CN103395787A - 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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CN103395787A
CN103395787A CN2013103430897A CN201310343089A CN103395787A CN 103395787 A CN103395787 A CN 103395787A CN 2013103430897 A CN2013103430897 A CN 2013103430897A CN 201310343089 A CN201310343089 A CN 201310343089A CN 103395787 A CN103395787 A CN 103395787A
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silicon
ore
furnace
purity
refining
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CN103395787B (en
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罗学涛
赖慧先
黄柳青
卢成浩
方明
陈娟
李锦堂
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Xiamen University
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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 device that is prepared HIGH-PURITY SILICON by silicon ore 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 device that is prepared HIGH-PURITY SILICON by silicon ore and preparation method thereof.
Background technology
Due to the pollution to environment of energy dilemma and traditional fossil energy, for realizing Sustainable development, countries in the world have all been put into effect corresponding policy and have been developed new forms of energy, adjust energy consumption structure.And sun power is inexhaustible clean energy, and will become the important means that 21 century solves 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., wherein, adopts the prepared solar cell of crystalline silicon because of advantages such as its stable performance, life-span length, is the main product of present photovoltaic industry.For solar-grade polysilicon, at present, most widely used production technique is improved Siemens, and at first this class technique be that silicon ore is reduced and obtains the industrial silicon that purity is at least 2N by carbon, and then industrial silicon is generated to SiHCl with the hydrogen chloride gas precursor reactant under the high temperature of 1400 ℃ of left and right 3(or SiCl 4), then pass through distilation, in Siemens reactor with high-purity H 2Reduction obtains the high purity polycrystalline silicon that purity can reach 12N.So far the polysilicon of 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, uses in a large number the hazardous gases such as liquid chlorine and hydrogen, has environment and potential safety hazard.Therefore, find the focal issue that novel low-cost solar level polysilicon production technology becomes industrial community and academia's concern.
In recent years, domestic and international many researchists are devoted to produce with the physical metallurgy method research of solar-grade polysilicon, the people such as Hiroyuki Baba as nippon company introduce the method that the said firm prepares solar-grade polysilicon: the Pure Silicon Metal take 99.5% (MG-Si) is raw material, with the argon plasma oxidation, remove boron, the vacuum electron beam dephosphorization, acquisition resistivity is the P type polysilicon of 1.0 Ω/cm, then removes metallic impurity through the method for directional freeze, obtains the solar-grade polysilicon of 6N.Norway Elkem company is by slag making acid washing method purifying polycrystalline silicon, in the silicon liquid of melting, add the liquid impurity such as oxide removal B, P, after solidifying, be ground into particle, then with acid wash, remove the metallic impurity of particle surface, then through operations such as directional freezes, make silicon ingot in specially designed apparatus for directional solidification.
Yet, all there is certain limitation in the main technique of metallurgy method at present, as Chinese patent CN101585536, be to adopt industrial silica fume to process through ultrasonic and gas stirring and pickling, remove the major impurity in the surperficial industrial silicon that exposes, then 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's temperature control, further purify, finally obtain polycrystal silicon ingot.Although it is to carry out a vacuum oven that this patent starts to follow-up operation from vacuum melting, but the silicon material of putting into stove is silicon ore obtains after the carbon reduction industrial silicon, in the process of reduction, also have a large amount of waste heats directly not to be applied, later stage also will pulverize industrial silicon pickling, this operation works under hard conditions, and energy consumption is large.Chinese patent CN101759187 has proposed a kind of by reactor and catcher device dimerous.Wherein, reactor is comprised of reductive agent deposit chamber and reaction chamber two portions.Catcher is comprised of one-level catcher and secondary catcher, controls liquid Zn and 7N level silicon tetrachloride gas 650~900 ℃ of reactions, and product is brought into catcher, and polysilicon vacuum distillation, directional freeze that collection is obtained obtain solar-grade polysilicon.Although this method is to have utilized the silicon tetrachloride of the 7N level that Siemens Method silicon tetrachloride gas metallurgical grade silicon tetrachloride gas obtains through distilation, the equipment requirements harshness of this method, be unfavorable for the reduction of cost and the scale operation of polysilicon.
In addition, smelting process also has fused salt electrolysis process.The method, take industrial silicon as raw material, adds the halogenide fused salt, adds thermal electrolysis, on negative electrode, forms high-purity siliceous deposits.This method is having some superiority except B with aspect P, in the degree of depth, removes micro-metals and acquires a certain degree of difficulty, and the silicon of generation need just can reach the specification of quality of solar-grade polysilicon after refining, be purified to more than 5N very difficult.Certain success is obtained in the fused salt electrolysis laboratory, but wants heavy industrialization to have equipment and technologic difficulty.
To sum up, present processing method is Shortcomings all, does not make good use of the waste heat in the reducing and smelting process or some operation of being purified to the technique of solar-grade polysilicon from industrial silicon is to appear in different stations to carry out, and a large amount of heats has scattered and disappeared, increase energy consumption, thereby increased cost.
Summary of the invention
The objective of the invention is the deficiencies such as high energy consumption, poor efficiency for prior art, low-cost and high efficiency a kind of device that is prepared HIGH-PURITY SILICON by silicon ore and preparation method thereof are provided.
The device for preparing HIGH-PURITY SILICON by silicon ore of the present invention is provided with mineral hot furnace, supporting electrode system and directional solidification furnace;
Described mineral hot furnace bottom is equipped with insulating brick, the 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 are passed the top of mineral hot furnace wall, between the top of 3 hollow main electrodes and mineral hot furnace wall, be provided with electrode clamping device, the electrode clamping device top is 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 the walkie fork lift truck of supporting electrode and tape gripper, supporting electrode can move freely, and for mineral hot furnace melting zone silicon liquid, comes out of the stove and flows out the refining of silicon liquid;
Described directional solidification furnace can freely move on to out the below of silicon mouth and accept silicon liquid, 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 the plumbago crucible outer wall, between plumbago crucible and ruhmkorff coil, is provided with insulation quilt, and bell is located at the plumbago crucible top, and viewport and infrared detecting group are located at bell top clamping plasma gun; Plasma gun is located on bell, by rifle body clamper, is controlled and is moved up and down.
A kind of method that is prepared HIGH-PURITY SILICON by silicon ore, adopt the described device that is prepared HIGH-PURITY SILICON by silicon ore, comprises the following steps:
1) will after silicon ore, oil coke and charcoal mixing, from the mineral hot furnace fire door, enter in stove, open 3 hollow main electrodes, raw material is heated, and reduction reaction is closed 3 hollow main electrodes after finishing, stopped heating, and from loading hopper, adding slag former, then open 3 hollow main electrode heating, after carrying out slag refining, close 3 hollow main electrodes, silicon liquid is standing again;
2) open the power supply of the ruhmkorff coil of directional solidification furnace, plumbago crucible is carried out to preheating;
3) rise the bell of directional solidification furnace, open supporting electrode, make silicon liquid after slag refining from the outlet of silicon liquid, flowing out, in this process, the supporting electrode system is carried out the secondary arc refining and produces high-temperature plasma the silicon liquid that flows through, and further removes the impurity such as boron phosphorus;
4) silicon liquid flows in plumbago crucible after the secondary arc refining, when influx is 0.8~1.2t, stops the refining of supporting electrode system electric arc, with silico briquette and wet SILICA FUME, blocks out the silicon mouth, covers simultaneously the directional freeze bell;
5) open aeration aperture and aspirating hole, to the mixed gas that passes into argon gas and water vapour in directional solidification furnace;
6) increase the ruhmkorff coil power, make the silicon liquid temp reach 1700~1800 ℃;
7) open plasma gun, plasma melting is carried out in silicon liquid surface;
8) regulate the ruhmkorff coil power, use the plasma gun supplementary heating, remain the temperature on silicon liquid surface at 1450~1520 ℃;
9) open water device for cooling;
10) after directional freeze completes, the silicon ingot furnace cooling, obtain 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 ℃, and the time of heating can be 3~4h; Described temperature of opening again 3 hollow main electrode heating can be 1600~1800 ℃, 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, the disposable mineral hot furnace of evenly putting into, 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%, and water vapour: 0~1.5%, the described flow velocity that passes into the mixed gas of argon gas and water vapour 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 ℃, and the exit water temperature can be 35~45 ℃, and flow velocity can be 10~15m 3/ h.
Prepared HIGH-PURITY SILICON silicon ingot is cut to bottom and top impurity enriched part, with ICP-MAS, measure the impurity content of different sites.
The invention provides a kind of device that is prepared HIGH-PURITY SILICON by silicon ore 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 are with loading hopper, for carbon reduction silicon ore and purification refining provide heat, charging simultaneously; Supporting electrode, for further high-temperature electric arc refining, is removed 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 take silicon ore, oil coke and coke as raw material, and the heat that provides by three main electrodes carries out reduction reaction, obtains industrial silicon; Again the slag agent is carried out to slag refining in three electrode cavity Implanted Silicon melting zones, the silicon liquid that obtains is poured in the plumbago crucible of prior preheating again and carries out directional freeze after the refining of supporting electrode high-temperature electric arc.Before directional freeze, by heating plasma, further remove the impurity such as boron phosphorus, in the directional freeze process, by heating plasma, remain the temperature of liquid level, finally obtain high-purity silicon ingot of 5.5~6N.The techniques such as the slag refining of the reduction of integrated silicon ore of the present invention, 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, is combined retailoring with the purification refining, take full advantage of the reduction waste heat, has overcome the shortcoming of traditional method, has reduced the energy consumption of pilot process.This is simple for process, can realize serialization production, is suitable for industrialization.
The 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 Fig. 1~3, respectively be labeled as: the 11-insulating brick; 12-mineral hot furnace wall; 13-oil coke, coke and silicon ore; The 14-slag; The 15-electrode clamping device; The 16-feed system; The 17-main electrode; The 18-electrode contact; The outlet of 19-silicon liquid; The 21-supporting electrode; The 22-insulcrete; The walkie fork lift truck of 23-tape gripper; The 301-water cooling plant; The 302-water-cooling subbase; The 303-ruhmkorff coil; The 304-insulation quilt; The 305-plumbago crucible; The 306-viewport; 307-rifle body clamper; The 308-bell; 309-aeration aperture, aspirating hole; The 310-infrared detecting group; The 311-plasma gun; 312-silicon liquid; The 313-silicon ingot.
Embodiment
The present invention is further illustrated in connection with accompanying drawing for following examples.
Referring to Fig. 1~3, the device embodiment for preparing HIGH-PURITY SILICON by silicon ore of the present invention is provided with mineral hot furnace, supporting electrode system and directional solidification furnace.
Described mineral hot furnace bottom is equipped with insulating brick 11, the 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 are passed the top of mineral hot furnace wall 12, between the top of 3 hollow main electrodes 17 and mineral hot furnace wall 12, be provided with electrode clamping device 15, electrode clamping device 15 tops are provided with liftable feed system 16; In Fig. 1, 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 for mineral hot furnace melting zone silicon liquid, comes out of the stove and flows out the refining of silicon liquid.
Described directional solidification furnace can freely move on to out the below of silicon mouth and accept silicon liquid 312, 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 walls, between plumbago crucible 305 and ruhmkorff coil 303, be provided with insulation quilt 304, bell 308 is located at plumbago crucible 305 tops, and viewport 306 and infrared detecting group 310 are located at bell 308 tops clamping plasma gun 311; Plasma gun 311 is located on bell 308, by rifle body clamper 307, is controlled and is moved up and down.In Fig. 3, mark 313 is silicon ingot.
Oil coke and charcoal that silicon ore and the granularity that by granularity is 50~100mm is 1~10mm evenly mix; 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 (2.8~3) by weight: (0.9~1.2): (0.1~0.3).The raw material that mixes is evenly added in stove from the mineral hot furnace fire door, and stove power is 6300~12500kVA.Open three main electrodes raw material is heated, heating and temperature control is at 1700~1900 ℃, and after the hold-time was controlled at 3~4h, reduction reaction finished, and closes three main electrodes, stopped heating.From loading hopper, adding slag former, select the composition of slag former to be by mass percentage Na 2CO 3(40%~60%): SiO 2(30%~55%): NaF(5%~25%), the disposable stove of evenly putting into, the weight ratio of silicon ore and slag former is (1~10): 2.Open three main electrode heating, keep furnace temperature between 1600~1800 ℃, to carry out slag refining, refining time is 0.2~0.8h; Close three main electrodes, silicon liquid time of repose is controlled at 0.2h, makes slag silicon separate.
Open the power supply of directional solidification furnace ruhmkorff coil, the ruhmkorff coil power is 360~750kW, and plumbago crucible is carried out to preheating, is located at 0.2~0.7h warm up time.Rise the bell of directional solidification furnace, open supporting electrode, make silicon liquid after slag refining from the outlet of silicon liquid, flowing out, in this process, the supporting electrode system is carried out the secondary arc refining and produces high-temperature plasma the silicon liquid that flows through, and further removes the impurity such as boron phosphorus.Silicon liquid flows in plumbago crucible after the secondary arc refining, when influx is 0.8~1.2t, stop the refining of supporting electrode system electric arc, with silico briquette and wet SILICA FUME, blocks out the silicon mouth.Simultaneously, cover the directional freeze bell.
Open aeration aperture, aspirating hole, to the mixed gas that passes into argon gas and water vapour in directional solidification furnace, volume fraction is argon gas: 98.5%~100%, and water vapour: 0~1.5%, intake is 20~30L/h.Increase the power of ruhmkorff coil power supply, the silicon liquid temp is reached between 1700~1800 ℃.Open plasma gun, the plasma body refining is carried out in silicon liquid surface, refining time is 0.3~0.5h, more further removes the impurity such as boron phosphorus.Regulate the ruhmkorff coil power, use the plasma gun supplementary heating, remain the temperature on silicon liquid surface between 1450~1520 ℃.Open water device for cooling, ingress's water temperature are 25 ℃, and between 35~45 ℃ of exit temperature, flow velocity is 10~15m 3/ h.
After directional freeze completes, silicon ingot 313 furnace cooling.The silicon ingot that obtains cuts bottom and top impurity enriched part, with ICP-MAS, measures the impurity content of different sites.
Below provide specific embodiment:
Embodiment 1
By the 2t granularity, be that the charcoal that the silicon ore of 50~100mm, oil coke that the 0.8t granularity is 1~10mm and 0.2t granularity are 1~10mm evenly mixes; The SiO in silicon ore wherein 2Content is 98%, and the carbon content of oil coke and charcoal is 50%.The 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), according to above-mentioned embodiment, carry out refining.To passing into volume fraction in directional solidification furnace, be that 99% argon gas and volume fraction are 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 ℃, and the spout temperature is 42 ℃, and flow velocity is 10m 3/ h, setting rate 8mm/h.Cut silicon ingot head 10% afterbody 20%, detect the impurity content at three positions of upper, middle and lower, 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
2t silicon ore, 0.8t oil coke and 0.2t charcoal are evenly mixed; The SiO in silicon ore wherein 2Content is 98%, and the carbon content of oil coke and charcoal is 50%.Reduction temperature is controlled at 1800 ℃, keeps 3h.The disposable Na that adds 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); To passing into volume fraction in directional solidification furnace, be that 98.5% argon gas and volume fraction are 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 ℃, and the spout temperature is 38 ℃, 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
2t silicon ore, 0.8t oil coke and 0.2t charcoal are evenly mixed; The SiO in silicon ore wherein 2Content is 99%, and the carbon content of oil coke and charcoal is 50%.Reduction temperature is controlled at 1800 ℃, keeps 3h.The disposable Na that adds 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); To passing into volume fraction in directional solidification furnace, be that 99% argon gas and volume fraction are 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 ℃, and the spout temperature is 40 ℃, 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
2t silicon ore, 0.8t oil coke and 0.2t charcoal are evenly mixed; The SiO in silicon ore wherein 2Content is 99%, and the carbon content of oil coke and charcoal is 80%.Reduction temperature is controlled at 1900 ℃, keeps 4h.The disposable Na that adds 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); To passing into volume fraction in directional solidification furnace, be that 99% argon gas and volume fraction are 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 ℃, and the spout temperature is 43 ℃, and flow velocity is 10m 3/ h, setting rate 8mm/h.Cut silicon ingot head 10% afterbody 20%, detect the impurity content at three positions of upper, middle and lower, 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
2t silicon ore, 0.8t oil coke and 0.2t charcoal are evenly mixed; The SiO in silicon ore wherein 2Content is 99%, and the carbon content of oil coke and charcoal is 80%.Reduction temperature is controlled at 1900 ℃, keeps 4h.The disposable Na that adds 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); To passing into volume fraction in directional solidification furnace, be that 98.5% argon gas and volume fraction are 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 ℃, and the spout temperature is 38 ℃, 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. a device that is prepared HIGH-PURITY SILICON by silicon ore, is characterized in that being provided with mineral hot furnace, supporting electrode system and directional solidification furnace;
Described mineral hot furnace bottom is equipped with insulating brick, the 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 are passed the top of mineral hot furnace wall, between the top of 3 hollow main electrodes and mineral hot furnace wall, be provided with electrode clamping device, the electrode clamping device top is 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 the walkie fork lift truck of supporting electrode and tape gripper, supporting electrode can move freely, and for mineral hot furnace melting zone silicon liquid, comes out of the stove and flows out the refining of silicon liquid;
Described directional solidification furnace can freely move on to out the below of silicon mouth and accept silicon liquid, 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 the plumbago crucible outer wall, between plumbago crucible and ruhmkorff coil, is provided with insulation quilt, and bell is located at the plumbago crucible top, and viewport and infrared detecting group are located at bell top clamping plasma gun; Plasma gun is located on bell, by rifle body clamper, is controlled and is moved up and down.
2. a method that is prepared HIGH-PURITY SILICON by silicon ore, is characterized in that adopting the device that is prepared as claimed in claim 1 HIGH-PURITY SILICON by silicon ore, said method comprising the steps of:
1) will after silicon ore, oil coke and charcoal mixing, from the mineral hot furnace fire door, enter in stove, open 3 hollow main electrodes, raw material is heated, and reduction reaction is closed 3 hollow main electrodes after finishing, stopped heating, and from loading hopper, adding slag former, then open 3 hollow main electrode heating, after carrying out slag refining, close 3 hollow main electrodes, silicon liquid is standing again;
2) open the power supply of the ruhmkorff coil of directional solidification furnace, plumbago crucible is carried out to preheating;
3) rise the bell of directional solidification furnace, open supporting electrode, make silicon liquid after slag refining from the outlet of silicon liquid, flowing out, in this process, the supporting electrode system is carried out the secondary arc refining and produces high-temperature plasma the silicon liquid that flows through, and further removes the impurity such as boron phosphorus;
4) silicon liquid flows in plumbago crucible after the secondary arc refining, when influx is 0.8~1.2t, stops the refining of supporting electrode system electric arc, with silico briquette and wet SILICA FUME, blocks out the silicon mouth, covers simultaneously the directional freeze bell;
5) open aeration aperture and aspirating hole, to the mixed gas that passes into argon gas and water vapour in directional solidification furnace;
6) increase the ruhmkorff coil power, make the silicon liquid temp reach 1700~1800 ℃;
7) open plasma gun, plasma melting is carried out in silicon liquid surface;
8) regulate the ruhmkorff coil power, use the plasma gun supplementary heating, remain the temperature on silicon liquid surface at 1450~1520 ℃;
9) open water device for cooling;
10) after directional freeze completes, the silicon ingot furnace cooling, obtain HIGH-PURITY SILICON.
3. a kind of method that is prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 1) 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 that is prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 1), and 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 that is prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 1), and the power of described mineral hot furnace is 6300~12500kVA, and the temperature of described heating is 1700~1900 ℃, and the time of heating is 3~4h; Described temperature of opening again 3 hollow main electrode heating can be 1600~1800 ℃, and the time of described refining can be 0.2~0.8h.
6. a kind of method that is prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 1), described slag former by mass percentage consist of Na 2CO 3(40%~60%): SiO 2(30%~55%): NaF(5%~25%) scum silica frost, the disposable mineral hot furnace of evenly putting into, the mass ratio of silicon ore and slag former can be (1~10): 2.
7. a kind of method that is 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), the capacity of described plumbago crucible is 1.5 tons.
8. a kind of method that is prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, it is characterized in that in step 5), the volume fraction of described mixed gas is argon gas: 98.5%~100%, and water vapour: 0~1.5%, the described flow velocity that passes into the mixed gas of argon gas and water vapour is 20~30L/h.
9. a kind of method that is prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 7), and the time of described melting is 0.3~0.5h.
10. a kind of method that is prepared HIGH-PURITY SILICON by silicon ore as claimed in claim 2, is characterized in that in step 9), and ingress's water temperature of described water cooling plant is 25 ℃, and the exit water temperature is 35~45 ℃, and flow velocity is 10~15m 3/ h.
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CN106555224A (en) * 2015-09-30 2017-04-05 枣庄市天工新能源器材有限公司 A kind of production method and production equipment of monocrystal silicon
CN107311180A (en) * 2017-05-25 2017-11-03 宁夏东梦能源股份有限公司 The method that low borosilicate is prepared using mineral hot furnace
CN110255566A (en) * 2019-05-15 2019-09-20 扬州盈航硅业科技有限公司 A kind of metallic silicon smelting deep impurity-removing device
WO2021212250A1 (en) * 2020-04-20 2021-10-28 力玄科技(上海)有限公司 Triangular plasma melting furnace

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CN101585536A (en) * 2009-07-04 2009-11-25 大连理工大学 Device and method for purifying solar energy level polysilicon

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106555224A (en) * 2015-09-30 2017-04-05 枣庄市天工新能源器材有限公司 A kind of production method and production equipment of monocrystal silicon
CN107311180A (en) * 2017-05-25 2017-11-03 宁夏东梦能源股份有限公司 The method that low borosilicate is prepared using mineral hot furnace
CN107311180B (en) * 2017-05-25 2019-06-28 宁夏东梦能源股份有限公司 The method for preparing low borosilicate using mineral hot furnace
CN110255566A (en) * 2019-05-15 2019-09-20 扬州盈航硅业科技有限公司 A kind of metallic silicon smelting deep impurity-removing device
WO2021212250A1 (en) * 2020-04-20 2021-10-28 力玄科技(上海)有限公司 Triangular plasma melting furnace

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