CN103011168A - Cleaning method of polycrystalline silicon raw material - Google Patents
Cleaning method of polycrystalline silicon raw material Download PDFInfo
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- CN103011168A CN103011168A CN2011102850539A CN201110285053A CN103011168A CN 103011168 A CN103011168 A CN 103011168A CN 2011102850539 A CN2011102850539 A CN 2011102850539A CN 201110285053 A CN201110285053 A CN 201110285053A CN 103011168 A CN103011168 A CN 103011168A
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Abstract
The invention discloses a cleaning method of a polycrystalline silicon raw material. The cleaning method comprises the following steps of crushing a polycrystalline silicon raw material, removing iron from silicon powder by a magnet, immersing the silicon powder in a hydrogen peroxide solution for 2-24h, carrying out wet-oxygen oxidation of the silicon powder, immersing the silicon powder in a mixed acid of hydrochloric acid and hydrofluoric acid, immersing the silicon powder in hydrofluoric acid for corrosion, putting the silicon powder into an ultrasonic water tank, carrying out ultrasonic cleaning, and drying the silicon powder in a vacuum furnace to obtain a target product. The cleaning method removes metal impurities in the silicon powder by pickling, realizes diffusion of the impurities into SiO2 by utilization of a ratio of the equilibrium concentration of boron in silicon to the equilibrium concentration of boron in SiO2, wherein the ratio is less than 1, and realizes removal of SiO2 containing a large amount of boron by pickling so that 4N-5N polycrystalline silicon can be obtained. The cleaning method has the advantages of simple processes, low cost, good safety and low pollution.
Description
Technical field
The present invention relates to a kind of purging method of polycrystalline silicon raw material.
Background technology
Polycrystalline silicon raw material is the main raw material of preparation silicon solar cell, manufacturing integration circuitry substrate, is the important foundation stone of Information of Development industry and New Energy Industry.In recent years, country advocates exploitation and the utilization of development new forms of energy, particularly renewable new forms of energy, and sun power is as renewable energy source and the free of contamination energy, so that the sun power industry development is rapid, causes the in short supply of polycrystalline silicon used for solar battery.Be the solar-grade polysilicon of 6N～7N with the technical grade polycrystalline silicon purifying of 1N～2N, existing method has chemical process and physical method.Chemical process has Siemens Method, improved Siemens and silane thermal decomposition process etc.Siemens Method is that Si and HCl reaction are generated SiHCl
3, with SiHCl
3After distill repeatedly was purified, logical hydrogen reducing went out HIGH-PURITY SILICON.Improved Siemens is the byproduct SiCl with siemens
4Reclaim.Silane thermal decomposition process is that silicon is generated SiH by chemical reaction
4, and then with SiH
4Resolve into HIGH-PURITY SILICON.These chemical processes are to remove the various impurity such as metal, boron, phosphorus in the silicon by rear purification of chemistry of silicones reaction, but cost is high, power consumption is large, equipment is complicated, also have the danger of polluting and exploding.
Physical method does not participate in chemical reaction as the body silicon that is purified, mainly be that to utilize tens kinds of metallic impurity equilibrium segregation coefficient K in silicon such as Fe, Al, Au be the characteristic of K＜＜1 much smaller than 1, wherein equilibrium segregation coefficient K be defined as impurity in solid phase silicon solubleness and in liquid-phase silicone the ratio of solubleness, adopt the methods such as directional freeze, zone-refine and pulling of crystals to carry out effective separating-purifying.But directly the technical grade polysilicon with 1N～2N carries out the method separating-purifyings such as directional freeze, zone-refine and pulling of crystals, and cost is still very high.
Summary of the invention
Technical problem to be solved by this invention provides a kind of purging method of polycrystalline silicon raw material, the impurity such as the metallic impurity in can limited removal polysilicon and boron, and processing method is simple, cost is low, process safety and have less pollution.
For solving the problems of the technologies described above, the purging method of polycrystalline silicon raw material provided by the invention comprises following processing step:
Step 1, the polycrystalline silicon material that will contain impurity are pulverized, and obtain 50 orders～400 purpose silica flours after the screening, remove iron in the described silica flour with magnet.
Step 2, the described silica flour of de-iron was soaked in superoxol 2 hours～24 hours.
Step 3, the described silica flour that will soak are put into elevated temperature vessel, container is put into carries out wet-oxygen oxidation in the High Temperature Furnaces Heating Apparatus again, again cooling.
The mixing acid that step 4, the described silica flour that takes out after will cooling off are put into hydrochloric acid and hydrofluoric acid soaks, and removes zone of oxidation and iron contamination in the sample, and water cleans described silica flour repeatedly to neutral.
Step 5, more described silica flour is corroded with hydrofluoric acid dips, remove the insoluble impurity in the described silica flour, then use the described silica flour of washed with de-ionized water to neutral.
Step 6, described silica flour is put into ultrasonic sink carry out ultrasonic cleaning in order to remove the impurity in described silicon material slit, the time of described ultrasonic cleaning is 10 minutes～120 minutes; Then use washed with de-ionized water 4 times～5 times.
Step 7, described silica flour is dried in vacuum oven, obtain target product.
Further improving is that the concentration of superoxol described in the step 2 is 20%～40%.
Further improving is that elevated temperature vessel described in the step 3 is quartz crucible.
Further improvement is, the temperature of wet-oxygen oxidation described in the step 3 is 400 ℃～1200 ℃, and the time of oxidation is 1 hour～24 hours.
Further improve and be, hydrochloric acid and hydrofluoric acid mixing acid hydrochloric acid by volume in the step 4: hydrofluoric acid=1～3: 1, the concentration of hydrochloric acid is 20%～30%, and the concentration of hydrofluoric acid is 40%, and soak time is 0.5 hour～8 hours.
Further improvement is, the concentration of the hydrofluoric acid in the step 5 is 20%～40%, and soak time is 0.5 hour～8 hours.
Further improving is that the temperature of ultrasonic cleaning described in the step 6 is 40 ℃～80 ℃.
Further improve and be, also need to the described silicon material of rinsed with deionized water in whizzer, until the pH value of the water that flows out is neutrality, dry with described vacuum oven again before in the step 7 described silica flour dry in vacuum oven.
Compared with prior art, the present invention has following beneficial effect:
1, the present invention can remove metallic impurity in the silica flour by pickling; And utilize boron equilibrium concentration and at SiO in silicon
2The ratio of middle equilibrium concentration makes boron impurities be diffused into SiO less than 1 through wet-oxygen oxidation
2In, remove to contain again the SiO of a large amount of boron by pickling
2Thereby, can obtain the polysilicon of 4N～5N.Through target product is carried out spectroscopic analysis, the present invention can be reduced to the summation of metallic impurity below the 100ppm, and the content of boron also is reduced to below the 0.5ppm.
2, superoxol soaks silica flour among the present invention, can not only remove the organism of silicon powder surface, also can play to the silica flour oxidation effect of catalysis simultaneously.
3, the present invention is simple to operate, and cost is low, and process safety and have less pollution can reach metallic impurity in effective reduction silicon and the content of boron simultaneously, for ingot casting of lower step provides better starting material.
4, the present invention uses ultrasonic wave, can with the impurity of effectively removing in the silicon slit, improve cleaning performance.
Description of drawings
The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments:
Fig. 1 is embodiment of the invention schema.
Embodiment
As shown in Figure 1, be embodiment of the invention schema.The purging method of embodiment of the invention polycrystalline silicon raw material comprises following processing step:
Step 1, the polycrystalline silicon material that will contain impurity are pulverized, and obtain 50 orders～400 purpose silica flours after the screening, remove iron in the described silica flour with magnet.
Step 2, the described silica flour of de-iron in being 20%～40% superoxol, concentration was soaked 2 hours～24 hours.
Step 3, the described silica flour that will soak are put into elevated temperature vessel such as quartz crucible, container are put into to carry out wet-oxygen oxidation in the High Temperature Furnaces Heating Apparatus again, again cooling.The temperature of described wet-oxygen oxidation is 400 ℃～1200 ℃, and the time of oxidation is 1 hour～24 hours.
The mixing acid that step 4, the described silica flour that takes out after will cooling off are put into hydrochloric acid and hydrofluoric acid soaks, and removes zone of oxidation and iron contamination in the sample, and water cleans described silica flour repeatedly to neutral.Wherein, hydrochloric acid and hydrofluoric acid mixing acid is hydrochloric acid by volume: hydrofluoric acid=1～3: 1, and the concentration of hydrochloric acid is 20%～30%, and the concentration of hydrofluoric acid is 40%, and soak time is 0.5 hour～8 hours.
Step 5, be the corrosion of 20%～40% hydrofluoric acid dips with described silica flour concentration again, soak time is 0.5 hour～8 hours, in order to remove the insoluble impurity in the described silica flour, then uses the described silica flour of washed with de-ionized water to neutral.
Step 6, described silica flour is put into ultrasonic sink carry out ultrasonic cleaning in order to remove the impurity in described silicon material slit, the time of described ultrasonic cleaning is 10 minutes～120 minutes; The temperature of described ultrasonic cleaning is 40 ℃～80 ℃.Then use washed with de-ionized water 4 times～5 times.
Step 7, described silica flour is used rinsed with deionized water in whizzer, until the pH value of the water that flows out be neutrality, dry with described vacuum oven again, obtain target product.
Preferred embodiment 1 of the present invention is:
The polycrystalline silicon material that will contain first impurity is pulverized, and the silica flour order number after the screening is 50 orders, then with the iron in the magnet absorption silicon material.Described silica flour being put into concentration again and be 40% superoxol soaked 24 hours.Then described silica flour is put into elevated temperature vessel, container is put into carries out wet-oxygen oxidation in the High Temperature Furnaces Heating Apparatus again, oxygen flow is 1000 ml/min, oxidizing temperature is 1200 ℃, the time of oxidation is 1 hour, and described silica flour outward appearance is purple or scarlet after the oxidation, then cooling.It is that the mixing acid of the hydrofluoric acid of 20% hydrochloric acid and 40% soaked 6 hours that the silica flour that takes out after the cooling is put into concentration, removes the impurity such as zone of oxidation and iron in the sample, and wherein, the hydrochloric acid in the described mixing acid and the volume ratio of hydrofluoric acid are 3: 1; Water cleans silica flour repeatedly to neutral.Be the corrosion in 0.5 hour of 40% hydrofluoric acid dips again with silica flour concentration, remove the insoluble impurity in the silica flour, then use the washed with de-ionized water silica flour to neutral.Silica flour is put into ultrasonic sink, and the impurity in the silicon material slit is removed in ultrasonic cleaning 15 minutes, then uses washed with de-ionized water 4 times～5 times, and silica flour is dried in vacuum oven, obtains target product.
Show with the detection of ICP-MS (inductivity coupled plasma mass spectrometry) method: the content summation of processing metallic impurity in the front silica flour is 1580ppm, the content summation of processing metallic impurity in the rear silica flour is 100ppm, silica flour boron-containing quantity before processing is 4ppm, and the silica flour boron-containing quantity after the processing is below the 0.8ppm.
Preferred embodiment 2 of the present invention is:
The polycrystalline silicon material that will contain first impurity is pulverized, and the silica flour order number after the screening is 200 orders, then with the iron in the magnet absorption silicon material.Described silica flour being put into concentration again and be 30% superoxol soaked 12 hours.Then described silica flour is put into elevated temperature vessel, container is put into carries out wet-oxygen oxidation in the High Temperature Furnaces Heating Apparatus again, oxygen flow is 1000 ml/min, oxidizing temperature is 800 ℃, the time of oxidation is 8 hours, and described silica flour outward appearance is purple or scarlet after the oxidation, then cooling.It is that the mixing acid of the hydrofluoric acid of 30% hydrochloric acid and 40% soaked 4 hours that the silica flour that takes out after the cooling is put into concentration, removes the impurity such as zone of oxidation and iron in the sample, and wherein, the hydrochloric acid in the described mixing acid and the volume ratio of hydrofluoric acid are 2: 1; Water cleans silica flour repeatedly to neutral.Be the corrosion in 2 hours of 40% hydrofluoric acid dips again with silica flour concentration, remove the insoluble impurity in the silica flour, then use the washed with de-ionized water silica flour to neutral.Silica flour is put into ultrasonic sink, and the impurity in the silicon material slit is removed in ultrasonic cleaning 15 minutes, then uses washed with de-ionized water 4 times～5 times, and silica flour is dried in vacuum oven, obtains target product.
Show with the detection of ICP-MS (inductivity coupled plasma mass spectrometry) method: the content summation of processing metallic impurity in the front silica flour is 1580ppm, the content summation of processing metallic impurity in the rear silica flour is 90ppm, silica flour boron-containing quantity before processing is 4ppm, and the silica flour boron-containing quantity after the processing is below the 0.5ppm.
Preferred embodiment 3 of the present invention is:
The polycrystalline silicon material that will contain first impurity is pulverized, and the silica flour order number after the screening is 400 orders, then with the iron in the magnet absorption silicon material.Described silica flour being put into concentration again and be 20% superoxol soaked 2 hours.Then described silica flour is put into elevated temperature vessel, container is put into carries out wet-oxygen oxidation in the High Temperature Furnaces Heating Apparatus again, oxygen flow is 1000 ml/min, oxidizing temperature is 400 ℃, the time of oxidation is 24 hours, and described silica flour outward appearance is purple or scarlet after the oxidation, then cooling.It is that the mixing acid of the hydrofluoric acid of 30% hydrochloric acid and 40% soaks that the silica flour that takes out after the cooling is put into concentration, removes the impurity such as zone of oxidation and iron in the sample, and wherein, the hydrochloric acid in the described mixing acid and the volume ratio of hydrofluoric acid are 1: 1; Water cleans silica flour repeatedly to neutral.Be the corrosion in 8 hours of 40% hydrofluoric acid dips again with silica flour concentration, remove the insoluble impurity in the silica flour, then use the washed with de-ionized water silica flour to neutral.Silica flour is put into ultrasonic sink, and the impurity in the silicon material slit is removed in ultrasonic cleaning 15 minutes, then uses washed with de-ionized water 4 times～5 times, and silica flour is dried in vacuum oven, obtains target product.
Show with the detection of ICP-MS (inductivity coupled plasma mass spectrometry) method: the content summation of processing metallic impurity in the front silica flour is 1580ppm, the content summation of processing metallic impurity in the rear silica flour is 84ppm, silica flour boron-containing quantity before processing is 4ppm, and the silica flour boron-containing quantity after the processing is below the 0.5ppm.
Abovely by specific embodiment the present invention is had been described in detail, but these are not to be construed as limiting the invention.In the situation that do not break away from the principle of the invention, those skilled in the art also can make many distortion and improvement, and these also should be considered as protection scope of the present invention.
Claims (8)
1. the purging method of a polycrystalline silicon raw material is characterized in that, comprises following processing step:
Step 1, the polycrystalline silicon material that will contain impurity are pulverized, and obtain 50 orders～400 purpose silica flours after the screening, remove iron in the described silica flour with magnet;
Step 2, the described silica flour of de-iron was soaked in superoxol 2 hours～24 hours;
Step 3, the described silica flour that will soak are put into elevated temperature vessel, container is put into carries out wet-oxygen oxidation in the High Temperature Furnaces Heating Apparatus again, again cooling;
The mixing acid that step 4, the described silica flour that takes out after will cooling off are put into hydrochloric acid and hydrofluoric acid soaks, and removes zone of oxidation and iron contamination in the sample, and water cleans described silica flour repeatedly to neutral;
Step 5, more described silica flour is corroded with hydrofluoric acid dips, remove the insoluble impurity in the described silica flour, then use the described silica flour of washed with de-ionized water to neutral;
Step 6, described silica flour is put into ultrasonic sink carry out ultrasonic cleaning in order to remove the impurity in described silicon material slit, the time of described ultrasonic cleaning is 10 minutes～120 minutes; Then use washed with de-ionized water 4 times～5 times;
Step 7, described silica flour is dried in vacuum oven, obtain target product.
2. the purging method of polycrystalline silicon raw material as claimed in claim 1, it is characterized in that: the concentration of superoxol described in the step 2 is 20%～40%.
3. the purging method of polycrystalline silicon raw material as claimed in claim 1, it is characterized in that: elevated temperature vessel described in the step 3 is quartz crucible.
4. the purging method of polycrystalline silicon raw material as claimed in claim 1, it is characterized in that: the temperature of wet-oxygen oxidation described in the step 3 is 400 ℃～1200 ℃, the time of oxidation is 1 hour～24 hours.
5. the purging method of polycrystalline silicon raw material as claimed in claim 1, it is characterized in that: hydrochloric acid and hydrofluoric acid mixing acid hydrochloric acid by volume in the step 4: hydrofluoric acid=1～3: 1, the concentration of hydrochloric acid is 20%～30%, and the concentration of hydrofluoric acid is 40%, and soak time is 0.5 hour～8 hours.
6. the purging method of polycrystalline silicon raw material as claimed in claim 1, it is characterized in that: the concentration of the hydrofluoric acid in the step 5 is 20%～40%, soak time is 0.5 hour～8 hours.
7. the purging method of polycrystalline silicon raw material as claimed in claim 1, it is characterized in that: the temperature of ultrasonic cleaning described in the step 6 is 40 ℃～80 ℃.
8. the purging method of polycrystalline silicon raw material as claimed in claim 1, it is characterized in that: also need to be with the described silicon material of rinsed with deionized water in whizzer before in the step 7 described silica flour being dried in vacuum oven, until the pH value of the water that flows out is neutral, dry with described vacuum oven again.
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105836748A (en) * | 2016-05-18 | 2016-08-10 | 南昌大学 | Method for preparing nano silicon powder through wet oxidation corrosion |
| CN107716431A (en) * | 2017-10-30 | 2018-02-23 | 镇江环太硅科技有限公司 | A kind of polycrystalline sheet stock cleaning method |
| CN107778009A (en) * | 2016-08-26 | 2018-03-09 | 辽宁省轻工科学研究院 | A kind of pressure-bearing prepares Ti3SiC2The reverse thermal expansion synthetic method of ceramics |
| CN108840341A (en) * | 2018-07-19 | 2018-11-20 | 江苏斯力康科技有限公司 | Metallic silicon surface treatment purification method |
| CN109037028A (en) * | 2018-06-22 | 2018-12-18 | 江苏京尚圆电气集团有限公司 | A kind of silicon material washing method |
| CN109457297A (en) * | 2018-11-15 | 2019-03-12 | 四川建志科技有限责任公司 | Crystal of zirconium oxide processes useless powder circulation utilization method |
| CN109663672A (en) * | 2019-01-15 | 2019-04-23 | 国网山东省电力公司电力科学研究院 | A kind of flotation agent and method for floating for isolating pure silicon from smelting product |
| CN109701947A (en) * | 2019-01-04 | 2019-05-03 | 内蒙古鄂尔多斯电力冶金集团股份有限公司 | A kind of cleaning device and cleaning method of polycrystalline silicon material |
| CN111044552A (en) * | 2019-12-31 | 2020-04-21 | 核工业北京地质研究院 | Method for recovering heat storage temperature based on silicon isotope fractionation relation |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109701947A (en) * | 2019-01-04 | 2019-05-03 | 内蒙古鄂尔多斯电力冶金集团股份有限公司 | A kind of cleaning device and cleaning method of polycrystalline silicon material |
| CN109663672A (en) * | 2019-01-15 | 2019-04-23 | 国网山东省电力公司电力科学研究院 | A kind of flotation agent and method for floating for isolating pure silicon from smelting product |
| CN111044552A (en) * | 2019-12-31 | 2020-04-21 | 核工业北京地质研究院 | Method for recovering heat storage temperature based on silicon isotope fractionation relation |
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Application publication date: 20130403 |