Combined XRD and XRF Technique for the Quantification of the Mass Balance in a Si Carbothermic Production Experiment

Martello, Elena Dal; Tranell, Gabriella; Raaness, Ola; Arnberg, L.

doi:10.2355/isijinternational.51.1492

Cited by 5 publications

(6 citation statements)

References 7 publications

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“…The graphite crucible has the advantage to withstand high temperatures, to be available in high purity even if it reacts with SiO(g), and to form SiC and Si; the amount of SiC and Si formed can be quantified. [30] In an industrial electric furnace, the charge follows different paths in its decent through the furnace, each of the paths with a different retention time. The shortest time from when the raw material is charged until it reaches the crater in an industrial furnace is typically 1-2 hours.…”

Section: B Experimental Setup and Proceduresmentioning

confidence: 99%

Study of Pellets and Lumps as Raw Materials in Silicon Production from Quartz and Silicon Carbide

Martello

Tranell

Gaal

et al. 2011

Metall Mater Trans B

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The use of high-purity carbon and quartz raw materials reduces the need for comprehensive refining steps after the silicon has been produced carbothermically in the electric reduction furnace. The current work aims at comparing the reaction mechanisms and kinetics occurring in the inner part of the reduction furnace when pellets or lumpy charge is used, as well as the effect of the raw material mix. Laboratory-scale carbothermic reduction experiments have been carried out in an induction furnace. High-purity silicon carbide and two different high-purity hydrothermal quartzes were charged as raw materials at different molar ratios. The charge was in the form of lumps (size, 2-5 mm) or as powder (size, 10-20 lm), mixed and agglomerated as pellets (size, 1-3 mm) and reacted at 2273 K (2000°C). The thermal properties of the quartzes were measured also by heating a small piece of quartz in CO atmosphere. The investigated quartzes have different reactivity in reducing atmosphere. The carbothermal reduction experiments show differences in the reacted charge between pellets and lumps as charge material. Solid-gas reactions take place from the inside of the pellets porosity, whereas reactions in lumps occur topochemically. Silicon in pellets is produced mainly in the rim zone. Larger volumes of silicon have been found when using lumpy charge. More SiO is produced when using pellets than for lumpy SiO 2 for the same molar ratio and heating conditions. The two SiC polytypes used in the carbothermal reduction experiments as carbon reductants presented different reactivity.

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Section: B Experimental Setup and Proceduresmentioning

confidence: 99%

Study of Pellets and Lumps as Raw Materials in Silicon Production from Quartz and Silicon Carbide

Martello

Tranell

Gaal

et al. 2011

Metall Mater Trans B

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“…The silicon related peaks in the PVA product were higher than those of CMC. The overall equation to calculate the weight fraction and yield is explained in previous works 11,21) and it is presented in eq. (9).…”

Section: Quanti Cation Of Productsmentioning

confidence: 99%

“…The carbon content was not considered in the products because, in this case, we have not ground the crucible as in previous works 11,21) and the focus was only on silicon products that we extracted from the crucible bottom. Silicon yield, 3C-SiC, 6H-SiC, and SiO 2 yields were estimated by eqs.…”

Section: Quanti Cation Of Productsmentioning

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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“…The hydrothermal quartz is a new high-purity source from a Norwegian deposit; it had been examined in previous studies. [27,28] The electronic grade silicon was supplied by Wacker, and the ultra-pure SiC was produced by reduction of hydrothermal quartz with high-purity carbon black. Ultra-pure saccharine by Danisco AS C 12 H 22 O 12 was used as a binder in the pellet production.…”

Section: A Materialsmentioning

confidence: 99%

Trace Elements in the Si Furnace. Part I: Behavior of Impurities in Quartz During Reduction

Martello

Tranell

Ostrovski

et al. 2013

Metall Mater Trans B

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Quartz and carbonaceous materials, which are used in the production of silicon as well as electrodes and refractories in the silicon furnace, contain trace elements mostly in the form of oxides. These oxides can be reduced to gaseous compounds and leave the furnace or stay in the reaction products-metal and slag. This article examines the behavior of trace elements in hydrothermal quartz and quartzite in the reaction of SiO2 with Si or SiC. Mixtures of SiO2 (quartz or quartzite), SiC, and Si in forms of lumps or pellets were heated to 1923 K and 2123 K (1650°C and 1850°C) in high purity graphite crucibles under Argon gas flow. The gaseous compounds condensed in the inner lining of the tube attached to the crucible. The phases present in the reacted charge and the collected condensates were studied quantitatively by X-ray diffraction (XRD) and qualitatively by Electron Probe Micro Analyzer (EPMA). Contaminants in the charge materials, reacted charge and condensate were analyzed by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). Muscovite in the mineral phase of quartz melted and formed two immiscible liquid phases: an Al-rich melt at the core of the mineral, and a SiO2-rich melt at the mineral boundaries. B, Mn, and Pb in quartz were removed during heating in reducing atmosphere at temperature above 1923 K (1650°C). Mn, Fe, Al and B diffused from quartz into silicon. P concentration was under the detection limit. Quartzite and hydrothermal quartz had different initial impurity levels: quartzite remained more impure after reduction experiment but approached purity of hydrothermal quartz upon silica reduction. Trace Elements in the Si Furnace. Part I: Behavior of Impurities in Quartz During Reduction ELENA DAL MARTELLO, GABRIELLA TRANELL, OLEG OSTROVSKI, GUANGQING ZHANG, OLA RAANESS, RUNE BERG LARSEN, KAI TANG, and PRAMOD KOSHY Quartz and carbonaceous materials, which are used in the production of silicon as well as electrodes and refractories in the silicon furnace, contain trace elements mostly in the form of oxides. These oxides can be reduced to gaseous compounds and leave the furnace or stay in the reaction products-metal and slag. This article examines the behavior of trace elements in hydrothermal quartz and quartzite in the reaction of SiO 2 with Si or SiC. Mixtures of SiO 2 (quartz or quartzite), SiC, and Si in forms of lumps or pellets were heated to 1923 K and 2123 K (1650°C and 1850°C) in high purity graphite crucibles under Argon gas flow. The gaseous compounds condensed in the inner lining of the tube attached to the crucible. The phases present in the reacted charge and the collected condensates were studied quantitatively by X-ray diffraction (XRD) and qualitatively by Electron Probe Micro Analyzer (EPMA). Contaminants in the charge materials, reacted charge and condensate were analyzed by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). Muscovite in the mineral phase of quartz melted and formed two immiscible liquid phases: an Al-rich melt at the core of the mineral, and a SiO ...

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Combined XRD and XRF Technique for the Quantification of the Mass Balance in a Si Carbothermic Production Experiment

Cited by 5 publications

References 7 publications

Study of Pellets and Lumps as Raw Materials in Silicon Production from Quartz and Silicon Carbide

Study of Pellets and Lumps as Raw Materials in Silicon Production from Quartz and Silicon Carbide

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

Trace Elements in the Si Furnace. Part I: Behavior of Impurities in Quartz During Reduction

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