and chromic anhydride thermal decomposition method. The process of preparing chromium oxide green by reducing sodium chromate with sulfur is to first reduce sodium chromate with sulfur as a reducing agent to prepare chromium hydroxide, and then calcinate chromium hydroxide to prepare chromium oxide green. The product contains high impurity ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/033
CPCC01G37/033
Inventor 李先荣陈宁董明甫王方兵黄先东周杨张良
Owner 绵阳市安剑皮革化工有限公司
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