Remove the method for nitrogen peroxide in a kind of salpeter solution rectifying
Technical field
The present invention relates in a kind of salpeter solution rectifying to remove the method for nitrogen peroxide, be specifically related to the method that a kind of high density waste nitric acid solution or low-quality salpeter solution carry out removing in the rectifying of manipulation of regeneration nitrogen peroxide.
Background technology
Nitric acid is a kind of important basic chemical industry raw material, is widely used in fields such as chemical industry, metallurgy, electronics, medicine, dyestuff, agricultural chemicals.Along with countries in the world are more and more stricter in the measure of being taked aspect the environment protection, carry out manipulation of regeneration to using the high density waste nitric acid and the low-quality nitric acid that are produced in the nitric acid process, thereby reach the purpose of repeated use, minimizing environmental pollution.On the other hand, owing to contain each metal ion species and some anionic impurities in the nitric acid starting material of large-scale industrial production, thereby require to remove foreign ion wherein.
Nitric acid is the stronger acid of a kind of oxidisability, boiling point is lower, under the situation of comparatively high temps, because its thermolability can be decomposed generation nitrogen peroxide, thereby cause nitric acid to show pale brown look, produce nitrogen peroxide tail gas, nitric acid produces nitrogen peroxide inevitably in the rectifying of manipulation of regeneration simultaneously, thereby influences the nitric acid quality.Its decomposition reaction formula is as follows:
4HNO
3→2H
2O+4NO
2↑+O
2↑。
Usually can carry out manipulation of regeneration and removal foreign ion wherein to high density waste nitric acid or low-quality nitric acid with the method for rectifying, be to feed high pure nitrogen after the rectifying in the nitric acid to wait and get rid of dissolved nitrogen peroxide, but part nitrogen peroxide can be diffused in the atmosphere, causes the pollution of oxynitride.
German patent DE 19920741A1 discloses a kind of salpeter solution warp with inferior quality and has concentrated the extraction rectifying method for preparing high-quality nitric acid, this method utilizes a kind of liquid extractant to stop the formation of nitric acid and water azeotrope, thereby reaches the purpose that concentrates with quality-improving.
U.S. Pat 6214173B1 discloses the system and method for a kind of on-site preparation and supply ultra-high purity nitric acid, adopts a kind of special device to prepare concentration greater than 68% nitric acid, makes it and can directly supply ultra-high purity nitric acid in semiconductor devices manufacturing works.
Above-mentioned patent does not all relate to the treatment process of the nitrogen peroxide that thermolysis is produced to nitric acid, and the open source literature report of this respect is not arranged at present yet.
Summary of the invention
The method of removing nitrogen peroxide is provided to provide in a kind of salpeter solution rectifying technical problem to be solved by this invention, to overcome the dark excessively quality problem of product nitric acid color that the nitrogen peroxide exhaust emissions brings in the salpeter solution rectifying environmental issue and rectifying obtain.
Technical conceive of the present invention is such: with high density waste nitric acid solution or inferior salpeter solution is raw material, adds strong oxidizer in rectifying, makes nitric acid decompose the nitrogen peroxide that produces and is oxidized into nitric acid, obtains the nitric acid of quality-improving.
For achieving the above object, the present invention realizes by the following technical solutions:
Remove the method for nitrogen peroxide in the described salpeter solution rectifying, specifically may further comprise the steps:
1) be that the low-quality salpeter solution feed liquid of 30-68wt% at room temperature adds in the glass reactor of being with rectifier unit with content, when 101 ℃ of gas phase temperatures, splash into strong oxidant solution, at gas phase temperature 100-103 ℃, collect the aqueous solution that contains a small amount of nitric acid under 1: 1 the condition of reflux ratio, at gas phase temperature 116-120 ℃, collect target product under 1: 1 the condition of reflux ratio.Perhaps
2) the high density waste nitric acid solvent feed of content greater than 68wt% at room temperature added in the glass reactor of being with rectifier unit, when 90 ℃ of salpeter solution temperature, splash into strong oxidant solution, at gas phase temperature 116-120 ℃, collect target product under 1: 1 the condition of reflux ratio.
Described strong oxidant solution is the oxidizing agent solution of potassium permanganate solution or energy oxidation nitrogen peroxide, and preferred strong oxidant solution is a potassium permanganate solution, and is as follows as the reaction formula of strong oxidizer with potassium permanganate solution:
KMnO
4+3NO
2+H
2O→2HNO
3+KNO
3+MnO
2
The mass ratio of described salpeter solution and strong oxidant solution is 250-10: 1.
The concentration of nitric acid is lower than 68wt% before rectifying, when at first steaming the aqueous solution cut that contains a small amount of nitric acid when gas phase temperature reaches 101 ℃, splash into strong oxidant solution, the nitrogen peroxide generation redox reaction with the nitric acid thermolysis is produced changes into nitric acid with nitrogen peroxide.
The concentration of nitric acid is greater than 68wt% before rectifying, because concentration of nitric acid has met or exceeded the azeotropic concentration of nitric acid and water, the aqueous solution cut that does not contain nitric acid in the process of rectifying splashes into strong oxidant solution and changes into nitric acid immediately to guarantee the nitrogen peroxide that the nitric acid thermolysis is produced in heating and rectifying thereafter.
Beneficial effect:
The present invention adds strong oxidizer in high density waste nitric acid solution or low-quality salpeter solution carry out the rectifying of manipulation of regeneration, make nitric acid decompose the nitrogen peroxide that produces and be oxidized into nitric acid, overcome the environmental protection difficult problem that the nitrogen peroxide exhaust emissions is brought, having solved nitric acid decomposes and produces nitrogen peroxide to atmospheric pollution and to the harm of environment, efficiently solve the dark excessively drawback of nitric acid product colour, promoted the quality of nitric acid.
The method of the invention is economical and practical, is beneficial to environmental protection, is suitable for large-scale industrial production.
Embodiment
Below in conjunction with specific embodiment technical scheme of the present invention is described in further detail, but embodiment does not limit protection scope of the present invention.
Embodiment 1
In the glass reactor that has well heater, stirring, thermometer, rectifying column device, add 68.2wt% salpeter solution 500ml under the room temperature, heat temperature raising under agitation, when the temperature of salpeter solution in the reactor reaches 90 ℃, beginning slowly drips 0.25mol/L potassium permanganate solution 7.10g, keeps the salpeter solution in the glass reactor to be incarnadine or muddy shape.When rectifying column top gas phase temperature reaches 118 ℃, keep 1: 1 reflux ratio, collect and obtain colourless nitric acid fraction 452ml, do not find the generation of nitrogen peroxide tail gas in the rectifying, nitric acid content is 67.6wt% after testing.
Embodiment 2
In the glass reactor that has well heater, stirring, thermometer, rectifying column device, add 35.0wt% salpeter solution 500ml under the room temperature, heat temperature raising under agitation is when rectifying column top gas phase temperature reaches 101 ℃, control reflux ratio 1: 1 steams the aqueous solution fraction that contains a small amount of nitric acid; Slowly drip 0.25mol/L potassium permanganate solution 9.80g simultaneously, keep the salpeter solution in the glass reactor to be incarnadine or muddy shape, when rectifying column top gas phase temperature reaches 118 ℃, collection obtains colourless nitric acid fraction 265ml, do not find the generation of nitrogen peroxide tail gas in the rectifying, nitric acid content is 54.0wt% after testing.
Should be noted that at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement the technical scheme of invention, and not breaking away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the claim scope of the present invention.