CN101734632A - Production method of nano silicon nitride powders - Google Patents
Production method of nano silicon nitride powders Download PDFInfo
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- CN101734632A CN101734632A CN200910216671A CN200910216671A CN101734632A CN 101734632 A CN101734632 A CN 101734632A CN 200910216671 A CN200910216671 A CN 200910216671A CN 200910216671 A CN200910216671 A CN 200910216671A CN 101734632 A CN101734632 A CN 101734632A
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- silicon nitride
- ammonium chloride
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Abstract
The invention relates to a production method of nano silicon nitride powders, which solves the problems of low production efficiency, expensive material and low product yield of the conventional method. The production method comprises the following steps of: (1) adding solid silicon nitride, silane and liquid ammonia into a mixer, gasifying in the mixer, and then heating the gasified gas mixture to 1200-1400 DEG.C in the honeycombed graphite of an intermediate-frequency coil to generate the gas mixture of the silicon nitride powder and the ammonium chloride gas; (2) collecting the solid silicon nitride powder and the ammonium chloride mixed powder at the bottom part when the gas mixture passes through a cooler and a bag collecting device with an inner temperature of 100-250 DEG.C, and enabling the gases which go out of the upper part of the device and carry the residual ammonium chloride and silicon tetrachloride to enter the cooler for circular treatment; (3) keeping the collected solid silicon nitride powder and the ammonium chloride mixed powder in nitrogen protective atmosphere, firstly heating at the temperature of 450-500 DEG.C to remove ammonium chloride and preserving the temperature for 1-2 hours, and then preserving the temperature for 4-6h at the temperature of 1350-1380 DEG.C for carrying out a crystallization treatment to obtain nano silicon nitride powders.
Description
Technical field:
What the present invention relates to is the method that a kind of ceramic technology field produces silicon nitride powder, specifically is a kind of polysilicon by-product silicon tetrachloride (SiCl that utilizes
4) production nano-silicon nitride (Si
3N
4) method of powder.
Background technology:
Along with large-scale developing and utilizing of green energy resource sun power, the consumption of photovoltaic cell raw material polysilicon is increasing, and the polysilicon production capacity of China in the coming years becomes how much levels to increase with output situation will become global production of polysilicon big country very soon.Yet, when significantly improving the polysilicon production capacity, must cause the bottleneck that is treated as industry development of by-product silicon tetrachloride.The best enterprise of present domestic polysilicon process technology controlled levels, polysilicon per ton will produce the silicon tetrachloride about 15t, the controlled levels difference in addition reached more than 20 ton, according to existing projects under and awaiting construction, the polysilicon aggregated capacity of China in 2010 will be broken through 20,000 tons/year level, mean that the silicon tetrachloride that has 300,000 tons/year at least must handle.Silicon tetrachloride is as a kind of high-risk chemical waste; tissue there is intense stimulus; the people is suffocated; silicon tetrachloride is heated or meets the water decomposition heat release; can emit obnoxious flavour; meet water and then can generate hydrochloric acid, human body, buildings, equipment etc. are had very big harm, can not handle with common method.For this reason, the safety and the environmental issue of the by-product silicon tetrachloride of production of polysilicon become increasingly conspicuous, how the safe handling silicon tetrachloride become be related to polysilicon industry can the key of healthy development problem.
Physical strength is big under the silicon nitride ceramics high temperature, thermal shock resistance good, wear-resisting, corrosion-resistant, has better hot properties than refractory alloy, it is a kind of novel high-temperature structural material, be the at first material of making ceramic engine, it is acknowledged as one of the most rising high temperature resistant structure ceramics.The silicon nitride ceramics of processability excellence at first must be prepared excellent beta-silicon nitride powder.Silicon tetrachloride synthesizing silicon nitride powder has not only utilized polysilicon by-product silicon tetrachloride, and turns waste into wealth, and produces the silicon nitride ceramic with high added value.
Find through literature search prior art, publication number is that the Chinese patent of CN1051153 discloses with liquid silicon tetrachloride and the gaseous ammonia method as the raw material production silicon nitride powder, this method is carried out in a two-tube reactor, under the normal temperature it is reacted, generate diimine silicon and ammonia chloride, the product that obtains is heated up in nonoxidizing atmosphere, make byproduct ammonia chloride distillation volatilization, continue to heat up, make diimine silicon be decomposed into silicon nitride, be warming up to certain temperature again and be incubated for some time, make the amorphous silicon nitride phase inversion become the α phase silicon nitride.This method technical process complexity, the cost high yield is low, is reflected in the two-tube reactor to carry out, and is difficult to scale operation.Publication number is that the Chinese patent of CN1280955 discloses a kind of gas-phase synthesizing method for preparing superfine silicon nitride powder, taking the direct current plasma arc is that to finish gas phase in the closed reaction vessel of thermal source synthetic, the base-material that is adopted is silicon tetrachloride and ammonia, both are in 1: 1.5-1.9 ratio (injecting liquid weight ratio in the unit time) injecting reactor, it is synthetic to finish gas phase in reactor, and directly become solid-state micro mist by quenching in the free setting process, in the reactor by defeated power of regulation and control plasma generator and N
2, H
2Ratio stabilizing ion arc, and keep temperature of reaction between 1000 ℃-1500 ℃ is removed the Si of chloride impurity generation high-purity nano level through the micro mist of quenching refinement through heating aftertreatment (vacuum drying oven in 380-450 ℃)
3N
4Micro mist.This method using plasma heating process needs working gas N
2And H
2, the equipment enlarging difficulty, cost is higher; The silicon nitride powder is made crystallization and is handled; Too high ammonia/silicon tetrachloride ratio has caused the waste of ammonia, and ammonia/silicon tetrachloride compared when hanging down, and will reduce the synthetic ratio of silicon nitride again.Also find in the retrieval, publication number is that the Chinese patent of CN 1445161 also discloses a kind of technology of utilizing plasma chemical vapor phase process to prepare beta-silicon nitride powder, utilize DC arc plasma to be thermal source, the gas (N2, H2 and Ar) of electric arc of flowing through is rapidly heated to high temperature (4800-5000 ℃) and enters in the reactor, meanwhile through the SiCl of vaporizer heating evaporation
4And NH
3Gas also enters reactor, SiCl
4And NH
3Ratio be 1: 5-10 (unit time in inject liquid weight ratio), take place to decompose fast and Si
3N
4Building-up reactions, temperature is controlled at 1100-1400 ℃, is delivered in the cold environment back by air-flow then and is cooled down fast, realizes gas solid separation and obtains the unformed Si of nano level through cloth bag collection machine again
3N
4Powder has NH
4The unformed beta-silicon nitride powder process of Cl removes ammonium chloride and the high temperature phase inversion obtains Si
3N
4Powder; under ammonia or ammonia and the protection of nitrogen mixture body, at first in moderate oven, handle removal ammonium chloride through 500-600 ℃, and then 1400-1550 ℃ of processing of process in the High Temperature Furnaces Heating Apparatus; amorphous silicon nitride is transformed into alpha silicon nitride, input-output ratio position 4.5: 1.There is the deficiency of above-mentioned patent (publication number is CN1280955) equally in this method, and promptly the using plasma heating process needs working gas N
2, H
2And Ar, the equipment enlarging difficulty, cost is also higher; Too high ammonia/silicon tetrachloride is than (5-10: 1), caused the waste of ammonia.The input-output ratio height is difficult to carry out large-scale commercial production.
Summary of the invention:
It is few to the purpose of this invention is to provide a kind of cost of investment, the production efficiency height, and it is few to expend the raw material liquid nitrogen, silicon nitride yield height, input-output ratio is low, can implement the production method of the nano silicon nitride powders of large-scale commercial production.
The present invention is achieved in that
The production method of nano silicon nitride powders of the present invention, reacting by heating still are by the mixing tank of bottom, and the water cooler on top and intermediary intermediate frequency coil are formed, the cellular graphite of the inner installation of intermediate frequency coil, intermediate frequency coil heating graphite, the reactant gases heated cellular graphite of flowing through comprises the steps:
(1) in mixing tank, adds solid-state nitration silicon, silane and liquefied ammonia, the weight percent that adds is: silicon tetrachloride: liquefied ammonia=1: 1.15-1.35, silane is the 2-5% of silicon tetrachloride and liquefied ammonia gross weight, above-mentioned three kinds of materials gasify in mixing tank, the cellular graphite of mixed airflow after the gasification in intermediate frequency coil is heated to 1200-1400 ℃ and generates beta-silicon nitride powder and ammonium chloride gas mixture, silane plays catalyst action
(2) gas mixture that comes out from cellular graphite is through water cooler and bag collection equipment, temperature is 100-250 ℃ in the bag collection equipment, collect solid-state nitration silica flour and ammonium chloride powder mix from the bottom, ammonium chloride and the silicon tetrachloride of the gas entrainment remnants that go out from top enter the water cooler circular treatment
(3) with the silicon nitride powder received and ammonium chloride powder mix in nitrogen protection atmosphere; earlier add heat extraction ammonium chloride at 450-500 ℃, soaking time is 1-2 hour, then under 1350-1380 ℃ of temperature; be incubated 4-6 hour and carry out the crystallization processing, get nano silicon nitride powders.
Compared with prior art, the present invention utilizes silicon tetrachloride and liquefied ammonia as main raw material, and silane is made catalyzer, and reaction chamber adopts Frequency Induction Heating synthesizing silicon nitride powder.Main advantage of the present invention is: (1) heating in medium frequency, need not N2, H2 and Ar gas, and production unit is simple, and the production efficiency height is easy to large-scale commercial production.(2) in commercially available dust collection device, can collect silicon nitride and ammonium chloride mixed powder.Obtain the beta-silicon nitride powder of particle diameter less than 50 nanometers (nm); (3) input-output ratio is low, reaches 1.50-1.70: 1.Owing to utilize silane as catalyzer, silane is easy to and ammonia gas react than silicon tetrachloride, and the synthetic silicon nitride powder plays the crystal seed effect, has promoted the reaction of silicon tetrachloride and ammonia, has reduced the add-on of ammonia, can not reduce the synthetic ratio of silicon nitride.
Description of drawings:
Fig. 1 is a process flow sheet of the present invention.
Embodiment:
Below embodiments of the invention are elaborated: present embodiment is being to implement under the prerequisite with the technical solution of the present invention, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.
Embodiment 1:
Adopting silicon tetrachloride (content is greater than 99%) and liquefied ammonia (content is greater than 99%) is main raw material, silane (content is greater than 99%) is catalyzer, the gasification back feeds reactor, the weight percent of silicon tetrachloride, liquefied ammonia and silane is 0.8: 1: 0.05,1300 ℃ of Frequency Induction Heating temperature, sack cleaner are collected solid-state nitration silica flour and ammonium chloride powder mix from the bottom.Receive powder mix in nitrogen protection atmosphere, earlier add heat extraction ammonium chloride at 480 ℃, soaking time is 1.5 hours, then silicon nitride powder under 1380 ℃ of temperature, thermal treatment 6 hours.
The silicon nitride powder quality of preparation is: α-Si
3N
4Weight percent is 94.8%, and Fe element wt per-cent is 0.086%, and Cl element wt per-cent is 0.78%, and granularity D50 is 42nm.Input-output ratio 1.58: 1.
Embodiment 2:
Adopting silicon tetrachloride (content is greater than 99%) and liquefied ammonia (content is greater than 99%) is main raw material, silane (content is greater than 99%) is catalyzer, the gasification back feeds reactor, silicon tetrachloride, liquefied ammonia and silane weight percent are 0.85: 1: 0.08,1350 ℃ of Frequency Induction Heating temperature, sack cleaner are collected solid-state nitration silica flour and ammonium chloride powder mix from the bottom.Receive powder mix in nitrogen protection atmosphere, earlier add heat extraction ammonium chloride at 450 ℃, soaking time is 2 hours, then silicon nitride powder under 1360 ℃ of temperature, thermal treatment 5 hours.
The silicon nitride powder quality of preparation is: α-Si
3N
4Weight percent is 94.2%, and Fe element wt per-cent is 0.075%, and Cl element wt per-cent is 0.88%, and granularity D50 is 38nm.Input-output ratio 1.50: 1.
Embodiment 3:
Adopting silicon tetrachloride (content is greater than 99%) and liquefied ammonia (content is greater than 99%) is main raw material, silane (content is greater than 99%) is catalyzer, the gasification back feeds reactor, silicon tetrachloride, liquefied ammonia and silane weight percent are 0.75: 1: 0.06,1400 ℃ of Frequency Induction Heating temperature, sack cleaner are collected solid-state nitration silica flour and ammonium chloride powder mix from the bottom.Receive powder mix in nitrogen protection atmosphere, earlier add heat extraction ammonium chloride at 500 ℃, soaking time is 1 hour, then silicon nitride powder under 1350 ℃ of temperature, thermal treatment 4 hours.
The silicon nitride powder quality of preparation is: α-Si
3N
4Weight percent is 94.5%, and Fe element wt per-cent is 0.092%, and Cl element wt per-cent is 0.62%, and granularity D50 is 48nm.Input-output ratio 1.70: 1.
Claims (1)
1. the production method of nano silicon nitride powders, reacting by heating still are by the mixing tank of bottom, and the water cooler on top and intermediary intermediate frequency coil are formed, the cellular graphite of the inner installation of intermediate frequency coil, intermediate frequency coil heating graphite, the reactant gases heated cellular graphite of flowing through comprises the steps:
(1) in mixing tank, adds solid-state nitration silicon, silane and liquefied ammonia, the weight percent that adds is: silicon tetrachloride: liquefied ammonia=1: 1.15-1.35, silane is the 2-5% of silicon tetrachloride and liquefied ammonia gross weight, above-mentioned three kinds of materials gasify in mixing tank, the cellular graphite of mixed airflow after the gasification in intermediate frequency coil is heated to 1200-1400 ℃ and generates beta-silicon nitride powder and ammonium chloride gas mixture, silane plays catalyst action
(2) gas mixture that comes out from cellular graphite cools off and bag collection equipment through water cooler, temperature is 100-250 ℃ in the bag collection equipment, collect solid-state nitration silica flour and ammonium chloride powder mix from the bottom, ammonium chloride and the silicon tetrachloride of the gas entrainment remnants that go out from top enter the water cooler circular treatment
(3) with the silicon nitride powder received and ammonium chloride powder mix in nitrogen protection atmosphere; earlier add heat extraction ammonium chloride at 450-500 ℃, soaking time is 1-2 hour, then under 1350-1380 ℃ of temperature; be incubated 4-6 hour and carry out the crystallization processing, get nano silicon nitride powders.
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|---|---|---|---|
| CN2009102166710A CN101734632B (en) | 2009-12-10 | 2009-12-10 | Production method of nano silicon nitride powders |
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|---|---|---|---|
| CN2009102166710A CN101734632B (en) | 2009-12-10 | 2009-12-10 | Production method of nano silicon nitride powders |
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| CN101734632A true CN101734632A (en) | 2010-06-16 |
| CN101734632B CN101734632B (en) | 2011-10-05 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102491291A (en) * | 2011-12-14 | 2012-06-13 | 合肥摩凯新材料科技有限公司 | Method for preparing high-purity silicon nitride micro-nano powder |
| CN103072960A (en) * | 2012-10-15 | 2013-05-01 | 宁波广博纳米新材料股份有限公司 | Production method of nano silicon nitride powder |
| CN105253864A (en) * | 2015-11-13 | 2016-01-20 | 宁波盛优科技服务有限公司 | Silicon nitride powder preparation method |
| CN105776176A (en) * | 2016-02-25 | 2016-07-20 | 佛山市南海万兴材料科技有限公司 | Nano-carbon powder preparation device |
| CN115536394A (en) * | 2022-09-23 | 2022-12-30 | 华能核能技术研究院有限公司 | Preparation method of high-temperature gas cooled reactor absorption ball with silicon nitride coating |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5595605A (en) * | 1979-01-10 | 1980-07-21 | Toyo Soda Mfg Co Ltd | High purity silicon nitride and production thereof |
| CN1142089C (en) * | 1999-06-30 | 2004-03-17 | 刘庆昌 | Gas-phase synthesis process of superfine silicon nitride powder |
-
2009
- 2009-12-10 CN CN2009102166710A patent/CN101734632B/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102491291A (en) * | 2011-12-14 | 2012-06-13 | 合肥摩凯新材料科技有限公司 | Method for preparing high-purity silicon nitride micro-nano powder |
| CN103072960A (en) * | 2012-10-15 | 2013-05-01 | 宁波广博纳米新材料股份有限公司 | Production method of nano silicon nitride powder |
| CN103072960B (en) * | 2012-10-15 | 2015-06-17 | 宁波广博纳米新材料股份有限公司 | Production method of nano silicon nitride powder |
| CN105253864A (en) * | 2015-11-13 | 2016-01-20 | 宁波盛优科技服务有限公司 | Silicon nitride powder preparation method |
| CN105253864B (en) * | 2015-11-13 | 2017-07-11 | 宁夏胜蓝化工环保科技有限公司 | A kind of preparation method of beta-silicon nitride powder |
| CN105776176A (en) * | 2016-02-25 | 2016-07-20 | 佛山市南海万兴材料科技有限公司 | Nano-carbon powder preparation device |
| CN115536394A (en) * | 2022-09-23 | 2022-12-30 | 华能核能技术研究院有限公司 | Preparation method of high-temperature gas cooled reactor absorption ball with silicon nitride coating |
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| CN101734632B (en) | 2011-10-05 |
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