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CN-121988256-A - Device and method for preparing NH4HF2HF melt

CN121988256ACN 121988256 ACN121988256 ACN 121988256ACN-121988256-A

Abstract

The application belongs to the technical field of NH 4 HF 2 /HF melt preparation by a synthesis reaction of HF and NH 3 , and particularly relates to a device and a method for preparing NH 4 HF 2 /HF melt. The device comprises an HF mass flow controller, an NH 3 mass flow controller and a tubular reaction system, wherein the HF mass flow controller and the NH 3 mass flow controller are connected in parallel to the tubular reaction system. The method comprises the steps of reacting HF with NH 3 at a mass flow ratio of (0.18-0.4) at 20-130 ℃ to obtain NH 4 HF 2 /HF melt. The application solves the problems of large liquid holdup, low heat exchange efficiency, insufficient continuity and the like in the existing electrolyte preparation technology.

Inventors

  • WANG YAOGANG
  • ZHANG YANYUAN
  • LUO JIANZHI
  • SHEN YONGMING
  • QIAO BEIBEI
  • LI SHUAINAN
  • ZHANG QIANCHENG
  • QIU SHIJIE

Assignees

  • 中船(邯郸)派瑞特种气体股份有限公司

Dates

Publication Date
20260508
Application Date
20260211

Claims (8)

  1. 1. An apparatus for preparing NH 4 HF 2 /HF melt, which is characterized by comprising an HF mass flow controller (1), an NH 3 mass flow controller (2) and a tubular reaction system (3); The HF mass flow controller (1) and the NH 3 mass flow controller (2) are connected in parallel to the tubular system (3); The inside of the tubular system (3) consists of a premixing unit (307), a distribution unit (308) and a heat exchange unit (309); The premixing unit (307) is provided with a baffle plate for condensing medium flow heat exchange; The distribution unit (308) is provided with a distributor, the distributor is provided with uniformly distributed through holes, and the diameter of each through hole is 3-30 mm; the heat exchange unit (309) is composed of a plurality of parallel pipes, wherein the number of the parallel pipes is the same as the number of the through holes of the distributor.
  2. 2. The apparatus for preparing an NH 4 HF 2 /HF melt as claimed in claim 1, wherein the baffle distance of the premixing unit (307) is 10 to 15mm and the gap between the baffle and the inner wall of the shell side is 0.5 to 1mm.
  3. 3. The apparatus for preparing NH 4 HF 2 /HF melt as claimed in claim 1, wherein the parallel pipeline has a diameter of 3-30mm, the interior of the pipeline is filled with SK internal components made of hastelloy, and the unit length is 5-15mm.
  4. 4. An apparatus for preparing an NH 4 HF 2 /HF melt according to claim 1, characterized in that the lines of the HF mass flow controller (1) and the NH 3 mass flow controller (2) are each connected to a nitrogen purge line (6).
  5. 5. The apparatus for preparing an NH 4 HF 2 /HF melt as claimed in claim 1, wherein the tubular reaction system (3) is made of hastelloy.
  6. 6. An apparatus for preparing an NH 4 HF 2 /HF melt according to claim 1, characterized in that the tubular reaction system (3) is also connected to a buffer tank or an electrolysis cell (4) for collecting the melt.
  7. 7. A process for preparing an NH 4 HF 2 /HF melt, based on an apparatus for preparing an NH 4 HF 2 /HF melt as claimed in any one of claims 1 to 6, characterized in that HF and NH 3 are fed to a tubular reaction system (3) in a mass flow ratio of 1 (0.18 to 0.4) and reacted at 20 to 130℃to give an NH 4 HF 2 /HF melt.
  8. 8. The method for preparing the NH 4 HF 2 /HF melt according to claim 7, wherein the mass ratio of NH 4 HF 2 to HF in the prepared NH 4 HF 2 /HF melt is (1-20): 1.

Description

Device and method for preparing NH4HF2HF melt Technical Field The application belongs to the technical field of NH 4HF2/HF melt preparation by a synthesis reaction of HF and NH 3, and particularly relates to a device and a method for preparing NH 4HF2/HF melt. Background With the rapid development of the electronic industry, especially the technical iteration and capacity expansion in the fields of semiconductor manufacturing, microelectronic etching, chemical vapor deposition, solar cell production and the like, nitrogen trifluoride (Nitrogen Trifluoride, abbreviated as NF 3) gas is used as a plasma etching gas and a cleaning gas with excellent performance, and the market demand thereof continues to increase rapidly. The NF 3 gas has the advantages of high etching rate, high selectivity, no pollution to the substrate and the like. In the prior art, NF 3 is mainly prepared by a molten salt electrolysis method, wherein an electrolyte is a molten mixture of ammonium bifluoride (NH 4HF2) and Hydrogen Fluoride (HF), which is generally expressed as NH 4 F NH F, and the electrolysis temperature is controlled between 80 ℃ and 130 ℃. The method for preparing the electrolyte mainly comprises the steps of putting solid NH 4HF2 and HF with certain mass into a mixing container, heating and dissolving the solid NH 4HF2 and the HF, and then performing electrolytic use, and directly introducing HF gas and ammonia gas into a reactor to react to generate NH 4HF2 and HF electrolyte with a specific mass ratio. Because the first method needs to process solid raw materials, the cost is high and the operation is complicated, the second method is mainly adopted in the current industrial production, namely, the electrolyte is directly generated through gas reaction. However, in the second method, each NF 3 production company commonly uses a tank, kettle, or tank reactor as a reaction vessel. The reactor has the defects of large liquid holdup, small heat exchange area, intermittent production and the like, and the danger in the production process is extremely high. The reaction of HF and NH 3 belongs to a strongly exothermic fluorination reaction, and releases a large amount of heat in a short time, which is classified as a high-risk chemical process under important supervision. In the prior industrial production and related patent technologies, the reactor for synthesizing the electrolyte is mainly a traditional tank, kettle equipment or a reactor with a conventional structure, and has a plurality of inherent defects. Chinese patent CN104947135B discloses a device for preparing nitrogen trifluoride gas, the electrolyte synthesis system uses a reaction kettle as a reaction vessel for NH 3 and HF, although the remote control of components such as a valve and a flowmeter is realized by an automatic control system, the manual direct operation is reduced, but the structural characteristic of the reaction kettle leads to large liquid holding capacity and small heat exchange area, and a large amount of heat released in the short time of the reaction of HF and NH 3 is difficult to be rapidly dissipated through the limited heat exchange area of the reaction kettle, which easily causes local overhigh temperature, may cause reaction runaway, may cause increase of impurity content in electrolyte, affects the quality of subsequent electrolytic products, and the electrolyte synthesis of the device still depends on batch reaction logic of the reaction kettle, the stability and efficiency of continuous production are to be improved, and the safety control requirement of high-risk process cannot be completely met. Chinese patent CN217140349U discloses an apparatus for preparing electrolyte with arbitrary proportion of nitrogen trifluoride, which adopts a static apparatus type reactor to replace the traditional reaction kettle, overcomes the defect of pollution of electrolyte by oil leakage of movable apparatus, and realizes continuous feeding, but the liquid holdup of the reactor is not reduced fundamentally, and the heat exchange area is not optimized pertinently. Chinese patent CN116103671A discloses a preparation method of electrolyte for nitrogen trifluoride and equipment thereof, adopts a three-section structure, replaces flow metering by weight metering, solves the problems of easy corrosion and inaccurate metering of the traditional flow metering device, reduces environmental pollution, but the reaction area of the equipment is still of a traditional reactor structure, has larger liquid holdup, and the heat generated by reaction needs to be assisted by an external condensation section for cooling, so that the heat exchange efficiency is limited, and the potential safety hazard of strong exothermic reaction can not be fundamentally solved. In summary, the reactor for synthesizing NH 3 electrolyte in the prior art has the following general problems that firstly, the liquid holdup is large, reaction materials accumulate, and once reaction is o