The present invention relates to a method for the preparation of solar grade silicon comprising crystallization of large high purity silicon crystals in a hyper eutectic binary or ternary alloy containing silicon, or a refined silicon melt, wherein small silicon crystals are added to the melt and the resulting large silicon crystals are separated from the melt.
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Slag composition gold.How to choose gold smelting flux - superb electromachinery.Copper slag or fayalite slag is a by-product obtained during the matte smelting converting and refining of copper fig 7 11 54 59 it has been estimated that for every tonne of copper produced about 2 2 tonnes of slag is generated 60 as a consequence of the relatively low grades of copper concentrates now.
Slagsilicon mass ratio2.4 x 10-6 mass transport in slag the kinetics of boron removal from liquid silicon during slag refining have been investigated in this research by means of several small-scale experimental studies at temperatures of 14500c to 16500c.Slag and silicon, in batch weights of 7 g, were heated together in an.
Kazuki morita took bachelor degree in 1983, master degree in 1985, and doctor of engineering in 1988 from the university of tokyo at the department of metallurgy.He has his expertise in physical chemistry on high temperature materials processing mostly related to iron- and steelmaking, silicon refining, and materials recycling as a professor at the department of materials engineering in the.
For slag refining, when the boron content of the molten silicon was higher than 2.0 mass ppm, the chemical reactions were the rate determining steps, which could mainly be attributed to the attenuation of the oxidant content or the basicity near the slag-silicon.
A direct metallurgical route for production of solar grade silicon can be five times more energy efficient than the conventional siemens process that uses more than 200kwhkg si.A metallurgical route would reduce the payback time the time during which the solar cell produces the same amount of energy that was used to create it significantly.
Electron beam technology is an effective means for purifying solar-grade silicon,refining refractory metals and its alloy,preparing high purity special steel and super clean steel,because it has the advantages of high energy density and vacuum degree and it can be.
Directional solidification of silicon as mentioned before is a key process step in the sog-si production through the metallurgical route.Significantly small segregation coefficient of many impurities except b and p between the solid and molten silicon provides proper conditions for silicon refining by directional solidification 8, 9.
The year of 2008 the production of global solar grade poly-silicon has reached 43500 tons, accounting for 65 of the global poly-silicon eg and sog 2.Szlufcilk et al 3 have made the solar cells with the efficiency of 12.38 out of the solar grade poly-silicon which was purified by metallurgical method it is a.
The rapid growth of the photovoltaics pv industry has resulted in a severe shortage of solar-grade si sog-si.Metallurgical-grade si mg-si must be refined prior to the removal of certain impurities because it is the raw material used in the production of sog-si , , ,.Boron b impurity higher than 0.3 ppmw could severely decrease the photoelectric conversion efficiency.
The main feed stock for solar cell called solar grade silicon sog-si falls into the status of serious shortage.Among new technologies for sog-si under researching, metallurgical process is one of the most potential appropriative methods1.Recently, some trial products of this process have been marketed and their solar cells have also come out.
While production of solar-grade silicon sog-si has been dominated recently by the modified siemens process and a fluidized bed reactor process, obtaining a stable supply of sog-si at lower cost.
While production of solar grade silicon sog-si has been dominated recently by the modified siemens process and a.Comprising of slag and solidification refining, acid leaching, vacuum melting and directional solidification steps, for producing sog-si from.
Solar silicon i 0830 0855 a.Souto, javier bullon, ramon ords, jm miguez, ferroatlantica, industrial scale vacuum application in the ferrosolar project 0855 0920 ye wang, wenhui ma, and kazuki morita, university of tokyo, removal of boron from molten silicon by cao sio 2 cacl 2 slag treatment.
As a new promising route for solar grade silicon sog-si production, metallurgical refining processes was developed in the early eighties of the last century, followed by the establishment of nedo-jfe process in the beginning of the 2000s, where p was removed by electron beam eb in vacuum conditions and b by ar-h2o plasma.
Production costs of sog-si, effective removal of the aforementioned impurity elements is essential for producing silicon through metallurgical means 5.Electromagnetic levitation eml refining is an ideal technique for containerless processing of liquid metals.
The world production of sog-si was estimated to be approximately 0.15 million metric ton in 2011.Seg-si is also produced chiefly by siemens process, and its world production was estimated to be about 0.03 million metric ton in 2011.Until now, silicon has not been practically produced by molten salt electrolysis.
Refining antimony information.Kaken research projects vacuum refining of molten.Refining antimony information - 3d antimony refinery machine in thailand - dom-na-kluc oct 18 2013 many oil refinery and petrochemical projects worth billions of u s dollars have antimony refining process machinery in myanmar.
Figure 26 shows that al, ca and mg elements could be removed by slag refining meanwhile their removal rates were 85.Figure 27 shows the analysis of metal impurity in silicon and slag by epma after refining for 2 h at 1823 k under sio 2 caoal 2 o 3 systems.It could be clearly seen that the distribution of.
The mechanism by which b is removed from si to a molten caosio 2 cacl 2 slag, and its subsequent evaporation to a gas phase at 1723 k, has been evaluated with a view to optimize the production of solar-grade si.By assuming a diffusion model for the transfer of b from si to molten slag, and its evaporation to a gas phase, the diffusion coefficient of b in slag was investigated.
The slag refining for boron removal from metallurgical grade silicon is a promising metallurgical process for producing solar grade silicon.In this paper, fecl 2 molten salt has been used as a new refining agent to remove boron from mg-si.The effects of refining.
The slag treatment on mg-si for sog-si production is based on the principle of liquid-liquid extraction in steel industry.The slag used for the extraction of impurities must dissolve individual impurities better than molten silicon does, the solubility of silicon in the slag must be low, and the slag must be nonreactive with molten silicon and.
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Thermodynamics on sog-si refining processes institute of industrial science,.Thermodynamics and processing on solar grade silicon sog-si production materials production and recycling engineering lab.Formerly ferrous metallurgy lab.2 slag sio 2 crucible molten si-mg alloy molten mgsio 3, sio 2 satd.
This study investigates the efficiency of b and p removal from ferrosilicon alloy via slag refining.Silicon was alloyed with iron and the alloy was subjected to different compositions of cao-sio-alo ternary slag at 1600 c.Distributions of b and p between alloy and slag phases were investigated by icp-oes analysis.Results indicate that oxygen potential and basicity of slag can.
The invention claimed is 1.A silicon feedstock for producing directionally solidified czochralski, float zone or multicrystalline silicon ingots, thin sheets and ribbons for the production of silicon wafers for pv solar cells, comprising a silicon feedstock containing between 0.0 ppma boron, between 0.1 and 10 ppma phosphorus, less than 150 ppma of metallic elements, and less than.