• Title/Summary/Keyword: Silicon powder

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Synthesis of Silicon Carbide Powder Using Recovered Silicon from Solar Waste Silicon Wafer (태양광 폐실리콘 웨이퍼 회수 실리콘을 활용한 탄화규소 분말 합성)

  • Lee, Yoonjoo;Kwon, Oh-Kyu;Sun, Ju-Hyeong;Jang, Geun-Yong;Choi, Joon-Chul;Kwon, Wooteck
    • Resources Recycling
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    • v.31 no.5
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    • pp.52-58
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    • 2022
  • Silicon carbide powder was prepared from carbon black and silicon recovered from waste solar panels. In the solar power generation market, the number of crystalline silicon modules exceeds 90%. As the expiration date of a photovoltaic module arrives, the development of technology for recovering and utilizing silicon is very important from an environmental and economic point of view. In this study, silicon was recovered as silicon carbide from waste solar panels: 99.99% silicon powder was recovered through purification from a 95.74% purity waste silicon wafer. To examine the synthesis characteristics of SiC powder, purified 99.99% silicon powder and carbon powder were mixed and heat-treated (1,300, 1,400 and 1,500 ℃) in an Ar atmosphere. The characteristics of silicon and silicon carbide powders were analyzed using particle size distribution analyzer, XRD, SEM, ICP, FT-IR, and Raman analysis.

A Study on the sand mold compression strength of the N-process mold mixed with JA-EUN-DO sand. (자은도사(慈恩島砂)를 이용(利用)한 N-Process의 주형강도(鑄型强度)에 관(關)한 연구(硏究))

  • Lee, Won-Sik
    • Journal of Korea Foundry Society
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    • v.4 no.2
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    • pp.102-107
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    • 1984
  • The variations of the mold compression strength were studied by varing the contents of the silicon powder and water glass, silion purities, and molecule rates of the water glass, when domestic JA EUN DO sand is mixed with water glass (sodium silicate) and metallic silicon or ferro - silicon powder by the self - hardening N - PROCESS method. The results obtained from this experiment are as follows; 1) The compression strength of the mold used with metalic powder was higher and more stable than to be used ferro - silicon powder. 2) 6% water glass of 2.8 molecule rate and 1.5% of ferro - silicon of 75% purity for the N - PROCESS used with JA EUN DO sand was suitable mixing rate. 3) The compression strength increased with self - hardening time, and the PH values of the mixture of silicon powder and water glass did not change after 2 hours, but the compression strength increased steadily due to the reaction of remained silicon. 4) It is recommended to take 24 hours for self - hardening time at least.

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Thermodynamic Consideration for SiC synthesis by Using Sludged Silicon Powder (폐슬러지를 이용한 SiC 합성에 관한 열역학적 고찰)

  • 최미령;김영철
    • Journal of the Semiconductor & Display Technology
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    • v.2 no.1
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    • pp.21-24
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    • 2003
  • Sludged silicon powders that are generated during silicon ingot slicing process have potential usage as silicon source in fabricating silicon carbide powders by adding carbon. A thermodynamic calculation is performed to consider a plausible formation condition for the silicon carbide powders. A thin silicon oxide layer around silicon powder is sufficient to supply equilibrium oxygen partial pressure at the formation temperature($1400^{\circ}C$) of the silicon carbide in the Si-C-O ternary system. Formation of silicon carbide by using the sludged silicon powders is more efficient than by using silicon oxide powders.

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Sintering of $Si_3N_4$ Powder Prepared by Self-Propagating High-Temperature Synthesis (SHS)

  • Bai, Ling;Zhao, Xing-Yu;Ge, Chang-Chun
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.268-269
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    • 2006
  • Preparation processing of sintered silicon nitride ceramics was emphatically investigated with Self-Propagating High-Temperature Synthesis (SHS) of silicon nitride prepared by ourselves as raw material. The results indicate that good sinter ability can be obtained with cheaply SHS of silicon nitride preparing silicon nitride materials. The cost of silicon nitride materials will be lowered.

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Application of cold isostatic pressing method for fabrication of SoG-Si powder compacts (태양전지급 폴리실리콘 성형체 제작을 위한 CIP법의 활용)

  • Lee, Ho-Moon;Shin, Je-Sik;Moon, Byung-Moon;Kwon, Ki-Hwan;Kim, Ki-Young
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.126-129
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    • 2009
  • In this study, it was aimed to develop the re-use technology of ultra-fine silicon powders, by-products during the current production process of high purity poly-Si feedstock. For this goal, the compacts of the silicon powders were tried to fabricate by CIP (Cold Isostatic Pressing) method using silicon rubber mold without chemical binder materials. The density ratio of the silicon powder compacts reached 74%. In order to simulate the actual handling and charging conditions of feedstock material in casting process, a shaking test was carried out and mass loss measured. Finally, the silicon powder compacts were melted using a cold crucible induction melting method and the purity assessment was conducted by Hall effect measurement.

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Preparation of Silicon Nitride-silicon Carbide Composites from Abrasive SiC Powders

  • Kasuriya, S.;Thavorniti, P.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1091-1092
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    • 2006
  • Silicon nitride - silicon carbide composite was developed by using an abrasive SiC powders as a raw material. The composites were prepared by mixing abrasive SiC powder with silicon, pressing and sintering at $1400^{\circ}C$ under nitrogen atmosphere in atmosphere controlled vacuum furnace. The proportion of silicon in the initial mixtures varied from 20 to 50 wt%. After sintering, crystalline phases and microstructure were characterized. All composites consisted of ${\alpha}-Si_3N_4$ and ${\beta}-Si_3N_4$ as the bonding phases in SiC matrix. Their physical and mechanical properties were also determined. It was found that the density of the obtained composites increased with an increase in the $Si_3N_4$ content formed in the reaction.

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Nitridation of Silicon Powder Compacts in Air (Air 분위기에서 규소성형체의 질화반응)

  • 최석홍;안영필
    • Journal of the Korean Ceramic Society
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    • v.25 no.4
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    • pp.380-384
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    • 1988
  • This investigation includes nitridation phenomena of silicon powder compacts in air. Nitridation reaction condition has been provided with using silicon nitride bed and active carbon additive. Reaction products are Oxynitride, $\alpha$-Si3N4, and $\beta$-Si3N4, Oxynitride(Si2N2O) phase in formed at outer surface layer ofsilicon powder compacts. $\alpha$-Si3N4, and $\beta$-Si3N4 are formed at inner region of powder compacts. Microstructural observation indicates that nitridation mechanism in this work is the same as conventional nitridation mechanism nitrogen gas.

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Application of Mechanochemical Processing for Preparation of Si3N4-based Powder Mixtures

  • Sopicka-Lizer, Malgorzata;Pawlik, Tomasz
    • Journal of the Korean Ceramic Society
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    • v.49 no.4
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    • pp.337-341
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    • 2012
  • Mechanochemical processing (MCP) involves several high-energy collisions of powder particles with the milling media and results in the increased reactivity/sinterability of powder. The present paper shows results of mechanochemical processing (MCP) of silicon nitride powder mixture with the relevant sintering additives. The effects of MCP were studied by structural changes of powder particles themselves as well as by the resulting sintering/densification ability. It has been found that MCP significantly enhances reactivity and sinterability of the resultant material: silicon nitride ceramics could be pressureless sintered at $1500^{\circ}C$. Nevertheless, a degree of a silicon nitride crystal lattice and powder particle destruction (amorphization) as detected by XRD studies, is limited by the specific threshold. If that value is crossed then particle's surface damage effects are prevailing thus severe evaporation overdominates mass transport at elevated temperature. It is discussed that the cross-solid interaction between particles of various chemical composition, triggered by many different factors during mechanochemical processing, including a short-range diffusion in silicon nitride particles after collisions with other types of particles plays more important role in enhanced reactivity of tested compositions than amorphization of the crystal lattice itself. Controlled deagglomeration of $Si_3N_4$ particles during the course of high-energy milling was also considered.

The Effect of Liquid Medium on Silicon Grinding and Oxidation during Wet Grinding Process (습식분쇄공정에서 액상매체가 실리콘 분쇄 및 산화특성에 미치는 영향)

  • Kwon, Woo Teck;Kim, Soo Ryong;Kim, Young Hee;Lee, Yoon Joo;Shin, Dong Geun;Won, Ji Yeon;Oh, Sea Cheon
    • Journal of the Korean Ceramic Society
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    • v.51 no.2
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    • pp.121-126
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    • 2014
  • The influence of a liquid medium duringa wet-milling process in the grinding and oxidation of silicon powder was investigated. Distilled water, dehydrated ethanol and diethylene glycol were used as the liquid media. The applied grinding times were 0.5, 3, and 12 h. Ground silicon powder samples were characterized by means of aparticle size analysis, scanning electron microscopy(SEM), x-ray powder diffraction (XRD), FT-IR spectroscopy and by a chemical composition analysis. From the results of the characterization process, we found that diethylene glycol is the most efficient liquid medium when silicon powder is ground using a wet-milling process. The FT-IR results show that the Si-O band intensity in an unground silicon powder is quite strongbecause oxygen becomes incorporated with silicon to form $SiO_2$ in air. By applying deionized water as a liquid medium for the grinding of silicon, the $SiO_2$ content increased from 4.12% to 31.7%. However, in the cases of dehydrated ethanol and diethylene glycol, it was found that the $SiO_2$ contents after grinding only changed insignificantly, from 4.12% to 5.91% and 5.28%, respectively.