Impact of Impurities in Metallurgical Grade Silicon on Removal Efficiency of Vacuum Evaporation

2011 ◽  
Vol 287-290 ◽  
pp. 1521-1525
Author(s):  
Kui Xian Wei ◽  
Wen Hui Ma ◽  
Yang Zhou ◽  
Ke Qiang Xie ◽  
Bin Yang ◽  
...  

Vacuum evaporation is usually utilized to remove volatile impurities in metallurgical grade silicon to prepare solar grade silicon by metallurgical routes. Especially phosphorus needs to be removed by vacuum evaporation. And the removal efficiency of impurities strongly influenced the quality and performance of products. In this paper, the removal efficiency of impurities is studied by using different raw material. The results indicated that the content of impurities in raw material had deep effect on the removal efficiency of vacuum evaporation. The high quality product can be obtained by vacuum evaporation only once from raw materials with the lower content of impurities whereas it is not for high content of impurities in raw material. This is due to the vapor-liquid equilibrium in the vacuum furnace. The impurities can be removed effectively by vacuum evaporation many times.

2011 ◽  
Vol 675-677 ◽  
pp. 873-876 ◽  
Author(s):  
Ke Qiang Xie ◽  
Zhan Liang Yu ◽  
Wen Hui Ma ◽  
Yang Zhou ◽  
Yong Nian Dai

In this paper, removal of iron from metallurgical grade silicon with pressure leaching is carried out. We investigated the factors such as the concentration of hydrochloric, particle size of raw material ground, temperature, pressure and reaction time, which influenced on the removal of iron. The results show that the optimum operating conditions for pressure leaching in hydrochloride are: acid concentration 4 mol/L, diameter for raw material less than 50 μm, leaching temperature 160 0C,leaching pressure 2.0 MPa, leaching time 2.0 h. The content of iron residual in MG-Si powder was reduced to about 200 ppmw. The removal efficiency of iron is up to 90.90 %.


2010 ◽  
Vol 156-157 ◽  
pp. 882-885 ◽  
Author(s):  
Yu Yan Hu ◽  
Dong Liang Lu ◽  
Tao Lin ◽  
Yu Liu ◽  
Bo Wang ◽  
...  

Refining of solar grade silicon by metallurgical method is the research hotspot of polycrystalline field. Slagging method is benefit to the removal of the impurities especially to boron exsisted in the raw silicon. In this study, the influence of the density, the viscosity and liquidus temperature of the slag components on the refining process were discussed, and then the slag system SiO2-Na2CO3 was choosed as the slagging agents. And then the impact factors on the removal efficiency of boron such as the composition of SiO2 and Na2CO3, the ratio of slag to silicon and the refining time were investigated by the orthogonal experiment. The results showed that the optimum parameters of the oxidation refining for removing boron were as follows: the main composition of the oxidant is “SiO2 : Na2CO3 = 60% : 40%”; the slag/silicon ratio is 0.5; time for refining is 60min at 1550 . The results indicated that the removal efficiency of boron was 88.28%, and the content of boron in MG-Si can be reduced to 7ppmw under the best refining process¬.


2018 ◽  
Vol 115 (3) ◽  
pp. 312 ◽  
Author(s):  
Rowaid Al-khazraji ◽  
Yaqiong Li ◽  
Lifeng Zhang

Boron (B) removal by slag refining using CaO–SiO2–CaCl2 was investigated in metallurgical-grade silicon (MG-Si) and 75 wt% Si–Sn alloy. Experiments were conducted at 1500 °C for 15 min. The microstructure was characterized before and after refining. The effects of acid leaching, basicity, and slag/Si mass ratio on B removal were investigated. Experimental results showed that acid leaching had no effect on B removal from MG-Si but had a clear effect on the refined Si–Sn alloy after slag refining. The final B concentration was highly affected by the CaO/SiO2 mass ratio with minimum value, where the content of B was reduced from 18.36 ppmw to 5.5 ppmw at the CaO/SiO2 = 1.2 for MG-Si slag refining and from 18.36 ppmw to 3.7 ppmw at CaO/SiO2 = 1.5 for 75 wt% Si–Sn alloy. Increasing the slag mass ratio by 2:1 mass ratio also increased B removal efficiency by approximately 15–20% more than an increase by 1:1.


Author(s):  
K. C. Manjunatha ◽  
H. S. Mohana ◽  
P. A. Vijaya

Intelligent process control technology in various manufacturing industries is important. Vision-based non-magnetic object detection on moving conveyor in the steel industry will play a vital role for intelligent processes and raw material handling. This chapter presents an approach for a vision-based system that performs the detection of non-magnetic objects on raw material moving conveyor in a secondary steel-making industry. At single camera level, a vision-based differential algorithm is applied to recognize an object. Image pixels-based differential techniques, optical flow, and motion-based segmentations are used for traffic parameters extraction; the proposed approach extends those futures into industrial applications. The authors implement a smart control system, since they can save the energy and control unnecessary breakdowns in a robust manner. The technique developed for non-magnetic object detection has a single static background. Establishing background and background subtraction from continuous video input frames forms the basis. Detection of non-magnetic materials, which are moving with raw materials, and taking immediate action at the same stage as the material handling system will avoid the breakdowns or power wastage. The authors achieve accuracy up to 95% with the computational time of not more than 1.5 seconds for complete system execution.


2018 ◽  
pp. 1820-1837
Author(s):  
K. C. Manjunatha ◽  
H. S. Mohana ◽  
P. A. Vijaya

Intelligent process control technology in various manufacturing industries is important. Vision-based non-magnetic object detection on moving conveyor in the steel industry will play a vital role for intelligent processes and raw material handling. This chapter presents an approach for a vision-based system that performs the detection of non-magnetic objects on raw material moving conveyor in a secondary steel-making industry. At single camera level, a vision-based differential algorithm is applied to recognize an object. Image pixels-based differential techniques, optical flow, and motion-based segmentations are used for traffic parameters extraction; the proposed approach extends those futures into industrial applications. The authors implement a smart control system, since they can save the energy and control unnecessary breakdowns in a robust manner. The technique developed for non-magnetic object detection has a single static background. Establishing background and background subtraction from continuous video input frames forms the basis. Detection of non-magnetic materials, which are moving with raw materials, and taking immediate action at the same stage as the material handling system will avoid the breakdowns or power wastage. The authors achieve accuracy up to 95% with the computational time of not more than 1.5 seconds for complete system execution.


2009 ◽  
Vol 72 (4) ◽  
pp. 826-836 ◽  
Author(s):  
BERNHARD NOWAK ◽  
THEDA von MUEFFLING

The aim of this investigation was to develop a treatment for combined porcine blood corpuscle concentrate (BCC) and porcine collagenous connective tissue (rind) so as to make more use of these slaughter by-products as an ingredient in a high-quality product such as salami-type sausage. For this study, BCC was preserved, standardized (sBCC) (15% NaCl and 25% protein content), and then added (proportion of sBCC to rind, 15:85) to rind subjected to different treatments designated A, B, and C (A, 2 h at 90°C; B, 5 min at 90°C; and C, 2 h at 3°C). One half of each mixture was again heated (designated A1, B1, and C1; F70, ∼15), and the other half was only cooled (designated A2, B2, and C2). The now colored, highly proteinaceous rind mixtures (A1 to C2) were then cooled and granulated (designated GBR-A1 to GBR-C2). Three of the granulates (GBRA1, -B1, and -B2) proved to be promising new raw materials: their aerobic plate counts were <log 4.0 CFU/g, and their color was appealing (L* values, 23.9 to 25.9; a* values, 17.7 to 22.2; b* values, 11.5 to 12.7). These granulates were then substituted for part (5%) of the meat in the production of fermented raw salami-type sausages. Two of the sausages (SA1 and SB1) were microbiologically stable (containing mainly lactobacilli) and had positive sensory, chemical, and physical properties (e.g., protein, 21%; water activity, 0.90; pH, between 5.3 and 5.4 on day 36) meeting all standards for commercially produced raw sausages. Our investigation yielded a practicable way to treat and combine two slaughter by-products for use in a high-quality meat product.


2013 ◽  
Vol 815 ◽  
pp. 773-777
Author(s):  
Liu Qing Huang ◽  
Hui Xian Lai ◽  
Ming Fang ◽  
Cheng Hao Lu ◽  
Juan Chen ◽  
...  

This paper presents a detailed analysis of the effect of slag refining and vacuum treatment on P removal from metallurgical-grade silicon using CaO-SiO2-CaCl2 slag. It demonstrates that both of CaO: SiO2 ratio and CaCl2 content have significant effects on the P removal. Increasing CaO: SiO2 ratio was found to decrease the P removal efficiency after slag refining and vacuum treatment, and the distribution of P shows a tendency to concentrate in the precipitated phase after slag refining. It is also determined that the highest removal efficiency of P was attained when CaCl2 content was 5wt%( CaO:SiO2=1:1), but no obvious change was observed on P distribution after slag refining of varying CaCl2 content.


2013 ◽  
Vol 813 ◽  
pp. 11-15
Author(s):  
Liu Qing Huang ◽  
Hui Xian Lai ◽  
Cheng Hao Lu ◽  
Ming Fang ◽  
Juan Chen ◽  
...  

This paper presents a detailed analysis of impurities distribution in metallurgical-grade silicon after CaO-SiO2-CaF2 and CaO-SiO2-CaCl2 slags refining. It demonstrates that the impurities removal efficiency generally increase in metallurgical-grade silicon after CaO-SiO2-CaCl2 slag refining compared to that after CaO-SiO2-CaF2 slag refining. It is also determined that metallic impurities like Fe, Al and Ca tend to co-deposit with Si to form Si-Ca based intermetallic compounds in the precipitate phase after slag refining.


Author(s):  
L. E. Glagoleva ◽  
N. P. Zatsepilina ◽  
M. V. Kopylov ◽  
S. O. Rodionov

The leading direction in the field of nutrition is the creation of a range of products that contribute to improving health when they are used daily in the diet. The urgency of studying bovine colostrum-colostrum, which is an immune-modeling animal raw material, has been substantiated. Colostrum is a natural source of all the ingredients needed to build immunity. Biologically active substances contained in cow colostrum contribute to: restoration of immunity; restoration of the intestines and stomach; strengthening the nervous system; renewal of brain cells; improving emotional tone and mood; increasing vitality and performance; slowing down the aging process; protection against diseases of the intestines and stomach, cardiovascular system, respiratory tract, diabetes, allergies, osteoporosis and a number of other diseases. Colostrum contains a minimum of 37 immune factors and 8 growth factors that help the body fight disease and promote good health and longevity. The classes of immunoglobulins contained in colostrum, which represent the bulk of whey proteins, have been studied. Colostrum is a limited source of raw materials, its production period is short, there are many opportunities for industrial use, but due to the small amount of raw materials, the market remains undeveloped, with the exception of food additives. Taking into account the extensive therapeutic and medicinal properties of colostrum, its unique composition and properties, its composition and physicochemical properties were investigated, the fractionation parameters were determined using various systems. To process the experimental studies, the STATISTICA 12 software package was used. To obtain the regression equation, the matrix data were processed using the Microsoft Excel 2010 software package. The analysis of the data obtained indicates the possibility and prospects of using colostroma in food production technology.


2020 ◽  
Vol 10 (18) ◽  
pp. 6222 ◽  
Author(s):  
Girts Bumanis ◽  
Jelizaveta Zorica ◽  
Diana Bajare

The potential of phosphogypsum (PG) as secondary raw material in construction industry is high if compared to other raw materials from the point of view of availability, total energy consumption, and CO2 emissions created during material processing. This work investigates a green hydraulic ternary system binder based on waste phosphogypsum (PG) for the development of sustainable high-performance construction materials. Moreover, a simple, reproducible, and low-cost manufacture is followed by reaching PG utilization up to 50 wt.% of the binder. Commercial gypsum plaster was used for comparison. High-performance binder was obtained and on a basis of it foamed lightweight material was developed. Low water-binder ratio mixture compositions were prepared. Binder paste, mortar, and foamed binder were used for sample preparation. Chemical, mineralogical composition and performance of the binder were evaluated. Results indicate that the used waste may be successfully employed to produce high-performance binder pastes and even mortars with a compression strength up to 90 MPa. With the use of foaming agent, lightweight (370–700 kg/m3) foam concrete was produced with a thermal conductivity from 0.086 to 0.153 W/mK. Water tightness (softening coefficient) of such foamed material was 0.5–0.64. Proposed approach represents a viable solution to reduce the environmental footprint associated with waste disposal.


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