Device for rapidly preparing beta-Si3N4 by gas-solid reaction, and method thereof

Patent metadata

Field	Value
Publication number	US-11602725-B2
Application number	US-202117540229-A
Country	US
Kind code	B2
Filing date	Dec 1, 2021
Priority date	Mar 8, 2021
Publication date	Mar 14, 2023
Grant date	Mar 14, 2023

Abstract

A device for rapidly preparing β-Si3N4 by gas-solid reaction and a method thereof, and relates to the technical field of recycling and reuse of waste fine silicon powder. The bottom of a stock bin communicates with a first opening and closing passage, a first connection passage, and the top of a first transitional bin; the bottom of the first transitional bin communicates with the first opening and closing passage, a second connection passage, and the top of a reaction bin; the bottom of the reaction bin communicates with a second opening and closing passage, the first connection passage, and the top of a second transitional bin; the bottom of the second transitional bin communicates with the top of a conveying passage through the first opening and closing passage; a material outlet of the conveying bin communicates with the collection bin.

First claim

What is claimed is:

1. A device for rapidly preparing β-Si 3 N 4 by gas-solid reaction, comprising a stock bin, a first transitional bin, a reaction bin, a second transitional bin, a conveying bin, and a collection bin, wherein the bottom of the stock bin communicates with a first opening and closing passage, a first connection passage, and the top of the first transitional bin in sequence; the bottom of the first transitional bin communicates with the first opening and closing passage, a second connection passage, and the top of the reaction bin in sequence; the bottom of the reaction bin communicates with a second opening and closing passage, the first connection passage, and the top of the second transitional bin in sequence; the bottom of the second transitional bin communicates with the top of the conveying passage through the first opening and closing passage; a material outlet of the conveying bin communicates with the collection bin; the first connection passage is a hollow pipeline and is provided with a pressure gauge, a vacuum pump, and a gas inlet on a side wall; the second connection passage is a hollow pipeline and is provided with a pressure gauge and a pressure exhaust valve on a side wall; and a gas intake pipeline is arranged in the middle of the second opening and closing passage.

2. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 1 , wherein the first opening and closing passage is composed of a first passage pipe, a fan blade fixing piece, at least three first fan blades, and a transmission pair; a ringlike fan blade fixing piece is fixed inside the first passage pipe; at least three first fan blades are provided; one end of each first fan blade is hinged to the fan blade fixing piece, and the bottom of the other end of the first fan blade is connected with a driven wheel of the transmission pair through a rotating shaft; the driven wheel is sleeved in the first passage pipe; the driven wheel is engaged with a driving wheel; the driving wheel is rotatably arranged in a side wall of the first passage pipe; one side of the driving wheel is provided with a rotating handle; and a free end of the rotating handle is located on an outer side of the first passage pipe.

3. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 1 , wherein the second opening and closing passage is composed of a second passage pipe, a fan blade fixing piece, at least three second fan blades, and a transmission pair; a ringlike fan blade fixing piece is fixed inside the second passage pipe; at least three second fan blades are provided; one end of each second fan blade is hinged to the fan blade fixing piece, and the bottom of the other end of the second fan blade is connected with a driven wheel of the transmission pair through a rotating shaft; the driven wheel is sleeved in the second passage pipe; the driven wheel is engaged with a driving wheel; the driving wheel is rotatably arranged in a side wall of the second passage pipe; one side of the driving wheel is provided with a rotating handle; a free end of the rotating handle is located on an outer side of the second passage pipe; the gas intake pipeline is composed of a gas intake pipe and a gas sprayer; one end of the gas intake pipe passes through the side wall of the second passage pipe and is connected with a gas intake device, and the other end of the gas intake pipe is connected with the gas sprayer; the gas sprayer is located at the bottom of the reaction bin; and at least three second fan blades is in close contact with an outer side wall of the gas intake pipe at the lower part of the gas sprayer after being closed.

4. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 1 , wherein a transfer guide plate is arranged on an inner side of the top of the second connection passage, and a rotating chute is arranged below the transfer guide plate.

5. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 1 , wherein the reaction bin is composed of a heating furnace tube, a heat insulation layer, a shell, at least one microwave generator, and at least one temperature measurement device; the heating furnace tube communicates with the second opening and closing passage; a space between the shell and the heating furnace tube is filled with a heat insulation layer; and the at least one microwave generator and the at least one temperature measurement device are distributed on the shell.

6. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 5 , wherein the at least one microwave generator comprises nine microwave generators, and the at least one temperature measurement device comprises three temperature measurement devices; the nine microwave generators are uniformly disposed along a height direction of the heating furnace tube as three rows; in each of the three rows, three of the nine microwave generators are uniformly distributed along a radial direction of the heating furnace tube; and the three temperature measurement devices are uniformly provided along the height direction of the heating furnace tube.

7. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 3 , wherein the second transitional bin is composed of an inner pipe and an outer pipe which are coaxially disposed; the gas intake pipe is wound on an outer side wall of the inner pipe; a gap formed by the outer side wall of the inner pipe and an inner side wall of the outer pipe is filled with a heat insulation material to preheat gas in the gas intake pipe.

8. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 1 , wherein the conveying bin is L-shaped, a horizontal section of which is internally provided with a transfer screw rod; one end of the transfer screw rod is connected with a motor; and the collection bin is arranged below the other end of the transfer screw rod.

9. The device for rapidly preparing the β-Si 3 N 4 by gas-solid reaction according to claim 8 , wherein a water cooling device is arranged on an outer side wall of the horizontal section of the conveying bin.

10. A method for rapidly preparing β-Si 3 N 4 by gas-solid reaction by using the device according to claim 1 comprising:
opening the first opening and closing passage between the stock bin and the first transitional bin so that waste fine silicon powder enters the first transitional bin, closing the first opening and closing passage, vacuumizing the first transitional bin, filling the first transitional bin with pure N 2 , and maintaining a pressure at 0.1 MPa to 0.3 MPa;
opening the first opening and closing passage between the first transitional bin and the reaction bin so that the waste fine silicon powder enters the reaction bin ( 3 ), spraying at least one of N 2 and NH 3 by the gas intake pipeline, synchronously heating reactants at a temperature rise rate of 100° C./min, maintaining a temperature for 5 min to 20 min when the temperature in the reaction bin reaches 1250+/−100° C., and maintaining a gas pressure in the reaction bin at 0.1 MPa to 0.3 MPa;
in a reaction process, synchronously vacuumizing the second transitional bin, then filling the second transitional bin with the pure N 2 , and maintaining the pressure at 0.1 MPa to 0.3 MPa; after the reaction process ends, opening the second opening and closing passage between the reaction bin and the second transitional bin; and after reaction products enter the second transitional bin, opening the first opening and closing passage between the second transitional bin and the conveying bin so that the reaction products enter, through the conveying

Assignees

• Univ Kunming Science & Technology

Inventors

• Xu Lei
• Zhang Libo
• Li Hang
• Han Zhaohui
• Liu Jianhua
• Xia Hongying
• Tang Zhimeng
• Guo Lirong

Classifications

• B01J19/2415

  Tubular reactors · CPC title

• B01J4/008

  Feed or outlet control devices · CPC title

• B01J4/002

  Nozzle-type elements (nozzle-type reactors B01J19/26) · CPC title

• B01J2219/00141

  Microwaves · CPC title

• Y02P20/10

  Process efficiency · CPC title