A kind of preparation method of ammonium chromate crystal

An ammonium chromate and crystal technology, which is applied in the field of preparation of ammonium chromate crystals, can solve the problems such as difficulty in obtaining potassium chromate raw materials, inability to obtain ammonium chromate crystals, long preparation process, etc. The effect of decomposing and shortening the preparation process

Active Publication Date: 2022-03-08
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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Problems solved by technology

[0014] The disadvantage of this method is that the raw material of potassium chromate is not easy to obtain, the cost is high, and the by-product potassium sulfate contains hexavalent chromium and cannot be sold outside.
[0018] As with ammonium sulfate metathesis technology, the disadvantage of this method is the recycling of by-products
[0024] Various methods for preparing ammonium chromate in the current industry, although the preparation of ammonium chromate crystals has been realized, the raw materials for preparation are all based on sodium chromate, the preparation process of raw materials is long, and the preparation cost is high. In addition, while ammonium chromate is obtained A large amount of chromium-containing products are produced by-product, and the utilization cost is high
Furthermore, the method disclosed in Chinese patent CN107585788A can only obtain ammonium dichromate crystals, but cannot obtain ammonium chromate crystals

Method used

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  • A kind of preparation method of ammonium chromate crystal
  • A kind of preparation method of ammonium chromate crystal
  • A kind of preparation method of ammonium chromate crystal

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[0047] As an aspect of the technical solution of the present invention, what it relates to is a kind of preparation method of ammonium chromate crystal, and it comprises:

[0048]Using ferrochrome carbon as the working electrode, and constructing an electrochemical reaction system with at least a counter electrode and an electrolyte, wherein the electrolyte includes ammonia water (below the saturation concentration) or a mixed solution of ammonia water and ammonium chromate;

[0049] Electrically connecting the working electrode and the counter electrode to the positive pole and the negative pole of the power supply, so that an electrochemical reaction occurs in the electrochemical reaction system, and a mixed slurry is obtained;

[0050] Separating the mixed slurry from solid to liquid, and then freezing the separated liquid phase system to obtain a solid;

[0051] The solid was sublimed and dried to obtain ammonium chromate crystals.

[0052] In some preferred embodiments, ...

Embodiment 1

[0080] Weigh 500g of carbon ferrochrome and put it into a titanium anode frame, place the nickel mesh as the cathode on both sides of the anode, add 750mL of pure ammonia water into the electrolytic cell with a volume of 1L, and use a peristaltic pump to circulate the electrolyte. The water bath will control the temperature of the electrolyte to be 50°C, and control the circulation flow of the electrolyte to be 72L / h. Then turn on the power supply, stop the power supply after 36 hours of electrolysis, wash the ferrochrome, and mix the electrolyte and washing water to filter. The filtrate was frozen at -20°C for 5 hours, and then vacuum-dried at -50°C under a pressure of 5 Pa for 12 hours after freezing to obtain bright yellow crystalline ammonium chromate powder.

[0081] For the XRD figure of the ammonium chromate crystal prepared in this embodiment, please refer to figure 1 shown, SEM image please refer to figure 2 Shown, please refer to the physical picture image 3 As ...

Embodiment 2

[0085] Weigh 550 g of carbon ferrochrome and put it into a nickel anode frame, place a rod-shaped hollow stainless steel cathode in the anode frame, and separate the cathode and anode with an insulating net. Add 800mL of a mixed solution of ammonia water and ammonium chromate at a ratio of 1:10 to the electrolytic cell, control the temperature of the electrolyte to 30°C through a constant temperature water bath, and control the circulation flow rate of the electrolyte to 0. Turn on the power, after 6 hours of electrolysis, stop the power supply. Use a centrifuge to separate the electrolyte from solid to liquid, measure the supernatant and place it at -15°C for freezing for 9 hours. After freezing, dry it in vacuum at -45°C under a pressure of 10 Pa for 18 hours to obtain bright yellow crystalline ammonium chromate powder.

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Abstract

The invention discloses a preparation method of ammonium chromate crystal. The preparation method comprises: using carbon ferrochrome as a working electrode, and constructing an electrochemical reaction system together with at least a counter electrode and an electrolyte solution, the electrolyte solution comprising ammonia water or a mixed solution of ammonia water and ammonium chromate solution; The working electrode and the counter electrode are electrically connected to the positive and negative electrodes of the power supply, so that the electrochemical reaction occurs in the electrochemical reaction system, and the solid-liquid separation is carried out after the mixed slurry is obtained, and then the separated liquid phase system is subjected to freezing treatment to obtain Solid matter; the solid matter is sublimated and dried to obtain ammonium chromate crystals. For the first time, the present invention uses the principle of sublimation to obtain ammonium chromate crystals, and adopts the method of freeze-drying to prepare ammonium chromate with a certain pore structure, and the ammonium chromate exhibits bright yellow color, and the present invention only needs electrolysis, press filtration and The freeze-drying method promptly obtains high-purity ammonium chromate crystals, and the purity of the ammonium chromate crystals can reach more than 99.6%.

Description

technical field [0001] The invention relates to a preparation method of inorganic salts, in particular to a preparation method of ammonium chromate crystals. Background technique [0002] Ammonium chromate is yellow crystal with ammonia smell, molecular formula is (NH 4 ) 2 CrO 4 , the relative molecular mass is 152.08, and begins to decompose at 180°C. It is soluble in water but insoluble in ethanol. The chemical properties of ammonium chromate are unstable, and it is easy to decompose when heated to form sodium dichromate; Ammonium dichromate, so ammonium chromate is often prepared on demand. [0003] Ammonium chromate is mainly used in mordant, photographic coating sensitizer, catalyst, corrosion inhibitor and chemical reagent. And because of its property of being easy to decompose when heated, it can be used as a raw material for the clean production of chromium salt products such as sodium red alum, chromium oxide and chromic anhydride. [0004] At present, there a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G37/14
CPCC01G37/14C01P2002/72C01P2004/03C01P2004/01C01P2006/80
Inventor 冯海涛田森梁建董亚萍李波张波李武郑竹林
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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