scholarly journals Methods of trichlorosilane synthesis for polycrystalline silicon production. Part 1: Direct synthesis

2021 ◽  
Vol 7 (1) ◽  
pp. 1-10
Author(s):  
Vladimir N. Jarkin ◽  
Oleg A. Kisarin ◽  
Tatyana V. Kritskaya
Keyword(s):  
Polycrystalline Silicon ◽  
Hydrogen Reduction ◽  
Direct Synthesis ◽  
Thermal Reduction ◽  
Combined Processes ◽  
Technical Grade ◽  
Reduction Methods ◽  
Grade Silicon ◽  
The Cost ◽  
Novel Applications

Novel technical solutions and ideas for increasing the yield of solar and semiconductor grade polycrystalline silicon processes have been analyzed. The predominant polycrystalline silicon technology is currently still the Siemens process including the conversion of technical grade silicon (synthesized by carbon-thermal reduction of quartzites) to trichlorosilane followed by rectification and hydrogen reduction. The cost of product silicon can be cut down by reducing the trichlorosilane synthesis costs through process and equipment improvement. Advantages, drawbacks and production cost reduction methods have been considered with respect to four common trichlorosilane synthesis processes: hydrogen chloride exposure of technical grade silicon (direct chlorination, DC), homogeneous hydration of tetrachlorosilane (conversion), tetrachlorosilane and hydrogen exposure of silicon (hydro chlorination silicon, HC), and catalyzed tetrachlorosilane and dichlorosilane reaction (redistribution of anti-disproportioning reaction). These processes remain in use and are permanently improved. Catalytic processes play an important role on silicon surface, and understanding their mechanisms can help find novel applications and obtain new results. It has been noted that indispensable components of various equipment and process designs are recycling steps and combined processes including active distillation. They provide for the most complete utilization of raw trichlorosilane, increase the process yield and cut down silicon cost.

scholarly journals Methods of trichlorosilane synthesis for polycrystalline silicon production

2021 ◽  
Vol 24 (1) ◽  
pp. 5-26
Author(s):  
V. N. Jarkin ◽  
O. A. Kisarin ◽  
T. V. Kritskaya
Keyword(s):  
Polycrystalline Silicon ◽  
Hydrogen Reduction ◽  
Thermal Reduction ◽  
Combined Processes ◽  
Technical Grade ◽  
Reduction Methods ◽  
Grade Silicon ◽  
The Cost ◽  
Novel Applications ◽  
Technical Solutions

Novel technical solutions and ideas for increasing the yield of solar and semiconductor grade polycrystalline silicon processes have been analyzed. The predominant polycrystalline silicon technology is currently still the Siemens process including the conversion of technical grade silicon (synthesized by carbon-thermal reduction of quartzites) to trichlorosilane followed by rectification and hydrogen reduction. The cost of product silicon can be cut down by reducing the trichlorosilane synthesis costs through process and equipment improvement. Advantages, drawbacks and production cost reduction methods have been considered with respect to four common trichlorosilane synthesis processes: hydrogen chloride exposure of technical grade silicon (direct chlorination, DC), homogeneous hydration of tetrachlorosilane (conversion), tetrachlorosilane and hydrogen exposure of silicon (hydro chlorination silicon, HC), and catalyzed tetrachlorosilane and dichlorosilane reaction (redistribution of anti-disproportioning reaction). These processes remain in use and are permanently improved. Catalytic processes play an important role on silicon surface, and understanding their mechanisms can help find novel applications and obtain new results. It has been noted that indispensable components of various equipment and process designs are recycling steps and combined processes including active distillation. They provide for the most complete utilization of raw trichlorosilane, increase the process yield and cut down silicon cost

scholarly journals Methods of trichlorosilane synthesis for polycrystalline silicon production. Part 2: Hydrochlorination and redistribution

2021 ◽  
Vol 7 (2) ◽  
pp. 33-43
Author(s):  
Vladimir N. Jarkin ◽  
Oleg A. Kisarin ◽  
Tatyana V. Kritskaya
Keyword(s):  
Polycrystalline Silicon ◽  
Hydrogen Reduction ◽  
Thermal Reduction ◽  
Combined Processes ◽  
Technical Grade ◽  
Reduction Methods ◽  
Grade Silicon ◽  
The Cost ◽  
Novel Applications ◽  
Technical Solutions

Novel technical solutions and ideas for increasing the yield of solar and semiconductor grade polycrystalline silicon processes have been analyzed. The predominant polycrystalline silicon technology is currently still the Siemens process including the conversion of technical grade silicon (synthesized by carbon-thermal reduction of quartzites) to trichlorosilane followed by rectification and hydrogen reduction. The cost of product silicon can be cut down by reducing the trichlorosilane synthesis costs through process and equipment improvement. Advantages, drawbacks and production cost reduction methods have been considered with respect to four common trichlorosilane synthesis processes: hydrogen chloride exposure of technical grade silicon (direct chlorination, DC), homogeneous hydration of tetrachlorosilane (conversion), tetrachlorosilane and hydrogen exposure of silicon (hydro chlorination silicon, HC), and catalyzed tetrachlorosilane and dichlorosilane reaction (redistribution of anti-disproportioning reaction). These processes remain in use and are permanently improved. Catalytic processes play an important role on silicon surface, and understanding their mechanisms can help find novel applications and obtain new results. It has been noted that indispensable components of various equipment and process designs are recycling steps and combined processes including active distillation. They provide for the most complete utilization of raw trichlorosilane, increase the process yield and cut down silicon cost.

The Preparation of Graphene via Thermal Reduction Method

2012 ◽  
Vol 557-559 ◽  
pp. 1539-1542
Author(s):  
Jian Fang Wang ◽  
Ya Nan Lv ◽  
Yin Long ◽  
Cheng An Tao ◽  
Hui Zhu
Keyword(s):  
Graphene Oxide ◽  
High Temperature ◽  
Smooth Surface ◽  
Reduction Method ◽  
Thermal Reduction ◽  
Thermal Reaction ◽  
Thermal Method ◽  
High Quality ◽  
Graphene Surface ◽  
Reduction Methods

In this paper, the graphene oxide reducing by photochemical-thermal reduction and high-temperature thermal reduction was studied to get qualified graphene and avoid the re-aggregation. The results show that graphene obtained by both of the two reduction methods all maintained the original well-layered morphology of the graphene oxide. The graphene had smooth surface and high quality as completely reduced by high-temperature thermal method. However, the reduction the photochemical-thermal reaction was not sufficient and caused many vesicles on the graphene surface due to the low temperature and the lack of reaction time.

scholarly journals Low-Temperature Molten Salt Synthesis and the Characterisation of Submicron-Sized Al8B4C7 Powder

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 70
Author(s):  
Cheng Liu ◽  
Xueyin Liu ◽  
Zhaoping Hou ◽  
Quanli Jia ◽  
Benjun Cheng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Molten Salt ◽  
Raw Materials ◽  
Reaction Medium ◽  
Thermal Reduction ◽  
Molten Salt Synthesis ◽  
Synthesis Process ◽  
Direct Reaction ◽  
Liquid Reaction ◽  
Reduction Methods

Submicron-sized (~200 nm) aluminium boron carbide (Al8B4C7) particles were synthesised from Al, B4C and carbon black raw materials in a molten NaCl-based salt at a relatively low temperature. The effects of the salt type/assembly and the firing temperature on the synthesis process were examined, and the relevant reaction mechanisms discussed. The molten salt played an important role in the Al8B4C7 formation process. By using a combined salt of 95%NaCl + 5%NaF, an effective liquid reaction medium was formed, greatly facilitating the Al8B4C7 formation. As a result, essentially phase-pure Al8B4C7 was obtained after 6 h of firing at 1250 °C. This temperature was 350–550 °C lower than that required by the conventional direct reaction and thermal reduction methods.

Physician data review to reduce cost per case and ALOS.

2013 ◽  
Vol 31 (31_suppl) ◽  
pp. 268-268
Author(s):  
Susan Schreiner ◽  
Theresa Franco
Keyword(s):  
Average Length ◽  
Communication Strategy ◽  
Net Income ◽  
Average Length Of Stay ◽  
Cancer Services ◽  
Reduction Methods ◽  
Critical Feedback ◽  
Reducing Costs ◽  
The Cost ◽  
Time Frames

268 Background: Reducing costs in health care is critical due to declining reimbursement. Physicians are often unaware of how their practices affect the cost of patient care and may have difficulty in making changes. The leadership of the Cancer Service Line believed a more targeted approach in sharing data would improve physician understanding and engagement to assist in greater standardization and cost reduction. Methods: An education and communication strategy was developed that involves the leadership of each specialty section of oncology. A dashboard was created with metrics such as clinic visits, surgical volume, cost per case, average length of stay, and net income. The data is presented in monthly, quarterly and annual time frames with trends to highlight progress and identify areas for improvement. Monthly meetings are conducted with key stakeholders to obtain critical feedback. Results: Consistent data has increased physician understanding of clinical businesses the business is doing and has prompted them to optimize clinical schedules and improve operational efficiencies. Outpatient and inpatient data regarding cost per case, ancillary costs, pharmaceutical usage, blood product utilization, and drug exchanges has driven practice changes. The ALOS is at almost an entire day below benchmarks and direct cost per case is at budgeted target. Standardization has occurred in the use of blood products and there has been an intentional shift of some interventions to the outpatient arena. Conclusions: The implementation of a robust education and communication strategy have resulted in active engagement and participation of physicians, significant practice changes in cancer care and heightened understanding of the relationship of practice to cost. A dashboard that trends relevant metrics shared at regular intervals with key providers impact the cost of cancer services without affecting the quality.

scholarly journals Some variance reduction methods for numerical stochastic homogenization

2016 ◽  
Vol 374 (2066) ◽  
pp. 20150168 ◽  
Author(s):  
X. Blanc ◽  
C. Le Bris ◽  
F. Legoll
Keyword(s):  
Monte Carlo ◽  
Variance Reduction ◽  
Stochastic Homogenization ◽  
Numerical Homogenization ◽  
Variance Reduction Techniques ◽  
Reduction Techniques ◽  
Effective Coefficients ◽  
Engineering Sciences ◽  
Reduction Methods ◽  
The Cost

We give an overview of a series of recent studies devoted to variance reduction techniques for numerical stochastic homogenization. Numerical homogenization requires that a set of problems is solved at the microscale, the so-called corrector problems. In a random environment, these problems are stochastic and therefore need to be repeatedly solved, for several configurations of the medium considered. An empirical average over all configurations is then performed using the Monte Carlo approach, so as to approximate the effective coefficients necessary to determine the macroscopic behaviour. Variance severely affects the accuracy and the cost of such computations. Variance reduction approaches, borrowed from other contexts in the engineering sciences, can be useful. Some of these variance reduction techniques are presented, studied and tested here.

Study on the Treatment of Oil-Produced Wastewater Using the Combined Processes Including Advanced Oxidation

2014 ◽  
Vol 641-642 ◽  
pp. 390-393
Author(s):  
Yun Chong Li ◽  
Rong Jun Su ◽  
Yu Su ◽  
Feng Ying Zhang ◽  
Bing Jie Ye ◽  
...  
Keyword(s):  
Biological Process ◽  
Ph Value ◽  
Biochemical Property ◽  
Advanced Oxidation ◽  
Complex Salt ◽  
Combined Processes ◽  
Secondary Oxidation ◽  
Combined Process ◽  
Aluminum Complex ◽  
The Cost

It is difficult to be degraded by biological process for some oil-produced wastewater containing high content of oil, salt, and COD. The combined process including advanced oxidation was adopted to handle it in this paper. The combined process including adsorption by furnace ash, coagulation by complex of ferro-aluminum salt, Fenton advanced oxidation, alkali out by NaOH and Fenton secondary oxidation was determined. Considering both the treatment effect and the cost, the optimizing process is as follows, the slurry of ferro-aluminum complex salt of 9% (m/m) was as a coagulant with a dosage of 0.8% (v/v); pH value of 3.2,Fe2+/H2O2of 1/2.5(v:v) and 30 mmol/L dosage of FeSO4⋅7H2O was confirmed in advanced oxidation phase; NaOH was as precipitant with a dosage of 1%(m/m); Finally, after the secondary oxidation, the COD value greatly dropped from original 5 422 mg/L of raw oil-produced wastewater to 185.3 mg/L of effluent with a removal as high as 96.6%. It meets the national discharge standard on oil-produced wastewater. BOD5/ COD also rose from 0.23 to 0.39 which indicated an improved biochemical property.

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