Function mechanism of CO-CO2 atmosphere on the formation of Na2SnO3 from SnO2 and Na2CO3 during the roasting process

2016 ◽  
Vol 301 ◽  
pp. 102-109 ◽  
Author(s):  
Bingbing Liu ◽  
Yuanbo Zhang ◽  
Zijian Su ◽  
Guanghui Li ◽  
Tao Jiang
Keyword(s):  
Function Mechanism ◽  
Roasting Process ◽  
Co2 Atmosphere

scholarly journals Effect of Quartz on the Preparation of Sodium Stannate from Cassiterite Concentrates by Soda Roasting Process

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 605
Author(s):  
Yuanbo Zhang ◽  
Benlai Han ◽  
Zijian Su ◽  
Xijun Chen ◽  
Manman Lu ◽  
...  
Keyword(s):  
Mole Fraction ◽  
Silicon Content ◽  
Ph Value ◽  
Phase Evolution ◽  
Conversion Ratio ◽  
Roasting Process ◽  
Value Range ◽  
Sodium Stannate ◽  
Roasting Temperature ◽  
Co2 Atmosphere

Sodium stannate (Na2SnO3) has been successfully prepared by a novel process of roasting cassiterite concentrates and sodium carbonate (Na2CO3) under CO–CO2 atmosphere, namely soda roasting-leaching process. However, more than 22 wt. % tin of the cassiterite was not converted into Na2SnO3 and entered the leach residues. Quartz (SiO2) is the predominant gangue in the cassiterite, and phase evolution of SnO2–SiO2–Na2CO3 system roasted under CO–CO2 atmosphere was still uncertain. In this study, the effect of SiO2 in cassiterite concentrates on preparation of Na2SnO3 was clarified. The results indicated that Na8SnSi6O18 was inevitably formed when cassiterite and Na2CO3 were roasted above 775 °C under CO–CO2 atmosphere via the reaction of SnO2 + 6SiO2 + 4Na2CO3 = Na8SnSi6O18 + 4CO2, and formation of Na8SnSi6O18 would be increased with increasing roasting temperature and Si/Sn mole fraction. In addition, it was found that Na8SnSi6O18 was insoluble in the leachate at pH value range of 1–14, which, therefore, was enriched in the leach residues. The silicon content of the cassiterite concentrates should be controlled as lower as possible to obtain a higher conversion ratio of Na2SnO3.

How Does Roasting Process Influence the Retention of Coffee Aroma Compounds by Lyophilized Coffee Extract?

2008 ◽  
Vol 73 (3) ◽  
pp. S165-S171 ◽  
Author(s):  
I. López-Galilea ◽  
I. Andriot ◽  
M. P. de Peña ◽  
C. Cid ◽  
E. Guichard
Keyword(s):  
Aroma Compounds ◽  
Roasting Process

scholarly journals Carbothermic Reduction and Nitridation Mechanism of Vanadium-Bearing Titanomagnetite Concentrate

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 730
Author(s):  
Wen Yu ◽  
Xiaojin Wen ◽  
Wei Liu ◽  
Jiangan Chen
Keyword(s):  
Phase Transformation ◽  
Carbothermic Reduction ◽  
Titanium Oxides ◽  
Distribution Characteristic ◽  
Reaction Behavior ◽  
Microstructure Transformation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Roasting Process ◽  
Rate Limiting

In this study, the carbothermic reduction and nitridation mechanism of vanadium-bearing titanomagnetite concentrate are investigated in terms of phase transformation, microstructure transformation, and thermodynamic analyses. The differences in the reaction behavior of titanomagnetite and ilmenite in vanadium-bearing titanomagnetite concentrate, as well as the distribution characteristic of V in the roasted products, are emphatically studied. It is observed that the reaction sequences of titanomagnetite and ilmenite transformations into nitride are as follows: Fe3−xTixO4→Fe2TiO4→FeTiO3→M3O5→(Ti, V)(N, C); FeTiO3→M3O5→Ti(N, C). The reduction of M3O5 to TiN is the rate-limiting step of the entire reaction, and metal iron is an important medium for transferring C for the reduction of M3O5. Titanomagnetite is faster to convert into nitride than ilmenite is, and the reasons for this are discussed in detail. During the entire roasting process, V mainly coexists with Ti and seems to facilitate the conversion of titanium oxides into (Ti, V)(N, C).

scholarly journals An Experimental Study of the Decomposition and Carbonation of Magnesium Carbonate for Medium Temperature Thermochemical Energy Storage

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1316
Author(s):  
Daniel Mahon ◽  
Gianfranco Claudio ◽  
Philip Eames
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Energy Storage ◽  
Magnesium Carbonate ◽  
Experimental Results ◽  
Future Research ◽  
Medium Temperature ◽  
Different Temperatures ◽  
Decomposition Enthalpy ◽  
Co2 Atmosphere

To improve the energy efficiency of an industrial process thermochemical energy storage (TCES) can be used to store excess or typically wasted thermal energy for utilisation later. Magnesium carbonate (MgCO3) has a turning temperature of 396 °C, a theoretical potential to store 1387 J/g and is low cost (~GBP 400/1000 kg). Research studies that assess MgCO3 for use as a medium temperature TCES material are lacking, and, given its theoretical potential, research to address this is required. Decomposition (charging) tests and carbonation (discharging) tests at a range of different temperatures and pressures, with selected different gases used during the decomposition tests, were conducted to gain a better understanding of the real potential of MgCO3 for medium temperature TCES. The thermal decomposition (charging) of MgCO3 has been investigated using thermal analysis techniques including simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), TGA with attached residual gas analyser (RGA) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) (up to 650 °C). TGA, DSC and RGA data have been used to quantify the thermal decomposition enthalpy from each MgCO3.xH2O thermal decomposition step and separate the enthalpy from CO2 decomposition and H2O decomposition. Thermal analysis experiments were conducted at different temperatures and pressures (up to 40 bar) in a CO2 atmosphere to investigate the carbonation (discharging) and reversibility of the decarbonation–carbonation reactions for MgCO3. Experimental results have shown that MgCO3.xH2O has a three-step thermal decomposition, with a total decomposition enthalpy of ~1050 J/g under a nitrogen atmosphere. After normalisation the decomposition enthalpy due to CO2 loss equates to 1030–1054 J/g. A CO2 atmosphere is shown to change the thermal decomposition (charging) of MgCO3.xH2O, requiring a higher final temperature of ~630 °C to complete the decarbonation. The charging input power of MgCO3.xH2O was shown to vary from 4 to 8136 W/kg with different isothermal temperatures. The carbonation (discharging) of MgO was found to be problematic at pressures up to 40 bar in a pure CO2 atmosphere. The experimental results presented show MgCO3 has some characteristics that make it a candidate for thermochemical energy storage (high energy storage potential) and other characteristics that are problematic for its use (slow discharge) under the experimental test conditions. This study provides a comprehensive foundation for future research assessing the feasibility of using MgCO3 as a medium temperature TCES material. Future research to determine conditions that improve the carbonation (discharging) process of MgO is required.

Efficient Recycling of Silver and Copper from Sintering Dust by Chlorination Roasting Process

2021 ◽  
Author(s):  
Hailin Long ◽  
Kaihua Chen ◽  
Caixia Xu ◽  
Haoyu Li ◽  
Huimin Xie ◽  
...  
Keyword(s):  
Roasting Process ◽  
Chlorination Roasting

scholarly journals Oxidation Roasting of Fine-Grained Carbonaceous Gold Ore: The Effect of Aeration Rate

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 558
Author(s):  
Hui Li ◽  
Wei Xiao ◽  
Jianping Jin ◽  
Yuexin Han
Keyword(s):  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Aeration Rate ◽  
Practical Significance ◽  
Gold Ore ◽  
Fine Grained ◽  
Roasting Process ◽  
Chemical Groups ◽  
Fine Carbon ◽  
Fine Gold

The oxidation roasting of carbon-bearing micro-fine gold can eliminate or weaken the robbing effect of carbonaceous materials and clay, and destroy the encapsulation of micro-fine gold. The micropores produced by gas escaping during the roasting process are conducive to the diffusion of leaching agents, thus enhancing the cyanide leaching of gold. In this paper, the influence of the aeration rate during roasting on the leaching rate of fine-grained carbonaceous gold ore and its mechanism were studied using thermodynamic calculations, crystal structure analysis, surface chemical groups and bonds analysis, microporous structure analysis, and surface morphology detection. Under suitable roasting conditions, the carbonaceous and pyrite in the ore are oxidized, while carbonate minerals such as dolomite and calcite as well as clay minerals are decomposed, and the gold-robbing materials lose their activity. The experimental results have theoretical and practical significance for the popularization and application of oxidation roasting technology of fine carbon-bearing gold ore.

Thermoelectric properties of PEDOT:PSS aerogel secondary-doped in supercritical CO2 atmosphere with low thermal conductivity

Polymer ◽  
2020 ◽  
Vol 206 ◽  
pp. 122912
Author(s):  
Naoya Yanagishima ◽  
Shinji Kanehashi ◽  
Hiromu Saito ◽  
Kenji Ogino ◽  
Takeshi Shimomura
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Supercritical Co2 ◽  
Low Thermal Conductivity ◽  
Co2 Atmosphere

Growth, seed yield and nutritional characteristics of pigeonpea grown under elevated CO2 atmosphere

2021 ◽  
Vol 43 (5) ◽  
Author(s):  
Divya K. Unnikrishnan ◽  
Rachapudi V. Sreeharsha ◽  
Attipalli R. Reddy
Keyword(s):  
Elevated Co2 ◽  
Seed Yield ◽  
Nutritional Characteristics ◽  
Co2 Atmosphere

Novel Green Method for the Synthesis of Monoacetin over Bifunctional Cu–Cr Phosphates under the CO2 Atmosphere

2020 ◽  
Author(s):  
Wei Luo ◽  
Yanqiu Chen ◽  
Junhua Liu ◽  
Yue Yang ◽  
Fang Wang ◽  
...  
Keyword(s):  
Green Method ◽  
Co2 Atmosphere
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