CN108557780B - A kind of preparation method of beta-silicon nitride powder - Google Patents
A kind of preparation method of beta-silicon nitride powder Download PDFInfo
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- CN108557780B CN108557780B CN201810391846.0A CN201810391846A CN108557780B CN 108557780 B CN108557780 B CN 108557780B CN 201810391846 A CN201810391846 A CN 201810391846A CN 108557780 B CN108557780 B CN 108557780B
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
- C01B21/068—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with silicon
- C01B21/0682—Preparation by direct nitridation of silicon
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
- C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
Abstract
The present invention relates to silicon nitride preparation fields, disclose a kind of preparation method of beta-silicon nitride powder, comprising: 1) equipment preheats；2) material heats: the mixture of silicon powder and ammonia, nitrogen being passed through mixing in the coil pipe of microwave plasma preheater respectively and are preheated to 700-750 DEG C, is then passed through material in the heating zone of suspension reactor inner cavity and continues to heat；Upward nitrogen swirling air stream, which is passed through, to heating zone simultaneously drives material rotation；3) react: material falls to reaction zone, while being passed through upward nitrogen swirling air stream to reaction zone and driving material rotation；Material is reacted at whereabouts generates silicon nitride；4) heat preservation cooling: silicon nitride and unreacted nitrogen enter heat preservation cooler, and first material is cooled down with water cooling, then are cooled down with water cooling and air cooling, finally use water-cooled cooling；5) gas powder separates.Beta-silicon nitride powder produced by the present invention is with high purity, partial size is thin, ɑ phase content is high, yield is high, it is fast to produce.
Description
Technical field
The present invention relates to silicon nitride preparation field more particularly to a kind of preparation methods of beta-silicon nitride powder.
Background technique
Silicon nitride is a kind of important structural ceramic material.It is a kind of superhard substance, itself has lubricity, and resistance to
Abrasion is atomic crystal；It is anti-oxidant when high temperature.And it can also resist cooling thermal impact, be heated to 1000 DEG C or more in air,
Quick refrigeration sharply heats again, will not fragmentation.There is so excellent characteristic just because of silicon nitride ceramics, people are usually sharp
The mechanical components such as bearing, blade of gas turbine, mechanical seal ring, permanent mold are manufactured with it.
Currently, domestic beta-silicon nitride powder production is mainly by following two method:
1, bell-type furnace electric heating or microwave heating nitrogen osmosis
Step: silicon powder → crucible → is passed through nitrogen preheating (about 8 hours 1000 degree) → heating reaction and synthesizes (about 20 hours
1200-1300 degree) discharging, (bulk, total about 50 is small for → heat preservation (about 10 hours 1000 degree) → cooling (about 8 hours 80 degree or less) →
When) → smashing and grinding → classification 3-5 times back and forth.This production technology wants 80 hours or more from powder is dosed into out, is adapted only to small rule
Mould production.
2, horizontal powder band electric heating or microwave heating self- propagating nitrogen osmosis
Step: silicon powder → strip platform → logical nitrogen preheating (about 8 hours 1000 degree) → powder band one end high temperature triggering is reacted,
Utilize exothermic heat of reaction heating Self-propagating Reaction Synthesis (time is according to powder band about 5-10 hours 1200-1300 degree of length) → heat preservation
(about 5 hours 1000 degree) → cooling (about 5 hours 80 degree or less) discharge, and (bulk, about 30 hours) → smashing and grinding → classification is back and forth
2-3 times.This production technology wants 50 hours or more from powder is dosed into out, invests larger.
The technical difficulty of aforementioned production method is:
1, temperature control is difficult: the state of reaction synthesis period: reaction (heat absorption) → synthesis (heat release) → reaction (heat absorption) →
It synthesizes (heat release), surface layer can cool down, and centre can not cool down.
2, reunite and agglomerate: silicon powder stacks pyroreaction synthesis, reunites after synthesis blocking, and silicon nitride is superhard substance, crushes
Grinding is the biggest problem.
If not can solve above-mentioned difficult point, following technical problem will be caused:
1, the low reaction of temperature not exclusively, causes purity low (siliceous), temperature is excessively high and can generate thermodynamic barrier and react and stop
Only, purity, while silicon nitride molecular crystal phase transformation β phase (the β phase of the generation more than 1250 DEG C, not sinterable irreversible) are influenced.
2, reunite blocking: abrasive material, container inside lining abrasion are big in smashing and grinding, and impurity is brought into.
3, intermittent production: equipment utilization is low, production capacity is low.
4, production management is difficult: equipment is more, workshop is big, link is more, technique is more, investment is big.
5, auxiliary facility is more: inhaling the auxiliary equipment such as dust, antistatic, the dynamic, noiseless of vibration isolation.
For this reason, it is necessary to develop a kind of new technology of beta-silicon nitride powder production to solve the above technical problems.
Summary of the invention
In order to solve the above-mentioned technical problems, the present invention provides a kind of preparation methods of beta-silicon nitride powder.The method of the present invention
Low energy consumption, and beta-silicon nitride powder obtained is with high purity, partial size is thin, α phase content is high, yield is high, it is fast to produce.
The specific technical proposal of the invention is: a kind of preparation method of beta-silicon nitride powder, comprising the following steps:
1) equipment preheats: by the inner cavity of coil pipe and suspension reactor in microwave plasma preheater microwave plasma fire
Torch is separately heated to 800-850 DEG C and 1350-1400 DEG C.
2) material heats: the mixture of silicon powder and ammonia, nitrogen being passed through in the coil pipe of microwave plasma preheater respectively
Mixing is preheated to 700-750 DEG C, and material is then passed through suspension reactor in the form of upward injection forms inverted conical shape aerosol
Continue to heat in the heating zone of inner cavity；Upward nitrogen swirling air stream, which is passed through, to heating zone simultaneously drives material rotation.Material exists
The residence time of heating zone is 70-90 seconds, and temperature is 1150-1250 DEG C when material falls to heating zone bottom.
In this step, Nitrogen ion body is transformed into nitrogen-atoms and nitrogen molecule.Ammonia is decomposed into hydrogen and nitrogen.Hydrogen and nitrogen
Abnormal active, hydrogen can be reacted with oxygen, play deoxidation.
3) react: material falls to reaction zone, while being passed through upward nitrogen swirling air stream to reaction zone and driving material rotation
Turn；Material is reacted at whereabouts generates silicon nitride, and 950-1000 DEG C is gradually cooled in dropping process, and material is in reaction zone
Residence time be 120-150 seconds.
4) heat preservation cooling: silicon nitride and unreacted nitrogen enter heat preservation cooler, and first material is cooled down with water cooling, then uses
Water cooling and air cooling cooling, finally use water-cooled cooling.
5) gas powder separates: carrying out gas powder separation to material, silicon nitride powder is packed, nitrogen recycling is utilized.
In the present invention, the reaction equation of beta-silicon nitride powder synthesis are as follows: 3Si+2N2=Si3N4+ heat.Its synthesis technology
Process are as follows: heating → reaction synthesis (heat release) → discharging.
The operation principle of the present invention is that: it applies a torch in suspension reactor boiler tube and heating zone is heated to about 1350-1400
Then nitrogen, silicon powder by preheating are passed through the heating zone of suspension reactor, in suspension by DEG C (nitrogen is protective gas) together
Powder absorbs furnace temperature and rises to about 1200 DEG C or so to reaction zone is fallen to, and reacts synthesizing silicon nitride, and side reaction, which becomes, falls simultaneously
Amount of heat is released, from the discharge hole for discharge of suspension reactor after reaction synthesis.
In above process, it needs to carry out the following simultaneously:
1, in order to promote to react, 1.3-1.5 kpa pressure is kept in furnace.
2, in heating zone in order to there is the sufficient time to absorb heat and fully reacting, it is necessary to powder be allowed to fall slowly.
3, synthetic reaction is that exothermic reaction needs to cool down to prevent exothermic heat of reaction temperature excessively high in reaction zone.
4, nitrogen becomes solid after nitrogen and silicon powder reaction synthesize and air pressure reduces, and needs to increase nitrogen pressure.
5, since reaction and heat release interweave together, powder is easy collision in whereabouts and generates reunion bulky grain.
Therefore, it is necessary to tonifying Qi, cooling, even temperature suspends, is pressurized, dispelling, and the present invention takes following method: in suspension reaction
The inner wall of device boiler tube is stitched equipped with air inlet, is stitched out from air inlet and is passed through supplement nitrogen, which is passed through in the form of swirling air stream, such as
This can blow afloat upwards silicon powder, so that silicon powder is suspended, while reaching tonifying Qi, cooling, samming, suspend, pressurization, increase the reaction time
Effect.
Preferably, the flow of nitrogen is 18-22cm in step 2)3/s；The flow of ammonia is 0.5-1cm3/s；Partial size is
The silicon powder of the 0.8-1.2vm amount of feeding is 1.2-1.8g/s；The residence time of silicon powder, ammonia, nitrogen in coil pipe is 50-60 seconds；Add
The pressure of hot-zone is 1.4-1.45 kPas.
Preferably, the flow of nitrogen swirling air stream is 10-15cm in step 2) and step 3)3/ s, pressure 1.45-1.5
KPa.
Preferably, in step 2), when Heating Zone Temperature reaches 1350-1400 DEG C, at the top of suspension reactor it is equal from
The power of sub- torch is down to 15-20 kilowatts and is used as heat preservation, and plasma is Nitrogen ion body, nitrogen flow 8-10cm3/s。
Preferably, material is first cooled to 700-750 DEG C with water cooling, time 60-70 second in step 4)；Water cooling is used again
500-550 DEG C is cooled to air cooling, time 90-120 second, 1-1.1 kPas of pressure；Finally with water-cooled cooling to 60 DEG C or less.
Preferably, gas powder disengaging time is 120-150 seconds, 0.5-1 kPas of pressure in step 5).
A kind of beta-silicon nitride powder production line, including feed unit, reaction member, receiving unit and recirculated water cooling unit.
The feed unit includes that silicon powder batch charging mechanism, nitrogen prepare supercharging device and microwave plasma preheater；It is described
Silicon powder batch charging mechanism prepares supercharging device with nitrogen and is connected to and provides respectively silicon powder and nitrogen with microwave plasma preheater respectively,
Nitrogen prepares supercharging device and is also connected to silicon powder batch charging mechanism as its supplying nitrogen to provide pressure.
The reaction member includes sequentially connected suspension reactor and heat preservation cooler；The microwave plasma preheater
It is connected to suspension reactor and provides silicon powder and nitrogen for it；The nitrogen prepares supercharging device and is connected to and mentions for it with heat preservation cooler
Nitrogen for cooling, heat preservation cooler are connected to respectively with silicon powder batch charging mechanism, microwave plasma preheater to recycle nitrogen again
Gas.
The receiving unit includes air powder splitter, wrapper and recycling nitrogen storage tank；The air powder splitter and heat preservation
Cooler is connected to, and the powder, gas in air powder splitter are delivered to the wrapper and recycling nitrogen storage tank respectively；The recycling
Nitrogen storage tank is connected to as its supplying nitrogen to provide pressure with silicon powder batch charging mechanism；Recycling nitrogen storage tank is also connect simultaneously with wrapper
It is provided for it and is packed for gas.
The recirculated water cooling unit includes water cooling pond and water cooling pump；The water cooling pond by the water cooling pump respectively with microwave
Plasma preheater, the heating device of suspension reactor, heat preservation cooler circulation loop connection.
The nitrogen prepare supercharging device also respectively with microwave plasma preheater, the heating device of suspension reactor and outstanding
The boiler tube of floating reactor connects and provides nitrogen.
The operation principle of the present invention is that: nitrogen prepares supercharging device and provides nitrogen raw material for microwave plasma preheater, together
When, nitrogen prepares supercharging device and also provides pressure for silicon powder batch charging mechanism, silicon powder is passed through in microwave plasma preheater,.?
Silicon powder and nitrogen after preheating, are passed through suspension reactor and are further heated and carried out instead in microwave plasma preheater
Synthesizing silicon nitride powder is answered, wherein nitrogen prepares supercharging device and provides nitrogen again for suspension reactor to supplement the nitrogen of consumption.
Reacting rear material, which enters in heat preservation cooler, to be kept the temperature, is cooled down.During this period, cold nitrogen and cold is led in Xiang Baowen cooler
But water.It wherein keeps the temperature the nitrogen in cooler after use and is passed into feed unit again to make full use of material.Last material into
Enter receiving unit, in air powder splitter, nitrogen is separated with silicon nitride, and beta-silicon nitride powder, which enters in wrapper, to be packed, system
Obtain finished product；And nitrogen enters recycling nitrogen storage tank, place to go has three: first is that the gas that is packed for as wrapper, second is that being silicon powder
The offer pressure of batch charging mechanism, third is that other work air valves use, gas recovery is made full use of.
In general, connection relationship design is reasonable, ingenious between each unit of the present invention, can be realized interaction, ingredient
Using energy and material, cost can be greatly reduced.
Preferably, the silicon powder batch charging mechanism include sequentially connected silicon powder feeding station, silicon powder feed bin, electric butterfly valve,
Screw rod feeder and silicon powder injector；The silicon powder injector is connected to microwave plasma preheater and provides silicon for it
Powder.
Preferably, the microwave plasma preheater include nitrogen pipeline, the first injector, microwave plasma torch,
Second injector, preheater shell and coil pipe.First injector is equipped with the silicon powder addition being connected to silicon powder batch charging mechanism
Mouthful, the feed end of the nitrogen pipeline prepares supercharging device with nitrogen respectively and heat preservation cooling device is connected to；Nitrogen pipeline goes out
Material end extends into the first injector, and the discharge end of the first injector is connect with the second injector；The microwave plasma fire
Torch is set in the second injector；The coil pipe is set in preheater shell, and the charging of the discharge end and coil pipe of the second injector
End connection, the discharge end of coil pipe extend outside preheater shell and connect with the suspension reactor；The nitrogen preparation pressurization
Device provides nitrogen for microwave plasma torch, and the water cooling pond connect cold to cool down with microwave plasma torch circulation loop
But.
The working principle of microwave plasma preheater of the present invention are as follows: prepare supercharging device through nitrogen and heat preservation cooler comes out
Nitrogen bring silicon powder into second injector through the first injector, the microwave plasma flame nitrogen plasma in the second injector
By the nitrogen in the second injector, silicon powder spirt coil pipe is passed through the jet pipe of suspension reactor from coil pipe.
The advantages of microwave plasma torch: 1, thermal power is high, energy conservation.2, its temperature is lower, with other plasma torch phases
Than, it is cooling without high-temperature water, therefore energy consumption is only 50% or less other plasma torches.3, the consumption of anode and cathode is not needed to change
Material.The main consumptive material of microwave is magnetron, and the service life was at 6000 hours or more, and general alternating current-direct current electric arc plasma torch about 200
Hour just needs to change electrode, and not only consumptive material is big but also influences production.4, the nitrogen of microwave plasma torch is as protective gas, etc.
Gas ions are nitrogen plasmas.Plasma torch, gas and powder are sprayed into coil pipe from the second injector, in flame and gas
Be reduced to set temperature with rear temperature, the nitrogen plasma in flame becomes nitrogen again, and nitrogen at this moment is very active, than other plus
The gas of hot mode is 10 times or more active.
The advantages of coil pipe is as follows: 1, preheating time is long, because silicon powder is of different sizes, internal and external temperature is uneven, other phases
The container intracavity of same volume is difficult to resolve certainly.2, solve expansion issues: coil pipe has elasticity, stretches after the expansion of coil pipe material to coil pipe space
Contracting, while solving sealing problem.3, inside pipe wall forms one layer of metal ceramics thin film (Nitriding of Steel Surface) in conjunction with nitrogen, nitridation
Metal surface afterwards is smooth, hardness is good, wear-resisting, high temperature resistant, increases service life.
Preferably, the pressure in first injector is less than the pressure in the second injector.It is so capable of forming negative
Pressure, so that material is continuously delivered in the second injector from the first injector.
Preferably, further include liquefied ammonia storage tank, the nitrogen tube on the liquefied ammonia storage tank and microwave plasma preheater
Road is connected to and provides liquefied ammonia for it.
The effect of liquefied ammonia storage tank is that a certain amount of liquefied ammonia can be mixed into nitrogen raw material, and liquefied ammonia is more than 800 DEG C or so
Nitrogen and hydrogen can be decomposed into.Wherein nitrogen can be used as raw material, and the effect of hydrogen can in gas, silicon powder
Oxygen, which reacts, produces water, to remove oxygen.The presence meeting of oxygen is so that oxidation reaction generation occurs at high temperature for silicon powder
Silica influences the purity of product, therefore should reduce the oxygen content in raw material as far as possible.
Preferably, the suspension reactor includes boiler tube, furnace shell, heating torch and jet pipe.The inner cavity of the boiler tube by
It is divided into heating zone and reaction zone under, the upper end of boiler tube is fixed with the heating torch of downward flame, under boiler tube
End is equipped with discharge port；The furnace shell is sheathed on outside boiler tube and is equipped with gap between boiler tube and furnace shell, is filled in the gap
Heat-preservation cotton；The jet pipe connect with the discharge end of microwave plasma preheater and wears furnace shell, boiler tube enters adding for boiler tube inner cavity
Hot-zone, and the end of jet pipe is equipped with nozzle, the nozzle is upward and below heating torch；The furnace shell enters equipped with nitrogen
Mouthful；A circle air inlet seam is equipped on the inner wall sustained height of boiler tube, it is oblique to boiler tube inner cavity that air inlet is sewn on vertical direction upper opening
On, air inlet is sewn on that horizontal plane upper opening is approximate with boiler tube inner wall curved surface or completely tangent and all openings are towards unanimously；The nitrogen
Gas, which prepares supercharging device and is connected to nitrogen inlet, provides nitrogen for it.
In suspension reactor of the present invention, the reaction equation of beta-silicon nitride powder synthesis are as follows: 3Si+2N2=Si3N4+ heat.
Its synthesis technology process are as follows: heating → reaction synthesis (heat release) → discharging.
The working principle of suspension reactor of the present invention are as follows: apply a torch in boiler tube and heating zone is heated to about 1400 DEG C of (nitrogen
Gas is protective gas), then nitrogen, the silicon powder by preheating are passed through are added to heating zone by jet pipe together, it will by nozzle
Gas powder sprays upwards, and in suspension powder absorption furnace temperature rises to about 1200 DEG C to reaction zone is fallen to, and reacts synthesizing silicon nitride, side
Reaction, which becomes, falls while releasing amount of heat, from discharge hole for discharge after reaction synthesis.
In above process, it needs to carry out the following simultaneously:
1, in order to promote to react, 1.3-1.5 kpa pressure is kept in furnace.
2, in heating zone in order to there is the sufficient time to absorb heat and fully reacting, it is necessary to powder be allowed to fall slowly.
3, synthetic reaction is that exothermic reaction needs to cool down to prevent exothermic heat of reaction temperature excessively high in reaction zone.
4, nitrogen becomes solid after nitrogen and silicon powder reaction synthesize and air pressure reduces, and needs to increase nitrogen pressure.
5, since reaction and heat release interweave together, powder is easy collision in whereabouts and generates reunion bulky grain.
Therefore, it is necessary to tonifying Qi, cooling, even temperature suspends, is pressurized, dispelling, and the present invention takes following method: in boiler tube
Wall sustained height is equipped with a circle air inlet seam, and air inlet is sewn on vertical direction upper opening to boiler tube inner cavity obliquely, and air inlet is sewn on water
Plane upper opening is approximate with boiler tube inner wall curved surface or completely tangent and all openings are towards unanimously.Nitrogen is passed through in nitrogen inlet simultaneously
Heat of the boiler tube radiation in heat-preservation cotton is stitched by air inlet and is sprayed into furnace by gas, nitrogen, logical from the air inlet seam for being located at heating zone
The nitrogen entered is passed through heating zone, forms swirling eddy and blows afloat silicon powder upwards, silicon powder is made to suspend, increases heating time, protect simultaneously
The heat of Wen Mianzhong takes back heating zone, realizes UTILIZATION OF VESIDUAL HEAT IN.The nitrogen being passed through from the air inlet seam for being located at reaction zone is passed through reaction zone,
It forms swirling eddy to blow afloat powder upwards, reaches tonifying Qi, cool down, samming suspends, pressurization, increases the reaction time, while will protect
The heat of warm cotton is taken back, and the heat dissipation of furnace shell is reduced, it is ensured that the high-purity of product, high fineness, high α phase (usual silicon nitride 1250
DEG C reaction is most fierce, and due to having pressure, the nitrogen of microwave plasma torch very active in reactor, this technique is 1150-
1200 DEG C, reaction is not likely to produce β phase when synthesizing).
Heat-preservation cotton can more effectively receive the radiations heat energy of boiler tube, make full use of to waste heat, while heat-preservation cotton will not
The circulation for stopping nitrogen, so that boiler tube inner cavity is identical as external pressure.
Preferably, being arranged with seal washer on the outer wall of the boiler tube, the seal washer is in heating zone and reaction
The joining place in area, and the gap seals between boiler tube and furnace shell are divided into two parts up and down by seal washer.
The heat-preservation cotton of heating zone and reaction zone is blocked with seal washer, effect is that torch is set to boiler tube upper end, heat
Amount is higher, therefore the heat-preservation cotton temperature for being located at heating zone is also higher, and the nitrogen of supplement can take back waste heat.And the heat preservation of lower section
Cotton temperature is lower, and in reaction zone it is desirable that heat release, therefore the higher upper section nitrogen of temperature should not be passed through the anti-of lower section
Answer area.
Preferably, being equipped with chamber neck in the boiler tube, the chamber neck is in the joining place of heating zone and reaction zone；Chamber neck
Upper end is in inverted cone-shaped, and the lower end of chamber neck is tapered in positive round.
Chamber neck is installed additional in the burner hearth upper half, forms heating zone and reaction zone, and heating zone hot gas in heating and thermal insulation circulates
The reduction of neck mouth flow is crossed, stops the too fast sinking of heat, plays heat insulation effect, makes to generate the temperature difference, sectional-regulated temperature up and down.
Further preferably, chamber neck uses the structure of thin-walled waisting, can reduce weight, slows down heat transfer.
Preferably, being equipped at least one layer of air inlet seam in the heating zone and reaction zone.
Preferably, the angle of the air inlet seam in the vertical direction obliquely is 30-50 degree.
Preferably, the air inlet, which is sewn on heating zone and reaction zone, is respectively equipped with 1 layer and 4 layers.
It is stitched in reaction zone setting multilayer air inlet, can be realized better eddy flow effect.
Preferably, the boiler tube is formed by multiple boiler tube unit vertical piles；The top of each boiler tube unit and
Bottom is respectively equipped with outer chamfer and inner chamfer, and the outer chamfer face is equipped with several equally distributed helicla flutes, multiple boiler tube lists
First vertical pile rear screw slot is stitched as the air inlet.
Preferably, the width of every helicla flute gradually broadens from outside to inside.
Gas outlet broadens, and the nitrogen entered in furnace can be promoted to collaborate the swirling eddy to be more, effect by pencil
More preferably.
Preferably, the heat preservation cooler include shell, the cooling inner casing of cooling coil and nitrogen, cooling nitrogen pipeline and
Nitrogen refrigerator；Its inner cavity is divided into upper and lower soaking zone and cooling section equipped with partition in the shell；The soaking zone is again
Be divided into twoth area up and down, the cooling inner casing of the nitrogen is set to area under the soaking zone in shell, the nitrogen prepare supercharging device with it is cold
But nitrogen pipeline connection provides nitrogen for it, and cooling nitrogen pipeline is connected to the cooling inner casing of nitrogen again, sets on cooling nitrogen pipeline
There is the nitrogen refrigerator, cooling nitrogen inner casing is also connected to microwave plasma preheater；The cooling coil from top to bottom divides
For three sections and it is respectively arranged in area on soaking zone, the cooling inner casing of nitrogen and cooling section, the upper end of cooling coil and suspension reactor
Discharge port connection, the discharge end of the lower end of cooling coil extends shell exterior；The bottom and top of shell be respectively equipped with into
The mouth of a river and water outlet, the partition are equipped with upper and lower outlet pass；The water cooling pond is connect with inlet and outlet respectively.
The principle of present invention heat preservation cooler are as follows: beta-silicon nitride powder and nitrogen enter the temperature of cooling coil from suspension reactor
About 950-1000 DEG C of degree, beta-silicon nitride powder at this temperature are easy to reunite, it is therefore desirable to which cooling heat preservation, the temperature of soaking zone are
700-750 DEG C, 250 DEG C of temperature difference or so.The cooling coil in area enters lower area after being cooled by water on soaking zone, and area is cold at present for this
But (unsuitable chilling, it is bad that chilling will lead to silicon nitride molecule pattern to about 500 DEG C of the temperature of coil pipe, and makes also not complete in material
The silicon powder and nitrogen of full response can not synthesizing silicon nitrides, it is therefore desirable to cool down stage by stage)；Lower area cooling water takes away partial heat,
Since summer and winter temperature round the clock is different, the temperature of recirculated cooling water is different, cannot stablize holding holding temperature, is further added by and freezed
Nitrogen adjusts holding temperature.Last beta-silicon nitride powder, which enters after cooling section further cools down, to discharge.Warm cooler comes out
Hot nitrogen send back in microwave plasma preheater and preheated again, take full advantage of waste heat and nitrogen resource, energy conservation and environmental protection.
Preferably, the quantity of nitrogen inlet is two on the furnace shell, it is located at the top and bottom of furnace shell；It is described
Cooler pan on lateral wall in heating zone and reaction zone on the discharge end of coil pipe, boiler tube and in the cooling inner casing of nitrogen
Temperature measuring point is respectively equipped on pipe；Form is respectively equipped on lateral wall in heating zone and reaction zone on the furnace shell；The furnace
The upper end of pipe and furnace shell is equipped with safe mouth；The outer wall of the furnace shell is equipped with pressure tap.
Temperature measuring point: for the temperature measuring point of coil pipe discharge end, the power of microwave plasma torch, control are controlled by temperature measuring point
Injector nitrogen flow and the flow for controlling silicon powder.For the temperature measuring point of suspension reactor, temperature is controlled by temperature measuring point,
If temperature is excessively high: the air inflow for reducing plasma torch power, increasing nitrogen inlet.If temperature is too low: increasing plasma torch
Power, the air inflow for reducing nitrogen inlet and jet pipe.For the temperature measuring point on cooling coil, the stream of recirculated cooling water can control
The temperature of amount and refrigeration nitrogen.
Pressure tap: the flow and pressure of the nitrogen of each nitrogen inlet are controlled by pressure tap.Due to the presence of air inlet seam, furnace
The interior air pressure between heat-preservation cotton is identical, heat-preservation cotton outer wall low temperature, no dust, and measuring cell device is not easy to failure.
Form: the form by being located at heating zone can observe flame and powder sprays；By the form for being located at reaction zone
It being capable of observing response.
Preferably, the nozzle is spiral nozzle；The heating torch is plasma torch；The boiler tube is graphite material
Matter；The coil pipe, the inner cavity of preheater shell and cooling coil are high-temperature alloy material；The shell and the cooling inner casing of nitrogen
For aluminum alloy material.
Gas powder can be formed upward umbrella shape mist and spray into heating zone by spiral nozzle, can increase the heating surface area of raw material,
Be conducive to material to be heated and react.
Furnace tube material is graphite, benefit are as follows:
1, graphite-pipe is thermally conductive fast, and wall internal-external temperature difference is no more than 1 DEG C, therefore can use contactless survey in tube skin
Temperature, so that the temperature measuring device service life is long, precision is high.
2, using high-density graphite pipe, high temperature resistant, it is thermally conductive it is good, conductive, thermal expansion coefficient is small, not due to expansion in exit orifice it is wrong
Position causes stuff-spraying pipe to fracture.
3, silicon powder is easy because rubbing, colliding and generate electrostatic in feeding, preheating, feeding, sprinkling, powder charge transfer
To boiler tube, continuous production static focus boiler tube sets off an explosion, is grounded by connecting wire.
Preferably, the nitrogen pipeline of the cooling nitrogen pipeline and microwave plasma preheater is respectively and in nitrogen cooling
The top of shell, bottom connection, and cooling nitrogen pipeline and nitrogen pipeline are located at the opposite side of the cooling inner casing of nitrogen.
Cooling nitrogen pipeline and nitrogen pipeline are respectively arranged on top, bottom and opposite side, nitrogen is exchanged
The heat of beta-silicon nitride powder is obtained, and the higher nitrogen of temperature is fed into microwave plasma preheater.
It is compared with the prior art, the beneficial effects of the present invention are:
1, use plasma torch as reacting under heating source micro-positive pressure, reaction temperature is reduced than other direct nitridation methods
50-100℃.Temperature is adjusted using spiral air flow in exothermic heat of reaction process, it is ensured that fully reacting, it is ensured that β phase is not generated, point
The pattern of son crystallization is advantageous to sintered article, and sintering activity is very good, ensure that the high-quality and stabilization of product.
2, the present invention realizes flowing water consecutive production, centralized control, high degree of automation.
3, beta-silicon nitride powder high-purity made from production line of the present invention, ultra-fine, high α phase (close to chemical reaction method), high yield
It measures, produce fast (from powder is dosed into out about 30 minutes, no grinding is classified link, and packaging is entered after discharging).
4, low consumption, pollution-free, few investment, low cost.
5, safe and clean, energy-saving and environmental protection.
6, it is difficult that domestic direct nitridation method temperature control hardly possible, smashing and grinding are solved.
7, production line of the present invention and main indicator ratio in the industry, quality improve 10%, and direct cost reduces by 40%, and power consumption reduces
3/4ths, the investment of same production capacity reduces 3/4ths.
Detailed description of the invention
Fig. 1 is a kind of integrated connection schematic diagram of the invention；
Fig. 2 is partial structural diagram of the invention；
Fig. 3 is a kind of structural schematic diagram of suspension reactor of the invention；
Fig. 4 is a kind of structural schematic diagram of air inlet seam in the boiler tube of suspension reactor of the present invention；
Fig. 5 is a kind of structural schematic diagram of boiler tube unit in suspension reactor of the present invention；
Fig. 6 is a kind of top view of boiler tube unit in suspension reactor of the present invention；
Fig. 7 is a kind of structural schematic diagram of helicla flute in suspension reactor of the present invention.
Appended drawing reference are as follows: boiler tube 1, furnace shell 2, heating torch 3, jet pipe 4, discharge port 5, nozzle 6, nitrogen inlet 7, air inlet seam
8, heat-preservation cotton 9, chamber neck 10, temperature measuring point 11, form 12, safe mouth 13, pressure tap 14, boiler tube unit 15, helicla flute 16, gasket
Enclose 17, heating zone A, reaction zone B, nitrogen pipeline 100, the first injector 101, microwave plasma torch 102, the second injector
103, the cooling inner casing 202 of preheater shell 104, coil pipe 105, silicon powder adding mouth 106, shell 200, cooling coil 201, nitrogen,
Cooling nitrogen pipeline 203, nitrogen refrigerator 204, partition 205, soaking zone 206, cooling section 207, water inlet 208, water outlet
209, upper and lower outlet pass 210, nitrogen prepare supercharging device 300, microwave plasma preheater 301, suspension reactor 302, heat preservation
Cooler 303, air powder splitter 304, wrapper 305, recycling nitrogen storage tank 306, water cooling pond 307, water cooling pump 308, silicon powder are thrown
Material station 309, silicon powder feed bin 310, electric butterfly valve 311, screw rod feeder 312, silicon powder injector 313, liquefied ammonia storage tank
314。
Specific embodiment
The present invention will be further described with reference to the examples below.
Total embodiment
A kind of preparation method of beta-silicon nitride powder, comprising the following steps:
1) equipment preheats: by the inner cavity of coil pipe and suspension reactor in microwave plasma preheater microwave plasma fire
Torch is separately heated to 800-850 DEG C and 1350-1400 DEG C.
2) material heat: respectively by silicon powder (purity 99.99%, feeding capacity 1.2-1.8g/s, partial size 0.8-1.2vm),
Ammonia (purity 99.999%, flow 0.5-1cm3/ s), nitrogen (purity 99.999%, flow 18-22cm3/ s) mixture is logical
Enter mixing in the coil pipe of microwave plasma preheater and is preheated to 700-750 DEG C.The mixture of silicon powder and ammonia, nitrogen are in coil pipe
Residence time be 50-60 seconds.Then material is passed through suspension reactor in the form of upward injection forms inverted conical shape aerosol
Continue to heat in the heating zone of inner cavity；Upward nitrogen swirling air stream (flow 10-15cm is passed through to heating zone simultaneously3/ s, pressure
1.45-1.5 kPas of power) drive material rotation.Residence time of the material in heating zone is 70-90 seconds, and material falls to heating zone
Temperature is 1150-1250 DEG C when bottom, and the pressure of heating zone is 1.4-1.45 kPas.When Heating Zone Temperature reaches 1350-1400
DEG C when, the power of the plasma torch at the top of suspension reactor is down to 15-20 kilowatts and is used as heat preservation, and plasma is Nitrogen ion
Body, nitrogen flow 8-10cm3/s。
3) react: material falls to reaction zone, while upward nitrogen swirling air stream (flow 10- is passed through to reaction zone
15cm3/ s, 1.45-1.5 kPas of pressure) drive material rotation；Material is reacted at whereabouts generates silicon nitride, and in dropping process
In be gradually cooled to 950-1000 DEG C, material is 120-150 seconds in the residence time of reaction zone.
4) heat preservation cooling: silicon nitride and unreacted nitrogen enter heat preservation cooler, are first cooled to material with water cooling
700-750 DEG C, time 60-70 second；500-550 DEG C is cooled to water cooling and air cooling again, time 90-120 second, pressure 1-1.1 thousand
Pa；Finally with water-cooled cooling to 60 DEG C or less.
5) gas powder separates: carrying out gas powder separation to material, gas powder disengaging time is 120-150 seconds, 0.5-1 kPas of pressure.
Then silicon nitride powder is packed, nitrogen recycling is utilized.
Embodiment 1
A kind of preparation method of beta-silicon nitride powder, comprising the following steps:
1) equipment preheats: by the inner cavity of coil pipe and suspension reactor in microwave plasma preheater microwave plasma fire
Torch is separately heated to 825 DEG C or so and 1375 DEG C or so.
2) material heats: respectively by silicon powder (purity 99.99%, feeding about 1.5g/s, partial size are 1vm or so) and ammonia
(purity 99.999%, flow 0.75cm3/ s), nitrogen (purity 99.999%, flow 20cm3/ s) it is passed through microwave plasma
Mixing is preheated to 725 DEG C or so in the coil pipe of preheater.The residence time of the mixture of silicon powder and ammonia, nitrogen in coil pipe is
55 seconds or so.Then material is passed through to the heating zone of suspension reactor inner cavity in the form of upward injection forms inverted conical shape aerosol
Inside continue to heat；Upward nitrogen swirling air stream (flow 12.5cm is passed through to heating zone simultaneously3/ s or so, pressure maintains
1.45-1.5 kPas) drive material rotation.Residence time of the material in heating zone is 80 seconds or so, and material falls to heating zone bottom
Temperature is 1200 DEG C or so when portion, and the pressure of heating zone maintains 1.4-1.45 kPas.When Heating Zone Temperature reaches 1375 DEG C of left sides
When right, the power of the plasma torch at the top of suspension reactor be down to 15-20 kilowatts of section be used as heat preservation, plasma for nitrogen from
Daughter, nitrogen flow 9cm3/s。
3) react: material falls to reaction zone, while to reaction zone being passed through upward nitrogen swirling air stream (flow is
12.5cm3/ s, pressure maintain 1.45-1.5 kPas) drive material rotation；Material is reacted at whereabouts generates silicon nitride, and
975 DEG C or so are gradually cooled in dropping process, material is 135 seconds in the residence time of reaction zone.
4) heat preservation cooling: silicon nitride and unreacted nitrogen enter heat preservation cooler, and material is first cooled to 725 with water cooling
DEG C or so, the time 65 seconds；525 DEG C or so are cooled to water cooling and air cooling again, the time 105 seconds, pressure maintained 1-1.1 kPas；
Finally with water-cooled cooling to 60 DEG C or less.
5) gas powder separates: carrying out gas powder separation to material, gas powder disengaging time is 135 seconds, and pressure maintains 0.5-1 thousand
Pa.Then silicon nitride powder is packed, nitrogen recycling is utilized.
As shown in Figure 1, a kind of beta-silicon nitride powder production line, including feed unit, reaction member, receiving unit and recirculated water
Cold unit.
The feed unit includes that silicon powder batch charging mechanism, nitrogen prepare supercharging device 300, microwave plasma preheater 301
With liquefied ammonia storage tank 314.The silicon powder batch charging mechanism prepares supercharging device with nitrogen and is connected to respectively with microwave plasma preheater
And silicon powder and nitrogen are provided respectively, nitrogen prepares supercharging device and is also connected to silicon powder batch charging mechanism as its supplying nitrogen to provide pressure
Power.
The reaction member includes sequentially connected suspension reactor 302 and heat preservation cooler 303；The microwave plasma
Preheater is connected to suspension reactor and provides silicon powder and nitrogen for it；The nitrogen prepares supercharging device and is connected to heat preservation cooler
Nitrogen for cooling is mentioned for it, heat preservation cooler is connected to respectively with silicon powder batch charging mechanism, microwave plasma preheater to recycle again
Utilize nitrogen.
The receiving unit includes air powder splitter 304, wrapper 305 and recycling nitrogen storage tank 306；The gas powder separation
Device is connected to heat preservation cooler, and the powder, gas in air powder splitter are delivered to the wrapper and recycling nitrogen storage tank respectively；
The recycling nitrogen storage tank is connected to as its supplying nitrogen to provide pressure with silicon powder batch charging mechanism；Recycle nitrogen storage tank also with packaging
Device, which is connected and provided for it, is packed for gas.
The recirculated water cooling unit includes water cooling pond 307 and water cooling pump 308；The water cooling pond is pumped by the water cooling to be distinguished
It is connect with microwave plasma preheater, the heating device of suspension reactor, heat preservation cooler circulation loop.
The nitrogen prepare supercharging device also respectively with microwave plasma preheater, the heating torch of suspension reactor and outstanding
The boiler tube of floating reactor connects and provides nitrogen.
Specifically:
As shown in Figure 1, the silicon powder batch charging mechanism includes sequentially connected silicon powder feeding station 309, silicon powder feed bin 310, electricity
Dynamic butterfly valve 311, screw rod feeder 312 and silicon powder injector 313；The silicon powder injector and microwave plasma preheater connect
Lead to and provides silicon powder for it.
As shown in Fig. 2, the microwave plasma preheater include nitrogen pipeline 100, the first injector 101, microwave etc. from
Sub- torch 102 (ceramic material), the second injector 103, preheater shell 104 and coil pipe 105.First injector is equipped with
The silicon powder adding mouth 106 being connected to silicon powder batch charging mechanism, the feed end of the nitrogen pipeline prepare supercharging device with nitrogen respectively
It is connected to heat preservation cooling device；The discharge end of nitrogen pipeline extends into the first injector, the discharge end of the first injector with
Second injector connects, and the pressure in the first injector is less than the pressure in the second injector.The microwave plasma torch is set
In in the second injector；The coil pipe is set in preheater shell, and the feed end of the discharge end of the second injector and coil pipe connects
It connects, thermal insulation medium is equipped between preheater shell and coil pipe, the discharge end of coil pipe extends outside preheater shell and hangs with described
Floating reactor connection.The nitrogen prepares supercharging device and provides nitrogen, the water cooling pond and microwave etc. for microwave plasma torch
Ion torch circulation loop is connected to cooling down.Nitrogen pipeline on the liquefied ammonia storage tank and microwave plasma preheater
It is connected to and provides liquefied ammonia for it.
As shown in figure 3, it is described include suspension reactor include boiler tube 1 (graphite boiler tube), furnace shell 2, heating torch 3 (wait from
Sub- torch) and jet pipe 4.The inner cavity of the boiler tube is from top to bottom divided into heating zone A and reaction zone B, and the upper end of boiler tube is fixed
There is the heating torch of downward flame, the lower end of boiler tube is equipped with discharge port 5.Chamber neck 10 is equipped in boiler tube, the chamber neck is in
The joining place of heating zone and reaction zone；The upper end of chamber neck is in inverted cone-shaped, and the lower end of chamber neck is tapered in positive round.The furnace shell is arranged
Gap is equipped with outside boiler tube and between boiler tube and furnace shell, gap is filled with heat-preservation cotton 9.Sealing is arranged on the outer wall of boiler tube
Washer 17, the seal washer is in the joining place of heating zone and reaction zone, and seal washer will be between boiler tube and furnace shell
Gap seals are divided into two parts up and down.It is described furnace shell is connect and worn with the discharge end of coil pipe, boiler tube enters boiler tube inner cavity
Heating zone, and the end of jet pipe be equipped with nozzle 6 (spiral nozzle), the nozzle upward and be located at heating torch below；It is described
Furnace shell is equipped with nitrogen inlet 7；A circle air inlet seam 8 is equipped on the inner wall sustained height of boiler tube (on heating zone and reaction zone
It is respectively equipped with 1 layer and 4 layers), air inlet is sewn on 45 degree of vertical direction upper opening angular boiler tube inner cavities obliquely (as shown in Figure 4), into
Air cleft is open and all openings tangent with boiler tube inner wall curved surface towards unanimously in the horizontal plane.The nitrogen prepare supercharging device with
Nitrogen inlet connection provides nitrogen for it.
As shown in Fig. 2, the heat preservation cooler includes the cooling inner casing 202 of shell 200, cooling coil 201 and nitrogen, cooling
Nitrogen pipeline 203 and nitrogen refrigerator 204.Its inner cavity is divided into upper and lower soaking zone 206 equipped with partition 205 in the shell
With cooling section 207；The soaking zone is divided into twoth area up and down again, and the cooling inner casing of the nitrogen is set to area under the soaking zone in shell,
The nitrogen, which prepares supercharging device and be connected to cooling nitrogen pipeline, provides nitrogen for it, cooling nitrogen pipeline again and nitrogen it is cooling in
Shell connection, cooling nitrogen pipeline are equipped with the nitrogen refrigerator, nitrogen of the cooling nitrogen inner casing also with microwave plasma preheater
The nitrogen pipeline of feed channel connection, cooling nitrogen pipeline and microwave plasma preheater respectively with the top of the cooling inner casing of nitrogen,
Bottom connection, and cooling nitrogen pipeline and nitrogen pipeline are located at the opposite side of the cooling inner casing of nitrogen.The cooling coil by up to
Under be divided into three sections and be respectively arranged in area on soaking zone, the cooling inner casing of nitrogen and cooling section, the upper end of cooling coil and boiler tube
Discharge port connection, the discharge end of the lower end of cooling coil extend shell exterior；The bottom and top of shell are respectively equipped with into water
Mouth 208 and water outlet 209, the partition are equipped with upper and lower outlet pass 210.The water cooling pond connects with inlet and outlet respectively
It connects.
Wherein, the quantity of nitrogen inlet is two on the furnace shell, is located at the top and bottom of furnace shell；The coil pipe
Discharge end, on the lateral wall in heating zone and reaction zone on boiler tube and on the cooling coil in the cooling inner casing of nitrogen
It is respectively equipped with temperature measuring point 11；Form 12 is respectively equipped on lateral wall in heating zone and reaction zone on the furnace shell；The furnace
The upper end of pipe and furnace shell is equipped with safe mouth 13；The outer wall of the furnace shell is equipped with pressure tap 14.The coil pipe, preheater shell
Inner cavity and cooling coil are high-temperature alloy material；The shell and the cooling inner casing of nitrogen are aluminum alloy material.
As shown in Figure 5, Figure 6, the boiler tube is formed by multiple 15 vertical piles of boiler tube unit；Each boiler tube unit
Top and bottom are respectively equipped with outer chamfer (45 degree) and inner chamfer (45 degree), and the outer chamfer face is equipped with multiple equally distributed
Helicla flute 16 (as shown in fig. 7, a plurality of be uniformly distributed from outside to inside into 60 ° of angle sulculuses is opened up in outer chamfer circumferential plane), often
The width of helicla flute gradually broadens from outside to inside.Upper and lower two boiler tubes unit vertical pile rear screw slot becomes the air inlet
Seam.
Embodiment 2
A kind of preparation method of beta-silicon nitride powder, comprising the following steps:
1) equipment preheats: by the inner cavity of coil pipe and suspension reactor in microwave plasma preheater microwave plasma fire
Torch is separately heated to 800 DEG C or so and 1350 DEG C or so.
2) material heats: respectively by silicon powder (purity 99.99%, feeding capacity 1.8g/s, partial size are 0.8vm or so) and ammonia
(purity 99.999%, flow 0.5cm3/ s), nitrogen (purity 99.999%, flow 18cm3/ s) to be passed through microwave plasma pre-
Mixing is preheated to 700 DEG C or so in the coil pipe of hot device.The mixture of silicon powder and ammonia, residence time of the nitrogen in coil pipe are 50
Second or so.Then material is passed through in the heating zone of suspension reactor inner cavity in the form of upward injection forms inverted conical shape aerosol
Continue to heat；Upward nitrogen swirling air stream (flow 10cm is passed through to heating zone simultaneously3/ s or so, pressure maintains 1.45-
1.5 kPas) drive material rotation.Residence time of the material in heating zone is 70 seconds or so, when material falls to heating zone bottom
Temperature is 1150 DEG C or so, and the pressure of heating zone maintains 1.4-1.45 kPas.When Heating Zone Temperature reaches 1350 DEG C or so,
The power of plasma torch at the top of suspension reactor is down to 15-20 kilowatts of section and is used as heat preservation, and plasma is Nitrogen ion body,
Nitrogen flow is 8cm3/s。
3) react: material falls to reaction zone, while to reaction zone being passed through upward nitrogen swirling air stream (flow is
10cm3/ s, pressure maintain 1.45-1.5 kPas) drive material rotation；Material is reacted at whereabouts generates silicon nitride, and under
950 DEG C or so are gradually cooled to during falling, material is 120 seconds in the residence time of reaction zone.
4) heat preservation cooling: silicon nitride and unreacted nitrogen enter heat preservation cooler, and material is first cooled to 700 with water cooling
DEG C or so, the time 60 seconds；500 DEG C or so are cooled to water cooling and air cooling again, the time 90 seconds, pressure maintained 1-1.1 kPas；Most
Afterwards with water-cooled cooling to 60 DEG C or less.
5) gas powder separates: carrying out gas powder separation to material, gas powder disengaging time is 120 seconds, and pressure maintains 0.5-1 thousand
Pa.Then silicon nitride powder is packed, nitrogen recycling is utilized.
The production line of the present embodiment difference from example 1 is that: the air inlet seam is in the vertical direction obliquely
Angle be 30 degree.And air inlet is sewn on heating zone and reaction zone and is respectively equipped with 1 layer and 5 layers.
Embodiment 3
A kind of preparation method of beta-silicon nitride powder, comprising the following steps:
1) equipment preheats: by the inner cavity of coil pipe and suspension reactor in microwave plasma preheater microwave plasma fire
Torch is separately heated to 850 DEG C or so and 1400 DEG C or so.
2) material heats: respectively by silicon powder (purity 99.99%, feeding capacity 1.2g/s partial size are 1.2vm or so) and ammonia
(purity 99.999%, flow 1cm3/ s), nitrogen (purity 99.999%, flow 22cm3/ s) it is passed through microwave plasma preheating
Mixing is preheated to 750 DEG C or so in the coil pipe of device.The mixture of silicon powder and ammonia, residence time of the nitrogen in coil pipe are 60 seconds
Left and right.Then by material by it is upward injection form inverted conical shape aerosol in the form of be passed through suspension reactor inner cavity heating zone in after
Continuous heating；Upward nitrogen swirling air stream (flow 15cm is passed through to heating zone simultaneously3/ s or so, pressure maintains 1.45-
1.5 kPas) drive material rotation.Residence time of the material in heating zone is 90 seconds or so, when material falls to heating zone bottom
Temperature is 1250 DEG C or so, and the pressure of heating zone maintains 1.4-1.45 kPas.When Heating Zone Temperature reaches 1400 DEG C or so,
The power of plasma torch at the top of suspension reactor is down to 15-20 kilowatts of section and is used as heat preservation, and plasma is Nitrogen ion body,
Nitrogen flow is 10cm3/s。
3) react: material falls to reaction zone, while to reaction zone being passed through upward nitrogen swirling air stream (flow is
15cm3/ s, pressure maintain 1.45-1.5 kPas) drive material rotation；Material is reacted at whereabouts generates silicon nitride, and under
1000 DEG C or so are gradually cooled to during falling, material is 150 seconds in the residence time of reaction zone.
4) heat preservation cooling: silicon nitride and unreacted nitrogen enter heat preservation cooler, and material is first cooled to 750 with water cooling
DEG C or so, the time 70 seconds；550 DEG C or so are cooled to water cooling and air cooling again, the time 120 seconds, pressure maintained 1-1.1 kPas；
Finally with water-cooled cooling to 60 DEG C or less.
5) gas powder separates: carrying out gas powder separation to material, gas powder disengaging time is 150 seconds, and pressure maintains 0.5-1 thousand
Pa.Then silicon nitride powder is packed, nitrogen recycling is utilized.
The production line of the present embodiment difference from example 1 is that: the air inlet seam is in the vertical direction obliquely
Angle be 50 degree.And air inlet is sewn on heating zone and reaction zone and is respectively equipped with 1 layer and 3 layers.
Production line of the invention produces compared with main indicator in the industry
| Index | Colleague | This reactor | Compare |
| The electricity charge | 40000 yuan/ton | 10000 yuan/ton | Save 30,000 yuan/ton |
| Wage | 10000 yuan/ton | 0.5 ten thousand yuan/ton | Save 0.5 ten thousand yuan/ton |
| Consumptive material | 0.6 ten thousand yuan/ton | 0.1 ten thousand yuan/ton | Save 0.5 ten thousand yuan/ton |
| It is total | 5.6 ten thousand yuan/ton | 1.6 ten thousand yuan/ton | Save 40,000 yuan/ton |
| Purity | 98% | 99.5% | Mention office 1.5% |
| α phase | 90% | 97% | Improve 7% |
| Partial size | 0.7-1 microns | 0.5-0.7 microns | It is 0.2 micron small |
| Same investment yield 1: 5 | 1 | 5 | 5 times |
Raw materials used in the present invention, equipment is unless otherwise noted the common raw material, equipment of this field；In the present invention
Method therefor is unless otherwise noted the conventional method of this field.
The above is only presently preferred embodiments of the present invention, is not intended to limit the invention in any way, it is all according to the present invention
Technical spirit any simple modification, change and equivalent transformation to the above embodiments, still fall within the technology of the present invention side
The protection scope of case.
Claims (10)
1. a kind of preparation method of beta-silicon nitride powder, it is characterised in that the following steps are included:
1) equipment preheats: by the inner cavity of coil pipe and suspension reactor in microwave plasma preheater microwave plasma torch point
800-850 DEG C and 1350-1400 DEG C are not heated to it；
2) material heats: the mixture of silicon powder and ammonia, nitrogen being passed through in the coil pipe of microwave plasma preheater mix respectively
It is preheated to 700-750 DEG C, material is then passed through suspension reactor inner cavity in the form of upward injection forms inverted conical shape aerosol
Heating zone in continue to heat；Upward nitrogen swirling air stream, which is passed through, to heating zone simultaneously drives material rotation；Material is heating
The residence time in area is 70-90 seconds, and temperature is 1150-1250 DEG C when material falls to heating zone bottom；
3) react: material falls to reaction zone, while being passed through upward nitrogen swirling air stream to reaction zone and driving material rotation；Object
Material is reacted at whereabouts generates silicon nitride, and 950-1000 DEG C is gradually cooled in dropping process, and material stops reaction zone
Staying the time is 120-150 seconds；
4) heat preservation cooling: silicon nitride and unreacted nitrogen enter heat preservation cooler, first material are cooled down with water cooling, then use water cooling
Cool down with air cooling, finally uses water-cooled cooling；
5) gas powder separates: carrying out gas powder separation to material, silicon nitride powder is packed, nitrogen recycling is utilized.
2. a kind of preparation method of beta-silicon nitride powder as described in claim 1, which is characterized in that in step 2, the stream of nitrogen
Amount is 18-22cm3/s；The flow of ammonia is 0.5-1cm3/s；The silicon powder that partial size the is 0.8-1.2vm amount of feeding is 1.2-1.8g/s；Silicon
The residence time of powder, ammonia, nitrogen in coil pipe is 50-60 seconds；The pressure of heating zone is 1.4-1.45 kPas.
3. a kind of preparation method of beta-silicon nitride powder as described in claim 1, which is characterized in that in step 2 and step 3),
The flow of nitrogen swirling air stream is 10-15cm3/ s, 1.45-1.5 kPas of pressure.
4. a kind of preparation method of beta-silicon nitride powder as described in claim 1, which is characterized in that in step 2, work as heating zone
When temperature reaches 1350-1400 DEG C, the power of the plasma torch at the top of suspension reactor is down to 15-20 kilowatts and is used as heat preservation,
Plasma is Nitrogen ion body, nitrogen flow 8-10cm3/s。
5. a kind of preparation method of beta-silicon nitride powder as claimed in claim 1 or 3, which is characterized in that in step 4), first use water
It is cold that material is cooled to 700-750 DEG C, time 60-70 second；It is cooled to 500-550 DEG C with water cooling and air cooling again, time 90-120
Second, 1-1.1 kPas of pressure；Finally with water-cooled cooling to 60 DEG C or less.
6. a kind of preparation method of beta-silicon nitride powder as described in claim 1, which is characterized in that in step 5), the separation of gas powder
Time is 120-150 seconds, 0.5-1 kPas of pressure.
7. a kind of preparation method of beta-silicon nitride powder as described in claim 1, which is characterized in that the beta-silicon nitride powder passes through
Beta-silicon nitride powder production line is made, and beta-silicon nitride powder production line includes feed unit, reaction member, receiving unit and recirculated water cooling
Unit；
The feed unit includes that silicon powder batch charging mechanism, nitrogen prepare supercharging device (300) and microwave plasma preheater
(301)；The silicon powder batch charging mechanism and nitrogen prepare supercharging device and are connected to microwave plasma preheater and provide respectively respectively
Silicon powder and nitrogen, nitrogen prepare supercharging device and are also connected to silicon powder batch charging mechanism as its supplying nitrogen to provide pressure；
The microwave plasma preheater includes nitrogen pipeline (100), the first injector (101), microwave plasma torch
(102), the second injector (103), preheater shell (104), coil pipe (105) and liquefied ammonia storage tank (314)；First injection
Device is equipped with the silicon powder adding mouth (106) that is connected to silicon powder batch charging mechanism, the feed end of the nitrogen pipeline respectively with nitrogen system
Standby supercharging device, liquefied ammonia storage tank are connected to heat preservation cooling device；The discharge end of nitrogen pipeline extends into the first injector,
The discharge end of first injector is connect with the second injector；The microwave plasma torch is set in the second injector；The disk
Pipe is set in preheater shell, and the feed end of the discharge end of the second injector and coil pipe connects, and the discharge end of coil pipe extends
Preheater shell is outer and connect with the suspension reactor；The nitrogen prepares supercharging device and provides nitrogen for microwave plasma torch
Gas, the water cooling pond are connect with microwave plasma torch circulation loop to cooling down；
The reaction member includes sequentially connected suspension reactor (302) and heat preservation cooler (303)；The microwave plasma
Preheater is connected to suspension reactor and provides silicon powder and nitrogen for it；The nitrogen prepares supercharging device and is connected to heat preservation cooler
Nitrogen for cooling is mentioned for it, heat preservation cooler is connected to respectively with silicon powder batch charging mechanism, microwave plasma preheater to recycle again
Utilize nitrogen；
The suspension reactor includes boiler tube (1), furnace shell (2), heating torch (3) and jet pipe (4)；The inner cavity of the boiler tube is by upper
Heating zone (A) and reaction zone (B) are divided under, the upper end of boiler tube is fixed with the heating torch of downward flame, boiler tube
Lower end be equipped with discharge port (5)；The furnace shell is sheathed on boiler tube outside and is equipped with gap between boiler tube and furnace shell, in the gap
Filled with heat-preservation cotton (9)；The jet pipe connect with the discharge end of microwave plasma preheater and wears furnace shell, boiler tube enters boiler tube
The heating zone of inner cavity, and the end of jet pipe is equipped with nozzle (6), the nozzle is upward and below heating torch；The furnace shell
It is equipped with nitrogen inlet (7)；A circle air inlet seam (8) is equipped on the inner wall sustained height of boiler tube, air inlet is stitched in the vertical direction
It is open to boiler tube inner cavity obliquely, it is approximate with boiler tube inner wall curved surface or completely tangent and all open that air inlet is sewn on horizontal plane upper opening
Mouth is towards unanimously；The nitrogen, which prepares supercharging device and is connected to nitrogen inlet, provides nitrogen for it；
The heat preservation cooler includes shell (200), cooling coil (201) and nitrogen cooling inner casing (202), cooling nitrogen pipeline
(203) and nitrogen refrigerator (204)；Its inner cavity is divided into upper and lower soaking zone (206) equipped with partition (205) in the shell
With cooling section (207)；The soaking zone is divided into twoth area up and down again, and the cooling inner casing of the nitrogen is set under the soaking zone in shell
Area, the nitrogen, which prepares supercharging device and be connected to cooling nitrogen pipeline, provides nitrogen for it, cooling nitrogen pipeline and cold with nitrogen
But inner casing is connected to, and cooling nitrogen pipeline is equipped with the nitrogen refrigerator, cooling nitrogen inner casing also with microwave plasma preheater
Connection；The cooling coil is from top to bottom divided into three sections and is respectively arranged in area on soaking zone, the cooling inner casing of nitrogen and cooling section,
The upper end of cooling coil and the discharge port of suspension reactor connect, and the discharge end of the lower end of cooling coil extends shell exterior；
The bottom and top of shell are respectively equipped with water inlet (208) and water outlet (209), and the partition is equipped with upper and lower outlet pass
(210)；The water cooling pond is connect with inlet and outlet respectively；
The receiving unit includes air powder splitter (304), wrapper (305) and recycling nitrogen storage tank (306)；The gas powder point
It is connected to from device with heat preservation cooler, the powder, gas in air powder splitter are delivered to the wrapper and recycling nitrogen storage respectively
Tank；The recycling nitrogen storage tank is connected to as its supplying nitrogen to provide pressure with silicon powder batch charging mechanism；Recycle nitrogen storage tank also with
Wrapper, which is connected and provided for it, is packed for gas；
The recirculated water cooling unit includes water cooling pond (307) and water cooling pump (308)；The water cooling pond is pumped by the water cooling to be distinguished
It is connect with microwave plasma preheater, the heating device of suspension reactor, heat preservation cooler circulation loop.
8. a kind of preparation method of beta-silicon nitride powder as claimed in claim 7, which is characterized in that the silicon powder batch charging mechanism packet
Include sequentially connected silicon powder feeding station (309), silicon powder feed bin (310), electric butterfly valve (311), screw rod feeder (312) and
Silicon powder injector (313)；The silicon powder injector is connected to microwave plasma preheater and provides silicon powder for it.
9. a kind of preparation method of beta-silicon nitride powder as claimed in claim 7, which is characterized in that covered on the outer wall of the boiler tube
Equipped with seal washer (17), the seal washer is in the joining place of heating zone and reaction zone, and seal washer by boiler tube with
Gap seals between furnace shell are divided into two parts up and down；Chamber neck (10) are equipped in the boiler tube, the chamber neck is in heating
The joining place in area and reaction zone；The upper end of chamber neck is in inverted cone-shaped, and the lower end of chamber neck is tapered in positive round.
10. a kind of preparation method of beta-silicon nitride powder as claimed in claim 7, which is characterized in that in the heating zone and instead
Area is answered to be equipped at least one layer of air inlet seam；The angle of the air inlet seam in the vertical direction obliquely is 30-50 degree.
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| CN201810391846.0A CN108557780B (en) | 2018-04-27 | 2018-04-27 | A kind of preparation method of beta-silicon nitride powder |
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| CN201810391846.0A CN108557780B (en) | 2018-04-27 | 2018-04-27 | A kind of preparation method of beta-silicon nitride powder |
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| CN110282609B (en) * | 2019-06-10 | 2020-04-21 | 宁夏秦氏新材料有限公司 | Rotary kiln method nitride self-spreading synthesis equipment |
| CN110204342B (en) * | 2019-06-10 | 2020-06-30 | 宁夏秦氏新材料有限公司 | Preparation method of sedimentation type self-propagating aluminum nitride |
| CN110182771B (en) * | 2019-06-10 | 2020-07-03 | 宁夏秦氏新材料有限公司 | Method for synthesizing silicon nitride by rotary kiln method |
| CN112299385B (en) * | 2020-10-10 | 2021-05-07 | 浙江宇耀新材料有限公司 | Nano aluminum nitride powder synthesis production line |
| CN112299384B (en) * | 2020-10-10 | 2022-02-11 | 浙江宇耀新材料有限公司 | Nano aluminum nitride powder synthesis device based on aluminum gasification reaction |
| CN113003549B (en) | 2021-03-08 | 2021-10-15 | 昆明理工大学 | Fast preparation of beta-Si by gas-solid reaction3N4And method thereof |
| CN116768636B (en) * | 2023-06-06 | 2024-03-29 | 衡阳凯新特种材料科技有限公司 | Continuous nitriding method silicon nitride powder production line |
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