Preparation method of nitrosyl sulfuric acid and method for separating sulfuric acid and phosphoric acid in industrial waste acid

A technology of nitroso sulfuric acid and nitric acid, which is applied in the preparation of alkali metal sulfites, chemical instruments and methods, phosphorus compounds, etc. The effect of reducing emissions and simple equipment

Active Publication Date: 2016-03-23
ZHEJIANG LINJIANG CHEM
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  • Claims
  • Application Information

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Problems solved by technology

This method is to firstly oxidize ammonia to nitrogen oxide gas, and then react with oleum in a concentrated sulfuric acid system to produce nitrosyl sulfuric acid. This method requires a high level of production technology and is fully automated. Large production capacity, tail gas treatment is also relatively simple, the content of the obtained product nitrosyl sulfuric acid can reach more than 70%, but the production of nitrosyl sulfuric acid by direct absorption method is currently only available when the absorption pressure is 0.3MPa, and the use of sieve plate absorption Nitrosyl sulfuric acid is produced by tower absorption reaction. This technology is imported from abroad. There are problems such as difficult operation and

Method used

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  • Preparation method of nitrosyl sulfuric acid and method for separating sulfuric acid and phosphoric acid in industrial waste acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Step (1): Add 8kg of sulfur and 50kg of sulfuric acid into a 250L reaction kettle, heat up to 200°C for 1.5h, and the sulfur dioxide gas generated is connected to the concentrated sulfuric acid drying kettle through the pipeline for drying;

[0057] Step (2): the dried sulfur dioxide imports in the two-stage series falling film absorption tower, reacts and absorbs through the mixed nitric acid solution B, and the mixed nitric acid solution B is that 96.5kg mass fraction is 98wt% nitric acid and 546.8kg mass fraction is 98wt % of the sulfuric acid mixed solution (15wt% nitric acid and 85wt% sulfuric acid), mixed nitric acid solution B enters by the second falling film absorption tower absorption liquid inlet, the content of the nitrosyl sulfuric acid of the second falling film absorption tower absorption liquid is After 10-20wt%, circulate to the first falling film absorption tower, after the concentration of the absorption liquid of the first falling film absorption towe...

Embodiment 2

[0062] Compared with Example 1, the difference is that the mixed nitric acid solution B is a mixed solution of 0.7:1 nitric acid and sulfuric acid in a mass ratio. The content of sulfur dioxide is 50.06wt%, and the absorption rate of sulfur dioxide is 98.7%.

Embodiment 3

[0064] Compared with Example 1, the difference is that the mixed nitric acid solution B is a mixed solution of 0.54:1 nitric acid and sulfuric acid in a mass ratio. The content of sulfur dioxide is 58.06wt%, and the absorption rate of sulfur dioxide is 99.3%.

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Abstract

The invention discloses a preparation method of nitrosyl sulfuric acid and a method for separating sulfuric acid and phosphoric acid in industrial waste acid. The preparation method comprises the following steps: (1), mixing sulfur with a sulfuric acid solution A, performing warming reaction to generate sulfur dioxide gas, and performing centrifugal treatment on waste acid after reaction to obtain waste acid containing a lot of phosphoric acid; and (2), drying the sulfur dioxide gas, and enabling the dried sulfur dioxide gas to react with a mixed nitric acid solution B in a multistage-series falling-film absorption tower, thereby obtaining nitrosyl sulfuric acid. According to the preparation method of nitrosyl sulfuric acid, disclosed by the invention, industrial waste acid containing nitric acid and sulfuric acid is used as a reaction raw material to realize waste recycling, and meanwhile the purpose of concentrating the phosphoric acid in the waste acid is achieved, so that an economical and effective treatment method is provided for the industrial waste acid.

Description

technical field [0001] The invention relates to the field of chemical production, in particular to a preparation of nitrosyl sulfuric acid and a method for separating sulfuric acid and phosphoric acid from industrial waste acids. Background technique [0002] Diazotization is an important reaction unit in organic synthesis, and sodium nitrite is a commonly used raw material for diazotization reaction. When there is an electron-withdrawing group on the benzene ring, the activity of the amino group is reduced, and a diazotization raw material with higher activity, nitrosylsulfuric acid, is needed. Compared with sodium nitrite, as a diazotization agent, nitrosyl sulfuric acid will not generate sodium sulfate salt during diazotization reaction, which is convenient for the concentrated recovery of dilute sulfuric acid in the subsequent process. [0003] Nitrosylsulfuric acid is a very unstable compound and usually needs to be dissolved in a certain concentration of sulfuric acid...

Claims

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Application Information

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IPC IPC(8): C01B21/094C01B25/234C01D5/14
Inventor 尹新吴然谢倩鲁承勇沈焕军
Owner ZHEJIANG LINJIANG CHEM
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