A process for preparing high-purity hydroxylamine by electromagnetic microwave-driven hydroxylamine salt pyrolysis and sublimation.

Abstract

This invention discloses a process for preparing high-purity hydroxylamine by electromagnetic microwave-driven hydroxylamine salt pyrolysis and sublimation. The process specifically involves: adding a reducing boron salt to an aqueous solution of hydroxylamine salt; reducing metal ions in the hydroxylamine salt under microwave conditions; then adsorbing the metal ions through an electromagnetic field; concentrating, crystallizing, and centrifuging to obtain hydroxylamine salt with a metal impurity content of less than 100 ppb; subsequently, the hydroxylamine salt undergoes low-temperature pyrolysis and sublimation under vacuum and electromagnetic microwave action to obtain hydroxylamine crystals with a metal impurity content of less than 0.1 ppb, with a sublimation yield ≥85%. These hydroxylamine crystals are dissolved in ultrapure water to obtain an aqueous solution of hydroxylamine with a metal impurity content of less than 0.1 ppb. This invention utilizes the synergistic effect of microwaves and electromagnetic fields to generate hydroxylamine crystals through pyrolysis and sublimation at a relatively low reaction temperature with high selectivity, achieving safe and efficient results with a single-pass yield of not less than 85% from the electromagnetic microwave-driven pyrolysis and sublimation of hydroxylamine sulfate and hydroxylamine phosphate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydroxylamine preparation, and particularly relates to a method for preparing hydroxylamine by decomposing or reacting hydroxylamine salt. BACKGROUND

[0002] Hydroxylamine, chemical formula H3NO or NH2OH, is an unstable white massive or needle-like crystal. It is extremely hygroscopic and soluble in water, liquid nitrogen and methanol. It is slightly soluble in diethyl ether, benzene, carbon disulfide and chloroform. The melting point is 32.05℃, and the boiling point is 70℃ (1.33kPa). Hydroxylamine is an inorganic substance, which has a wide range of industrial applications and is widely used in the fields of pharmaceutical synthesis, developing technology, semiconductor cleaning and the like. For example, it is used as an intermediate of medical raw materials and agricultural chemical products, a reducing agent, a metal surface treatment agent, fiber treatment and dyes.

[0003] After the semiconductor integrated circuit photoresist layer coating, imaging, ion implantation and dry etching, the residue of the material of the photoresist layer needs to be completely removed. In particular, the sidewall polymer generated in the aluminum, aluminum alloy or silicon oxide etching process is difficult to be removed by the traditional cleaning solution. For such etching residues, the hydroxylamine type cleaning solution has a good cleaning effect. However, free hydroxylamine has extremely unstable characteristics. For example, in the presence of metal ions (especially heavy metal ions, even trace amounts of Cu 2+ , Fe 3+ , Fe 2+ , Co 2+ , Ni 2+ ), the N in hydroxylamine is in a negative 1-valence chemical state, and the empty d orbital is easy to accept the oxygen atom of the large electronegativity NH2OH to form coordination, so that the p empty orbital in the valence electron orbital of the iron ion can accommodate the electron donor, and the disproportionation reaction can be generated to generate ammonia, nitrogen and nitrogen oxides. It is easy to decompose under high temperature or high concentration conditions, unstable, and violently explodes when heated.

[0004] In the 1990s of last century, the American DuPont Company proposed to introduce hydroxylamine into the semiconductor cleaning process, and thus the application of hydroxylamine free base was further expanded. In order to be used in the electronic industry, it is usually required that the concentration of impurities, especially metal ions, is sufficiently low than 1ppb, that is, it is required to be "electronic grade". At the same time, the purity requirement of hydroxylamine is increasing. However, due to the instability of hydroxylamine, a stabilizer needs to be added to avoid the decomposition of hydroxylamine.

[0005] Patent document (US5808150) introduces diethylene triamine pentaacetic acid or triethylene tetramine hexaacetic acid as a stabilizer added to a solution containing hydroxylamine. However, there are the following problems in the hydroxylamine solution containing the stabilizer: the decomposition of hydroxylamine cannot be sufficiently inhibited under high temperature or high concentration or in the presence of metal impurities such as Fe.

[0006] Patent document CN101146739A discloses a method for stabilizing hydroxylamine during the production of hydroxylamine free base, namely, adding the stabilizer ethylenediamine N,N-di(o-hydroxyphenylacetic acid), which can stabilize hydroxylamine under high temperature, high concentration or with trace amounts of iron.

[0007] Patent document CN101910057A discloses a method for improving the stability of hydroxylamine solutions by adding oxime. This method is not suitable for industrial-scale implementation and may incur uneconomical and high additional safety costs.

[0008] Patent document CN110983370 A describes a method for preparing free hydroxylamine solution by electrolysis and electrodialysis, but the yield of this method is low and the production equipment requirements are strict.

[0009] Patent document PCT / EP2002 / 007273 relates to a method for preparing hydroxylamine salt by reacting an aqueous solution of a hydroxylamine salt with an alkali to obtain a mixture and separating the hydroxylamine of the salt from the mixture by distillation. Although partial decomposition of hydroxylamine can be avoided by complexing with metal ions, the decomposition of hydroxylamine is unavoidable due to the high temperature and alkaline conditions.

[0010] Patent document CN103539742A discloses a method for preparing free hydroxylamine: hydroxylamine salt is added dropwise with alkaline solution under stirring, and after the neutralization reaction is completed, the mixture is filtered. A stabilizer is added to the filtrate and the mixture is then distilled under reduced pressure. The fraction obtained is free hydroxylamine. This method for preparing aqueous hydroxylamine salt contains metal compound impurities in the range of 1 ppm from the beginning of manufacturing.

[0011] Patent document CN117361454 A adds hydroxylamine phosphate to a sublimation device containing a receiver. The device is depressurized and heated to perform thermal decomposition, which can solidify in the receiver to obtain high-purity hydroxylamine crystals. The crystals are then dissolved in high-purity water to obtain an aqueous solution of hydroxylamine. During sublimation, the concentration of metal impurities increases with the concentration of hydroxylamine. Conventional heating methods for sublimation also carry the risk of explosion.

[0012] Therefore, we propose a new method for producing high-purity hydroxylamine to address the problems mentioned above, such as high metal impurity ion content, metal ion enrichment during distillation, and increased metal ion enrichment during conventional thermal decomposition, which may lead to high-level explosions during hydroxylamine production. Summary of the Invention

[0013] The process of this invention utilizes the synergistic effect of microwaves and electromagnetics to generate hydroxylamine crystals through pyrolysis and sublimation at a relatively controllable reaction temperature and with high selectivity. This achieves excellent results with a single-pass yield of not less than 85% from the electromagnetic microwave-driven pyrolysis and sublimation of hydroxylamine sulfate and hydroxylamine phosphate.

[0014] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is: the present invention provides a process for preparing high-purity hydroxylamine by electromagnetic microwave-driven hydroxylamine salt pyrolysis and sublimation, the process being as follows:

[0015] A reducing boron salt is added to an aqueous solution of hydroxylamine salt. Metal ions in the hydroxylamine salt are reduced under electromagnetic microwave conditions. Then, the metal ions are adsorbed by an electromagnetic field. After concentration, crystallization, and centrifugation, hydroxylamine salt with a metal impurity content of less than 100 ppb is obtained. Then, the hydroxylamine salt is decomposed and sublimated at low temperature under vacuum and electromagnetic microwave conditions to obtain hydroxylamine crystals with a metal impurity content of less than 0.1 ppb, with a sublimation yield of ≥85%. The hydroxylamine crystals are dissolved in ultrapure water to obtain a hydroxylamine solution with a metal impurity content of less than 0.1 ppb.

[0016] A further technical solution adopted in this invention is as follows: the process for preparing high-purity hydroxylamine by electromagnetic microwave-driven hydroxylamine salt pyrolysis and sublimation includes the following steps:

[0017] Step 1: Reduce metal ions: Add hydroxylamine salt to a container according to the mass ratio, add 2-5 times the weight of pure water, add a reducing boron salt at 0.5%-2.5% of the weight of hydroxylamine salt, turn on the heat, and reflux for 2-3 hours until the reflux is complete.

[0018] Step 2: Separation of metal ions: Under stirring conditions, the metal ions that have been reduced are introduced into an electromagnetic field and cooled to adsorb as elemental metals. The mixture is then filtered through an ultrafiltration membrane. Diethylenetriaminepentaacetic acid is added to the filtrate, and the mixture is concentrated under reduced pressure. After cooling and recrystallization, the mixture is centrifuged to obtain hydroxylamine salts with a metal impurity content of less than 100 ppb after concentration, crystallization, and centrifugation.

[0019] Step 3: Electromagnetic Microwave Sublimation: Hydroxylamine salt is transferred into an electromagnetic microwave rotary sublimator. The electromagnetic microwave rotary sublimator is turned on, and the vacuum in the sublimation chamber is evacuated to below 1 kPa. Sublimation is carried out under the action of microwave and high-frequency electromagnetic 0.2-2 keV pulsed irradiation. During the sublimation process, the microwave and electromagnetic power are adjusted. The sublimation gas is condensed in a low-temperature cold trap to obtain hydroxylamine crystals with a metal impurity content of less than 0.1 ppb. The sublimation yield is ≥85%.

[0020] Furthermore, the process also includes step four: preparing a hydroxylamine solution: dissolving hydroxylamine crystals in ultrapure water to prepare hydroxylamine with a certain mass fraction and a metal impurity content of less than 0.1 ppb.

[0021] Furthermore, the reducing boron salt is sodium borohydride and / or potassium borohydride, and the reducing boron salt is 0.8%-1.8% of the weight of the hydroxylamine salt.

[0022] Furthermore, the hydroxylamine salt is hydroxylamine phosphate or hydroxylamine sulfate.

[0023] Furthermore, the amount of diethylenetriaminepentaacetic acid added in step two is 0.1%-0.3% of the weight of the recrystallized hydroxylamine salt.

[0024] Furthermore, the ultrafiltration membrane mentioned in step two is a modified polytetrafluoroethylene membrane that does not contain metal ions.

[0025] Furthermore, the cooling and recrystallization process in step two is repeated more than twice.

[0026] Furthermore, after concentration, crystallization, and centrifugation, hydroxylamine salts with a metal impurity content of less than 50 ppb are obtained.

[0027] Furthermore, metallic impurities refer to Fe, Co, Ni metals or metal ions, but are not limited to the aforementioned metallic materials.

[0028] Furthermore, the sealing element of the electromagnetic microwave rotary sublimator described in step three is made of silicon carbide.

[0029] In further detail, in step three, the vacuum level in the sublimation chamber is 10Pa-300Pa.

[0030] Furthermore, in step three, the sublimation occurs under the action of microwave and high-frequency electromagnetic 0.2-2keV pulsed irradiation. To adjust the microwave power and electromagnetic frequency, the pressure fluctuation of the vacuum pressure gauge during the sublimation process is controlled to be ≤200pa. The sublimated gas is condensed in a low-temperature cold trap at -30℃ to -20℃.

[0031] The beneficial effects of this invention are:

[0032] This invention provides a process for preparing high-purity hydroxylamine by electromagnetic microwave-driven hydroxylamine salt pyrolysis and sublimation. The advantages of this process are that it uses electromagnetic and microwave technology, combined with chemical reduction, to treat the metal ions, and utilizes electromagnetic microwave high-frequency instantaneous pyrolysis of hydroxylamine salt to obtain high-quality hydroxylamine products under low temperature and high vacuum conditions. The hydroxylamine is dissolved in an appropriate solution to obtain hydroxylamine solution products with different quality requirements (metal impurity content is less than 0.01 ppb).

[0033] Furthermore, this process significantly improves the stability of hydroxylamine production, avoiding both decomposition caused by metal ion catalysis and decomposition due to high temperature and alkalinity. This solution can be applied in the semiconductor field, maximizing the stability of semiconductor cleaning solutions.

[0034] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0035] The following specific embodiments illustrate the detailed implementation of the present invention. Those skilled in the art can easily understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented in other different ways, that is, different modifications and changes can be made without departing from the scope disclosed in the present invention.

[0036] Example 1:

[0037] Add 500g of hydroxylamine phosphate (or sulfate) to a three-necked flask, add 1600ml of pure water (based on the weight of the hydroxylamine salt), and add 6g of the reducing boron salt (based on the weight of the hydroxylamine salt). Turn on the heating and reflux for 2 hours. After reflux, under stirring, introduce an electromagnetic field and cool down to adsorb the reduced metal ions into elemental metals (15 min in this case). First, filter with an ultrafiltration membrane, add diethylenetriaminepentaacetic acid to the filtrate, then filter the ultrafiltration membrane filtrate with a nanofiltration membrane, concentrate under reduced pressure, cool down and recrystallize 3 times, and centrifuge to obtain hydroxylamine salts of Fe, Co, Ni and other metals or metal ions (content 48 ppb).

[0038] Electromagnetic microwave sublimation: Hydroxylamine salt is transferred into an electromagnetic microwave rotary sublimator. The electromagnetic microwave rotary sublimator is turned on, and the vacuum in the sublimation chamber is evacuated to below 60 Pa. Sublimation is carried out under the action of microwave and high-frequency electromagnetic pulse irradiation of 0.2-2 keV. During the sublimation process, the vacuum pressure change in the sublimation chamber is controlled to be < ±50 Pa by adjusting the microwave and electromagnetic power. The sublimation gas is condensed in a low-temperature cold trap at -25℃ to obtain hydroxylamine crystals with a metal impurity content of less than 0.07 ppb, with a sublimation yield of 89%. The crystals are dissolved in ultrapure water to prepare a 50% mass fraction hydroxylamine aqueous solution with a metal impurity content of 0.04 ppb.

[0039] Example 2:

[0040] Add 300g of hydroxylamine phosphate (sulfate) to a three-necked flask, add 1200ml of pure water (based on the weight of the hydroxylamine salt), and add 4.5g of the reducing boron salt (based on the weight of the hydroxylamine salt). Turn on the heat and reflux for 3 hours. After reflux, under stirring, introduce an electromagnetic field and cool down to adsorb the reduced metal ions into elemental metals (15 min). First, filter with an ultrafiltration membrane, add diethylenetriaminepentaacetic acid to the filtrate, then filter the ultrafiltration membrane filtrate with a nanofiltration membrane, concentrate under reduced pressure, cool down and recrystallize 4 times, and centrifuge to obtain hydroxylamine salts of Fe, Co, Ni and other metals or metal ions (content 21 ppb).

[0041] Electromagnetic microwave sublimation: Hydroxylamine salt is transferred into an electromagnetic microwave rotary sublimator. The rotary sublimator is turned on, and the vacuum in the sublimation chamber is evacuated to below 20 Pa. Sublimation is carried out under the action of microwave and high-frequency electromagnetic pulse irradiation of 0.2-2 keV. During the sublimation process, the vacuum pressure change in the sublimation chamber is controlled to be < ±20 Pa by adjusting the microwave and electromagnetic power. The sublimation gas is condensed in a low-temperature cold trap at -28℃ to obtain hydroxylamine crystals with a metal impurity content of 0.07 ppb, with a sublimation yield of 93%. The crystals are dissolved in ultrapure water to prepare 50% mass fraction hydroxylamine with a metal impurity content of 0.03 ppb.

[0042] Example 3:

[0043] 800g of hydroxylamine phosphate (sulfate) salt was added to a three-necked flask, along with 2600ml of pure water (by weight of the hydroxylamine salt) and 13g of reducing boron salt (by weight of the hydroxylamine salt). Heating was started and the mixture was refluxed for 3 hours. After reflux, the mixture was stirred and then placed in an electromagnetic field. The reduced metal ions were adsorbed as elemental metals (25 min). The mixture was first filtered through an ultrafiltration membrane, and diethylenetriaminepentaacetic acid was added to the filtrate. The filtrate was then filtered through a nanofiltration membrane, concentrated under reduced pressure, and recrystallized twice under reduced temperature. After centrifugation, hydroxylamine salts of Fe, Co, Ni, and other metals or metal ions were obtained (content 88 ppb).

[0044] Electromagnetic microwave sublimation: Hydroxylamine salt is transferred into an electromagnetic microwave rotary sublimator. The electromagnetic microwave rotary sublimator is turned on, and the vacuum in the sublimation chamber is evacuated to below 50 Pa. Sublimation is carried out under the action of microwave and high-frequency electromagnetic pulse irradiation of 0.2-2 keV. During the sublimation process, the vacuum pressure change in the sublimation chamber is controlled to be < ±30 Pa by adjusting the microwave and electromagnetic power. The sublimation gas is condensed in a low-temperature cold trap at -29℃ to obtain hydroxylamine crystals with a metal impurity content of 0.09 ppb, with a sublimation yield of 85%. The crystals are dissolved in ultrapure water to prepare 50% mass fraction hydroxylamine with a metal impurity content of 0.04 ppb.

[0045] Example 4:

[0046] 100g of hydroxylamine phosphate (sulfate) salt was added to a three-necked flask, along with 400ml of pure water (by weight of the hydroxylamine salt). The reducing boron salt was 1g (by weight of the hydroxylamine salt). Heating was started and the mixture was refluxed for 3 hours. After reflux, the mixture was stirred and then placed in an electromagnetic field. The reduced metal ions were adsorbed as elemental metals (25 min). The mixture was first filtered through an ultrafiltration membrane, and diethylenetriaminepentaacetic acid was added to the filtrate. The filtrate was then filtered through a nanofiltration membrane. The mixture was concentrated under reduced pressure, and the solution was recrystallized five times under reduced temperature. After centrifugation, hydroxylamine salts of Fe, Co, Ni, and other metals or metal ions were obtained (content 15 ppb).

[0047] Electromagnetic microwave sublimation: Hydroxylamine salt is transferred into an electromagnetic microwave rotary sublimator. The electromagnetic microwave rotary sublimator is turned on, and the vacuum in the sublimation chamber is evacuated to below 20 Pa. Sublimation is carried out under the action of microwave and high-frequency electromagnetic pulse irradiation of 0.2-2 keV. During the sublimation process, the vacuum pressure change in the sublimation chamber is controlled to be < ±10 Pa by adjusting the microwave and electromagnetic power. The sublimation gas is condensed in a low-temperature cold trap at -25℃ to obtain hydroxylamine crystals with a metal impurity content of less than 0.02 ppb, with a sublimation yield of 92%. The crystals are dissolved in ultrapure water to prepare 50% mass fraction hydroxylamine with a metal impurity content of 0.01 ppb.

[0048] Example 5:

[0049] Add 80g of hydroxylamine phosphate (sulfate) to a three-necked flask, add 300ml of pure water (by weight of hydroxylamine), and add 1.4g of reducing boron salt (by weight of hydroxylamine). Heat and reflux for 3 hours. After reflux, under stirring, introduce an electromagnetic field and cool to adsorb the reduced metal ions into elemental metals (25 min). Filter the solution using an ultrafiltration membrane, add diethylenetriaminepentaacetic acid to the filtrate, and then filter the ultrafiltration membrane filtrate using a nanofiltration membrane. Concentrate under reduced pressure, cool and recrystallize 5 times, and centrifuge to obtain hydroxylamine salts of Fe, Co, Ni, and other metals or metal ions (content 12 ppb).

[0050] Electromagnetic microwave sublimation: Hydroxylamine salt is transferred into an electromagnetic microwave rotary sublimator. The electromagnetic microwave rotary sublimator is turned on, and the vacuum in the sublimation chamber is evacuated to below 10 Pa. Sublimation is carried out under the action of microwave and high-frequency electromagnetic pulse irradiation of 0.2-2 keV. During the sublimation process, the vacuum pressure change in the sublimation chamber is controlled to be < ±10 Pa by adjusting the microwave and electromagnetic power. The sublimation gas is condensed in a low-temperature cold trap at -25℃ to obtain hydroxylamine crystals with a metal impurity content of 0.02 ppb, with a sublimation yield of 92%. The crystals are dissolved in ultrapure water to prepare 50% mass fraction hydroxylamine with a metal impurity content of 0.01 ppb.

[0051] As can be seen from the above embodiments, this process uses electromagnetic and microwave technology, combined with chemical reduction, to treat the metal ions, and utilizes electromagnetic microwave high-frequency instantaneous cracking of hydroxylamine salt to obtain high-quality hydroxylamine products under low temperature and high vacuum conditions. Hydroxylamine is dissolved in an appropriate solution to obtain high-quality hydroxylamine with different mass concentration requirements and metal impurity content below 0.01 ppb. This process is suitable for the industrial mass production of high-purity hydroxylamine.

[0052] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure made using the content of the present invention specification, or any direct or indirect application in other related technical fields, shall also be included within the patent protection scope of the present invention.

Claims

1. A process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation, characterized by: The method comprises the following steps: adding a reducing boron-containing salt into an aqueous solution of hydroxylamine salt, reducing metal ions in the hydroxylamine salt under microwave conditions, adsorbing the metal ions by an electromagnetic field, concentrating and crystallizing, centrifuging, and obtaining hydroxylamine salt with metal impurities less than 100 ppb; then, sublimating the hydroxylamine salt under the action of vacuum and electromagnetic microwave at low temperature, obtaining hydroxylamine crystals with metal impurities less than 0.1 ppb, and the sublimation yield is greater than or equal to 85%; and dissolving the hydroxylamine crystals in ultrapure water to obtain hydroxylamine aqueous solution with metal impurities less than 0.1 ppb.

2. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 1, wherein: The process comprises the following steps: Step one, reducing metal ions: adding hydroxylamine salt into a container, adding pure water with a weight of 2-5 times that of the hydroxylamine salt, adding a reducing boron-containing salt with a weight of 0.5%-2.5% of the hydroxylamine salt, starting heating, refluxing for 2-3 hours, and stopping refluxing; Step two, separating metal ions: under stirring conditions, entering an electromagnetic field, adsorbing part of the reduced metal ions into metal elements, filtering by an ultrafiltration membrane, adding diethylenetriamine pentaacetic acid into the filtrate, concentrating under reduced pressure, recrystallizing under cooling, centrifuging, and obtaining hydroxylamine salt with metal impurities less than 100 ppb; Step three, electromagnetic microwave sublimation: transferring the hydroxylamine salt into an electromagnetic microwave rotary sublimator, starting the electromagnetic microwave rotary sublimator, vacuumizing to less than 1 kPa in the sublimation chamber, sublimating under the action of microwave and high-frequency electromagnetic 0.2-2 keV pulse irradiation, adjusting the microwave power and electromagnetic frequency during the sublimation process, condensing the sublimation gas by a low-temperature cold trap, obtaining hydroxylamine crystals with metal impurities less than 0.1 ppb, and the sublimation yield is greater than or equal to 85%.

3. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation according to claim 1 or 2, characterized in that: The reducing boron-containing salt is sodium borohydride and / or potassium borohydride, and the reducing boron-containing salt is 0.8%-1.8% of the weight of the hydroxylamine salt.

4. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 2, wherein: The amount of diethylenetriamine pentaacetic acid added in step two is 0.1%-0.3% of the weight of the hydroxylamine salt after recrystallization.

5. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 2, wherein: The ultrafiltration membrane in step two is a modified polytetrafluoroethylene membrane without metal ions.

6. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 2, wherein: The number of recrystallization under cooling in step two is greater than 2 times.

7. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 2, wherein: The sealing element of the electromagnetic microwave rotary sublimator in step three is made of silicon carbide.

8. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 2, wherein: The vacuum degree in the sublimation chamber in step three is 10 Pa-300 Pa.

9. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 2, wherein: The sublimation under the action of microwave and high-frequency electromagnetic 0.2-2 keV pulse irradiation in step three is adjusting the microwave power and electromagnetic frequency to control the fluctuation pressure of the vacuum pressure gauge during the sublimation process to be less than or equal to 200 Pa, and condensing the sublimation gas by a low-temperature cold trap at-30℃ to-20℃.

10. The process for the production of high purity hydroxylamine by electromagnetic microwave driven hydroxylamine salt cleavage sublimation as claimed in claim 1 or 2, wherein: Concentrating, crystallizing, and centrifuging to obtain hydroxylamine salt with metal impurities less than 50 ppb.