CN108557825A - A kind of method that low cost removes carbon, nitrogen impurity in polysilicon - Google Patents
A kind of method that low cost removes carbon, nitrogen impurity in polysilicon Download PDFInfo
- Publication number
- CN108557825A CN108557825A CN201810090754.9A CN201810090754A CN108557825A CN 108557825 A CN108557825 A CN 108557825A CN 201810090754 A CN201810090754 A CN 201810090754A CN 108557825 A CN108557825 A CN 108557825A
- Authority
- CN
- China
- Prior art keywords
- silicon
- melting
- electron gun
- carbon
- solidification
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/02—Silicon
- C01B33/037—Purification
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Silicon Compounds (AREA)
Abstract
The invention belongs to polycrystalline silicon smelting technical field, more particularly to the method for carbon, nitrogen impurity in a kind of low cost removal polysilicon.The present invention is by during electron-beam smelting, the higher edge skin material of oxygen content being added into raw material, the melting environment of oxidisability is built, makes the carbon dissolved in silicon, nitrogen be combined to form volatile oxidizing gas with oxygen, to be removed.Product carbon made from this method, nitrogen impurity removal effect are good, and have the characteristics that at low cost, purification efficiency is high.
Description
Technical field
The invention belongs to polycrystalline silicon smelting technical field, more particularly to carbon, nitrogen impurity in a kind of low cost removal polysilicon
Method.
Background technology
Solar-grade polysilicon is the main raw material(s) of photovoltaic industry, with the sustainable development of photovoltaic industry, to polysilicon
The demand of material is growing.China has become the maximum output state of polysilicon and demand state, and largely relies on import, and it is still necessary to expand
Big production scale.However, being reallocated by the impurity in preparation process and melting environment pollutes, the yield of polycrystalline silicon ingot casting
Less than 70%, ingot top region is rich in nitrogen impurity rich in carbon impurity, edge, can not directly utilize.The part silicon material is carried out
Purification, regains the polycrystalline silicon material of high-purity, realizes that the regeneration of silicon materials, economy and social effect are great.
After metallurgy method prepares the ingot casting process of solar-grade polysilicon, the yield of ingot casting is only 70%, top and
The ingot casting region of side nearly 30% has accumulated a large amount of SiC, Si3N4It is mingled with and metal impurities, the purity in these regions is only 3N
(99.9%).By preceding described, metal impurities have extremely effective purification mode at present.But for C, N and its generation is precipitated
SiC, Si3N4Nonmetal inclusion particle, due to the diversity in its source in various techniques, but also studying its distribution and going
Except there are certain difficulty, though achieving certain effect to the control of carbon, nitrogen impurity in traditional handicraft now, still cannot
Meet requirement of the higher quality solar cell to silicon materials, the also extremely difficult recycling of discarded tailing.
Existing method and shortcoming：
1, it filters
Filtering technique is mainly using ceramic sponge strainer, the polyethylene glycol and oil in divided silicon slurry material at room temperature
Dirt or the at high temperature SiC and Si in divided silicon tailing3N4Particulate Inclusion.When flowing through filter device containing the silicon liquid being mingled with,
Si3N4The main surface for being enriched in filter screen, and SiC is mainly attached to ceramic material surfaces in the hole in strainer, fills out simultaneously
Hole has been mended, particle has further been hindered and passes through strainer.The process of filtering is the process of a gradation in batches, be cannot achieve continuous
Production, and the particle only for grain size more than 10 μm has preferable separating effect, and the smaller Particulate Inclusion of grain size is detached
Inefficiency, and a large amount of silicon liquids are adhered in inner wall in the process, cause the loss of silicon material.
2, electromagnetism detaches
Electromagnetic separation technology is widely used in the nonmetal inclusion particle in separation metal bath now.Since silicon is melting
Conductivity under state differs larger compared with SiC, is considered as conductive melt.Therefore researcher considers to pass through electromagnetism in recent years
It detaches to realize that the separation of SiC particulate and Si in silicon tailing, domestic scholars have studied high frequency magnetic field, strong induced current in silicon
The centrifugation of SiC finds to apply after high-intensity magnetic field SiC due to the trend of the effect oriented melt edge enrichment of electromagnetic force.But
It studies the high frequency magnetic field using 50kHz or more, and current value greatly wastes the energy in 200A or more, separation process.
3, directional solidification
Since the directional solidification technique that polycrystalline silicon ingot or purifying furnace uses is molten with segregating to less than 1 impurity for segregation coefficient
Effect at the top of body.Since C the and N segregation coefficients in silicon are respectively less than 1.Make impurity segregation to molten by way of directional solidification
To have the function that C and N in divided silicon at the top of body.But due to the extremely weak mobility of melt in directional solidification furnace, although trip
From C and N can with solid liquid interface promote and segregate to final solidified region, but its supersaturation be precipitated particle phase SiC and
Si3N4The ingot casting being distributed widely in after solidification, cannot achieve the separation of particle and silicon.
Invention content
To solve the above problem of the existing technology, the present invention provides carbon, nitrogen in a kind of low cost removal polysilicon
The method of impurity.By during electron-beam smelting, the higher edge skin material of oxygen content being added into raw material, builds oxidisability
Melting environment makes the carbon dissolved in silicon, nitrogen be combined to form volatile oxidizing gas with oxygen, to be removed.The party
Product carbon made from method, nitrogen impurity removal effect are good, and have the characteristics that at low cost, purification efficiency is high.
To achieve the above object, the technical solution adopted by the present invention is as follows：It is a kind of low cost removal polysilicon in carbon, azepine
The method of matter, it is characterized in that：Include the following steps：
A. dispensing：Top skin that polysilicon is generated in ingot casting or purification process, edge skin material are as raw material, wherein top skin
SiC, Si are rich in material3N4Hard inclusions contain higher oxygen impurities in edge skin material, according to raw material proportioning formula calculate needed for
The quality of each section raw material：
In formula, n/m is the ratio of edge skin material and top blank, MO、MCAnd MNIt is the molal weight of oxygen, carbon, nitrogen respectively,
wOIt is the oxygen content in edge skin material, wCAnd wNIt is the content for pushing up carbon and nitrogen in cladding respectively；
B. it feeds：Silicon raw material is cleaned according to said ratio, after mixing, feed bin, melting kettle, feeding trolley are respectively charged into
In, with high-purity silicon material shop fixtures in solidification crucible；
C. pre- thermionic electron guns：After charging, electron beam furnace vacuumizes, and starts preheating 3 when vacuum degree is less than 0.5Pa
Electron gun, wherein 2 irradiate melting kettle electron gun, another 1 irradiates solidification crucible electron gun, preheats 20-40min, has preheated
Enter the melting silicon materials stage at rear；
D. melting silicon materials：The situation of change of vacuum degree is protected in the melting conditions and fusion process observed in window according to the observation
It demonstrate,proves vacuum and is less than 0.5Pa, gradually increase the electron gun power of 2 irradiation melting kettles to 300kW, single rifle is according to 10kW-30kW-
50kW-100kW-150kW-200kW-250kW -300kW increase monitor system, and power is kept to make silicon in melting kettle in 300kW
Material is completely melt, and starts to react with quartz sand；The electron gun power of irradiation solidification crucible is gradually increased to 250kW, according to
10kW-30kW-50kW-100kW-150kW-200kW-250kW increases monitor system, and power is kept to make solidification crucible in 250kW
The silicon material of interior shop fixtures is completely melt；
E. silicon material melting：The electron gun power of 2 irradiation melting kettles continues to keep 300kW melting silicon materials 10-60min；
F. silicon liquid is toppled over：The 2 of melting kettle will be irradiated to close electron gun, silicon liquid is toppled over, after the completion of toppling over, by another 1
The electron gun power for irradiating solidification crucible keeps 250kW；
G. after the completion of toppling over, feed bin valve is opened, then a certain amount of silicon raw material is added in melting kettle, irradiation solidification
The electron gun of crucible still keeps 250kW, in addition 2 the electron gun of irradiation melting kettle is carried out silicon again according to step C to step E
Expect that fusing, silicon material melting, silicon material toppling process, number of repetition are carried out according to the quality of required silicon ingot；
H. drop beam solidification：After melting, the electron gun for irradiating solidification crucible carries out drop beam solidification, takes silicon ingot after cooling
Go out.
The purity of high-purity silicon material is in 5N or more in the step B.
Beam is dropped in the step H and is solidified as 250kW-200kW-150kW-120kW -0, and interval is 5 minutes.
The present invention selects the top skin of polycrystalline silicon ingot casting/purification process generation, edge skin material as raw material, utilizes electron-beam smelting
The feature environment for building temperature and pressure-oxidisability, makes carbon, nitrogen be combined to form volatile substances with oxygen, to be evaporated
It removes, removes the significant effect of carbon, azepine prime element in silicon, and raw materials used have the advantages that low cost, industrial applications foreground
It is wide.
Specific implementation mode
The present invention is further described with reference to embodiments：
Embodiment 1
A kind of method that low cost removes carbon, nitrogen impurity in polysilicon, specifically includes following steps：
A. dispensing：Top skin that polysilicon is generated in ingot casting or purification process, edge skin material are as raw material, wherein top skin
SiC, Si are rich in material3N4Etc. hard inclusions, higher oxygen impurities are contained in edge skin material.Needed for the calculating of raw material proportioning formula
Each section raw material quality：
In formula, n/m is the ratio of edge skin material and top blank, MO、MCAnd MNIt is the molal weight of oxygen, carbon, nitrogen respectively,
wOIt is the oxygen content in edge skin material, wCAnd wNIt is the content for pushing up carbon and nitrogen in cladding respectively；
B. it feeds：Silicon raw material is cleaned according to said ratio, after mixing, feed bin, melting kettle, feeding trolley are respectively charged into
In.With high-purity silicon material shop fixtures in solidification crucible, the purity of high-purity silicon material is in 5N or more；
C. pre- thermionic electron guns：After charging, electron beam furnace vacuumizes, and starts preheating 3 when vacuum degree is less than 0.5Pa
Electron gun, wherein 2 irradiate melting kettle electron gun, another 1 irradiates solidification crucible electron gun, 20min is preheated, after the completion of preheating
Into the melting silicon materials stage；
D. melting silicon materials：The situation of change of vacuum degree is protected in the melting conditions and fusion process observed in window according to the observation
It demonstrate,proves vacuum and is less than 0.5Pa, gradually increase the electron gun power of 2 irradiation melting kettles to 300kW, according to 10kW-30kW-
50kW-100kW-150kW-200kW-250kW -300kW (single rifle) increase monitor system, and power is kept to make melting earthenware in 300kW
Silicon material is completely melt in crucible, and starts to react with quartz sand；The electron gun power of irradiation solidification crucible is gradually increased to 250kW,
Increase monitor system according to 10kW-30kW-50kW-100kW-150kW-200kW-250kW, power is kept to make solidification in 250kW
The silicon material of shop fixtures is completely melt in crucible；
E. silicon material melting：The electron gun power of 2 irradiation melting kettles continues to keep 300kW melting silicon materials 10min；
F. silicon liquid is toppled over：The 2 of melting kettle will be irradiated to close electron gun, silicon liquid is toppled over, after the completion of toppling over, by another 1
The electron gun power for irradiating solidification crucible keeps 250kW；
G. after the completion of toppling over, feed bin valve is opened, then a certain amount of silicon raw material is added in melting kettle, irradiation solidification
The electron gun of crucible still keeps 250kW, in addition 2 the electron gun of irradiation melting kettle is carried out silicon again according to step C to step E
Expect that fusing, silicon material melting, silicon material toppling process, number of repetition are carried out according to the quality of required silicon ingot；
H. drop beam solidification：After melting, the electron gun for irradiating solidification crucible carries out drop beam solidification, 250kW-200kW-
150kW-120kW -0 (interval 5 minutes), takes out silicon ingot after cooling.
Embodiment 2
Carbon in a kind of low cost removal polysilicon described in the present embodiment, nitrogen impurity each step of method and embodiment
Identical in 1, different technical parameters are：
1) step C electron guns preheat 30min；
2) melting silicon material 35min in step E.
Embodiment 3
Carbon in a kind of low cost removal polysilicon described in the present embodiment, nitrogen impurity each step of method and embodiment
Identical in 1, different technical parameters are：
1) step C electron guns preheat 40min；
2) melting silicon material 60min in step E.
Finally it should be noted that：The above embodiments are only used to illustrate the technical solution of the present invention., rather than its limitations；To the greatest extent
Present invention has been described in detail with reference to the aforementioned embodiments for pipe, it will be understood by those of ordinary skill in the art that：Its according to
So can with technical scheme described in the above embodiments is modified, either to which part or all technical features into
Row equivalent replacement；And these modifications or replacements, various embodiments of the present invention technology that it does not separate the essence of the corresponding technical solution
The range of scheme.
Claims (3)
1. a kind of method of carbon, nitrogen impurity in low cost removal polysilicon, it is characterized in that：Include the following steps：
A. dispensing：Top skin that polysilicon is generated in ingot casting or purification process, edge skin material are as raw material, wherein in the cladding of top
Rich in SiC, Si3N4Hard inclusions contain higher oxygen impurities in edge skin material, according to raw material proportioning formula calculate needed for each portion
Divide the quality of raw material：
In formula, n/m is the ratio of edge skin material and top blank, MO、MCAnd MNIt is the molal weight of oxygen, carbon, nitrogen, w respectivelyOIt is side
Oxygen content in cladding, wCAnd wNIt is the content for pushing up carbon and nitrogen in cladding respectively；
B. it feeds：Silicon raw material is cleaned according to said ratio, after mixing, is respectively charged into feed bin, melting kettle, feeding trolley,
With high-purity silicon material shop fixtures in solidification crucible；
C. pre- thermionic electron guns：After charging, electron beam furnace vacuumizes, and starts preheating 3 when vacuum degree is less than 0.5Pa electronics
Rifle, wherein 2 irradiate melting kettle electron gun, another 1 irradiates solidification crucible electron gun, 20-40min is preheated, after the completion of preheating
Into the melting silicon materials stage；
D. melting silicon materials：The situation of change of vacuum degree ensures true in the melting conditions and fusion process observed in window according to the observation
Sky is less than 0.5Pa, gradually increases the electron gun power of 2 irradiation melting kettles to 300kW, single rifle is according to 10kW-30kW-
50kW-100kW-150kW-200kW-250kW -300kW increase monitor system, and power is kept to make silicon in melting kettle in 300kW
Material is completely melt, and starts to react with quartz sand；The electron gun power of irradiation solidification crucible is gradually increased to 250kW, according to
10kW-30kW-50kW-100kW-150kW-200kW-250kW increases monitor system, and power is kept to make solidification crucible in 250kW
The silicon material of interior shop fixtures is completely melt；
E. silicon material melting：The electron gun power of 2 irradiation melting kettles continues to keep 300kW melting silicon materials 10-60min；
F. silicon liquid is toppled over：The 2 of melting kettle will be irradiated to close electron gun, silicon liquid is toppled over, after the completion of toppling over, by another 1 irradiation
The electron gun power of solidification crucible keeps 250kW；
G. after the completion of toppling over, feed bin valve is opened, then a certain amount of silicon raw material is added in melting kettle, irradiates solidification crucible
Electron gun still keep 250kW, in addition 2 the electron gun of irradiation melting kettle carried out silicon material again according to step C to step E melt
Change, silicon material melting, silicon material toppling process, number of repetition are carried out according to the quality of required silicon ingot；
H. drop beam solidification：After melting, the electron gun for irradiating solidification crucible carries out drop beam solidification, takes out silicon ingot after cooling.
2. the method for carbon, nitrogen impurity in a kind of low cost removal polysilicon according to claim 1, it is characterized in that：It is described
The purity of high-purity silicon material is in 5N or more in step B.
3. the method for carbon, nitrogen impurity in a kind of low cost removal polysilicon according to claim 1, it is characterized in that：It is described
Beam is dropped in step H and is solidified as 250kW-200kW-150kW-120kW -0, and interval is 5 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810090754.9A CN108557825B (en) | 2018-01-30 | 2018-01-30 | Method for removing carbon and nitrogen impurities in polycrystalline silicon at low cost |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810090754.9A CN108557825B (en) | 2018-01-30 | 2018-01-30 | Method for removing carbon and nitrogen impurities in polycrystalline silicon at low cost |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108557825A true CN108557825A (en) | 2018-09-21 |
| CN108557825B CN108557825B (en) | 2021-02-09 |
Family
ID=63530037
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810090754.9A Active CN108557825B (en) | 2018-01-30 | 2018-01-30 | Method for removing carbon and nitrogen impurities in polycrystalline silicon at low cost |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108557825B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2026814C1 (en) * | 1991-07-08 | 1995-01-20 | Иркутский филиал Всесоюзного научно-исследовательского и проектного института алюминиевой, магниевой и электродной промышленности | Method of high-pure silicon preparing |
| CN102992327A (en) * | 2012-12-17 | 2013-03-27 | 青岛隆盛晶硅科技有限公司 | Method and equipment for purifying polycrystalline silicon through solidification crucible rotary electron beam melting |
| CN104649276A (en) * | 2013-11-22 | 2015-05-27 | 青岛隆盛晶硅科技有限公司 | Method and device for efficient removal of impurity oxygen from polysilicon by electron beam melting |
| CN104651930A (en) * | 2013-11-22 | 2015-05-27 | 青岛隆盛晶硅科技有限公司 | Apparatus for preparing polysilicon through electron beam deoxygenation and preliminary ingot casting coupling, and method thereof |
| CN106894084A (en) * | 2017-01-16 | 2017-06-27 | 大工（青岛）新能源材料技术研究院有限公司 | A kind of method for changing electron beam purifying polycrystalline silicon solidification crucible shop fixtures mode |
| CN107055546A (en) * | 2017-01-16 | 2017-08-18 | 大工（青岛）新能源材料技术研究院有限公司 | A kind of method that electronic torch melting removes polycrystalline Impurity As in Si |
-
2018
- 2018-01-30 CN CN201810090754.9A patent/CN108557825B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2026814C1 (en) * | 1991-07-08 | 1995-01-20 | Иркутский филиал Всесоюзного научно-исследовательского и проектного института алюминиевой, магниевой и электродной промышленности | Method of high-pure silicon preparing |
| CN102992327A (en) * | 2012-12-17 | 2013-03-27 | 青岛隆盛晶硅科技有限公司 | Method and equipment for purifying polycrystalline silicon through solidification crucible rotary electron beam melting |
| CN104649276A (en) * | 2013-11-22 | 2015-05-27 | 青岛隆盛晶硅科技有限公司 | Method and device for efficient removal of impurity oxygen from polysilicon by electron beam melting |
| CN104651930A (en) * | 2013-11-22 | 2015-05-27 | 青岛隆盛晶硅科技有限公司 | Apparatus for preparing polysilicon through electron beam deoxygenation and preliminary ingot casting coupling, and method thereof |
| CN106894084A (en) * | 2017-01-16 | 2017-06-27 | 大工（青岛）新能源材料技术研究院有限公司 | A kind of method for changing electron beam purifying polycrystalline silicon solidification crucible shop fixtures mode |
| CN107055546A (en) * | 2017-01-16 | 2017-08-18 | 大工（青岛）新能源材料技术研究院有限公司 | A kind of method that electronic torch melting removes polycrystalline Impurity As in Si |
Non-Patent Citations (1)
| Title |
|---|
| SHIQIANG QIN: "SiC sedimentation and carbon migration in mc-si by electron beam melting with slow cooling pattern", 《MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108557825B (en) | 2021-02-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Liu et al. | Recycling high purity silicon from solar grade silicon cutting slurry waste by carbothermic reduction in the electric arc furnace | |
| CN101585536B (en) | Device and method for purifying solar energy level polysilicon | |
| US20120164055A1 (en) | Method of removal of impurities from silicon | |
| Yu et al. | Effect of electromagnetic stirring on the enrichment of primary silicon from Al–Si melt | |
| CN107572532A (en) | A kind of method of titanium silicon materials direct preparation of high-purity silicon and titanium silicon | |
| Yu et al. | Si purification by enrichment of primary Si in Al-Si melt | |
| JP4842701B2 (en) | Method for separating silicon carbide from silicon and apparatus used therefor | |
| CN102153088B (en) | Method for carrying out slagging, pickling and boron removal on metal silicon | |
| Li et al. | Recycling of silicon scraps by electron beam melting coupled with directional solidification and its mechanism of impurity removal | |
| CN105274619B (en) | It is a kind of to strengthen the method for removing boron in metallurgical grade silicon | |
| CN102139879A (en) | Method for purifying polysilicon by using silicon and tin alloy | |
| JPH0476925B2 (en) | ||
| JPH09165212A (en) | Production of silicone raw material powder for solar cell and silicone ingot for solar cell | |
| CN108101064B (en) | Method for separating hard impurities in silicon by temperature gradient | |
| CN108557825A (en) | A kind of method that low cost removes carbon, nitrogen impurity in polysilicon | |
| CN104860316B (en) | A kind of electron beam solidification crucible and the method for excluding metal impurities | |
| CN108128779A (en) | A kind of method of carbon, nitrogen impurity in removal polysilicon | |
| Li et al. | Slag refining for separation of SiC inclusions from Si | |
| Li et al. | Purification of metallurgical-grade silicon combining Sn–Si solvent refining with gas pressure filtration | |
| Meng et al. | Enrichment and separation behaviors of impurities from stripped copper wire with super-gravity fields | |
| Zou et al. | Recycling of silicon from waste PV diamond wire sawing silicon powders: A strategy of Na2CO3-assisted pressure-less sintering and acid leaching | |
| CN108328618B (en) | Method for separating hard inclusions in silicon by electromagnetic induction directional solidification | |
| CN114480864B (en) | Method for remelting, centrifugal and electroselection grading purification of aluminum-silicon-iron alloy | |
| Xiao et al. | Potential routes for recycling and reuse of silicon kerf | |
| TW201416457A (en) | Manufacturing method of high purity Au powder using drying method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |