scholarly journals Solar Metallurgy for Sustainable Zn and Mg Production in a Vacuum Reactor Using Concentrated Sunlight

2020 ◽  
Vol 12 (17) ◽  
pp. 6709 ◽  
Author(s):  
Srirat Chuayboon ◽  
Stéphane Abanades
Keyword(s):  
Carbon Black ◽  
Metal Oxides ◽  
Activated Charcoal ◽  
Carbothermal Reduction ◽  
Total Pressure ◽  
Operation Mode ◽  
Inert Atmosphere ◽  
Pure Metal ◽  
Reactor Outlet ◽  
Reaction Extent

Solar carbothermal reduction of volatile metal oxides represents a promising pyro-metallurgical pathway for the sustainable conversion of both metal oxides and sunlight into metal commodities and fuels in a single process. Nevertheless, there are several scientific challenges in discovering suitable metal oxides candidates for the ease of oxygen extraction from metal oxides to enhance the reaction extent and in designing reactors for the efficient absorption of incident solar radiation to minimize losses. In this study, ZnO and MgO were considered as volatile metal oxides candidates, and their reaction behaviors were studied and compared through gas species production rate, metal oxides conversion, and yield. A solar reactor prototype was developed to facilitate solar carbothermal reduction of ZnO and MgO with different reducing agents comprising activated charcoal and carbon black. The process was operated in a batch operation mode under vacuum and atmospheric pressures to demonstrate the flexibility and reliability of this system for co-production of metals (Zn/Mg) and CO. As a result, decreasing total pressure enhanced conversion of ZnO and MgO, leading to increased Zn and Mg. However, in the case of ZnO, CO yield decreased with decreasing total pressure at the expense of favored CO2 as a result of the decrease of residence time. In contrast, CO2 formation was negligible in the case of MgO, and CO yield thus increased with decreasing pressure. Using activated charcoal as the reducing agent exhibited better conversion of both ZnO and MgO than carbon black thanks to the higher available specific surface area for chemical reactions. MgO and ZnO conversion above 97% and 78%, respectively, and high-purity Mg and Zn content were accomplished, as evidenced by the recovered products at the reactor outlet and filter containing pure metal. In addition, Mg product exhibited strong oxidation reactivity with air, thus requiring inert atmosphere for the handling of Mg-rich powders to avoid direct exposure to air.

scholarly journals Ultrafast carbothermal reduction of silica to silicon using a CO2 laser beam

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Seok-Ho Maeng ◽  
Hakju Lee ◽  
Min Soo Park ◽  
Suhyun Park ◽  
Jaeki Jeong ◽  
...  
Keyword(s):  
Carbon Black ◽  
Laser Beam ◽  
Carbothermal Reduction ◽  
Gas Flow ◽  
Crystalline Silicon ◽  
Reduction Process ◽  
Reaction Chamber ◽  
Raman Shift ◽  
Influence Of Process Parameters ◽  
Laser Beam Intensity

AbstractWe report the extraction of silicon via a carbothermal reduction process using a CO2 laser beam as a heat source. The surface of a mixture of silica and carbon black powder became brown after laser beam irradiation for a few tens of seconds, and clear peaks of crystalline silicon were observed by Raman shift measurements, confirming the successful carbothermal reduction of silica. The influence of process parameters, including the laser beam intensity, radiation time, nitrogen gas flow in a reaction chamber, and the molar ratios of silica/carbon black of the mixture, on the carbothermal reduction process is explained in detail.

Synthesis of SiC Nanowires with Silica Sol and Carbon Black

2011 ◽  
Vol 287-290 ◽  
pp. 449-452
Author(s):  
Yi Wei ◽  
Fu Wang ◽  
Wen Bin Cao
Keyword(s):  
Carbon Black ◽  
Carbothermal Reduction ◽  
Graphite Crucible ◽  
Silica Sol ◽  
Sic Nanowires ◽  
Graphite Plate ◽  
Vs Mechanism ◽  
Acetylene Carbon ◽  
Acetylene Carbon Black ◽  
Sic Particle

Nanometer-sized β-SiC were synthesized by carbothermal reduction of silica sol with acetylene carbon black at 1600 °C for 2h. Three kinds (straight, bamboo-like, branch-like) of SiC nanowires were deposited on the graphite plate, while SiC particle agglomerates and nanowires were formed in the graphite crucible. All the nanowires were formed via VS mechanism through the reaction between gaseous SiO and CO produced from the process of carbothermal reduction.

Accessibility of the Carbon Black Particle Surface to Elastomers

1970 ◽  
Vol 43 (2) ◽  
pp. 464-469 ◽  
Author(s):  
P. Aboytes ◽  
A. Voet
Keyword(s):  
Carbon Black ◽  
Particle Surface ◽  
Carbon Black Particle ◽  
Carbon Chain ◽  
Chain Structure ◽  
Inert Atmosphere ◽  
Chemical Surface ◽  
Molecular Weights ◽  
Surface Areas ◽  
Black Surface

Abstract Experimental carbon blacks were prepared with the generally encountered slit-shaped pores of discrete dimensions of 9,12.5, and 16 A˚ width in greatly differing size distribution. Equilibrium adsorption in the saturation range was determined in n-hexane for butadiene—styrene elastomers of the SBR type of average molecular weights of 1500; 2000; 15,000; and 300,000. In attempting to correlate the saturation adsorption values with carbon black surface areas, it was found that a simple linear relation in the range investigated could only be obtained by assuming that pores of 9 A˚ width were inaccessible to SBR of 1500 and 2000 MW; that pores of 9 and 12.5 A˚ width were inaccessible to SBR of 15,000 MW; and that all pores smaller than 20 A˚ width were inaccessible to SBR of 300,000 MW. The data indicated that there are no differences between high, regular and low structure blacks in saturation elastomer adsorption under conditions of equivalent dispersion. Equally, upon breaking the persistent carbon chain structure by dry ball milling in an inert atmosphere and equalizing the chemical surface properties by removal of surface oxides, no difference in elastomer adsorption from solution was observed. It must be concluded that commonly used high molecular elastomers do not have any access to smaller carbon black pores. Since access to the surface is a prerequisite for reinforcement, it is obvious that the surface in the pores of carbon black generally does not participate in reinforcing elastomers. The elastomer adsorbed per unit external black surface area appears to be independent of the carbon chain structure, indicating that the so called surface activity of the carbon black is independent of the chain length.

The Effect of Gadolinium Ion Doping on Electronic Conductivity of LiFePO4/C

2020 ◽  
Vol 860 ◽  
pp. 69-74
Author(s):  
Iman Rahayu ◽  
Engela Evy Ernawati ◽  
Atiek Rostika Noviyanti ◽  
Yusra Linda ◽  
Diana Rakhmawaty ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Carbon Black ◽  
Carbothermal Reduction ◽  
Carbon Coating ◽  
Electronic Conductivity ◽  
Synthesis Method ◽  
Lithium Ion ◽  
The Poor ◽  
Ion Doping ◽  
High Theoretical Capacity

In the recent years, LiFePO4 has been widely developed as a cathode for lithium ion batteries because it has high theoretical capacity (170 mAh/g), good stability and is also environmentally friendly. However, the poor electronic conductivity (~10-9 S/cm) and low diffusion coefficient of lithium ion (~10-15-10-14 cm2/s) are limiting its application. Some solutions to overcome this problem are carbon coating and doping metal ions. This study aims to determine the effect of Gd3+ ion doping on the electronic conductivity of LiFePO4/C. The synthesis method was used is carbothermal reduction with Fe2O3, Gd2O3, LiH2PO4 and carbon black reagents. The synthesized LiFe1-xGdxPO4/C was characterized using XRD, SEM-EDS, and four point probes. The results obtained showed that gadolinium ion doping increased the conductivity of LiFePO4/C from 1.8952 x10-6 to 8.69x10-6 Scm-1 using 0.07 mol ion Gd3+.

Sintering of Commercial B4C with Synthesized B4C Additions

2008 ◽  
Vol 591-593 ◽  
pp. 588-592
Author(s):  
Rosa Maria da Rocha ◽  
Jonas S. Gutierres ◽  
Francisco Cristóvão Lourenço de Melo
Keyword(s):  
Thermal Stability ◽  
Carbon Source ◽  
Carbon Black ◽  
Boron Carbide ◽  
Carbothermal Reduction ◽  
Pressureless Sintering ◽  
High Chemical ◽  
Powder Mixtures ◽  
B4c Powder ◽  
Sintered Materials

Boron Carbide is a ceramic material of technological application due to its extreme hardness and high chemical and thermal stability. The effect of synthesized boron carbide addition on pressureless sintering and hot-pressing of a commercial B4C was investigated. B4C synthesized by carbothermal reduction using carbon black as carbon source was mixtured in 10, 30 and 50 wt% to a commercial B4C. Powder mixtures were compacted into pellets and sintered by pressureless sintering at 2050 °C/30min Samples were compared to a pure commercial B4C and characterization results have not showed great differences. Relative densities of as-sintered materials exceed 93% of theoretical for all compositions and microhardness Hv of ∼ 32 GPa was obtained.

THE ADSORPTION OF SODIUM MYRISTATE BY CARBON BLACK

1949 ◽  
Vol 27f (11) ◽  
pp. 426-428 ◽  
Author(s):  
Marguerite A. Reade ◽  
A. S. Weatherburn ◽  
C. H. Bayley
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Fatty Acid ◽  
Carbon Black ◽  
Surface Area ◽  
Activated Charcoal ◽  
Carbon Blacks ◽  
Preferential Adsorption

The adsorption of sodium myristate from 0.1% aqueous solution by a series of carbon blacks and an activated charcoal has been measured at 70 °C. In every case a preferential adsorption of fatty acid was observed. The extent of adsorption of both the fatty acid and alkali components of the soap increased with decreasing particle size, i.e., with increasing surface area, of the carbons. The adsorption by activated charcoal was considerably higher than that obtained with even the finest of the carbon blacks.

scholarly journals Influence of Desulfurization with Fe2O3 on the Reduction of Nickel Converter Slag

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2423
Author(s):  
Guangsheng Wei ◽  
Yun Wang ◽  
Rong Zhu ◽  
Lingzhi Yang
Keyword(s):  
Metal Oxides ◽  
Sulfur Content ◽  
Carbothermal Reduction ◽  
Converter Slag ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Copper Recovery ◽  
Desulfurization Rate ◽  
Residual Sulfur ◽  
Nickel Converter

Generally in the nickel converter slag, metals are mainly in the form of sulfides, which are difficult to separate from slag. Although metal oxides in the slag, such as NiO, CoO, and Cu2O, are easily reduced into metal using carbon, the presence of sulfur inhibits the reduction reaction. In this study, the addition of Fe2O3 to nickel converter slag produced desulfurized slag, which enhanced the carbothermal reduction process. Increasing the desulfurization rate promoted the conversion of sulfides into oxides in slag, which significantly increased the activity of NiO, Cu2O, and Fe2O3. However, the residual sulfur content had no significant effect on the activity of FeO and CoO, due to the high initial FeO content and cobalt existing mainly in the form of oxides. The optimum addition of Fe2O3 was 15.0 g per 100 g nickel slag, while the desulfurization ratio was 36.84% and the rates of nikel, cobalt and copper recovery were 95.33%, 77.73%, and 73.83%, respectively.

Effect of MgO Coating on the Hydration Resistance of MgO-CaO Clinkers

2011 ◽  
Vol 695 ◽  
pp. 324-327 ◽  
Author(s):  
Hong Feng Yin ◽  
Yan Long Ma ◽  
Jun Yang
Keyword(s):  
Carbon Source ◽  
Carbon Black ◽  
Reaction Temperature ◽  
Carbothermal Reduction ◽  
Processing Parameters ◽  
Holding Time ◽  
Deposition Mechanism ◽  
The Poor ◽  
Hydration Resistance ◽  
Prolonged Holding

To overcome the disadvantage of MgO-CaO refractories, as the poor hydration resistance, MgO coating on the MgO-CaO clinker was fabricated by carbothermal reduction MgO with carbon as reduction agent and then the oxidation of Mg vapor. Effect of processing parameters (such as carbon source, reaction temperature and holding time) on the hydration resistance of MgO-CaO clinkers were investigated by hydration resistance test and SEM. The results indicated that the hydration resistance of treated MgO-CaO clinkers was improved when carbon black was used as reduction agent due to easy reaction with MgO than the graphite and coke. The high reaction temperature among 1450~1600°C and prolonged holding time within 4 h resulted in improvement of the hydration resistance of treated MgO-CaO clinker. Deposition mechanism of MgO coating on the MgO-CaO clinker was discussed.

Synthesis of Rod-Like α-SiAlON by Carbothermal Reduction-Nitridation

2008 ◽  
Vol 368-372 ◽  
pp. 888-890
Author(s):  
Xian Feng Leng ◽  
Yan Gai Liu ◽  
Ming Hao Fang ◽  
Zhao Hui Huang
Keyword(s):  
Carbon Black ◽  
Reaction Temperature ◽  
Carbothermal Reduction ◽  
Addition Agent ◽  
Pure Sio2

Rod-like α-sialon was synthesized successfully using pure SiO2 and AlN as the starting materials, carbon black as reductant, CaF2 and Y2O3 as addition agent by carbothermal reduction-nitridation. The effects of reaction temperature (1450°C, 1500°C, 1600°C and 1700°C) and additive (Li2CO3, CaF2, Y2O3 and Y2O3+CaF2) on phases and microstructure of the final products were studied by XRD and SEM. The results showed that α-sialon was synthesized by carbothermal reduction-nitridation at 1700°C for 3 hours. The morphology of the synthesized α-sialon was rod-like.

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