CN101850976A - Method for removing boron in silicon metal in transfer ladle - Google Patents
Method for removing boron in silicon metal in transfer ladle Download PDFInfo
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- CN101850976A CN101850976A CN200910048706A CN200910048706A CN101850976A CN 101850976 A CN101850976 A CN 101850976A CN 200910048706 A CN200910048706 A CN 200910048706A CN 200910048706 A CN200910048706 A CN 200910048706A CN 101850976 A CN101850976 A CN 101850976A
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Abstract
The invention relates to a method for removing boron in silicon metal in a transfer ladle, which comprises the following steps of: first placing liquid silicon metal obtained by reduction in a submerged arc furnace into the transfer ladle; then blowing a preheated mixed gas into the liquid silicon metal from the bottom of the transfer ladle, wherein the mixed gas consists of highly-pure oxygen, steam and argon; and finally making the fully-reacted and purified liquid silicon metal flow out of the bottom of the transfer ladle and casting the liquid silicon metal to obtain highly-pure silicon metal. In the method, the mixed gas consisting of the highly-pure oxygen, steam and argon is preheated at the high temperature and is blown into the silicon metal in a melting state from the bottom of the transfer ladle, so boron and phosphorus removal effect is remarkable; and other impurities are oxidized to generate volatile substances which are carried away by the gas or float on the surface of the liquid silicon metal, so the impurities in the silicon metal are remarkably reduced. Compared with other boron removal methods, the technology has the advantages of remarkable economic advantages, the capacity of greatly reducing energy consumption and shortening an impurity removal process, and great significance to the industrial production of low-cost and highly-pure silicon metal.
Description
Technical field:
The present invention relates to a kind of silicon purification techniques, more specifically to a kind of method of in the transhipment bag, removing boron in the Pure Silicon Metal.
Background technology:
Pure Silicon Metal is the important source material of making semiconducter device and solar cell, general method of producing Pure Silicon Metal is that high-purity quartz is put into the hot stove fusing in ore deposit, make reductive agent with carbonaceous, in the hot stove in ore deposit, silica is reduced into silicon, can obtain 98～99.9% Pure Silicon Metal.And the required silicon purity of solar cell is at 5 more than 9, and the required silicon purity of semiconducter device is at 9 more than 9, and different purposes will have different requirements to impurity.Because silicon metal purity is too low, can not directly do solar cell and semiconducter device, impurity is mainly nonmetallic impurity and metallic impurity such as Fe, Al, Ca such as carbon, boron, phosphorus, Pure Silicon Metal is used in solar cell and semiconductor device, must adopt physics method or chemical method will further purify to Pure Silicon Metal, wherein falling boron is that can it as the critical process of solar cell grade silicon.
In Pure Silicon Metal, foreign matter content is usually more than 0.5%, and wherein the concentration of boron and phosphorus impurities is (20～60) x10-6, and the concentration of metallic impurity Fe is (1600～3000) x10-6, and the concentration of Al is (1200～4000) x10-6.Except that boron, C can make SiC analyse on the surface when solidifying, and the carbon of solid solution can form CO by oxidation refining and be removed; Phosphorus can utilize the higher characteristics vacuum of its vapour pressure to remove; The segregation coefficient of other metallic impurity is all less, about 10-5 or littler, so can be removed by methods such as directional freezes.Because the segregation coefficient of boron in silicon greater than 0.8, is difficult to by the method for directional freeze they be removed.And how much boron impurity content can determine the conduction type and the doping effect of silicon materials.At present, the main method of removing boron impurity in the Pure Silicon Metal is with the Pure Silicon Metal heat fused, to this Pure Silicon Metal solution surface winding-up high temperature, high speed plasma jet, make boron form oxide compound and removed, but can easily form silicon oxide film at the liquid metal silicon face like this, the removal speed of boron is slow, and the treatment time is long, the cost height is difficult to realize suitability for industrialized production.
Summary of the invention:
The objective of the invention is to provide at the prior art weak point a kind of manufacture craft simple, low-cost, in the transhipment bag, remove the method for boron in the Pure Silicon Metal expeditiously.
The objective of the invention is to realize by following measure: a kind of method of removing boron in the Pure Silicon Metal in transhipment is wrapped is characterized in that this method comprises: at first the liquid metal silicon after the reduction in the hot stove in ore deposit to transhipment being wrapped; Then the mixed gas after the preheating is blown into the liquid metal silicon from transhipment bag bottom, described mixed gas is made up of high purity oxygen gas, water vapour, argon gas; Liquid metal silicon after fully reacting impurity elimination flows out from transhipment bag bottom and casts, and obtains highly purified Pure Silicon Metal.
Concentration of oxygen is 0-25% in the described mixed gas of being made up of high purity oxygen gas, water vapour, argon gas, and the concentration of water vapour is 5-20%, and all the other are argon gas.
The concentration of described water vapour was best at 20% o'clock.
The temperature of described liquid metal silicon is 1600～1800 ℃.
The optimum temps of described liquid metal silicon is 1800 ℃.
The purity of argon gas is greater than 99.999% in the described mixed gas of being made up of high purity oxygen gas, water vapour, argon gas, and the purity of oxygen is greater than 99.999%, and water vapor purity is greater than 99.99%.
Described high purity oxygen gas, water vapour, argon gas preheating temperature remain on more than 1800 ℃.
Described high purity oxygen gas, water vapour, argon gas mixed before pressurizer, entered to the transhipment bag through pressurizer.
The time of described abundant reaction is 2.4～2.6 hours.
Compared with prior art, because the method for in the transhipment bag, removing boron in the Pure Silicon Metal that has adopted the present invention to propose, be blown into Pure Silicon Metal inside under the molten state from transhipment bag bottom by the high purity oxygen gas under the preheating high temperature, water vapour and argon gas mixed gas, it is obvious to remove boron and phosphorus impurities effect, other parts impurity generates easy performance material through peroxidation and is walked or swim in the Pure Silicon Metal fluid surface by gas-entrained, and the impurity in the Pure Silicon Metal is obviously descended.This technology is compared with other removal boron method and had tangible economic advantages, can significantly reduce energy expenditure, shortens impurity elimination technology, realizes suitability for industrialized production low-cost, high purity metal silicon, and is significant to scale operation.
Description of drawings:
Fig. 1 is that Pure Silicon Metal is removed the boron synoptic diagram in the transhipment bag.
1-alternating current arc discharge electrode wherein; 2-transports inclusion; The 3-thermal insulating warm-keeping layer; 4-liquid metal silicon; 5-goes out the silicon mouth; The spongy porous of 6-air port; 7-four-way blast pipe; 8-mixed gas pre-heating system; The 9-winding heater; The 10-pressurizer; 11-pressure regulation and control system; 12-high purity oxygen gas pressure controlled valve; 13-high purity water vapor pressure control valve; 14-high-purity argon gas pressure controlled valve; The 15-refining vessel; 16-100～130V AC power.
Embodiment:
Below in conjunction with accompanying drawing embodiment is elaborated:
Method of the present invention follows these steps to implement:
At first, the Pure Silicon Metal to the transhipment bag of the liquid metal silicon after the reduction in the hot stove in ore deposit is put in the transhipment bag refining vessel, and with alternating current arc discharge heating.Heating makes the Pure Silicon Metal fluid temperature remain on 1600～1800 ℃.Secondly, open mixed gas high purity oxygen gas, water vapour, argon gas pre-heating system, the mixed gas of pressurizer of flowing through enters pre-heating system, the purity of argon gas is greater than 99.999% in the described mixed gas of being made up of high purity oxygen gas, water vapour, argon gas, the purity of oxygen is greater than 99.999%, and water vapor purity is greater than 99.99%.Gas is heated, and the temperature that makes mixed gas makes water vapour resolve into oxygen and hydrogen more than 1800 ℃.Once more, according to the pressure ratio that the pressure regulation and control system is regulated high purity oxygen gas, water vapour and argon gas, control its flow, make the concentration ratio of oxygen, water vapour and argon gas reach requirement, the content of oxygen is 0-25%, and the concentration of water vapour is 5-25%, and all the other are argon gas (50-95%).By pressurizer, guarantee that under certain flow velocity, the pressure ratio of oxygen, water vapour and argon gas is in steady state, make mixed gas enter pre-heating system with constant voltage greater than hydraulic bottom pressure.Continue it; mixed gas is blown into the Pure Silicon Metal melt from transhipment bag bottom with certain speed; arrive the liquid-state silicon surface then; the main effect of argon gas is to form protective atmosphere; boron in the liquid metal silicon and hydrogen and oxygen generate materials such as easy volatile hydroborate; phosphorus in the liquid metal silicon is evaporative removal at high temperature; the gas that is blown into can carry these reactant gasess, reaction powder and reaction liquid and evaporate in the air; other metallic impurity in the liquid metal silicon then with the oxygen generation oxide compound that reacts, swim in Pure Silicon Metal liquid surface.
In being blown into the mixed gas process, along with the concentration of water vapour is high more, it is fast more that the boron in the Pure Silicon Metal is removed speed, but the also quickening accordingly of the silicon oxide film formation speed on Pure Silicon Metal liquid surface, thereby hinder the also increase accordingly of probability of removing boron.Therefore, water vapour should have a suitable concentration value, and the silicon oxide film that the liquid-state silicon surface is formed is little to removing the boron influence, and the speed of removal boron is high and stable, test shows that the concentration of water vapour is the highest can go boron impurity fastest when 20% (intrinsic standoff ratio).
The mixed gas that temperature is higher than 1800 ℃ high purity water steam, hydrogen, argon gas and oxygen after preheating is blown into liquid metal silicon by container bottom, and air inlet port divides three the tunnel to enter silicon liquid, guarantees that mixed gas fully contacts with liquid-state silicon.Inlet pipe is made by copper tube.Control the flow of water vapour and oxygen by the reverse feedback controller, the mixed gas that they are blown into carries out according to the air pressure per-cent of setting.
Pure Silicon Metal liquid is in being blown into the mixed gas process, and gas is blown into the stirring that has been equivalent to accelerate the Pure Silicon Metal melt, and diffusion of contaminants is accelerated, and the chemical reaction aggravation helps the removal of impurity.
Pure Silicon Metal liquid behind the removal impurity flows out from the refining vessel bottom, and the impurity that swims in the metal liquid silicon face will be stayed in the refining vessel at last, dispose at last.Pure Silicon Metal liquid is removed boron and evaporation phosphorus in 1600～1800 ℃ of temperature ranges, the content of phosphorus is less than 3ppmwt after testing for the product that obtains, and the content of boron is less than 1ppmwt, and finishing purifies obtains high-purity polycrystalline.
Exemplifying embodiment below further specifies:
Embodiment 1: the liquid metal silicon 500kg after the reduction in the hot stove in ore deposit to transhipment bag 15 refining vessels, is opened AC power 14, make the 1 discharge heating of arc-over electrode, make the temperature of molten metal silicon remain on 1650～1660 ℃.Open the air pressure valve 13 and the ar pressure valve 14 of oxygen pneumatic valve 12, water vapour, the content that makes oxygen is 20%, and the content of water vapour is 10%, and all the other are argon gas; Mixed gas is 350 liters/minute through the flow behind the pressurizer 10, and heat 9 by pre-heating system 8 usefulness heater coils and heat, mixed gas is remained on more than 1800 ℃, be blown in the metal liquid silicon 4 by the spongy porous air port 6 that prevents to flow backwards then, make the abundant contact reacts of high purity water steam, argon gas, hydrogen and oxygen and liquid-state silicon; Mixed gas rises to silicon liquid surface from the bottom through metal liquid silicon, and bubble rolls, and plays the liquid-state silicon effect of stirring, the reaction of aggravation mixed gas and impurity.Be blown into 150 minutes, through going out silicon mouth 5 pouring liquid silicon casting molds, the content of its boron is 0.79ppmwt after testing then, and phosphorus content is 2.3ppmwt.
Embodiment 2: with the Pure Silicon Metal fusing of 500kg, the temperature that keeps Pure Silicon Metal liquid is at 1700～1710 ℃.The content that makes oxygen is 15%, and the content of water vapour is 15%, and all the other are argon gas; The flow of mixed gas is 350 liters/minute, and remains on more than 1800 ℃ by the pre-heating system Heating temperature and to be blown in the liquid-state silicon, is blown into 150 minutes, and through going out the running castings of silicon mouth, the content of its boron is 0.56ppmwt after testing then, and phosphorus content is 1.9ppmwt.
Embodiment 3: with the Pure Silicon Metal fusing of 500kg, the temperature that keeps Pure Silicon Metal liquid is at 1800 ℃.The content that makes oxygen is 10%, and the content of water vapour is 20%, and all the other are argon gas; Other condition such as above-mentioned implementation condition are identical, the flow of mixed gas is similarly 350 liters/minute, and allow temperature remain on more than 1800 ℃ by pre-heating system heating to be blown in the liquid-state silicon, be blown into 150 minutes, then through going out the running castings of silicon mouth, the content of its boron is 0.37ppmwt after testing, and phosphorus content is 1.4ppmwt.
The foregoing description is not purchased into limitation of the present invention, and all employings are equal to the technical scheme that form obtained of replacement or equivalent transformation, all drop within protection scope of the present invention.
Claims (9)
1. a method of removing boron in the Pure Silicon Metal in transhipment is wrapped is characterized in that this method comprises: at first the liquid metal silicon after the reduction in the hot stove in ore deposit to transhipment being wrapped; Then the mixed gas after the preheating is blown into the liquid metal silicon from transhipment bag bottom, described mixed gas is made up of high purity oxygen gas, water vapour, argon gas; Liquid metal silicon after fully reacting impurity elimination flows out from transhipment bag bottom and casts, and obtains highly purified Pure Silicon Metal.
2. the method for removing boron in the Pure Silicon Metal in transhipment bag according to claim 1 is characterized in that concentration of oxygen is 0-95% in the described mixed gas of being made up of high purity oxygen gas, water vapour, argon gas, and the concentration of water vapour is 5-20%, and all the other are argon gas.
3. the method for removing boron in the Pure Silicon Metal in the transhipment bag according to claim 2 is characterized in that the concentration of described water vapour was the best at 20% o'clock.
4. the method for removing boron in the Pure Silicon Metal in the transhipment bag according to claim 1 and 2, the temperature that it is characterized in that described liquid metal silicon is 1650～1800 ℃.
5. the method for removing boron in the Pure Silicon Metal in the transhipment bag according to claim 4, the optimum temps that it is characterized in that described liquid metal silicon is 1800 ℃.
6. the method for in the transhipment bag, removing boron in the Pure Silicon Metal according to claim 1 and 2, the purity that it is characterized in that argon gas in the described mixed gas of being made up of high purity oxygen gas, water vapour, argon gas is greater than 99.999%, the purity of oxygen is greater than 99.999%, and water vapor purity is greater than 99.99%.
7. the method for removing boron in the Pure Silicon Metal in the transhipment bag according to claim 1 and 2 is characterized in that described high purity oxygen gas, water vapour, argon gas preheating temperature remain on more than 1800 ℃.
8. the method for removing boron in the Pure Silicon Metal in the transhipment bag according to claim 1 and 2 is characterized in that described high purity oxygen gas, water vapour, argon gas mixed before pressurizer, enter to the transhipment bag through pressurizer.
9. the method for removing boron in the Pure Silicon Metal in the transhipment bag according to claim 1 and 2, the time that it is characterized in that described abundant reaction is 2.4～2.6 hours.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN200910048706A CN101850976A (en) | 2009-04-01 | 2009-04-01 | Method for removing boron in silicon metal in transfer ladle |
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| CN200910048706A CN101850976A (en) | 2009-04-01 | 2009-04-01 | Method for removing boron in silicon metal in transfer ladle |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102701212A (en) * | 2012-05-17 | 2012-10-03 | 华南师范大学 | Method for removing boron and phosphorus and purifying industrial silicon by using metallurgic method |
| CN102718221A (en) * | 2012-06-28 | 2012-10-10 | 厦门大学 | Polycrystalline silicon self-plugging casting device |
| CN102774840A (en) * | 2012-07-16 | 2012-11-14 | 华南师范大学 | Technique for purifying industrial silicon by metallurgical method |
| CN103058199A (en) * | 2013-01-21 | 2013-04-24 | 昆明理工大学 | Method for external refining purification of industrial silicon |
| CN103641120A (en) * | 2013-12-02 | 2014-03-19 | 昆明理工大学 | Method for refining and purifying industrial silicon melt outside wet oxygen furnace |
| CN104528726A (en) * | 2015-01-20 | 2015-04-22 | 邹祖康 | Water vapor silicon clearing method |
| CN105838907A (en) * | 2016-05-23 | 2016-08-10 | 宜兴市昱元能源装备技术开发有限公司 | Titanium purification device and use method |
| CN111412760A (en) * | 2020-04-01 | 2020-07-14 | 深圳市赛迈特悬浮冶金科技有限公司 | Method for improving molten pool uniformity by argon blowing technology in suspension smelting technology |
| CN111498852A (en) * | 2020-04-23 | 2020-08-07 | 北方民族大学 | Device for producing high-purity industrial silicon and preparation method thereof |
| CN111807372A (en) * | 2020-07-21 | 2020-10-23 | 昆明理工大学 | Method for top-blown refining of silicon wafer cutting waste |
| CN114162781A (en) * | 2021-12-27 | 2022-03-11 | 李东峰 | Method and system for producing hydrogen from liquid steel slag |
| CN114231762A (en) * | 2021-12-16 | 2022-03-25 | 株洲科能新材料股份有限公司 | Method for purifying high-purity indium |
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2009
- 2009-04-01 CN CN200910048706A patent/CN101850976A/en active Pending
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102701212A (en) * | 2012-05-17 | 2012-10-03 | 华南师范大学 | Method for removing boron and phosphorus and purifying industrial silicon by using metallurgic method |
| CN102701212B (en) * | 2012-05-17 | 2014-08-13 | 华南师范大学 | Method for removing boron and phosphorus and purifying industrial silicon by using metallurgic method |
| CN102718221A (en) * | 2012-06-28 | 2012-10-10 | 厦门大学 | Polycrystalline silicon self-plugging casting device |
| CN102718221B (en) * | 2012-06-28 | 2014-06-11 | 厦门大学 | Polycrystalline silicon self-plugging casting device |
| CN102774840A (en) * | 2012-07-16 | 2012-11-14 | 华南师范大学 | Technique for purifying industrial silicon by metallurgical method |
| CN102774840B (en) * | 2012-07-16 | 2014-05-28 | 华南师范大学 | Technique for purifying industrial silicon by metallurgical method |
| CN103058199A (en) * | 2013-01-21 | 2013-04-24 | 昆明理工大学 | Method for external refining purification of industrial silicon |
| CN103641120A (en) * | 2013-12-02 | 2014-03-19 | 昆明理工大学 | Method for refining and purifying industrial silicon melt outside wet oxygen furnace |
| CN104528726A (en) * | 2015-01-20 | 2015-04-22 | 邹祖康 | Water vapor silicon clearing method |
| CN104528726B (en) * | 2015-01-20 | 2016-06-29 | 邹祖康 | A kind of clear silicon process of steam |
| CN105838907A (en) * | 2016-05-23 | 2016-08-10 | 宜兴市昱元能源装备技术开发有限公司 | Titanium purification device and use method |
| CN105838907B (en) * | 2016-05-23 | 2017-12-19 | 宜兴市昱元能源装备技术开发有限公司 | Titanium purifying plant and application method |
| CN111412760A (en) * | 2020-04-01 | 2020-07-14 | 深圳市赛迈特悬浮冶金科技有限公司 | Method for improving molten pool uniformity by argon blowing technology in suspension smelting technology |
| CN111498852A (en) * | 2020-04-23 | 2020-08-07 | 北方民族大学 | Device for producing high-purity industrial silicon and preparation method thereof |
| CN111807372A (en) * | 2020-07-21 | 2020-10-23 | 昆明理工大学 | Method for top-blown refining of silicon wafer cutting waste |
| CN114231762A (en) * | 2021-12-16 | 2022-03-25 | 株洲科能新材料股份有限公司 | Method for purifying high-purity indium |
| CN114162781A (en) * | 2021-12-27 | 2022-03-11 | 李东峰 | Method and system for producing hydrogen from liquid steel slag |
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Application publication date: 20101006 |