CN110217803B - System and method for preparing primary boron oxide with long crystal grade - Google Patents
System and method for preparing primary boron oxide with long crystal grade Download PDFInfo
- Publication number
- CN110217803B CN110217803B CN201910574693.8A CN201910574693A CN110217803B CN 110217803 B CN110217803 B CN 110217803B CN 201910574693 A CN201910574693 A CN 201910574693A CN 110217803 B CN110217803 B CN 110217803B
- Authority
- CN
- China
- Prior art keywords
- nitrogen
- furnace
- vacuum
- primary
- dehydration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229910052810 boron oxide Inorganic materials 0.000 title claims abstract description 71
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 239000013078 crystal Substances 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims description 50
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 347
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 164
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 156
- 208000005156 Dehydration Diseases 0.000 claims abstract description 155
- 230000018044 dehydration Effects 0.000 claims abstract description 155
- 238000009529 body temperature measurement Methods 0.000 claims abstract description 42
- 238000004321 preservation Methods 0.000 claims abstract description 40
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims abstract description 39
- 239000004327 boric acid Substances 0.000 claims abstract description 39
- 238000010438 heat treatment Methods 0.000 claims abstract description 26
- 230000008569 process Effects 0.000 claims description 26
- 238000003756 stirring Methods 0.000 claims description 25
- 239000002994 raw material Substances 0.000 claims description 23
- VGTPKLINSHNZRD-UHFFFAOYSA-N oxoborinic acid Chemical compound OB=O VGTPKLINSHNZRD-UHFFFAOYSA-N 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 21
- 238000003860 storage Methods 0.000 claims description 19
- 238000007667 floating Methods 0.000 claims description 17
- 238000006243 chemical reaction Methods 0.000 claims description 15
- 238000007599 discharging Methods 0.000 claims description 8
- 230000000694 effects Effects 0.000 claims description 7
- 238000000746 purification Methods 0.000 claims description 7
- 230000000149 penetrating effect Effects 0.000 claims description 6
- 238000005086 pumping Methods 0.000 claims description 4
- 239000010453 quartz Substances 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 229910001873 dinitrogen Inorganic materials 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 238000004519 manufacturing process Methods 0.000 description 10
- 239000000428 dust Substances 0.000 description 8
- 238000001704 evaporation Methods 0.000 description 7
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 6
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- 230000002349 favourable effect Effects 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 230000036541 health Effects 0.000 description 4
- 239000000498 cooling water Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 230000017525 heat dissipation Effects 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 238000012858 packaging process Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 238000006424 Flood reaction Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000012938 design process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B35/00—Boron; Compounds thereof
- C01B35/08—Compounds containing boron and nitrogen, phosphorus, oxygen, sulfur, selenium or tellurium
- C01B35/10—Compounds containing boron and oxygen
- C01B35/1027—Oxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Abstract
A system for preparing primary boron oxide of a long crystal grade comprising: the primary dehydration furnace, the secondary dehydration furnace and the vacuum heat preservation furnace are sequentially connected from top to bottom; the primary dehydration furnace is provided with a hopper, a nitrogen inlet pipe, a speed reducing motor, a vacuum pipe, a temperature measurement TC, a feeding switch and a spiral hot air deflector; the top of the secondary dehydration furnace is communicated with the primary dehydration furnace through a feeding switch, and is provided with a vacuum tube, a temperature measurement TC, a nitrogen inlet pipeline, a feeding switch, a multi-stage slow flow device and an air blower; the top of the vacuum heat preservation furnace is communicated with the secondary dehydration furnace through a feeding switch and is provided with a spiral heating wire, a temperature measurement TC, a barometer and a vacuum tube; a nitrogen treatment device; the nitrogen treatment device is provided with a booster pump, an air duct heater and a nitrogen purifying chamber; the nitrogen purifying chamber is provided with a nitrogen outlet and is respectively connected with two nitrogen inlet pipelines through a three-way valve; a vacuum main pipe; the vacuum main pipe is provided with a condenser and a filter element. The system can sufficiently and uniformly dehydrate boric acid, avoids foreign matter pollution, and has good continuity and high stability.
Description
Technical Field
The invention relates to the technical field of boron oxide synthesis, in particular to a system and a method for preparing primary boron oxide with a long crystal grade.
Background
In recent years, gallium arsenide semiconductors are in great demand for light-emitting devices and high-frequency devices, and besides the positive expansion of industry companies, the improvement of crystal yield will greatly promote the expansion of productivity to meet market demands. At present, the crystal growth yield of gallium arsenide produced in China is generally below 70%, and a remarkable gap exists between the crystal growth yield of gallium arsenide produced in China and the crystal growth yield of related technology abroad reaching above 80%; therefore, developing new techniques to improve the crystal growth yield of gallium arsenide and further improve the electrical properties of semiconductor crystals is a technical problem to be solved by those skilled in the art.
As an important raw material for gallium arsenide single crystal growth, the high-purity boron oxide plays an important role in improving the crystal growth yield of gallium arsenide. However, in the preparation method of high-purity boron oxide in the prior art, the dehydration process of raw material boric acid is very simple, and specifically comprises the following steps: sequentially filtering the hydrolyzed high-purity boric acid mixed solution, evaporating and drying at 100 ℃ to obtain primary dehydrated high-purity boric acid, loading the primary dehydrated high-purity boric acid into a flat-bottom stainless steel tray with the length of 40cm multiplied by 30cm, sequentially baking the primary dehydrated high-purity boric acid mixed solution for 8-14 h through a baking box with the temperature of 110-160 ℃, standing and cooling the primary dehydrated high-purity boric acid mixed solution to normal temperature, and obtaining a dried high-purity boric acid package; the process has the following disadvantages, although the equipment cost is low (only a baking box is used) and the operation is simple:
(1) Long time, average baking time about 12 hours; (2) The primary dehydrated high-purity boric acid placed on the flat-bottom stainless steel tray is inconvenient to turn over, the primary dehydrated high-purity boric acid is dehydrated only by long-time baking, the dehydration of the caking part or the inside of the material block is insufficient, and the raw materials outside the material block or at the loose part are relatively dry; (3) The hidden trouble of foreign matter pollution is very easy to cause the exceeding of impurities such as aluminum, iron, calcium and the like in a micro dust environment because the baking oven can not form a vacuum environment; more importantly, the defects of the subsequent process caused by insufficient dehydration of boric acid specifically comprise:
(1) the boron oxide loss is serious when the boron oxide with a long crystal grade is prepared, the actual existing technology has the defects of insufficient dehydration of boric acid and serious bubbling in a platinum crucible, and the boron oxide yield is only about 50% through measurement and calculation; (2) the trace water in the boron oxide of the subsequent finished product is excessive, so that the defect of the crystal growth process is caused, the water content of the boron oxide of the subsequent actual crystal growth grade exceeds 200ppm required by the specification in the prior art, and reaches 300-500 ppm, the CPK value of the manufacturing process capacity index is lower than 0.5 (the normal value is more than 1.33), the crystal growth rate is 10-15% lower than that of the boron oxide of an entrance resident due to the excessive trace water, and the expansion and contraction pipe is higher than 15% of that of the contrast object, the boron oxide of the prior art adopted in each month causes 5-10 sets of explosion damage (about 1 ten thousand yuan in value) of a hearth, and the phenomenon of the explosion hearth does not exist in the boron oxide of the contrast object resident; (3) due to incomplete dehydration of boric acid, the volatilization of boric acid is serious under the high-temperature condition in a hearth for preparing high-purity long-crystal-grade boron oxide, 5 mu micro dust in a pouring workshop and a packaging workshop reaches 50-200 ten thousand/cubic foot, serious exceeding is caused, and long-term inhalation can harm staff occupational health.
Disclosure of Invention
In view of the above, the invention aims to provide a system and a method for preparing primary boron oxide with a long crystal grade, which can sufficiently and uniformly dehydrate boric acid, avoid foreign matter pollution, and have good production continuity and high product stability.
The invention provides a system for preparing primary boron oxide with a long crystal grade, which comprises the following steps:
the primary dehydration furnace, the secondary dehydration furnace and the vacuum heat preservation furnace are sequentially connected from top to bottom;
the top of the primary dehydration furnace is provided with a hopper, a first nitrogen inlet pipe and a gear motor, the side wall of the primary dehydration furnace is provided with a first vacuum pipe and a first temperature measurement TC, the bottom of the primary dehydration furnace is provided with a second temperature measurement TC and a first feeding switch, and the inside of the primary dehydration furnace is provided with a spiral hot air deflector communicated with the first nitrogen inlet pipe;
the top of the secondary dehydration furnace is communicated with the primary dehydration furnace through the first feeding switch, a second vacuum tube and a third temperature measurement TC are arranged on the side wall of the secondary dehydration furnace, a second nitrogen inlet pipeline and a second feeding switch are arranged at the bottom of the secondary dehydration furnace, and a multi-stage slow flow device and an air blower communicated with the second nitrogen inlet pipeline are arranged in the secondary dehydration furnace;
the top of the vacuum heat preservation furnace is communicated with the secondary dehydration furnace through the second feeding switch, a spiral heating wire penetrating through the furnace body is arranged in the vacuum heat preservation furnace, and a fourth temperature measurement TC and a third vacuum tube of the barometer are arranged on the side wall of the vacuum heat preservation furnace;
the nitrogen treatment device is respectively connected with the first nitrogen inlet pipeline and the second nitrogen inlet pipeline; the nitrogen treatment device is sequentially provided with a booster pump, an air duct heater and a nitrogen purification chamber along the nitrogen flow direction; the nitrogen purifying chamber is provided with a nitrogen outlet, and the nitrogen outlet is respectively connected with a first nitrogen inlet pipeline and a second nitrogen inlet pipeline through a three-way valve;
a vacuum main pipe connected to the first vacuum pipe, the second vacuum pipe and the third vacuum pipe respectively; the vacuum main pipe is provided with a condenser and a filter element arranged outside the condenser.
Preferably, the spiral hot air deflector includes:
a nitrogen diversion main pipe arranged along the central shaft of the primary dewatering furnace; the nitrogen diversion main pipe is communicated with the first nitrogen inlet pipe;
an integrated stirring blade spirally arranged along the nitrogen diversion main pipe;
the disc type air outlet is arranged at the bottom of the nitrogen diversion main pipe; the bottom surface evenly distributed of disc air outlet has a plurality of air-out direction and the opposite abnormal shape water conservancy diversion mouth of the stirring direction of nitrogen gas water conservancy diversion main pipe.
Preferably, the multistage slow-flow device comprises:
a plurality of storage trays alternately arranged along two sides of the inner wall of the secondary dewatering furnace from top to bottom;
the storage tray includes: a tray body; the edge of the tray body is provided with a frame, and the other side connected with the inner wall of the secondary dehydration furnace is provided with a discharge hole with a narrowed opening;
a discharging hole narrowed through the opening is connected with the wedge-shaped overflow hole of the tray body; the wedge-shaped overflow port is gradually widened along the opening of the discharge port;
the wedge-shaped overflow port of the storage disc arranged above is vertically opposite to the disc body of the storage disc arranged below;
the number of the storage trays is 3-6.
Preferably, the blower includes:
a main air supply pipe;
a plurality of air supply branch pipes which are arranged around the air supply main pipe in a divergent manner;
the bottom of the air supply branch pipe is closed, a plurality of holes downwards in the air outlet direction are uniformly distributed around the air supply branch pipe, and a spherical surface opening is formed in the pipe body above the holes;
a floating ball placed in each air supply branch pipe; the floating ball can move up and down in the air supply branch pipe for placing the floating ball, and cannot pass through the spherical surface opening.
Preferably, the spiral heating wire is encapsulated by a quartz tube.
The invention also provides a method for preparing the primary boron oxide with a long crystal grade, which adopts the system described by the technical scheme and comprises the following steps:
a) In a nitrogen environment, carrying out primary dehydration on a boric acid raw material at 95-150 ℃ to obtain metaboric acid; the primary dehydration process is carried out under the diversion of nitrogen hot air;
b) Carrying out secondary dehydration on the metaboric acid obtained in the step a) at 220-260 ℃ under the condition of vacuumizing to obtain boron oxide in a molten state; the secondary dehydration process is carried out by deep dehydration through multistage slow flow under the air supply of high-temperature nitrogen;
c) Vacuum heat preservation is carried out on the boron oxide in the molten state obtained in the step b), and primary boron oxide with a long crystal grade is obtained.
Preferably, the primary dehydration in step a) is specifically performed by:
stirring boric acid raw material at 95-105 ℃ and 25-35 rpm for 30-60 min; then heating to 140-150 ℃ under the condition of vacuumizing, and stirring at 40-60 rpm during the heating process; stirring is continued for 90-120 min to obtain metaboric acid.
Preferably, the secondary dehydration process in step b) is specifically:
and (3) keeping 220-260 ℃ under the air supply of high-temperature nitrogen, feeding and vacuumizing simultaneously, and deep dehydration is carried out on metaboric acid dissolved by gradual overflow through multistage slow flow for 1-2 h, so as to obtain the boron oxide in a molten state.
Preferably, the temperature of the vacuum insulation in step c) is 220 ℃ to 250 ℃.
Preferably, the step b) further includes:
when the boron oxide in a molten state stops the high-temperature nitrogen air supply, the high-temperature nitrogen pressure is increased to 330-380 ℃, the vacuum pumping is kept for 2-4 hours, and the deep dehydration effect of the reaction materials is improved.
The invention provides a system and a method for preparing primary boron oxide with a long crystal grade, wherein the system comprises the following steps: the primary dehydration furnace, the secondary dehydration furnace and the vacuum heat preservation furnace are sequentially connected from top to bottom; the top of the primary dehydration furnace is provided with a hopper, a first nitrogen inlet pipe and a gear motor, the side wall of the primary dehydration furnace is provided with a first vacuum pipe and a first temperature measurement TC, the bottom of the primary dehydration furnace is provided with a second temperature measurement TC and a first feeding switch, and the inside of the primary dehydration furnace is provided with a spiral hot air deflector communicated with the first nitrogen inlet pipe; the top of the secondary dehydration furnace is communicated with the primary dehydration furnace through the first feeding switch, a second vacuum tube and a third temperature measurement TC are arranged on the side wall of the secondary dehydration furnace, a second nitrogen inlet pipeline and a second feeding switch are arranged at the bottom of the secondary dehydration furnace, and a multi-stage slow flow device and an air blower communicated with the second nitrogen inlet pipeline are arranged in the secondary dehydration furnace; the top of the vacuum heat preservation furnace is communicated with the secondary dehydration furnace through the second feeding switch, a spiral heating wire penetrating through the furnace body is arranged in the vacuum heat preservation furnace, and a fourth temperature measurement TC, a barometer and a third vacuum tube are arranged on the side wall of the vacuum heat preservation furnace; the nitrogen treatment device is respectively connected with the first nitrogen inlet pipeline and the second nitrogen inlet pipeline; the nitrogen treatment device is sequentially provided with a booster pump, an air duct heater and a nitrogen purification chamber along the nitrogen flow direction; the nitrogen purifying chamber is provided with a nitrogen outlet, and the nitrogen outlet is respectively connected with a first nitrogen inlet pipeline and a second nitrogen inlet pipeline through a three-way valve; a vacuum main pipe connected to the first vacuum pipe, the second vacuum pipe and the third vacuum pipe respectively; the vacuum main pipe is provided with a condenser and a filter element arranged outside the condenser. Compared with the prior art, the system and the method provided by the invention can realize full and uniform dehydration of boric acid, avoid foreign matter pollution, and have good production continuity and high product stability. Experimental results show that the purity of the primary boron oxide with the crystal growth grade prepared by the system and the method provided by the invention is more than 98%.
Meanwhile, the system provided by the invention is closed in the whole process, is favorable for preventing external pollution of products, provides good raw materials for semiconductor crystal growth, and is a necessary premise for improving the crystal characteristics and stability; the packaging process flow also well prevents the problem that the occupational health of staff is damaged by the volatilization of the micro powder dust into the air.
Drawings
FIG. 1 is a schematic diagram of a system for preparing primary boron oxide of a long crystal grade according to an embodiment of the present invention;
FIG. 2 is a schematic view of a spiral hot air deflector according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a multistage buffer according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of an air blower according to an embodiment of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a system for preparing primary boron oxide with a long crystal grade, which comprises the following steps:
the primary dehydration furnace, the secondary dehydration furnace and the vacuum heat preservation furnace are sequentially connected from top to bottom;
the top of the primary dehydration furnace is provided with a hopper, a first nitrogen inlet pipe and a gear motor, the side wall of the primary dehydration furnace is provided with a first vacuum pipe and a first temperature measurement TC, the bottom of the primary dehydration furnace is provided with a second temperature measurement TC and a first feeding switch, and the inside of the primary dehydration furnace is provided with a spiral hot air deflector communicated with the first nitrogen inlet pipe;
the top of the secondary dehydration furnace is communicated with the primary dehydration furnace through the first feeding switch, a second vacuum tube and a third temperature measurement TC are arranged on the side wall of the secondary dehydration furnace, a second nitrogen inlet pipeline and a second feeding switch are arranged at the bottom of the secondary dehydration furnace, and a multi-stage slow flow device and an air blower communicated with the second nitrogen inlet pipeline are arranged in the secondary dehydration furnace;
the top of the vacuum heat preservation furnace is communicated with the secondary dehydration furnace through the second feeding switch, a spiral heating wire penetrating through the furnace body is arranged in the vacuum heat preservation furnace, and a fourth temperature measurement TC, a barometer and a third vacuum tube are arranged on the side wall of the vacuum heat preservation furnace;
the nitrogen treatment device is respectively connected with the first nitrogen inlet pipeline and the second nitrogen inlet pipeline; the nitrogen treatment device is sequentially provided with a booster pump, an air duct heater and a nitrogen purification chamber along the nitrogen flow direction; the nitrogen purifying chamber is provided with a nitrogen outlet, and the nitrogen outlet is respectively connected with a first nitrogen inlet pipeline and a second nitrogen inlet pipeline through a three-way valve;
a vacuum main pipe connected to the first vacuum pipe, the second vacuum pipe and the third vacuum pipe respectively; the vacuum main pipe is provided with a condenser and a filter element arranged outside the condenser.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a system for preparing primary boron oxide with a long crystal grade according to an embodiment of the present invention; wherein 1 is a primary dehydration furnace, 2 is a secondary dehydration furnace, 3 is a vacuum heat preservation furnace, 4 is a hopper, 5 is a first nitrogen gas inlet pipe, 6 is a speed reducing motor, 7 is a first vacuum pipe, 8 is a first temperature measurement TC,9 is a second temperature measurement TC,10 is a first feeding switch, 11 is a spiral hot air deflector, 12 is a second vacuum pipe, 13 is a third temperature measurement TC,14 is a second nitrogen gas inlet pipe, 15 is a second feeding switch, 16 is a multi-stage slow-flow device, 17 is an air blower, 18 is a spiral heating wire, 19 is a fourth temperature measurement TC,20 is a barometer, 21 is a third vacuum pipe, 22 is a nitrogen gas treatment device, 23 is a booster pump, 24 is an air duct heater, 25 is a nitrogen gas purifying chamber, 26 is a nitrogen gas outlet, 27 is a three-way valve, 28 is a vacuum main pipe, 29 is a condenser, and 30 is a filter element; a is nitrogen, b is vacuumized, and c is cooling water.
In the invention, the system for preparing the primary boron oxide with the long crystal grade comprises a primary dehydration furnace (1), a secondary dehydration furnace (2) and a vacuum heat preservation furnace (3), a nitrogen treatment device (22) and a vacuum main pipe (28) which are sequentially connected from top to bottom. In the invention, the primary dehydration furnace (1) is used for primary dehydration of boric acid raw materials; the boric acid raw material is not particularly limited, and filtered hydrolyzed high purity boric acid well known to those skilled in the art may be used.
In the invention, the furnace body of the primary dewatering furnace (1) is of a conical cylindrical cavity structure, and the outside is provided with the heat insulation layer, so that heat dissipation can be avoided.
In the invention, a hopper (4), a first nitrogen inlet pipe (5) and a speed reducing motor (6) are arranged at the top of the primary dewatering furnace (1); the hopper (4) is provided with vacuum and is used for feeding; the first nitrogen inlet pipe (5) is used for introducing nitrogen into the primary dehydration furnace body (1); the speed reducing motor (6) is used for providing stirring power for the spiral hot air deflector (11).
In the invention, a first vacuum tube (7) and a first temperature measurement TC (8) are arranged on the side wall of the primary dehydration furnace (1); the first vacuum tube (7) is used for vacuumizing the primary dehydration furnace (1) and discharging the evaporated gas of primary dehydration; the first temperature measurement TC (8) is used for detecting the furnace temperature, and the air duct heater (24) is timely adjusted to meet the requirements of the production process by detecting the furnace temperature.
In the invention, the bottom of the primary dewatering furnace (1) is provided with a second temperature measurement TC (9) and a first feeding switch (10); the second temperature measurement TC (9) is used for detecting the furnace temperature, and the air duct heater (24) is timely adjusted to meet the requirements of the production process by detecting the furnace temperature; the first feeding switch (10) is used for feeding.
In the invention, a spiral hot air deflector (11) communicated with the first nitrogen inlet pipe (5) is arranged inside the primary dewatering furnace (1), and the structural schematic diagram of the spiral hot air deflector is shown in fig. 2. In the present invention, the spiral hot air deflector (11) includes:
a nitrogen diversion main pipe arranged along the central shaft of the primary dewatering furnace (1);
an integrated stirring blade spirally arranged along the nitrogen diversion main pipe;
and the disc type air outlet is arranged at the bottom of the nitrogen diversion main pipe.
In the invention, the nitrogen diversion main pipe is communicated with the first nitrogen inlet pipe (5); the bottom surface evenly distributed of disc air outlet has a plurality of air-out direction and the opposite abnormal shape water conservancy diversion mouth of the stirring direction of nitrogen gas water conservancy diversion main pipe.
In the invention, the spiral hot air deflector (11) is used for guiding nitrogen, and the nitrogen is finally sent out from the disc type air outlet through the nitrogen guiding main pipe by the first nitrogen inlet pipe (5); and the stirring function is also realized under the action of the integrated stirring blade; in addition, the air outlet direction of the special-shaped diversion port is opposite to the stirring direction of the nitrogen diversion main pipe, so that the disc type air outlet is prevented from being blocked by granular boric acid, and the air supply is kept smooth.
The spiral hot air deflector (11) ensures that primary dehydrated particles can be turned up and down, thereby greatly improving the dehydration efficiency; the integrated structure realizes diversion and stirring at the same time, so that the heat utilization efficiency of the primary dewatering furnace (1) is effectively ensured; in addition, the special-shaped diversion port can effectively ensure that the material can not be plugged into the air outlet when the material is stirred.
In the invention, the top of the secondary dewatering furnace (2) is communicated with the primary dewatering furnace (1) through the first feeding switch (10). In the invention, the secondary dewatering furnace (2) is used for carrying out secondary dewatering on the feeding of the primary dewatering furnace (1).
In the invention, the furnace body of the secondary dehydration furnace (2) is of a conical cylindrical cavity structure, and the outside is of a heat preservation layer, so that heat dissipation can be avoided.
In the invention, the side wall of the secondary dehydration furnace (2) is provided with a second vacuum tube (12) and a third temperature measurement TC (13); the second vacuum tube (12) is used for vacuumizing the secondary dehydration furnace (2) and discharging evaporation gas for secondary dehydration; the third temperature measurement TC (13) is used for detecting the furnace temperature, and the air duct heater (24) is timely adjusted to meet the requirements of the production process by detecting the furnace temperature.
In the invention, a second nitrogen inlet pipeline (14) and a second feeding switch (15) are arranged at the bottom of the secondary dewatering furnace (2); the second nitrogen inlet pipeline (14) is used for introducing nitrogen into the furnace body of the secondary dehydration furnace (2); the second feeding switch (15) is used for feeding.
In the invention, a multistage slow flow device (16) and an air blower (17) communicated with the second nitrogen inlet pipeline (14) are arranged in the secondary dehydration furnace (2).
In the present invention, the schematic structure of the multistage buffer (16) is shown in fig. 3. In the present invention, the multistage buffer (16) includes:
a plurality of material storage trays which are alternately arranged along the two sides of the inner wall of the secondary dehydration furnace (2) from top to bottom; is used for receiving the feeding materials.
In the present invention, the tray includes:
a tray body; the edge of the tray body is provided with a frame, and the other side connected with the inner wall of the secondary dehydration furnace (2) is provided with a discharge hole with a narrowed opening;
a discharging hole narrowed through the opening is connected with the wedge-shaped overflow hole of the tray body; the wedge-shaped overflow port is gradually widened along the opening of the discharge port.
In the invention, the wedge-shaped overflow port of the upper storage tray is vertically opposite to the tray body of the lower storage tray; the feeding of the primary dewatering furnace (1) is firstly connected to the uppermost storage tray in the secondary dewatering furnace (2), dissolved materials are controlled to overflow with less discharging through a discharging port with a narrowed opening, and flow down to the next storage tray through a wedge-shaped overflow port, and the like, so that the layer-by-layer connection is realized; the wedge-shaped overflow port is gradually widened along the opening of the discharge port, so that the contact area of the material and hot air flow can be enlarged, the detention time of the material and the hot air flow at the overflow port can be prolonged, and the full dehydration is facilitated.
In the present invention, the number of the storage trays is preferably 3 to 6, more preferably 4; the multilayer structure is favorable for increasing the contact area of the dissolved material feeding and high-temperature material storage disc, and is more favorable for evaporating water vapor.
In addition, the frame at the edge of the tray body is preferably circular arc-shaped, so that the area of the storage tray can be further increased, and the full contact between the feeding and the storage tray is facilitated.
In the invention, the air blower (17) is communicated with the second nitrogen inlet pipeline (14); the schematic structure is shown in fig. 4.
In the present invention, the blower (17) includes:
a main air supply pipe; the air supply main pipe is communicated with the second nitrogen inlet pipeline (14);
a plurality of air supply branch pipes which are arranged around the air supply main pipe in a divergent manner; the bottom of the air supply branch pipe is closed, a plurality of holes downwards in the air outlet direction are uniformly distributed around the air supply branch pipe, and a spherical surface opening is formed in the pipe body above the holes;
a floating ball placed in each air supply branch pipe; the floating ball can move up and down in the air supply branch pipe for placing the floating ball, and cannot pass through the spherical surface opening. In the invention, the floating ball is preferably a stainless steel ball with a hollow structure.
In the invention, high-temperature nitrogen from a second nitrogen inlet pipeline (14) enters an air supply branch pipe from an air supply main pipe and is sent out through a hole; at this time, the floating ball is positioned at the bottom of the air supply branch pipe; when the molten boron oxide is continuously increased and hot air (high-temperature nitrogen) is closed, the floating ball floats to the spherical surface opening, so that the molten boron oxide is prevented from flowing back to the air supply main pipe; at this time, the booster pump (23) is started and the temperature is raised until the high-temperature nitrogen can press down the floating ball below the air supply port of the air blower (17), so that the viscosity of the reaction material at the bottom of the furnace can be reduced, and the deep dehydration effect of the reaction material can be improved.
In the invention, the secondary dehydration furnace (2) effectively carries out high-temperature reaction and dehydration on the dissolved materials through a multi-stage buffer (16) for a sufficient time and a larger contact area; and the deep dehydration can be carried out through the floating ball movement under a plurality of furnace temperature conditions by combining the air blower (17).
In the invention, the top of the vacuum heat preservation furnace (3) is communicated with the secondary dehydration furnace (2) through the second feeding switch (15). In the invention, the vacuum holding furnace (3) is used for vacuum holding boron oxide in a molten state.
In the invention, the furnace body of the vacuum heat preservation furnace (3) is cylindrical, the two ends are hemispherical surfaces, and the outside is a heat preservation layer, so that heat dissipation can be avoided.
In the invention, the spiral heating wire (18) penetrating through the furnace body is arranged in the vacuum heat preservation furnace (3), so that the heat energy can be utilized to the maximum extent, and the boron oxide in the furnace body is heated sufficiently and uniformly; the spiral heating wire (18) is preferably encapsulated by a quartz tube.
In the invention, the side wall of the vacuum heat preservation furnace (3) is provided with a fourth temperature measurement TC (19), a barometer (20) and a third vacuum tube (21); the fourth temperature measurement TC (19) is used for detecting the furnace temperature, and the power of the spiral heating wire (18) is timely adjusted through the detected furnace temperature so as to meet the requirements of the production process; the barometer (20) is used for detecting the furnace pressure; the third vacuum tube (21) is used for vacuumizing the vacuum holding furnace (3) and exhausting the vacuum holding evaporation gas.
According to the invention, the vacuum heat preservation furnace (3) is adopted to keep the melting state of the boron oxide, so that primary boron oxide with a long crystal grade is obtained, the pollution of the traditional heater to the boron oxide with the long crystal grade is effectively prevented, and the heat energy utilization efficiency is also improved; the vacuum heat preservation furnace (3) provides a good raw material state for preventing boron oxide from absorbing water and moisture secondarily in an air environment and entering the next application; more importantly, the boron oxide in a molten state can be stored for a long time, so that the continuity of the design process flow is ensured, and the boron oxide in the molten state can be smoothly conveyed out at any time through the discharge hole for further application.
In the invention, the nitrogen treatment device (22) is respectively connected with a first nitrogen inlet pipeline (5) and a second nitrogen inlet pipeline (14); for providing high purity (high temperature) nitrogen. The source of the nitrogen gas is not particularly limited in the present invention, and industrial nitrogen gas well known to those skilled in the art may be used.
In the invention, the nitrogen treatment device (22) is sequentially provided with a booster pump (23), an air duct heater (24) and a nitrogen purification chamber (25) along the nitrogen flow direction; the booster pump (23) is used for providing power for nitrogen gas delivery; the air duct heater (24) adopts a hot air device which is well known to a person skilled in the art and can heat nitrogen; the temperature adjustment range of the air duct heater (24) is 100-800 ℃, so that the heating and air supply of nitrogen required by boric acid fractional dehydration reaction are satisfied; the nitrogen purifying chamber (25) is preferably a high-efficiency air supply purifying and filtering device and is used for purifying nitrogen; and then the nitrogen gas is placed in the air duct heater (24), so that the filtering of micro dust in the nitrogen gas and metal particles generated by the air duct heater (24) is facilitated, and the pollution of external foreign matters to products is eliminated.
In the invention, the nitrogen purification chamber (25) is provided with a nitrogen outlet (26), and the nitrogen outlet (26) is respectively connected with the first nitrogen inlet pipeline (5) and the second nitrogen inlet pipeline (14) through a three-way valve (27).
In the invention, the vacuum main pipe (28) is respectively connected with the first vacuum pipe (7), the second vacuum pipe (12) and the third vacuum pipe (21); vacuum was drawn by a vacuum pump. In the invention, the vacuum main pipe (28) is provided with a condenser (29) and a filter element (30) arranged outside the condenser (29); the condenser (29) condenses the evaporating gas (high-temperature boric acid, water vapor and the like) conveyed by the first vacuum tube (7), the second vacuum tube (12) and the third vacuum tube (21) through cooling water, so that the enrichment effect of high Wen Pengsuan and water vapor mixed gas dust is realized; a filter element (30) outside the condenser (29) is used for filtering the air dust.
The system and the method provided by the invention can be used for fully and uniformly dehydrating boric acid, avoid foreign matter pollution, and have good production continuity and high product stability. In addition, the system provided by the invention is totally enclosed, is favorable for preventing external pollution of products, provides good raw materials for semiconductor crystal growth, and is a necessary premise for improving the crystal characteristics and stability; the packaging process flow also well prevents the problem that the occupational health of staff is damaged by the volatilization of the micro powder dust into the air.
The invention also provides a method for preparing the primary boron oxide with a long crystal grade, which adopts the system described by the technical scheme and comprises the following steps:
a) In a nitrogen environment, carrying out primary dehydration on a boric acid raw material at 95-150 ℃ to obtain metaboric acid; the primary dehydration process is carried out under the diversion of nitrogen hot air;
b) Carrying out secondary dehydration on the metaboric acid obtained in the step a) at 220-260 ℃ under the condition of vacuumizing to obtain boron oxide in a molten state; the secondary dehydration process is carried out by deep dehydration through multistage slow flow under the air supply of high-temperature nitrogen;
c) Vacuum heat preservation is carried out on the boron oxide in the molten state obtained in the step b), and primary boron oxide with a long crystal grade is obtained.
The method comprises the steps of firstly, carrying out primary dehydration on boric acid raw materials at 95-150 ℃ in a nitrogen environment to obtain metaboric acid. The source of the nitrogen gas is not particularly limited in the present invention, and industrial nitrogen gas well known to those skilled in the art may be used. The boric acid raw material is not particularly limited, and filtered hydrolyzed high purity boric acid well known to those skilled in the art may be used.
In the invention, the primary dehydration process is performed under the diversion of nitrogen hot air; according to the invention, nitrogen is preferably ventilated to the primary dehydration furnace (1) for 5-10 min through the spiral hot air deflector (11), and the dry and dust-free state of the hearth is kept. In the present invention, the primary dehydration process is preferably specifically:
stirring boric acid raw material at 95-105 ℃ and 25-35 rpm for 30-60 min; then heating to 140-150 ℃ under the condition of vacuumizing, and stirring at 40-60 rpm during the heating process; continuously stirring for 90-120 min to obtain metaboric acid;
more preferably:
stirring boric acid raw material at 100 ℃ and 30rpm for 30-60 min; then heating to 140-150 ℃ under the condition of vacuumizing, and stirring at 40-60 rpm during the heating process; stirring is continued for 90-120 min to obtain metaboric acid.
The invention realizes the evaporation of water in the boric acid raw material at 95-105 ℃ and reacts at 140-150 ℃ to generate metaboric acid (HBO) 2 ) Playing a role in further dehydration.
After the metaboric acid is obtained, the invention carries out secondary dehydration on the metaboric acid obtained in the step a) under the condition of vacuumizing at 220-260 ℃ to obtain the boron oxide in a molten state. In the invention, the secondary dehydration process is carried out by deep dehydration through multistage slow flow under the air supply of high-temperature nitrogen. In the present invention, the secondary dehydration process is preferably specifically:
maintaining 220-260 ℃ under high-temperature nitrogen air supply, feeding while vacuumizing, and deep dehydration is carried out on metaboric acid dissolved by gradual overflow of a multistage slow flow for 1-2 h to obtain boron oxide in a molten state;
more preferably:
and (3) maintaining 230-240 ℃ under the air supply of high-temperature nitrogen, feeding and vacuumizing simultaneously, and carrying out deep dehydration on metaboric acid dissolution by gradually overflowing through multistage slow flow for 1-2 h to obtain the boron oxide in a molten state.
According to the invention, boric acid dehydration in different states is segmented, so that furnace temperature control of product reaction is realized in different dehydration furnaces, and effective control of product reaction is ensured, thereby ensuring full and uniform dehydration.
In the present invention, the secondary dehydration process preferably further comprises:
when the boron oxide in a molten state stops the high-temperature nitrogen air supply, the high-temperature nitrogen pressure is increased to 330-380 ℃, the vacuum pumping is kept for 2-4 hours, and the deep dehydration effect of the reaction materials is improved. According to the invention, the air blower (17) is adopted, and molten boron oxide gradually submerges all holes of an air supply opening at the lower part of the air blower (17), so far, viscous reactants float stainless steel floating balls in the air blower (17) and prop against the spherical opening of the inner circle of the pipeline; at the moment, the high-temperature nitrogen pressure is increased to enable the temperature to be increased to 330-380 ℃, the vacuum pumping is kept for 2-4 hours, and the deep dehydration effect of the reaction materials is improved.
After the boron oxide in the molten state is obtained, the invention carries out vacuum heat preservation on the obtained boron oxide in the molten state to obtain primary boron oxide with a long crystal grade. In the present invention, the temperature of the vacuum insulation is preferably 220℃to 250 ℃.
The invention provides a system and a method for preparing primary boron oxide with a long crystal grade, wherein the system comprises the following steps: the primary dehydration furnace, the secondary dehydration furnace and the vacuum heat preservation furnace are sequentially connected from top to bottom; the top of the primary dehydration furnace is provided with a hopper, a first nitrogen inlet pipe and a gear motor, the side wall of the primary dehydration furnace is provided with a first vacuum pipe and a first temperature measurement TC, the bottom of the primary dehydration furnace is provided with a second temperature measurement TC and a first feeding switch, and the inside of the primary dehydration furnace is provided with a spiral hot air deflector communicated with the first nitrogen inlet pipe; the top of the secondary dehydration furnace is communicated with the primary dehydration furnace through the first feeding switch, a second vacuum tube and a third temperature measurement TC are arranged on the side wall of the secondary dehydration furnace, a second nitrogen inlet pipeline and a second feeding switch are arranged at the bottom of the secondary dehydration furnace, and a multi-stage slow flow device and an air blower communicated with the second nitrogen inlet pipeline are arranged in the secondary dehydration furnace; the top of the vacuum heat preservation furnace is communicated with the secondary dehydration furnace through the second feeding switch, a spiral heating wire penetrating through the furnace body is arranged in the vacuum heat preservation furnace, and a fourth temperature measurement TC, a barometer and a third vacuum tube are arranged on the side wall of the vacuum heat preservation furnace; the nitrogen treatment device is respectively connected with the first nitrogen inlet pipeline and the second nitrogen inlet pipeline; the nitrogen treatment device is sequentially provided with a booster pump, an air duct heater and a nitrogen purification chamber along the nitrogen flow direction; the nitrogen purifying chamber is provided with a nitrogen outlet, and the nitrogen outlet is respectively connected with a first nitrogen inlet pipeline and a second nitrogen inlet pipeline through a three-way valve; a vacuum main pipe connected to the first vacuum pipe, the second vacuum pipe and the third vacuum pipe respectively; the vacuum main pipe is provided with a condenser and a filter element arranged outside the condenser. Compared with the prior art, the system and the method provided by the invention can realize full and uniform dehydration of boric acid, avoid foreign matter pollution, and have good production continuity and high product stability. Experimental results show that the purity of the primary boron oxide with the crystal growth grade prepared by the system and the method provided by the invention is more than 98%.
Meanwhile, the system provided by the invention is closed in the whole process, is favorable for preventing external pollution of products, provides good raw materials for semiconductor crystal growth, and is a necessary premise for improving the crystal characteristics and stability; the packaging process flow also well prevents the problem that the occupational health of staff is damaged by the volatilization of the micro powder dust into the air.
In order to further illustrate the present invention, the following examples are provided.
Example 1
The schematic structural diagram of the system for preparing primary boron oxide with a long crystal grade provided in embodiment 1 of the present invention is shown in fig. 1; wherein 1 is a primary dehydration furnace, 2 is a secondary dehydration furnace, 3 is a vacuum heat preservation furnace, 4 is a hopper, 5 is a first nitrogen gas inlet pipe, 6 is a speed reducing motor, 7 is a first vacuum pipe, 8 is a first temperature measurement TC,9 is a second temperature measurement TC,10 is a first feeding switch, 11 is a spiral hot air deflector, 12 is a second vacuum pipe, 13 is a third temperature measurement TC,14 is a second nitrogen gas inlet pipe, 15 is a second feeding switch, 16 is a multi-stage slow-flow device, 17 is an air blower, 18 is a spiral heating wire, 19 is a fourth temperature measurement TC,20 is a barometer, 21 is a third vacuum pipe, 22 is a nitrogen gas treatment device, 23 is a booster pump, 24 is an air duct heater, 25 is a nitrogen gas purifying chamber, 26 is a nitrogen gas outlet, 27 is a three-way valve, 28 is a vacuum main pipe, 29 is a condenser, and 30 is a filter element; a is nitrogen, b is vacuumized, and c is cooling water.
The working process for preparing the primary boron oxide with the long crystal grade by adopting the system is as follows:
(1) The filtered high-purity boric acid raw material is metered and put into a hopper (4), and then the raw material is added into a primary dehydration furnace (1) in batches from the hopper (4) to 3kg; then, the nitrogen is ventilated to the primary dehydration furnace (1) for 5min to 10min through a spiral hot air deflector (11), and the dry and dust-free state of the hearth is kept;
starting an air duct heater (24) to enable the furnace temperature of the primary dehydration furnace (1) to reach 100 ℃, and keeping the temperature of 100+/-5 ℃ for 30-60 min; in the process, a speed reducing motor (6) is started to keep a low-speed stirring state of the spiral hot air deflector (11) at 30rpm, and high-purity boric acid particles are turned over from bottom to top under the action of the spiral hot air deflector (11); the process mainly comprises evaporating water adsorbed by high-purity boric acid raw material after hydrolysis and filtration at 100deg.C under normal pressure; in the running process, the temperature measurement change of the furnace body can be observed every 10 minutes through the temperature measurement of the first temperature measurement TC (8), and the heat supply temperature of the air duct heater (24) is timely adjusted to ensure that the furnace temperature of the primary dewatering furnace (1) meets the requirements;
starting a vacuum pump to vacuumize the primary dehydration furnace (1) through a vacuum main pipe (28), and adjusting the power of an air duct heater (24) to enable the furnace temperature of the primary dehydration furnace (1) to reach 140-150 ℃; continuously maintaining the stirring state of the spiral hot air deflector (11) at 40-60 rpm in the heating process, and running for 90-120 min; the process mainly comprises the reaction to generate metaboric acid (HBO) 2 ) The specific reaction formula is: h 3 BO 3 ＝HBO 2 +H 2 O。
(2) The nitrogen is ventilated to the secondary dehydration furnace (1) for 5min to 10min through an air blower (17), and the dry and dust-free state of the hearth is maintained;
starting an air duct heater (24) to enable the furnace temperature of the secondary dehydration furnace (2) to be increased to 230-240 ℃ and kept for 30min, so as to ensure the temperature uniformity of the multistage flow buffer (16) in the hearth; then a first feeding switch (10) at the bottom of the primary dehydration furnace (1) is opened, and metaboric acid (HBO) is fed in the feeding amount of 200g/min 2 ) Putting into a secondary dehydration furnace (2); feeding and starting a vacuum pump at the same time, and vacuumizing the secondary dehydration furnace (2) through a vacuum main pipe (28);
metaboric acid (HBO) 2 ) After being put into a secondary dehydration furnace (2), slowly flows down layer by layer through a multi-stage buffer (16); the process mainly comprises the steps of deep dehydration and gradual dehydration of water to generate boron oxide (partial incomplete reaction is still metaboric acid), wherein the specific reaction formula is as follows: 2HBO 2 ＝B 2 O 3 +H 2 O；
3kg of raw materials are dissolved in 1-2 h and gradually overflowed to the furnace bottom, and molten boron oxide gradually floods all holes of an air supply port at the lower part of the air supply device (17), so far, viscous reactants float stainless steel floating balls in the air supply device (17) and prop against the spherical surface opening of the inner circle of the pipeline; at the moment, starting a booster pump (23), continuously heating to 330-380 ℃ until high-temperature nitrogen can press down the stainless steel floating ball below an air supply opening of an air blower (17), and keeping vacuumizing for 2-4 hours; the process can reduce the viscosity of the reaction material at the bottom of the furnace, improve the deep dehydration effect of the reaction material, and obtain the boron oxide in a molten state, wherein the purity of the boron oxide is 98%.
(3) Starting a vacuum pump to vacuumize the vacuum heat preservation furnace (3) through a vacuum main pipe (28); heating to 220-250 ℃ through a spiral heating wire (18); then a second feeding switch (15) at the bottom of the secondary dehydration furnace (2) is opened, and the boron oxide in a molten state obtained in the step (2) is fed into a vacuum heat preservation furnace (3) for vacuum heat preservation, so that primary boron oxide with a long crystal grade is obtained; and the material is used for preparing high-purity boron oxide after discharging.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. A method for preparing primary boron oxide of a long crystal grade, which is characterized in that a system for preparing primary boron oxide of a long crystal grade is adopted, and the system for preparing primary boron oxide of a long crystal grade comprises:
the primary dehydration furnace, the secondary dehydration furnace and the vacuum heat preservation furnace are sequentially connected from top to bottom;
the top of the primary dehydration furnace is provided with a hopper, a first nitrogen inlet pipe and a gear motor, the side wall of the primary dehydration furnace is provided with a first vacuum pipe and a first temperature measurement TC, the bottom of the primary dehydration furnace is provided with a second temperature measurement TC and a first feeding switch, and the inside of the primary dehydration furnace is provided with a spiral hot air deflector communicated with the first nitrogen inlet pipe;
the top of the secondary dehydration furnace is communicated with the primary dehydration furnace through the first feeding switch, a second vacuum tube and a third temperature measurement TC are arranged on the side wall of the secondary dehydration furnace, a second nitrogen inlet pipeline and a second feeding switch are arranged at the bottom of the secondary dehydration furnace, and a multi-stage slow flow device and an air blower communicated with the second nitrogen inlet pipeline are arranged in the secondary dehydration furnace;
the top of the vacuum heat preservation furnace is communicated with the secondary dehydration furnace through the second feeding switch, a spiral heating wire penetrating through the furnace body is arranged in the vacuum heat preservation furnace, and a fourth temperature measurement TC, a barometer and a third vacuum tube are arranged on the side wall of the vacuum heat preservation furnace;
the nitrogen treatment device is respectively connected with the first nitrogen inlet pipeline and the second nitrogen inlet pipeline; the nitrogen treatment device is sequentially provided with a booster pump, an air duct heater and a nitrogen purification chamber along the nitrogen flow direction; the nitrogen purifying chamber is provided with a nitrogen outlet, and the nitrogen outlet is respectively connected with a first nitrogen inlet pipeline and a second nitrogen inlet pipeline through a three-way valve;
a vacuum main pipe connected to the first vacuum pipe, the second vacuum pipe and the third vacuum pipe respectively; the vacuum main pipe is provided with a condenser and a filter element arranged outside the condenser;
the spiral hot air deflector includes:
a nitrogen diversion main pipe arranged along the central shaft of the primary dewatering furnace; the nitrogen diversion main pipe is communicated with the first nitrogen inlet pipe;
an integrated stirring blade spirally arranged along the nitrogen diversion main pipe;
the disc type air outlet is arranged at the bottom of the nitrogen diversion main pipe; a plurality of special-shaped diversion ports with the air outlet direction opposite to the stirring direction of the nitrogen diversion main pipe are uniformly distributed on the bottom surface of the disc-type air outlet;
the method comprises the following steps:
a) In a nitrogen environment, carrying out primary dehydration on a boric acid raw material at 95-150 ℃ to obtain metaboric acid; the primary dehydration process is carried out under the diversion of nitrogen hot air;
b) Carrying out secondary dehydration on the metaboric acid obtained in the step a) at 220-260 ℃ under the condition of vacuumizing to obtain boron oxide in a molten state; the secondary dehydration process is carried out by deep dehydration through multistage slow flow under the air supply of high-temperature nitrogen;
c) Vacuum heat preservation is carried out on the boron oxide in the molten state obtained in the step b), and primary boron oxide with a long crystal grade is obtained.
2. The method of claim 1, wherein the multi-stage buffer comprises:
a plurality of storage trays alternately arranged along two sides of the inner wall of the secondary dewatering furnace from top to bottom;
the storage tray includes: a tray body; the edge of the tray body is provided with a frame, and the other side connected with the inner wall of the secondary dehydration furnace is provided with a discharge hole with a narrowed opening;
a discharging hole narrowed through the opening is connected with the wedge-shaped overflow hole of the tray body; the wedge-shaped overflow port is gradually widened along the opening of the discharge port;
the wedge-shaped overflow port of the storage disc arranged above is vertically opposite to the disc body of the storage disc arranged below;
the number of the storage trays is 3-6.
3. The method of claim 1, wherein the blower comprises:
a main air supply pipe;
a plurality of air supply branch pipes which are arranged around the air supply main pipe in a divergent manner;
the bottom of the air supply branch pipe is closed, a plurality of holes downwards in the air outlet direction are uniformly distributed around the air supply branch pipe, and a spherical surface opening is formed in the pipe body above the holes;
a floating ball placed in each air supply branch pipe; the floating ball can move up and down in the air supply branch pipe for placing the floating ball, and cannot pass through the spherical surface opening.
4. The method of claim 1, wherein the spiral heating wire is encapsulated by a quartz tube.
5. The method according to claim 1, characterized in that the primary dewatering process in step a) is in particular:
stirring boric acid raw material at 95-105 ℃ and 25-35 rpm for 30-60 min; then heating to 140-150 ℃ under the condition of vacuumizing, and stirring at 40-60 rpm during the heating process; stirring is continued for 90-120 min to obtain metaboric acid.
6. The method according to claim 1, characterized in that the secondary dewatering process in step b) is in particular:
and (3) keeping 220-260 ℃ under the air supply of high-temperature nitrogen, feeding and vacuumizing simultaneously, and deep dehydration is carried out on metaboric acid dissolved by gradual overflow through multistage slow flow for 1-2 h, so as to obtain the boron oxide in a molten state.
7. The method according to claim 1, wherein the temperature of the vacuum hold in step c) is 220 ℃ to 250 ℃.
8. The method according to any one of claims 1 to 7, wherein step b) further comprises:
when the boron oxide in a molten state stops the high-temperature nitrogen air supply, the high-temperature nitrogen pressure is increased to 330-380 ℃, the vacuum pumping is kept for 2-4 hours, and the deep dehydration effect of the reaction materials is improved.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910574693.8A CN110217803B (en) | 2019-06-28 | 2019-06-28 | System and method for preparing primary boron oxide with long crystal grade |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910574693.8A CN110217803B (en) | 2019-06-28 | 2019-06-28 | System and method for preparing primary boron oxide with long crystal grade |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110217803A CN110217803A (en) | 2019-09-10 |
| CN110217803B true CN110217803B (en) | 2024-02-13 |
Family
ID=67815418
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910574693.8A Active CN110217803B (en) | 2019-06-28 | 2019-06-28 | System and method for preparing primary boron oxide with long crystal grade |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110217803B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4908196A (en) * | 1986-07-16 | 1990-03-13 | Societa Chimica Larderello S.P.A. | Boric oxide preparation method |
| JPH0312320A (en) * | 1989-06-08 | 1991-01-21 | Nippon Telegr & Teleph Corp <Ntt> | Production of boron oxide |
| US5651949A (en) * | 1993-11-24 | 1997-07-29 | U.S. Borax Inc. | Production of boric oxide |
| JP2007238371A (en) * | 2006-03-08 | 2007-09-20 | Nippon Denko Kk | Apparatus and method for manufacturing boron oxide |
| CN103523793A (en) * | 2013-10-08 | 2014-01-22 | 清远先导材料有限公司 | Method for preparing anhydrous boron oxide |
| CN108622912A (en) * | 2018-07-11 | 2018-10-09 | 广东先导先进材料股份有限公司 | The production method of high temperature covering agent grade boric oxide |
| CN210419269U (en) * | 2019-06-28 | 2020-04-28 | 广东先导先进材料股份有限公司 | System for preparing long-crystal-grade primary boron oxide |
-
2019
- 2019-06-28 CN CN201910574693.8A patent/CN110217803B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4908196A (en) * | 1986-07-16 | 1990-03-13 | Societa Chimica Larderello S.P.A. | Boric oxide preparation method |
| JPH0312320A (en) * | 1989-06-08 | 1991-01-21 | Nippon Telegr & Teleph Corp <Ntt> | Production of boron oxide |
| US5651949A (en) * | 1993-11-24 | 1997-07-29 | U.S. Borax Inc. | Production of boric oxide |
| CN1183088A (en) * | 1995-05-01 | 1998-05-27 | 美国博拉克有限公司 | Production of boric oxide |
| JP2007238371A (en) * | 2006-03-08 | 2007-09-20 | Nippon Denko Kk | Apparatus and method for manufacturing boron oxide |
| CN103523793A (en) * | 2013-10-08 | 2014-01-22 | 清远先导材料有限公司 | Method for preparing anhydrous boron oxide |
| CN108622912A (en) * | 2018-07-11 | 2018-10-09 | 广东先导先进材料股份有限公司 | The production method of high temperature covering agent grade boric oxide |
| CN210419269U (en) * | 2019-06-28 | 2020-04-28 | 广东先导先进材料股份有限公司 | System for preparing long-crystal-grade primary boron oxide |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110217803A (en) | 2019-09-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2021088314A1 (en) | Edge-defined film-fed growth-based sapphire crystal growth furnace capable of multiple replacement of seed crystals | |
| WO2020224186A1 (en) | Ingot furnace for directional solidification growth of crystalline silicon and application | |
| CN107056108B (en) | A kind of cooling conveying of land plaster and accelerated ageing equipment | |
| CN110217803B (en) | System and method for preparing primary boron oxide with long crystal grade | |
| CN210419269U (en) | System for preparing long-crystal-grade primary boron oxide | |
| CN111334857B (en) | SiP crystal growth regulation and control method | |
| CN108315813A (en) | A kind of preparation method of polycrystalline silicon ingot casting | |
| CN108622912A (en) | The production method of high temperature covering agent grade boric oxide | |
| CN102479875A (en) | Solar cell attenuation device | |
| CN104233460B (en) | Reaction chamber and MOCVD equipment provided with reaction chamber | |
| CN204693960U (en) | A kind of green brick tea heat-wind circulate drying system | |
| CN206779400U (en) | A kind of brass production line horizontal caster of stabilization | |
| CN207019436U (en) | A kind of drying equipment of ammonium paratungstate | |
| CN211400737U (en) | Dry finished product cooling device of wet process phosphoric acid production monocalcium phosphate | |
| CN210425988U (en) | Multistage abnormal shape unhurried current device | |
| CN209588668U (en) | A kind of screw propulsion atmosphere sintering furnace producing ternary lithium electric material | |
| CN101740656B (en) | Process for removing warpage through cold annealing of crystalline silicon solar cell sheet | |
| CN210566354U (en) | Carborundum preparation is filled valve with Ar convenient to adjust | |
| CN210683240U (en) | Cadmium sulfide production system for manufacturing thin-film solar chips | |
| CN109875975A (en) | A kind of natural vitamin E soft capsule preparation process | |
| CN204725710U (en) | A kind of high temperature flash distillation master batch drying device | |
| CN210567528U (en) | High-efficient precooling apparatus of BOG pipeline | |
| CN201250169Y (en) | Glass furnace | |
| CN217179046U (en) | Finished product vacuum cooling system of sodium fluosilicate device | |
| CN219092000U (en) | Quartz reactor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20211220 Address after: 511517 workshop a, No.16, Chuangxing Third Road, high tech Zone, Qingyuan City, Guangdong Province Applicant after: Guangdong lead Microelectronics Technology Co.,Ltd. Address before: 511517 area B, no.27-9 Baijia Industrial Park, Qingyuan high tech Zone, Guangdong Province Applicant before: FIRST SEMICONDUCTOR MATERIALS Co.,Ltd. |
|
| TA01 | Transfer of patent application right | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |