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Preparation method of electronic grade nitric acid

An electronic grade, nitric acid technology, applied in the field of nitric acid synthesis, can solve the problem that the impurity content of the product cannot reach the purity of electronic grade, and achieve the effect of simple operation and improved purity

Active Publication Date: 2014-07-16
SHANGHAI BASF POLYURETHANE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] Due to the limitation of raw material processing technology and equipment anti-corrosion protection technology, the impurity content of the product generally cannot reach the purity of electronic grade

Method used

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  • Preparation method of electronic grade nitric acid

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Experimental program
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Effect test

Embodiment 1

[0025] Such as figure 1 The shown flow chart of preparing electronic grade nitric acid, in the flow process of preparing nitric acid, the equipment used comprises tail gas heater 1, polytetrafluoroethylene screen demister 2 connected with tail gas heater 1, process gas cooler 3. Absorption tower 4, bleaching tower 5 connected with absorption tower 4 and precision filter 6 connected with bleaching tower 5. The precision filter 6 is a polytetrafluoroethylene nanofiltration membrane filter with a precision of 0.1 μm.

[0026] The air that has been filtered and purified by two-stage bag filter and the ammonia gas that has been filtered by permanent magnet and silk screen in two stages, and then heated and evaporated at a pressure of 5 bar are reacted in the reactor. The reaction temperature is 865°C. The pressure is 2.8bar, and the volume ratio of ammonia to air is 10.28% during the reaction. The synthesized gas is cooled to a temperature of 130°C in the tail gas heater 1, and th...

Embodiment 2

[0029] Such as figure 1 The shown flow chart of preparing electronic grade nitric acid, in the flow process of preparing nitric acid, the equipment used comprises tail gas heater 1, polytetrafluoroethylene screen demister 2 connected with tail gas heater 1, process gas cooler 3. Absorption tower 4, bleaching tower 5 connected with absorption tower 4 and precision filter 6 connected with bleaching tower 5. The precision filter 6 is a polytetrafluoroethylene nanofiltration membrane filter with a precision of 1.0 μm.

[0030] The air that has been filtered and purified by two-stage bag filters and the ammonia gas that has been filtered by permanent magnets and silk screens in two stages, and then heated and evaporated at a pressure of 5 bar are reacted in the reactor. The reaction temperature is 865°C. The pressure is 2.8bar, and the volume ratio of ammonia to air is 10.28% during the reaction. The synthesized gas is cooled to a temperature of 140°C in the tail gas heater 1, and...

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Abstract

The invention discloses a method for preparing electronic grade nitric acid. The method of the present invention comprises the following steps: the nitric acid obtained by condensing the nitrogen oxide gas obtained by ammoxidation in the reactor of the double pressurized nitric acid synthesis process is removed by a polytetrafluoroethylene screen demister, and the remaining nitrogen oxide gas is mixed with the demister Ionized water reacts and becomes colorless nitric acid after being bleached. The colorless nitric acid is filtered through a precision filter to obtain electronic grade nitric acid. The precision filter is polytetrafluoroethylene with a precision of 0.1 μm to 1.0 μm Nanofiltration membrane filter. The nitric acid prepared by the method of the present invention can reach the specification of electronic grade.

Description

technical field [0001] The invention belongs to the field of nitric acid synthesis, in particular to a method for preparing electronic-grade nitric acid. Background technique [0002] The industrial production of nitric acid uses the ammonia oxidation method, which utilizes three main chemical reactions to obtain nitric acid: [0003] I) 4NH 3 +5O 2 →4NO+6H 2 O(g); [0004] II) 2NO+O 2 (g)→2NO 2 (g); [0005] III) 3NO 2 (g)+H 2 O→2HNO 3 +NO(g). [0006] The existing production process adopts different ammonia oxidation reaction pressure and nitric oxide absorption pressure to produce nitric acid. The more advanced process adopts the "double pressurization" technology, that is, the ammoxidation reaction is carried out at a pressure of 2 to 3.5 bar, and the absorption reaction is carried out at a pressure of 9.5 to 11.5 bar. [0007] The compressed air and ammonia are mixed into the reactor, and the energy of the high-temperature gas after ammonia oxidation is grad...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B21/40
Inventor 刘建成张翊贾培世
Owner SHANGHAI BASF POLYURETHANE