The mercury removal mechanism of selenium mercury material by soda roasting

2021 ◽  
Vol 118 (5) ◽  
pp. 513
Author(s):  
Shan Zhu ◽  
Na Yang ◽  
Lin Zhang
Keyword(s):  
Activation Energy ◽  
Kinetic Equation ◽  
Dynamic Model ◽  
Raw Material ◽  
Mercury Removal ◽  
Internal Diffusion ◽  
Removal Mechanism ◽  
Roasting Process ◽  
Model Control ◽  
Control Step

In the present work, Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were employed in the investigation of roasting mechanism, roasting dynamic model, control step of soda roasting process of selenium–mercury material. The results indicated that at the beginning of the roasting process, the control step might be interface chemical reaction for the first 30 min, and the kinetic equation might be 1−(1−R)⅓ = Kt with a activation energy E1 = 40.50 kT/mol. However, as the roasting proceeded, internal diffusion gradually became the control step for 90–135 min, and the kinetic equation might be 1−⅔R−(1−R)⅔ = Dt with a activation energy E2 = 6.75 kT/mol. The SEM analysis of the roasted selenium–mercury materials indicated that the dynamic model of soda roasting attributed to the shrinkage model was reasonable. Combined with the results obtained by SEM and EDS of the roasted selenium–mercury materials, we concluded that the addition of too much Na2CO3 might lead to the formation of molten crystalline phase in the inner of the roasted selenium–mercury materials, changing the mercury removal mechanism of the roasting process. Meanwhile, Se had a tendency to segregate at where the content of Na was relatively high. In order to study the mechanism of diffusion, Na2O2 of 9% was added to one of the samples. According to the results, we concluded that the diffusion of products (such as HgxOy) from the inside of the raw material was the control step of internal diffusion.

scholarly journals Tagasaste, leucaena and paulownia: three industrial crops for energy and hemicelluloses production

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  
Keyword(s):  
Activation Energy ◽  
Acid Hydrolysis ◽  
Energy Production ◽  
Combustion Process ◽  
Operating Conditions ◽  
Raw Material ◽  
Energy Of Combustion ◽  
Increasing Temperature ◽  
Hydrolysis Of ◽  
Chamaecytisus Proliferus

Abstract Background Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production. Results The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses. Conclusions Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.

Molecular-level insights into mercury removal mechanism by pyrite

2018 ◽  
Vol 344 ◽  
pp. 104-112 ◽  
Author(s):  
Yingju Yang ◽  
Jing Liu ◽  
Feng Liu ◽  
Zhen Wang ◽  
Sen Miao
Keyword(s):  
Molecular Level ◽  
Mercury Removal ◽  
Removal Mechanism

Dynamic Model of Rapeseed Oil Hydrolysis Reaction in Sub-Critical Water

2013 ◽  
Vol 860-863 ◽  
pp. 510-513 ◽  
Author(s):  
Yi Zhe Li ◽  
Hua Wang ◽  
Gui Rong Bao
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Dynamic Model ◽  
Rapeseed Oil ◽  
Reaction Order ◽  
Volume Ratio ◽  
Hydrolysis Reaction ◽  
Water Volume ◽  
Oil Water ◽  
Oil Hydrolysis

Experiments of Rapeseed Oil Hydrolysis Reaction in Sub-Critical Water (250-300°C, 5-60min) are Conducted in this Paper. Results Show that the Best Conditions for Rapeseed Oil Hydrolysis are Reaction Temperature 290°C, Oil-Water Volume Ratio 1:3, Reaction Time 40min, and Conversion Rate 98.9%. Meanwhile, Kinetic Analysis of this Hydrolysis Reaction is Presented. we Learn that Hydrolysis Reaction Order is 0.7778, Activation Energy is 55.34kJ/mol and the Dynamic Model is .

Synthesis of Lanthanum Oxide Using Lanthanum Chloride by Hydrogen-Oxygen Flame Pyrolysis Route

2014 ◽  
Vol 633-634 ◽  
pp. 499-503 ◽  
Author(s):  
Shou Feng Xue ◽  
Wen Yuan Wu ◽  
Xue Bian ◽  
Zhen Feng Wang ◽  
Zhi Ren Yang
Keyword(s):  
Rare Earth ◽  
Lanthanum Oxide ◽  
New Technology ◽  
Air Pollutant ◽  
Lanthanum Chloride ◽  
Raw Material ◽  
Rare Earth Compound ◽  
Roasting Process ◽  
Hydrogen Flame ◽  
Water Pollutant

Nowadays, people should pay more attention on the environment problems that had advent along with the development of rare earth metallurgy industry. A large number of water pollutant, air pollutant and solid pollutant were discharged in the process of synthesis of rare earth compound by precipitation and roasting process. In order to solve the industry pollution problems, a new technology route was developed for the preparation of lanthanum oxide using lanthanum chloride as raw material by oxy-hydrogen flame route. The experiment results showed that lanthanum chloride could directly convert to lanthanum oxide under high temperature by the combustion of mixture gas of hydrogen-oxygen that provided by oxy-hydrogen generator continuously. The phase composition of obtained product was characterized by XRD and the conversion rate of lanthanum chloride and the reaction mechanism were discussed.

scholarly journals Thermodynamic evaluation of the stabilization indicators of milk quality as influenced by a complex protector

2020 ◽  
Vol 161 ◽  
pp. 01112
Author(s):  
Irina Vladimirovna Davidenko ◽  
Elena Alexandrovna Moliboga ◽  
Dmitry Mikhailovich Ivanov
Keyword(s):  
Activation Energy ◽  
Whey Proteins ◽  
Control Sample ◽  
Weight Ratio ◽  
Milk Proteins ◽  
Fermented Milk ◽  
Raw Material ◽  
Thermodynamic Evaluation ◽  
Organoleptic Characteristics ◽  
Ionic Calcium

In the present article the authors discuss the possibility of increasing of the suitability of milk as a raw material for cheese production through preservation of native properties of milk proteins, in the first place biologically complete whey proteins as well as the weight ratio of total and ionic calcium. For thermodynamic evaluation of the biosystem we used activation energy (Ea), chemical, physical and organoleptic characteristics. As a result: a methodology has been developed for determination of foodstuffs activation energy; it was determined that with increase in the proportion of the pectin introduced the activation energy and structuredness of the biosystem also increases, when the proportion of pectin is 0.5% the activation energy is 1.788 kJ/mol, when the proportion of pectin is 3% the activation energy is 2.241 kJ/mol, which means the increase by 25%; in the studied pasteurization standard, the maximum content of calcium is observed at 85oC and is equal to 133.8 mg%., in the control sample of milk the content of calcium is 130 mg%; addition of a complex food additive as a protector makes it possible to preserve native properties of the biosystem and guarantees formation of a denser protein coagulum which allows producing high-quality fermented milk products and cheeses.

Preparation of Pyrrhotite from Ammonium Jarosite and Estimation of Activation Energy in Reducing Atmosphere

2019 ◽  
Vol 17 (9) ◽  
Author(s):  
Xiaoling Ma ◽  
Hongbin Tan ◽  
Faqin Dong ◽  
Bowen Li ◽  
Jinfeng Liu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Value Added ◽  
Cost Effective ◽  
Raw Material ◽  
Sulfuric Acid Production ◽  
Reducing Atmosphere ◽  
Heat Treated ◽  
Simple Processing ◽  
Oxide Phases ◽  
Ammonium Jarosite

Abstract Ammonium jarosite sediment is a by-product of hydrometallurgical process used to extract zinc metal, which, which contains heavy metal ions and raises severe environmental concerns The transformation of jarosite sediment into high-value-added sulfide products through simple processing is a cost-effective and efficient strategy to overcome environmental and waste management issues. Herein, the influence of sulfur on thermal decomposition of ammonium jarosite is investigated in reducing atmosphere. The results reveal that the presence of sulfur promoted the decomposition of ammonium jarosite and szomolnokite and iron oxide phases have been observed after being heat treated at 300 °C. Moreover, after heat treatment at 700 °C, the decomposition of jarosite/sulfur mixture resulted in the formation of pyrrhotite phase, which can be used as a raw material for sulfuric acid production. Lastly, the activation energy of pyrrhotite formation has been estimated by using KAS equation and found to be 216.2 kJ/mol in reducing atmosphere.

scholarly journals Effects of sodium roasting on the leaching rate of boron-bearing tailings and its mechanism analysis

2018 ◽  
Vol 5 (8) ◽  
pp. 172342
Author(s):  
Chengxi Zou ◽  
Zhenyu Tang ◽  
Wei Xie ◽  
Hanguang Fu ◽  
Jiacai Kuang ◽  
...  
Keyword(s):  
Scientific Basis ◽  
Raw Material ◽  
Sodium Borate ◽  
Mechanism Analysis ◽  
Leaching Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Roasting Process ◽  
Roasting Temperature ◽  
Theoretical Amount

The study reported was intended to improve the leaching rate of boron-bearing tailings, using a method of sodium roasting that uses boron-bearing tailings as the raw material and Na 2 CO 3 as the sodium agent. The effects of the roasting temperature and Na 2 CO 3 amount on the leaching rate of boron-bearing tailings are mainly evaluated. The morphology and composition of the samples after sodium roasting are analysed by scanning electron microscopy and X-ray diffraction. The results show that sodium roasting can significantly improve the leaching rate of boron-bearing tailings. Under the optimal conditions where roasting temperature is 950°C, Na 2 CO 3 amount is five times the theoretical amount and roasting time is 2 h, the leaching rate of boron-bearing tailings is up to 86.78%. Based on the analysis of the characterization results and the mechanism analysis of the sodium roasting process, the main reason for the increase of leaching rate is the reaction between Na 2 O produced by the decomposition of Na 2 CO 3 and the boron in boron-bearing tailings resulting in soluble sodium borate. The results provide a scientific basis for the efficient comprehensive use of boron-bearing tailings.

Methodological approaches to the formation and forecasting of new sectors of the economy of commodity regions

2018 ◽  
Author(s):  
Зоя Васильева ◽  
Zoya Vasil'eva ◽  
Павел Вчерашний ◽  
Pavel Vcherashniy ◽  
Ирина Филимоненко ◽  
...  
Keyword(s):  
Graduate Students ◽  
Conceptual Model ◽  
Dynamic Model ◽  
Technological Development ◽  
Raw Material ◽  
Knowledge Sources ◽  
Krasnoyarsk Region ◽  
Advanced Technologies ◽  
New Knowledge ◽  
Methodological Approaches

The monograph developed: a conceptual model of multi-sector development of the economy of the raw material region; a method of assessing the potential of technological development of the region for "pulling" production chains of advanced technologies: a method of developing scenario options for the development of new sectors of the economy: a quasi-dynamic model of predicting the parameters of new knowledge sources: a method of assessing the integrated effects of technological development; diagnostics of promising technologies for the formation of new sectors of the economy of the Krasnoyarsk region and the forecast until 2030. The monograph can be useful for researchers, specialists involved in the development of the sector economy, as well as teachers, graduate students and masters of economic specialties.

Effects of Reaction Temperature on Hydrocracking of Asphaltene over NiMo/γ-Al2O3

2011 ◽  
Vol 393-395 ◽  
pp. 1189-1192
Author(s):  
Ying Xian Zhao ◽  
Bo Shen
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Molecular Weight ◽  
Kinetic Equation ◽  
Apparent Activation Energy ◽  
Average Molecular Weight ◽  
Liquid Product ◽  
Order Kinetic ◽  
Increasing Temperature ◽  
Order Kinetic Equation

The hydrocracking of a pentane-insoluble asphaltene over NiMo/γ-Al2O3 at 623 - 703 K was investigated. The second order kinetic equation fits experimental data of asphaltene conversion adequately, giving the apparent activation energy to be 144 kJ/mol over the temperature range. Average molecular weight of liquid product was reduced significantly with increasing temperature.

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