scholarly journals Modeling of metals reducing from B2O3-CaO-Fe2O3-ZnO melts by CO-CO2 mixtures

2020 ◽  
Vol 62 (4) ◽  
pp. 94-98
Author(s):  
Alexander S. Vusikhis ◽  
◽  
Evgeny N. Selivanov ◽  
Stanislav N. Tyushnyakov ◽  
Victor P. Chentsov ◽  
...  
Keyword(s):  
Thermodynamic Modeling ◽  
Iron Reduction ◽  
Selective Reduction ◽  
Distillation Process ◽  
Oxide Melt ◽  
Second Stage ◽  
Reduction Processes ◽  
Gas Consumption ◽  
Three Stages ◽  
The Given

Thermodynamic modeling technique has been developed to predict the conditions of metals reduction from oxide melt by gas during bubbling processes. The technique provides approximation to real systems with periodic removal of metal phase and gases from the working body. The given work presents thermodynamic modeling results of Zinc and Iron reduction processes from B2O3-CaO-Fe2O3-ZnО melts by СО-СО2 different composition mixtures in the 1273-1673 K temperature range. Approximation to real processes is used. Zinc and Iron oxides content in the melt and its reducing degree have been estimated during the calculations. Three stages of the process have been obtained by the calculations. Reducing of Fe2O3 to Fe3O4 and FeO is realized in the first stage. Concentration of Fe2O3 (СFe2O3) decreases almost to zero while СFe3O4 и СFeO have been increased simultaneously. Concentration of СFe3O4 reaches its maximum to the end of process. Transition of Fe3O4 → FeO takes place in second stage when СFeO reaches its maximum, and Zinc and Fe begin its reducing. Temperature increase promotes metallization by Zinc, but decreases by Iron. An increase of input gas CO/CO2 ratio leads to Fe reducing degree. It thereby ensures required indicators of the Zinc selective reduction achievement but requires more gas consumption. The relationships between CZnO and φZn depending on temperature and amount of reducing input gas consumption have been obtained. Given work results may be useful for precut estimation of the probable parameters of Zinc distillation process from the melt. Besides, these results may be useful as the basis for the experimental results analysis.

scholarly journals Thermodynamic modeling of iron and zinc reduction from B2O3 ‒ CaO ‒ Fe2O3 ‒ ZnО melt by СО ‒ CO2 and H2 ‒ Н2О mixtures

2021 ◽  
Vol 64 (7) ◽  
pp. 488-497
Author(s):  
A. S. Vusikhis ◽  
L. I. Leont’ev ◽  
E. N. Selivanov
Keyword(s):  
Thermodynamic Modeling ◽  
Iron Reduction ◽  
Working Fluid ◽  
Oxide Melt ◽  
Second Stage ◽  
Third Stage ◽  
Iron And Zinc ◽  
Gas Consumption ◽  
Three Stages ◽  
Zinc Reduction

The paper presents the thermodynamic modeling results of zinc and iron reduction from B2O3 ‒ CaO ‒ Fe2O3 ‒ ZnО melts by CO ‒ CO2 and H2 ‒ H2O mixtures containing 0 – 60 % CO2 (H2O) at 1273 – 1673 K using a technique describing the reduction of metals from an oxide melt by gas in bubbling processes, under conditions that provide an approximation to real systems. Its originality is equilibrium determination for each individual portion of gas supplied into the working fluid. The reducible metals oxides content in each calculation cycle is taken from the previous data. During the calculations, changes in the content of zinc (СZnO ) and iron (СFe2O3 , СFe3O4 and СFeO ) oxides in the melt and the degree of their reduction were estimated. When using CO or H2 as a reducing agent, this process proceeds in three stages. In the first stage, Fe2O3 is reduced to Fe3O4 and FeO. CFe2O3 values decrease to almost zero, while CFe3O4 and CFeO increase simultaneously. By the end of the stage, СFe3O4 reaches its maximum value. At the second stage, the Fe3O4 → FeO transition occurs, when СFeO values reach its maximum. At these stages, there is a slight increase in the CZnO . At the third stage, the values CFeO and CZnO decrease, and iron and zinc are reduced. An increase in temperature dramatically reduces the gas consumption for zinc reduction by 2 – 3 times, and the replacement of CO with H2 reduces it by less than 20 %. In the presence of oxidizing agents (CO or H2O), only zinc is reduced. The process ends when the final content of zinc oxide in the melt corresponds to the equilibrium with the initial gas composition. The higher the temperature, the less CZnO is. The obtained data are useful for the development of technologies for the selective recovery of metals.

scholarly journals Thermodynamic modeling of nickel and iron reduction from B2O3 – CaO – Fe2O3 – NiO melt by СО – СО2 and Н2 – Н2О mixtures

2021 ◽  
Vol 64 (5) ◽  
pp. 353-359
Author(s):  
A. S. Vusikhis ◽  
L. I. Leont’ev ◽  
E. N. Selivanov
Keyword(s):  
Thermodynamic Modeling ◽  
Iron Reduction ◽  
Selective Reduction ◽  
Gas Composition ◽  
Oxide Melt ◽  
Second Stage ◽  
Maximum Value ◽  
Working Medium ◽  
Third Stage ◽  
Successive Calculation

To predict the conditions for metals reduction from an oxide melt by gas in bubbling processes, a thermodynamic modeling technique has been developed that provides an approximation to real systems. The main difference between the accepted method and the well-known one is in conducting successive calculation cycles with withdrawal of the generated gases and the metal phase from the working medium. This paper presents the results of thermodynamic modeling of nickel and iron reduction processes from B2O3 – CaO– Fe2O3 – NiO melts by mixtures of CO– CO2 and H2 – H2O containing 0 – 60 % CO2 (H2O) in the temperature range of 1273 – 1673 K. The calculations evaluated the content of nickel and iron oxides in the melt and the degree of their reduction. It is shown that, regardless of the gas composition, this process proceeds in several stages. At the first stage, Fe2O3 is reduced to Fe3O4 and FeO. СFe2O3 values decrease to almost zero, while СFe3O4 and CFeO increase simultaneously. By the end of the phase, СFeO reaches its maximum value. At the second stage, the Fe3O4 → FeO transition occurs, when СFe3O4 values reach maximum, nickel and iron begin to reduce to metal. At reduction by CO– CO2 mixture, an increase in temperature reduces the metallization of both nickel and iron. Similarly, an increase in the CO2 content of the introduced gas affects. During interaction of the oxide melt with a gas containing 60 % CO2 , the third stage is absent. At reduction by H2 – H2O mixture, an increase in temperature reduces the metallization of nickel, but increases metallization of iron. With increasing water vapor content in the introduced gas, the degree of metallization of both nickel and iron decreases. The obtained data are useful for creating technologies for selective reduction of metals and formation of ferronickel of the required composition.

scholarly journals Metal reduction by hydrogen from the B2O3-СaO-Ni(Zn, Pb, Cu)O melts thermodynamic modeling

2020 ◽  
Vol 61 (2) ◽  
pp. 145-151
Author(s):  
Alexander S. Vusikhis ◽  
◽  
Evgeny N. Selivanov ◽  
Stanislav N. Tyushnyakov ◽  
Viktor P. Chentsov ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Thermodynamic Modeling ◽  
Reduction Process ◽  
Reducing Agent ◽  
Metal Reduction ◽  
Oxide Melt ◽  
Reduction Processes ◽  
Lead And Zinc ◽  
Nickel Copper ◽  
Copper Lead

Thermodynamic modeling is used to describe the metal reduction processes by hydrogen from oxide melt in the B2O3-CaO- MeO (Me – Ni, Zn, Pb, Cu) system. Open systems approximation with periodic removal of metal particles and gases from the working melt composition is used in the method. By this work we present the thermodynamic modeling results of metal reduction processes (Ni, Cu, Pb, Zn) by Hydrogen. The reducible metals oxides content in the all melts was 3 mass %, and the mass ratio of B2O3/CaO was taken as 3 to be close to eutectic composition. The calculations made it possible to determine such parameters as oxide melt compositions and elements reduction degree depending on the induced gas quantity. of the Nickel, Copper, Lead and Zinc reduction process simulation from B2O3-CaO-MeO melts proved the reduction process by Hydrogen is similar to that which was earlier established when Carbon monoxide was used as the reducing agent. When Copper is reduced from CuO, the process occurs with intermediate Cu2O oxide formation (CuO → Cu2O → Cu). The Nickel (NiO → Ni), Lead (PbO → Pbs + Pbg) and Zinc (ZnO → Zng) recovery have been realized by one stage. The non-ferrous metals change content in the oxide melt and the degrees of its reduction depending on temperature and reducing agent quantity introduced are described by the second-order polynomial functional equations. Comparison of the Carbon monoxide and Hydrogen used for Nickel, Copper, Lead, and Zinc reducing to 90% metallization degree proved much less Hydrogen consumption.

scholarly journals Thermodynamic modeling of nickel and iron reduction from multicomponent silicate melt in bubbling process. Report 2. Reducing agent – a mixture OF Н2 – Н2О

2018 ◽  
Vol 61 (10) ◽  
pp. 794-799 ◽  
Author(s):  
A. S. Vusikhis ◽  
L. I. Leont’ev ◽  
D. Z. Kudinov ◽  
E. N. Selivanov
Keyword(s):  
Carbon Monoxide ◽  
Iron Oxide ◽  
Nickel Oxide ◽  
Thermodynamic Modeling ◽  
Iron Reduction ◽  
Nickel Content ◽  
Reduction Process ◽  
Gas Mixture ◽  
Degree Of Reduction ◽  
Oxide Melt

A number of technologies in ferrous and non-ferrous metallurgy  are based on bubbling processes. For prediction of melting parameters  including the reduction of metals from oxide melt by a reducing gas  in a bubbling layer in industrial aggregates, a thermodynamic modeling technique is proposed based on calculation of the equilibrium in  oxide-melt-metal-gas system. Originality of the technique is that equilibrium is determined for each unit dose of gas introduced into the  working body, with the contents of oxides of metals being reduced in  each subsequent design cycle equal to the equilibrium in the previous  one. For the analysis NiO (1.8  %) – FeO (17.4  %) – CaO (13.5  %)  –  MgO  (1.9  %) – SiO2 (58.0  %) – Al2O3 (7.4  %) oxide system was  taken, closely corresponding to composition of oxidized nickel ore.  The ratio of Н2О/Н2 in gas mixture varies between 0 and 1.0. (1823  K),  amount and composition of formed metal (ferronickel), as well as the  indices (the ratio of slag and metal, the degree of reduction of metals)  are important in implementation of the process under commodity conditions. The increase in hydrogen consumption monotonously reduces  the content of nickel oxide in the melt, while the content of iron oxide  initially increases, and then decreases.  When H2 is introduced in an  amount of about 50 m3 per ton of the melt, the content of nickel oxide  in it is reduced to 0.017  %, and of iron oxide to 16.7  %. Resulting ferronickel contains 61  % Ni, ratio of slag and metal – 42  units. Further  increase in H2 consumption leads to preferential iron reduction. An increase in H2O/H2 ratio worsens the results of reduction of metals from  the melt: decrease in degree of reduction of nickel and iron, increase  in nickel content in the alloy, and the ratio of slag and metal. However,  even with a H2 / H2O ratio of 1.0, which corresponds to 50  % of H2O  in the gas mixture, reduction process does not stop. For comparison,  the work presents data on change in content of nickel and iron oxides,  when metals are restored from similar melts with carbon monoxide.  At a nickel recovery rate of 98  %, indicators are close in case of using  both H2 and CO. However, to achieve them, it is required 2.5  times less hydrogen, and 1.36 times less mixture in which H2O/H2  =  0.11  (H2  –  90  %) than carbon monoxide.

scholarly journals Thermodynamic Modeling of Iron and Nickel Reduction from B2O3-CaO-FeO-NiO Melts

2020 ◽  
Author(s):  
A.S. Vusikhis ◽  
L.I. Leontiev ◽  
E.N. Selivanov ◽  
V.P. Chentsov
Keyword(s):  
Carbon Monoxide ◽  
Thermodynamic Modeling ◽  
Open System ◽  
Iron Reduction ◽  
Nickel Extraction ◽  
Residual Content ◽  
Oxide Melt ◽  
Closed Systems ◽  
Joint Reduction ◽  
Gas Bubbling

At present, during solving theoretical and applied problems of metallurgical technologies improving, thermodynamic modeling (TDM) methods are widely used to calculate multicomponent and multiphase systems. However, existing methodology TДM are intended for the balance analysis in the ”closed” systems. The authors of [9] proposed a technique that allows, using TDMs, to describe metal reduction processes during gas bubbling of multicomponent oxide melts in approximation to “open” real systems. The applicability of the methods is estimated using the example of joint Nickel and Iron reduction modeling in the B2O3-CaO-FeO-NiO system by Carbon monoxide for ”open” and ”closed” systems. The data obtained comparison for ”open” and ”closed” systems show that the consecutive output of products (gas and metal) from working medium promotes achievement of the best parameters for Nickel extraction to alloy and to its residual content in oxide melt. Using this technique, the TДM process of joint reduction of Nickel and Iron in system B2O3-CaO-FeO-NiO by Carbon monoxide in ”open” system was undertaken at various temperatures in the 1273-1773K interval. Keywords: thermodynamic modeling, ”closed” system, ”open” system, joint reduction, Carbon monoxide, oxide melt, gas bubbling

The Coherence of Mary Barton: Romance, Realism, and Utopia

2015 ◽  
Vol 5 (3) ◽  
pp. 185-200
Author(s):  
Robert Z. Birdwell
Keyword(s):  
Thomas Carlyle ◽  
The Novel ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
Three Stages ◽  
Mode Of Production

Critics have argued that Elizabeth Gaskell's first novel, Mary Barton (1848), is split by a conflict between the modes of realism and romance. But the conflict does not render the novel incoherent, because Gaskell surpasses both modes through a utopian narrative that breaks with the conflict of form and gives coherence to the whole novel. Gaskell not only depicts what Thomas Carlyle called the ‘Condition of England’ in her work but also develops, through three stages, the utopia that will redeem this condition. The first stage is romantic nostalgia, a backward glance at Eden from the countryside surrounding Manchester. The second stage occurs in Manchester, as Gaskell mixes romance with a realistic mode, tracing a utopian drive toward death. The third stage is the utopian break with romantic and realistic accounts of the Condition of England and with the inadequate preceding conceptions of utopia. This third stage transforms narrative modes and figures a new mode of production.

The Subject Matter of Intellectual Property

2017 ◽  
Author(s):  
Justine Pila
Keyword(s):  
Intellectual Property ◽  
Subject Matter ◽  
Final Stage ◽  
Theoretical Framework ◽  
Trade Mark ◽  
Second Stage ◽  
Essential Properties ◽  
The Subject ◽  
Three Stages ◽  
The Relationship

This book offers a study of the subject matter protected by each of the main intellectual property (IP) regimes. With a focus on European and UK law particularly, it considers the meaning of the terms used to denote the objects to which IP rights attach, such as ‘invention’, ‘authorial work’, ‘trade mark’, and ‘design’, with reference to the practice of legal officials and the nature of those objects specifically. To that end it proceeds in three stages. At the first stage, in Chapter 2, the nature, aims, and values of IP rights and systems are considered. As historically and currently conceived, IP rights are limited (and generally transferable) exclusionary rights that attach to certain intellectual creations, broadly conceived, and that serve a range of instrumentalist and deontological ends. At the second stage, in Chapter 3, a theoretical framework for thinking about IP subject matter is proposed with the assistance of certain devices from philosophy. That framework supports a paradigmatic conception of the objects protected by IP rights as artifact types distinguished by their properties and categorized accordingly. From this framework, four questions are derived concerning: the nature of the (categories of) subject matter denoted by the terms ‘invention’, ‘authorial work’, ‘trade mark’, ‘design’ etc, including their essential properties; the means by which each subject matter is individuated within the relevant IP regime; the relationship between each subject matter and its concrete instances; and the manner in which the existence of a subject matter and its concrete instances is known. That leaves the book’s final stage, in Chapters 3 to 7. Here legal officials’ use of the terms above, and understanding of the objects that they denote, are studied, and the results presented as answers to the four questions identified previously.

scholarly journals Duopoly price competition with limited capacity

2021 ◽  
Author(s):  
A. Bërdëllima
Keyword(s):  
Price Competition ◽  
Small Firms ◽  
Common Knowledge ◽  
Limited Capacity ◽  
Equilibrium Outcome ◽  
Second Stage ◽  
Duopoly Model ◽  
Full Capacity ◽  
Stage Game ◽  
The Given

AbstractWe study a variation of the duopoly model by Kreps and Scheinkman (1983). Firms limited by their capacity of production engage in a two stage game. In the first stage they commit to levels of production not exceeding their capacities which are then made common knowledge. In the second stage after production has taken place firms simultane- ously compete in prices. Solution of this sequential game shows that the unique Cournot equilibrium outcome as in Kreps and Scheinkman is not always guaranteed. However the Cournot outcome is still robust in the sense that given sufficiently large capacities this equilibrium holds. If capacities are sufficiently small, firms decide to produce at their full capacity and set a price which clears the market at the given level of output.

scholarly journals Effect of Sago Starch Modifications on Polystyrene/Thermoplastic Starch Blends

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2867
Author(s):  
Mohamad Kahar Ab Wahab ◽  
Halimatul Syahirah Mohamad ◽  
Elammaran Jayamani ◽  
Hanafi Ismail ◽  
Izabela Wnuk ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Succinic Anhydride ◽  
Void Formation ◽  
Thermoplastic Starch ◽  
Sago Starch ◽  
Second Stage ◽  
Starch Blends ◽  
Three Stages ◽  
Blending Process ◽  
Starch Modifications

The preparation of polystyrene/thermoplastic starch (PS/TPS) blends was divided into three stages. The first stage involved the preparation of TPS from sago starch. Then, for the second stage, PS was blended with TPS to produce a TPS/PS blend. The ratios of the TPS/PS blend were 20:80, 40:60, 60:40, and 80:20. The final stage was a modification of the composition of TPS/PS blends with succinic anhydride and ascorbic acid treatment. Both untreated and treated blends were characterized by their physical, thermal, and surface morphology properties. The obtained results indicate that modified blends have better tensile strength as the adhesion between TPS and PS was improved. This can be observed from SEM micrographs, as modified blends with succinic anhydride and ascorbic acid had smaller TPS dispersion in PS/TPS blends. The micrograph showed that there was no agglomeration and void formation in the TPS/PS blending process. Furthermore, modified blends show better thermal stability, as proved by thermogravimetric analysis. Water uptake into the TPS/PS blends also decreased after the modifications, and the structural analysis showed the formation of a new peak after the modification process.

Opposition-based learning Multi-Verse Optimizer with disruption operator for optimization problems

2021 ◽  
Author(s):  
Mohammad Shehab ◽  
Laith Abualigah
Keyword(s):  
Real World ◽  
Optimization Problems ◽  
Second Stage ◽  
Opposition Based Learning ◽  
High Fitness ◽  
Fitness Value ◽  
Speed Up ◽  
Disruption Operator ◽  
The Given ◽  
Real World Problems

Abstract Multi-Verse Optimizer (MVO) algorithm is one of the recent metaheuristic algorithms used to solve various problems in different fields. However, MVO suffers from a lack of diversity which may trapping of local minima, and premature convergence. This paper introduces two steps of improving the basic MVO algorithm. The first step using Opposition-based learning (OBL) in MVO, called OMVO. The OBL aids to speed up the searching and improving the learning technique for selecting a better generation of candidate solutions of basic MVO. The second stage, called OMVOD, combines the disturbance operator (DO) and OMVO to improve the consistency of the chosen solution by providing a chance to solve the given problem with a high fitness value and increase diversity. To test the performance of the proposed models, fifteen CEC 2015 benchmark functions problems, thirty CEC 2017 benchmark functions problems, and seven CEC 2011 real-world problems were used in both phases of the enhancement. The second step, known as OMVOD, incorporates the disruption operator (DO) and OMVO to improve the accuracy of the chosen solution by giving a chance to solve the given problem with a high fitness value while also increasing variety. Fifteen CEC 2015 benchmark functions problems, thirty CEC 2017 benchmark functions problems and seven CEC 2011 real-world problems were used in both phases of the upgrade to assess the accuracy of the proposed models.

Sign in / Sign up

Export Citation Format

Share Document