CN103395787B - Apparatus and preparation method for high purity silicon from silicon ore - Google Patents

Apparatus and preparation method for high purity silicon from silicon ore Download PDF

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CN103395787B
CN103395787B CN201310343089.7A CN201310343089A CN103395787B CN 103395787 B CN103395787 B CN 103395787B CN 201310343089 A CN201310343089 A CN 201310343089A CN 103395787 B CN103395787 B CN 103395787B
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silicon
ore
furnace
purity
refining
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CN103395787A (en
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罗学涛
赖惠先
黄柳青
卢成浩
方明
陈娟
李锦堂
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Xiamen University
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Abstract

The invention provides an apparatus and a preparation method for high purity silicon from silicon ore, which relates to a preparation method for high purity silicon. The apparatus is provided with a submerged arc furnace, an auxiliary electrode system and a directional solidification furnace, wherein the submerged arc furnace is provided with a main electrode, the auxiliary electrode system is provided with an auxiliary electrode, an insulation plate and a handcart, and the directional solidification furnace is provided with a water cooling device, an induction coil, a graphite crucible, an inflation hole, a gun body holder, an air exhaust hole, an infrared detector and a plasma gun. The preparation method comprises the following steps: mixing the silicon ore, oil coke and charcoal, allowing an obtained mixture to enter into the submerged arc furnace for heating and adding a slagging agent for slagging and refining; starting the power supply of the directional solidification furnace and the auxiliary electrode to allow a silicon liquid obtained after slagging and refining to flow into the crucible; opening the inflation hole and the air exhaust hole and introducing argon and water vapor into the directional solidification furnace; allowing the temperature of the silicon liquid to reach 1700 to 1800 DEG C; starting the plasma gun and carrying out melting on the surface of the silicon liquid; maintaining the surface temperature of the silicon liquid to be 1450 to 1520 DEG C; starting the water cooling device; and cooling a silicon ingot after completion of directional solidification so as to obtain high purity silicon.

Description

A kind of by silicon ore device preparing HIGH-PURITY SILICON and preparation method thereof
Technical field
The present invention relates to a kind of preparation method of HIGH-PURITY SILICON, especially relate to a kind of by silicon ore device preparing HIGH-PURITY SILICON and preparation method thereof.
Background technology
Because energy dilemma and traditional fossil energy are to the pollution of environment, for realizing Sustainable development, corresponding policy has all been put into effect to develop new forms of energy in countries in the world, adjustment energy consumption structure.And sun power is inexhaustible clean energy, and will 21 century be become solve the important means of energy problem and environmental problem because of advantages such as it is widely distributed, cleanliness without any pollution.
Solar cell comprises crystal silicon cell, hull cell, organic solar batteries, quantum dot array solar cell etc., and wherein, the solar cell of employing prepared by crystalline silicon, because of advantages such as its stable performance, life-span length, is the main product of current photovoltaic industry.For solar-grade polysilicon, at present, most widely used production technique is improved Siemens, and first this kind of technique be that silicon ore is obtained by carbon reduction the industrial silicon that purity is at least 2N, and then industrial silicon is generated SiHCl with hydrogen chloride gas precursor reactant under the high temperature of about 1400 DEG C 3(or SiCl 4), then through distilation, with high-purity H in Siemens reactor 2reduction obtains the high purity polycrystalline silicon that purity can reach 12N.So far the polysilicon in the whole world more than 80% is all by this explained hereafter.These class methods have many deficiencies and shortcoming, and such as initial investment is large, energy consumption is large, cost is high, the construction period is long, and intermediate product is poisonous, and a large amount of hazardous gas such as use liquid chlorine and hydrogen etc., exists environment and potential safety hazard.Therefore, the focal issue that novel low-cost solar level polysilicon production technology becomes industrial community and academia's concern is found.
In recent years, domestic and international many researchists are devoted to the research of producing solar-grade polysilicon by physical metallurgy method, the people such as Hiroyuki Baba as nippon company introduces the method that solar-grade polysilicon is prepared by the said firm: the Pure Silicon Metal (MG-Si) with 99.5% is raw material, with argon plasma oxidation except boron, vacuum electron beam dephosphorization, obtain the P type polysilicon that resistivity is 1.0 Ω/cm, then remove metallic impurity through the method for directional freeze, obtain the solar-grade polysilicon of 6N.Elkem company of Norway is by slag making acid washing method purifying polycrystalline silicon, the impurity such as liquid oxide removal B, P are added in the silicon liquid of melting, particle is ground into after solidifying, then remove the metallic impurity of particle surface with acid wash, then obtain silicon ingot through operations such as directional freezes in specially designed apparatus for directional solidification.
But, the main technique of current metallurgy method all has some limitations, as Chinese patent CN101585536 adopts industrial silica fume through ultrasonic and gas stirring and pickling process, remove the major impurity in the industrial silicon of surface exposure, then purify further via vacuum induction melting, the semicontinuous unidirectional solidification of three district's temperature controls, high vacuum electron beam melting and the semicontinuous unidirectional solidification of secondary three district temperature control, finally obtain polycrystal silicon ingot.Although this patent is carry out in a vacuum oven to follow-up operation from vacuum melting, but the silicon material putting into stove is the industrial silicon that silicon ore obtains after carbon reduction, in the process of reduction, also have a large amount of waste heats not directly to be applied, industrial silicon also will be pulverized and pickling by the later stage, this operation works under hard conditions, and energy consumption is large.Chinese patent CN101759187 proposes a kind of by reactor and catcher device dimerous.Wherein, reactor is made up of reductive agent reserve room and reaction chamber two portions.Catcher is made up of one-level catcher and second capture device, and control liquid Zn and 7N level silicon tetrachloride gas are 650 ~ 900 DEG C of reactions, and product is brought into catcher, and by collecting, the polysilicon vacuum obtained distills, directional freeze obtains solar-grade polysilicon.Although this method is the silicon tetrachloride that make use of the 7N level that Siemens Method silicon tetrachloride gas metallurgical level silicon tetrachloride gas obtains through distilation, the equipment requirements of this method is harsh, is unfavorable for the reduction of cost and the scale operation of polysilicon.
In addition, smelting process also has fused salt electrolysis process.The method is raw material with industrial silicon, adds halogenide fused salt, adds thermal electrolysis, and negative electrode is formed high-purity siliceous deposits.This method is having some superiority except B with except in P, and remove micro-metals in the degree of depth and acquire a certain degree of difficulty, the silicon of generation just need can reach the specification of quality of solar-grade polysilicon after refining, is purified to more than 5N very difficult.Fused salt electrolysis laboratory obtains certain success, but wants heavy industrialization to there is equipment and technologic difficulty.
To sum up, current processing method all Shortcomings, do not make good use of the waste heat in reducing and smelting process or are appear in different stations to carry out from some operation that industrial silicon is purified to the technique of solar-grade polysilicon, and scattered and disappeared a large amount of heats, increase energy consumption, thus add cost.
Summary of the invention
The object of the invention is the deficiency such as high energy consumption, poor efficiency for prior art, low cost and high efficiency a kind of by silicon ore device preparing HIGH-PURITY SILICON and preparation method thereof is provided.
The device preparing HIGH-PURITY SILICON by silicon ore of the present invention is provided with mineral hot furnace, supporting electrode system and directional solidification furnace;
Insulating brick is equipped with bottom described mineral hot furnace, mineral hot furnace side has the outlet of silicon liquid, the top of mineral hot furnace wall is provided with equally distributed 3 hollow main electrodes, 3 hollow main electrodes pass the top of mineral hot furnace wall, be provided with electrode clamping device between 3 hollow main electrodes and the top of mineral hot furnace wall, above electrode clamping device, be provided with liftable feed system;
Described supporting electrode system is provided with the walkie fork lift truck of supporting electrode, insulcrete and tape gripper, supporting electrode is located on the walkie fork lift truck of tape gripper, insulcrete is located between supporting electrode and the walkie fork lift truck of tape gripper, supporting electrode can move freely, and comes out of the stove for melting zone silicon liquid in mineral hot furnace and flows out the refining of silicon liquid;
Silicon liquid is accepted in the below that described directional solidification furnace freely can move on to out silicon mouth, and directional solidification furnace is provided with water cooling plant, water-cooling subbase, ruhmkorff coil, insulation quilt, plumbago crucible, viewport, aeration aperture, rifle body clamper, bell, aspirating hole, infrared detecting group and plasma gun; Water cooling plant is located in water-cooling subbase, and ruhmkorff coil is located on plumbago crucible outer wall, is provided with insulation quilt between plumbago crucible and ruhmkorff coil, and bell is located at plumbago crucible top, and viewport and infrared detecting group are located at bell top and are clamped plasma gun; Plasma gun is located on bell, is controlled to move up and down by rifle body clamper.
Prepared a method for HIGH-PURITY SILICON by silicon ore, adopt the described device being prepared HIGH-PURITY SILICON by silicon ore, comprise the following steps:
1) enter in stove from mineral hot furnace fire door after silicon ore, oil coke and charcoal being mixed, open 3 hollow main electrodes, raw material is heated, after reduction reaction terminates, closes 3 hollow main electrodes, stop heating, and add slag former from loading hopper, then open 3 hollow main electrode heating, after carrying out slag refining, close 3 hollow main electrodes again, silicon liquid leaves standstill;
2) open the power supply of the ruhmkorff coil of directional solidification furnace, preheating is carried out to plumbago crucible;
3) bell of directional solidification furnace is risen, open supporting electrode, the silicon liquid after slag refining is flowed out from the outlet of silicon liquid, in this process, supporting electrode system is carried out secondary arc refining to the silicon liquid flow through and produces high-temperature plasma, removes the impurity such as boron phosphorus further;
4) silicon liquid flows in plumbago crucible after secondary arc refining, when influx is 0.8 ~ 1.2t, stops the refining of supporting electrode system electric arc, blocks out silicon mouth, cover directional freeze bell simultaneously by silico briquette and wet SILICA FUME;
5) open aeration aperture and aspirating hole, in directional solidification furnace, pass into the mixed gas of argon gas and water vapour;
6) increase ruhmkorff coil power, make silicon liquid temp reach 1700 ~ 1800 DEG C;
7) open plasma gun, plasma melting is carried out to silicon liquid surface;
8) regulate ruhmkorff coil power, use plasma gun supplementary heating, maintain the temperature on silicon liquid surface at 1450 ~ 1520 DEG C;
9) open water device for cooling;
10), after directional freeze completes, silicon ingot furnace cooling, obtains HIGH-PURITY SILICON.
In step 1), the SiO in described silicon ore 2content can be 98% ~ 100%, and the granularity of silicon ore can be 50 ~ 100mm, and the carbon content of described oil coke and charcoal can be 25% ~ 100%, and the granularity of oil coke and charcoal can be 1 ~ 10mm; The mass ratio of silicon ore, oil coke and charcoal can be (2.8 ~ 3): (0.9 ~ 1.2): (0.1 ~ 0.3); The power of described mineral hot furnace can be 6300 ~ 12500kVA, and the temperature of described heating can be 1700 ~ 1900 DEG C, and the time of heating can be 3 ~ 4h; Described temperature of opening 3 hollow main electrode heating again can be 1600 ~ 1800 DEG C, and the time of described refining can be 0.2 ~ 0.8h;
Described slag former composition by mass percentage can be Na 2cO 3(40% ~ 60%): SiO 2(30% ~ 55%): NaF(5% ~ 25%) scum silica frost, disposablely evenly put into mineral hot furnace, the mass ratio of silicon ore and slag former can be (1 ~ 10): 2.
In step 2) in, the power of described ruhmkorff coil can be 360 ~ 750kW; The time of described preheating can be 0.2 ~ 0.7h.
In step 4), the capacity of described plumbago crucible can be 1.5 tons.
In step 5), the volume fraction of described mixed gas is argon gas: 98.5% ~ 100%, water vapour: 0 ~ 1.5%, described in pass into the mixed gas of argon gas and water vapour flow velocity can be 20 ~ 30L/h.
In step 7), the time of described melting can be 0.3 ~ 0.5h.
In step 9), ingress's water temperature of described water cooling plant can be 25 DEG C, and exit water temperature can be 35 ~ 45 DEG C, and flow velocity can be 10 ~ 15m 3/ h.
Obtained HIGH-PURITY SILICON silicon ingot is cut bottom and top impurity enriched part, measure the impurity content of different sites with ICP-MAS.
The invention provides a kind of by silicon ore device preparing HIGH-PURITY SILICON and preparation method thereof.Main device comprises mineral hot furnace and directional solidification furnace.Wherein, mineral hot furnace is provided with three main electrodes and a supporting electrode; Three main electrodes with loading hopper, for carbon reduction silicon ore and purification refining provide heat, simultaneously charging; Supporting electrode is used for further high-temperature electric arc refining, removes the impurity such as boron phosphorus.The composition of directional solidification furnace comprises ruhmkorff coil, plasma gun, insulation quilt, water-cooling subbase, infrared detecting group and adopts the plumbago crucible of spraying silicon nitride coating.Main points of the present invention are that, with silicon ore, oil coke and coke for raw material, the heat provided by three main electrodes carries out reduction reaction, obtains industrial silicon; Slag agent injected in silicon melting zone from three electrode cavity and carry out slag refining, the silicon liquid obtained is poured in the plumbago crucible of prior preheating and carries out directional freeze after the refining of supporting electrode high-temperature electric arc.Before directional freeze, removed the impurity such as boron phosphorus further by heating plasma, in directional freeze process, maintained the temperature of liquid level by heating plasma, finally obtain the high purity silicon ingot of 5.5 ~ 6N.The techniques such as the reduction of integrated silicon ore of the present invention, the slag refining of silicon liquid, electric arc refining, plasma oxidation, provide less energy-consumption, low cost, high efficiency production method and production equipment for preparing solar-grade polysilicon.
The present invention take silicon ore as raw material, retailoring is combined with purification refining, makes full use of reduction waste heat, overcomes the shortcoming of traditional method, decreases the energy consumption of pilot process.This is simple for process, can realize continuous prodution, be suitable for industrialization.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the mineral hot furnace of the embodiment of the present invention.
Fig. 2 is the schematic diagram of the supporting electrode system of the embodiment of the present invention.
Fig. 3 is the schematic diagram of the directional solidification furnace of the embodiment of the present invention.
In figs. 1 to 3, be respectively labeled as: 11-insulating brick; 12-mineral hot furnace wall; 13-oil coke, coke and silicon ore; 14-slag; 15-electrode clamping device; 16-feed system; 17-main electrode; 18-electrode contact; 19-silicon liquid exports; 21-supporting electrode; 22-insulcrete; The walkie fork lift truck of 23-tape gripper; 301-water cooling plant; 302-water-cooling subbase; 303-ruhmkorff coil; 304-insulation quilt; 305-plumbago crucible; 306-viewport; 307-rifle body clamper; 308-bell; 309-aeration aperture, aspirating hole; 310-infrared detecting group; 311-plasma gun; 312-silicon liquid; 313-silicon ingot.
Embodiment
Following examples will the present invention is further illustrated by reference to the accompanying drawings.
See Fig. 1 ~ 3, the device embodiment preparing HIGH-PURITY SILICON by silicon ore of the present invention is provided with mineral hot furnace, supporting electrode system and directional solidification furnace.
Insulating brick 11 is equipped with bottom described mineral hot furnace, mineral hot furnace side has silicon liquid outlet 19, the top of mineral hot furnace wall 12 is provided with equally distributed 3 hollow main electrodes 17,3 hollow main electrodes 17 pass the top of mineral hot furnace wall 12, be provided with electrode clamping device 15 between 3 hollow main electrodes 17 and the top of mineral hot furnace wall 12, above electrode clamping device 15, be provided with liftable feed system 16; In FIG, mark 13 is oil coke, coke and silicon ore, and 14 is slag, and 18 is electrode contact.
Described supporting electrode system is provided with the walkie fork lift truck 23 of supporting electrode 21, insulcrete 22 and tape gripper, supporting electrode 21 is located on the walkie fork lift truck 23 of tape gripper, insulcrete 22 is located between the walkie fork lift truck 23 of supporting electrode 21 and tape gripper, supporting electrode 21 can move freely, and comes out of the stove for melting zone silicon liquid in mineral hot furnace and flows out the refining of silicon liquid.
Silicon liquid 312 is accepted in the below that described directional solidification furnace freely can move on to out silicon mouth, and directional solidification furnace is provided with water cooling plant 301, water-cooling subbase 302, ruhmkorff coil 303, insulation quilt 304, plumbago crucible 305, viewport 306, aeration aperture, rifle body clamper 307, bell 308, aspirating hole 309, infrared detecting group 310 and plasma gun 311; Water cooling plant 301 is located in water-cooling subbase 302, ruhmkorff coil 303 is located on plumbago crucible 305 outer wall, insulation quilt 304 is provided with between plumbago crucible 305 and ruhmkorff coil 303, bell 308 is located at plumbago crucible 305 top, and viewport 306 and infrared detecting group 310 are located at bell 308 top and are clamped plasma gun 311; Plasma gun 311 is located on bell 308, is controlled to move up and down by rifle body clamper 307.In figure 3, marking 313 is silicon ingot.
Oil coke and the charcoal Homogeneous phase mixing of to be the silicon ore of 50 ~ 100mm and granularity by granularity be 1 ~ 10mm; Wherein, the SiO in silicon ore 2content is preferably 98% ~ 100%, and the carbon content of oil coke and charcoal is preferably 25% ~ 100%; The blending ratio of silicon ore, oil coke and charcoal is by weight (2.8 ~ 3): (0.9 ~ 1.2): (0.1 ~ 0.3).Evenly added in stove from mineral hot furnace fire door by the raw material mixed, stove power is 6300 ~ 12500kVA.Open three main electrodes to heat raw material, heating and temperature control is at 1700 ~ 1900 DEG C, and the hold-time controls after 3 ~ 4h, and reduction reaction terminates, and closes three main electrodes, stops heating.From loading hopper, add slag former, select the composition of slag former to be Na by mass percentage 2cO 3(40% ~ 60%): SiO 2(30% ~ 55%): NaF(5% ~ 25%), disposablely evenly put into stove, the weight ratio of silicon ore and slag former is (1 ~ 10): 2.Open three main electrode heating, keep furnace temperature to carry out slag refining between 1600 ~ 1800 DEG C, refining time is 0.2 ~ 0.8h; Close three main electrodes, silicon liquid time of repose controls at 0.2h, and slag silicon is separated.
Open the power supply of directional solidification furnace ruhmkorff coil, ruhmkorff coil power is 360 ~ 750kW, and carry out preheating to plumbago crucible, warm up time is located at 0.2 ~ 0.7h.Rise the bell of directional solidification furnace, open supporting electrode, the silicon liquid after slag refining is flowed out from the outlet of silicon liquid, in this process, supporting electrode system is carried out secondary arc refining to the silicon liquid flow through and produces high-temperature plasma, removes the impurity such as boron phosphorus further.Silicon liquid flows in plumbago crucible after secondary arc refining, when influx is 0.8 ~ 1.2t, stops the refining of supporting electrode system electric arc, blocks out silicon mouth by silico briquette and wet SILICA FUME.Meanwhile, directional freeze bell is covered.
Open aeration aperture, aspirating hole, in directional solidification furnace, pass into the mixed gas of argon gas and water vapour, volume fraction is argon gas: 98.5% ~ 100%, water vapour: 0 ~ 1.5%, and intake is 20 ~ 30L/h.Increase the power of ruhmkorff coil power supply, silicon liquid temp is reached between 1700 ~ 1800 DEG C.Open plasma gun, carry out plasma body refining to silicon liquid surface, refining time is 0.3 ~ 0.5h, then removes the impurity such as boron phosphorus further.Regulate ruhmkorff coil power, use plasma gun supplementary heating, maintain the temperature on silicon liquid surface between 1450 ~ 1520 DEG C.Open water device for cooling, ingress's water temperature is 25 DEG C, and between outlet temperature 35 ~ 45 DEG C, flow velocity is 10 ~ 15m 3/ h.
After directional freeze completes, silicon ingot 313 furnace cooling.Obtain silicon ingot cut bottom and top impurity enriched part, with ICP-MAS mensuration different sites impurity content.
Below provide specific embodiment:
Embodiment 1
Be the silicon ore of 50 ~ 100mm by 2t granularity, the charcoal Homogeneous phase mixing of 0.8t granularity to be the oil coke of 1 ~ 10mm and 0.2t granularity be 1 ~ 10mm; SiO wherein in silicon ore 2content is 98%, and the carbon content of oil coke and charcoal is 50%.Slag former add-on is 0.5t, and proportioning is Na 2cO 3(50%): SiO 2(30%): NaF(20%) refining slag agent (slag silicon ratio is 1: 2), carries out refining according to above-mentioned embodiment.Pass in directional solidification furnace volume fraction be 99% argon gas and volume fraction be the mixed gas of 1% water vapour, intake is 30L/h, with plasma body refined silicon liquid surface 0.5h.Ingress's temperature of water coolant is 25 DEG C, and spout temperature is 42 DEG C, and flow velocity is 10m 3/ h, setting rate 8mm/h.Cut silicon ingot head 10% afterbody 20%, detect the impurity content at upper, middle and lower three positions, silicon ingot center, the average content of P and B is respectively 0.09ppmw and 0.3ppmw, and the purity of polysilicon is 99.99952%.
Embodiment 2
By 2t silicon ore, 0.8t oil coke and 0.2t charcoal Homogeneous phase mixing; SiO wherein in silicon ore 2content is 98%, and the carbon content of oil coke and charcoal is 50%.Reduction temperature controls at 1800 DEG C, keeps 3h.The disposable Na adding 0.5t 2cO 3(55%): SiO 2(35%) slag refining 0.5h is carried out in: NaF(10%) refining slag agent (slag silicon ratio is 1: 2); Pass in directional solidification furnace volume fraction be 98.5% argon gas and volume fraction be the mixed gas of 1.5% water vapour, intake is 20L/h, plasma body refined silicon liquid surface 0.3h.Ingress's temperature of water coolant is 25 DEG C, and spout temperature is 38 DEG C, and flow velocity is 15m 3/ h, setting rate 25mm/h.Cut silicon ingot head 10% afterbody 20%, detect the impurity content of silicon ingot center upper, middle and lower, the average content of P and B is respectively 0.18ppmw and 0.35ppmw, and the purity of polysilicon is 99.99896%.
Embodiment 3
By 2t silicon ore, 0.8t oil coke and 0.2t charcoal Homogeneous phase mixing; SiO wherein in silicon ore 2content is 99%, and the carbon content of oil coke and charcoal is 50%.Reduction temperature controls at 1800 DEG C, keeps 3h.The disposable Na adding 1t 2cO 3(50%): SiO 2(30%) slag refining 0.5h is carried out in: NaF(20%) refining slag agent (slag silicon ratio is 1: 1); Pass in directional solidification furnace volume fraction be 99% argon gas and volume fraction be the mixed gas of 1% water vapour, intake is 20L/h, plasma body refined silicon liquid surface 0.5h.Ingress's temperature of water coolant is 25 DEG C, and spout temperature is 40 DEG C, and flow velocity is 12m 3/ h, setting rate 25mm/h.Cut silicon ingot head 10% afterbody 20%, detect the impurity content of silicon ingot center upper, middle and lower, the average content of P and B is respectively 0.13ppmw and 0.32ppmw, and the purity of polysilicon is 99.99925%.
Embodiment 4
By 2t silicon ore, 0.8t oil coke and 0.2t charcoal Homogeneous phase mixing; SiO wherein in silicon ore 2content is 99%, and the carbon content of oil coke and charcoal is 80%.Reduction temperature controls at 1900 DEG C, keeps 4h.The disposable Na adding 1t 2cO 3(55%): SiO 2(35%) slag refining 0.8h is carried out in: NaF(10%) refining slag agent (slag silicon ratio is 1: 1); Pass in directional solidification furnace volume fraction be 99% argon gas and volume fraction be the mixed gas of 1% water vapour, intake is 30L/h, plasma body refined silicon liquid surface 0.5h.Ingress's temperature of water coolant is 25 DEG C, and spout temperature is 43 DEG C, and flow velocity is 10m 3/ h, setting rate 8mm/h.Cut silicon ingot head 10% afterbody 20%, detect the impurity content at upper, middle and lower three positions, silicon ingot center, the average content of P and B is respectively 0.1ppmw and 0.28ppmw, and the purity of polysilicon is 99.999721%.
Embodiment 5
By 2t silicon ore, 0.8t oil coke and 0.2t charcoal Homogeneous phase mixing; SiO wherein in silicon ore 2content is 99%, and the carbon content of oil coke and charcoal is 80%.Reduction temperature controls at 1900 DEG C, keeps 4h.The disposable Na adding 2t 2cO 3(50%): SiO 2(30%) slag refining 0.8h is carried out in: NaF(20%) refining slag agent (slag silicon ratio is 2: 1); Pass in directional solidification furnace volume fraction be 98.5% argon gas and volume fraction be the mixed gas of 1.5% water vapour, intake is 20L/h, plasma body refined silicon liquid surface 0.3h.Ingress's temperature of water coolant is 25 DEG C, and spout temperature is 38 DEG C, and flow velocity is 15m 3/ h, setting rate 25mm/h.Cut silicon ingot head 10% afterbody 20%, detect the impurity content of silicon ingot center upper, middle and lower, the average content of P and B is respectively 0.15ppmw and 0.32ppmw, and the purity of polysilicon is 99.999101%.

Claims (10)

1. prepared a device for HIGH-PURITY SILICON by silicon ore, it is characterized in that being provided with mineral hot furnace, supporting electrode system and directional solidification furnace;
Insulating brick is equipped with bottom described mineral hot furnace, mineral hot furnace side has the outlet of silicon liquid, the top of mineral hot furnace wall is provided with equally distributed 3 hollow main electrodes, 3 hollow main electrodes pass the top of mineral hot furnace wall, be provided with electrode clamping device between 3 hollow main electrodes and the top of mineral hot furnace wall, above electrode clamping device, be provided with liftable feed system;
Described supporting electrode system is provided with the walkie fork lift truck of supporting electrode, insulcrete and tape gripper, supporting electrode is located on the walkie fork lift truck of tape gripper, insulcrete is located between supporting electrode and the walkie fork lift truck of tape gripper, supporting electrode can move freely, and comes out of the stove for melting zone silicon liquid in mineral hot furnace and flows out the refining of silicon liquid;
Silicon liquid is accepted in the below that described directional solidification furnace freely can move on to out silicon mouth, and directional solidification furnace is provided with water cooling plant, water-cooling subbase, ruhmkorff coil, insulation quilt, plumbago crucible, viewport, aeration aperture, rifle body clamper, bell, aspirating hole, infrared detecting group and plasma gun; Water cooling plant is located in water-cooling subbase, and ruhmkorff coil is located on plumbago crucible outer wall, is provided with insulation quilt between plumbago crucible and ruhmkorff coil, and bell is located at plumbago crucible top, and viewport and infrared detecting group are located at bell top and are clamped plasma gun; Plasma gun is located on bell, is controlled to move up and down by rifle body clamper.
2. prepared a method for HIGH-PURITY SILICON by silicon ore, it is characterized in that adopting the device being prepared HIGH-PURITY SILICON as claimed in claim 1 by silicon ore, said method comprising the steps of:
1) enter in stove from mineral hot furnace fire door after silicon ore, oil coke and charcoal being mixed, open 3 hollow main electrodes, raw material is heated, after reduction reaction terminates, closes 3 hollow main electrodes, stop heating, and add slag former from loading hopper, then open 3 hollow main electrode heating, after carrying out slag refining, close 3 hollow main electrodes again, silicon liquid leaves standstill;
2) open the power supply of the ruhmkorff coil of directional solidification furnace, preheating is carried out to plumbago crucible;
3) bell of directional solidification furnace is risen, open supporting electrode, the silicon liquid after slag refining is flowed out from the outlet of silicon liquid, in this process, supporting electrode system is carried out secondary arc refining to the silicon liquid flow through and produces high-temperature plasma, further removing boron impurities phosphorus;
4) silicon liquid flows in plumbago crucible after secondary arc refining, when influx is 0.8 ~ 1.2t, stops the refining of supporting electrode system electric arc, blocks out silicon mouth, cover directional freeze bell simultaneously by silico briquette and wet SILICA FUME;
5) open aeration aperture and aspirating hole, in directional solidification furnace, pass into the mixed gas of argon gas and water vapour;
6) increase ruhmkorff coil power, make silicon liquid temp reach 1700 ~ 1800 DEG C;
7) open plasma gun, plasma melting is carried out to silicon liquid surface;
8) regulate ruhmkorff coil power, use plasma gun supplementary heating, maintain the temperature on silicon liquid surface at 1450 ~ 1520 DEG C;
9) open water device for cooling;
10), after directional freeze completes, silicon ingot furnace cooling, obtains HIGH-PURITY SILICON.
3. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 1) in, the SiO in described silicon ore 2content is 98% ~ 100%, and the granularity of silicon ore is 50 ~ 100mm; The carbon content of described oil coke and charcoal is 25% ~ 100%, and the granularity of oil coke and charcoal can be 1 ~ 10mm.
4. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, it is characterized in that in step 1) in, the mass ratio of silicon ore, oil coke and charcoal can be (2.8 ~ 3): (0.9 ~ 1.2): (0.1 ~ 0.3).
5. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 1) in, the power of described mineral hot furnace is 6300 ~ 12500kVA, and the temperature of described heating is 1700 ~ 1900 DEG C, and the time of heating is 3 ~ 4h; Described temperature of opening 3 hollow main electrode heating again can be 1600 ~ 1800 DEG C, and the time of described refining can be 0.2 ~ 0.8h.
6. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 1) in, described slag former by mass percentage consist of Na 2cO 3(40% ~ 60%): SiO 2the scum silica frost of (30% ~ 55%): NaF (5% ~ 25%), disposablely evenly puts into mineral hot furnace, and the mass ratio of silicon ore and slag former can be (1 ~ 10): 2.
7. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 2) in, the power of described ruhmkorff coil is 360 ~ 750kW; The time of described preheating is 0.2 ~ 0.7h; In step 4) in, the capacity of described plumbago crucible is 1.5 tons.
8. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 5) in, described in pass into the mixed gas of argon gas and water vapour flow velocity be 20 ~ 30L/h.
9. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 7) in, the time of described melting is 0.3 ~ 0.5h.
10. a kind of method being prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 9) in, ingress's water temperature of described water cooling plant is 25 DEG C, and exit water temperature is 35 ~ 45 DEG C, and flow velocity is 10 ~ 15m 3/ h.
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