Direct Carbothermic Silica Reduction from Purified Silica to Solar-Grade Silicon

Itaka, Kenji; Ogasawara, Takuya; Boucetta, Abderahmane; Benioub, Rabie; Sumiya, Masatomo; Hashimoto, Takuya; Koinuma, Hideomi; Furuya, Yasubumi

doi:10.1088/1742-6596/596/1/012015

Cited by 9 publications

(7 citation statements)

References 4 publications

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“…This range is much lower that the temperatures typically achieved in the Acheson-or Lely-type processes for commercial production of SiC and is similar to the temperature range proposed by Moshtaghioun et al [37] of 1473.15 to 1723.15 K (1200 to 1450°C) for microwave production of SiC. For the formation of Si metal from SiO 2 and C, much higher temperatures would be required; [38] however, Si metal formation is beyond the scope of the current paper.…”

Section: Experimental Setup For Sic Formationsupporting

confidence: 72%

Silicon Carbide Formation Enhanced by In-Situ-Formed Silicon Nitride: An Approach to Capture Thermal Energy of CO-Rich Off-Gas Combustion

Preez

Beukes

Zyl

et al. 2018

Metall Mater Trans B

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Carbothermic smelting of ores to produce metals or alloys in alternating current open/semiclosed and closed submerged arc furnaces, or in closed direct current furnaces, results in large volumes of CO-rich off-gas being generated. Most of the CO-rich off-gas is cleaned and flared on stacks, since the storing of large volumes is problematic due to the associated toxic and explosive risks. Flaring of CO-rich off-gas results in significant wastage of energy. In this study, an alternative method to partially capture the thermal energy associated with off-gas combustion, in the form of silicon carbide (SiC) generated from waste materials (quartz and anthracite fines), is proposed. SiC can partially replace conventional carbonaceous reductants used to produce alloys such as ferrochromium. The influences of quartz and anthracite particle size, treatment temperature, and gaseous atmosphere (nitrogen or air) on SiC formation were investigated. A quartz-anthracite mixture with 90 pct of the particles< 350.9 lm carbothermically treated at 1873.15 K (1600°C) resulted in almost complete conversion of quartz to SiC in both nitrogen and air atmospheres. The study indicated significant potential for industrial application of the process.

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Section: Experimental Setup For Sic Formationsupporting

confidence: 72%

Silicon Carbide Formation Enhanced by In-Situ-Formed Silicon Nitride: An Approach to Capture Thermal Energy of CO-Rich Off-Gas Combustion

Preez

Beukes

Zyl

et al. 2018

Metall Mater Trans B

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“…3. The fundamental speci cation of this system are almost the same as those of our previous reports 16) except a 10-times increase in the volume of the crucible. The evacuation system of this apparatus is composed of a rotary pump and a diffusion pump, which can reach 10 −3 Pa in vacuum.…”

Section: Reduction Processsupporting

confidence: 66%

“…To accelerate the Si production rate, it was reported that the addition of SiC could serve as a barrier to gaseous SiO, which may lead to the acceleration of the reaction and an increase in Si formation. 16,17) By means of adding SiC as the initial raw material, a partial amount of SiC is consumed in eqs. (5) and (3).…”

Section: Reduction Processmentioning

confidence: 99%

Optimization of the Granulation Binders of High-Purity Carbothermic Reduction for Solar-Grade Silicon

et al. 2016

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The direct carbothermic reduction process from high-purity silica is promising for next-generation low-cost silicon solar cells. In this process, the granulation process is essential to avoid blowout of the silica powder. In this study, we investigated the effect of binders on this reduction process using four kinds of binders. The real-time monitoring of the chamber pressure and quadrupole mass spectroscopic analysis indicated the sign of the blowout phenomena of the generated CO gas and decomposition gas of the binders. In the case of starch and sucrose, the strengths of granules were not enough to the process with the pressure of the generated CO gas, while the granules with enough strength, namely, the ones with polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC), resulted in silicon yield of 33.8% and 27.8%, respectively.

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“…Currently, the process of polysilicon production via monosilane pyrolysis in a fluidized bed reactor (FBR) [10,11] represents one of the most promising, albeit technologically and instrumentally complex, approaches enabling to reduce the cost of polysilicon by (15)(16)(17)(18)(19)(20)% compared to the classical Siemens method [12]. Another approach, which originated in 1980s, is direct purification of metallurgicalgrade silicon (MG-Si) to produce upgraded metallurgical-grade silicon (UMG-Si) meeting the requirements for solar-grade silicon (SoG-Si) [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Metallothermic and carbothermic processes of obtaining silicon by reducing silica are well known, although, the use of organic reducers (petroleum coke, wood chips, etc.) leads to contamination of silicon with hard-toremove impurities of boron and phosphorous, which presents an obstacle to its use in solar energy [18].…”

Section: Introductionmentioning

confidence: 99%

Obtaining homogeneous silicon in the process of alumothermic reduction of silicon dioxide

Chumikov¹,

Klimenov²,

Tokmoldin³

et al. 2019

Eurasian j. phys. funct. mater.

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The influence of charge components on emergence of a homogeneous phase of silicon in the process of silicon dioxide reduction by aluminium has been studied. Optimal process parameters affecting the quality of the end product have been identified. These include the ratio of components of the synthetic charge (CaO, SiO 2 , CaF 2), the optimal amount of SiO 2 , the optimal amount of a reducing agent (Al) and the optimal Si/slag ratio. The homogeneous phase of silicon is easily separated from the slag, which contributes to the reduction of waste silicon during further technological operations.

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Direct Carbothermic Silica Reduction from Purified Silica to Solar-Grade Silicon

Cited by 9 publications

References 4 publications

Silicon Carbide Formation Enhanced by In-Situ-Formed Silicon Nitride: An Approach to Capture Thermal Energy of CO-Rich Off-Gas Combustion

Silicon Carbide Formation Enhanced by In-Situ-Formed Silicon Nitride: An Approach to Capture Thermal Energy of CO-Rich Off-Gas Combustion

Optimization of the Granulation Binders of High-Purity Carbothermic Reduction for Solar-Grade Silicon

Obtaining homogeneous silicon in the process of alumothermic reduction of silicon dioxide

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