Important process variables in chromate ion exchange

1986 ◽  
Vol 20 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Arup K. Sengupta ◽  
Dennis. Clifford
Keyword(s):  
Ion Exchange ◽  
Important Process ◽  
Process Variables ◽  
Chromate Ion

Chromate ion-exchange process at alkaline pH

1986 ◽  
Vol 20 (9) ◽  
pp. 1177-1184 ◽  
Author(s):  
Arup K. Sengupta ◽  
Dennis Clifford ◽  
Suresh Subramonian
Keyword(s):  
Ion Exchange ◽  
Exchange Process ◽  
Alkaline Ph ◽  
Ion Exchange Process ◽  
Chromate Ion

scholarly journals Modeling of REE and Fe Extraction from a Concentrate from Araxá (Brazil)

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 451 ◽  
Author(s):  
Marisa Nascimento ◽  
Flávio Lemos ◽  
Rogério Guimarães ◽  
Clóvis Sousa ◽  
Paulo Soares
Keyword(s):  
Laboratory Experiments ◽  
Earth Element ◽  
Process Variable ◽  
Optimization Method ◽  
Chemical Processing ◽  
Important Process ◽  
Mass Ratio ◽  
Process Variables ◽  
Acid Processing ◽  
Roasting Temperature

The study aimed to employ a comprehensive methodology for the acid processing of a rare earth element (REE) concentrate obtained from the ore from Araxá (MG-Brazil). The most important process variables have been identified and their levels determined to maximize REE extraction (%RE) and minimize Fe extraction (%Fe). The thermodynamic analysis showed that the roasting temperature (TF) is crucial for the control of Fe solubilization in the aqueous leaching step of the acid processing. A statistic design of laboratory experiments and a process optimization method were applied to address the interaction among the process variables. Experimental results showed that a TF of about 700 °C can significantly reduce the Fe concentration in the aqueous leaching liquor. Mathematical models were proposed to predict the effect of process variable on REE and Fe extraction of the concentrate. A multi-objective technique was employed for optimization of chemical processing and the best conditions were reached for roasting temperature (TF) = 700 °C, acid to sample mass ratio (ACs) = 0.8 and leaching time (tL) = 20 min, which led to %RE = 96.91% and %Fe = 21.69%.

How do avatar attractiveness and customization impact online gamers’ flow and loyalty?

2019 ◽  
Vol 29 (2) ◽  
pp. 349-366 ◽  
Author(s):  
Gen-Yih Liao ◽  
T.C.E. Cheng ◽  
Ching-I Teng
Keyword(s):  
Structural Equation Modeling ◽  
Social Identity ◽  
Structural Equation ◽  
Design Methodology ◽  
Total Concentration ◽  
Equation Modeling ◽  
Important Process ◽  
Process Variables ◽  
Content Type ◽  
Flow Theories

Purpose Avatars are known to be influential in gaming communication. However, little is known about how avatar attractiveness and customization impact online gamers’ flow, i.e., the experience of total concentration with intrinsic enjoyment and loyalty. Grounded in social identity and flow theories, the purpose of this paper is to construct a model to explain how avatar attractiveness and customization can impact online gamers’ flow and loyalty. Design/methodology/approach The responses of 1,944 online gamers are collected. Structural equation modeling is used for analyses. Findings The analytical results indicate that avatar attractiveness and customization are positively related to avatar identification, which is positively related to flow, and then to online gamer loyalty. In addition, avatar identification and flow are important process variables in the above relations. Originality/value This study is novel in being the first attempt to apply social identity and flow theories to explain how avatar attractiveness and customization contribute to online gamers’ flow and loyalty.

Enantioselective extraction of hydrophilic 2-chloromandelic acid enantiomers by hydroxypropyl-β-cyclodextrin: experiments and modeling

2013 ◽  
Vol 67 (2) ◽  
Author(s):  
Cong-Shan Zhou ◽  
Ping Xu ◽  
Ke-Wen Tang ◽  
Xin-Yu Jiang ◽  
Tao Yang ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Extraction Efficiency ◽  
Reactive Extraction ◽  
Phase Reaction ◽  
Important Process ◽  
Process Variables ◽  
Model Data ◽  
Cyclodextrin Derivatives ◽  
Enantioselective Extraction ◽  
Extraction Model

AbstractEnantioselective extraction of hydrophilic 2-chloromandelic acid (CMA) enantiomers from organic to aqueous phase with hydroxypropyl-β-cyclodextrin (HP-β-CD) as the selector was investigated. Equilibrium of the extraction system was modeled using a reactive extraction model with a homogeneous aqueous phase reaction. The influence of important process variables on the extraction efficiency, such as the type of the organic solvent and β-cyclodextrin derivatives (β-CDs), concentration of the selector, pH and temperature, was investigated by experiment and modeling. Important parameters of this model were determined experimentally. Results showed that the experimental data agree with the model prediction perfectly and the model was further applied to accurately predict the extraction efficiency influenced simultaneously by pH and the concentration of HP-β-CD. Combining the experiment and the model data, the best extraction conditions were: pH of 2.5, HP-β-CD concentration of 0.05 mol L−1, and temperature of 5°C, providing the enantioselectivity of 1.285 and the performance factor (pf) of 0.011.

Modeling chromate ion-exchange processes

AIChE Journal ◽  
1988 ◽  
Vol 34 (12) ◽  
pp. 2019-2029 ◽  
Author(s):  
Arup K. Sengupta ◽  
Lois Lim
Keyword(s):  
Ion Exchange ◽  
Exchange Processes ◽  
Chromate Ion

Chromate Ion Exchange

2021 ◽  
pp. 115-147
Author(s):  
Arup K. Sengupta
Keyword(s):  
Ion Exchange ◽  
Chromate Ion

Extrusion of Soft- and Medium-Grade Alloys

2000 ◽  
pp. 149-186
Keyword(s):  
Aluminum Alloys ◽  
Best Practices ◽  
Cross Sections ◽  
Extrusion Pressure ◽  
Important Process ◽  
Process Variables ◽  
Ram Speed

Abstract This chapter discusses the extrusion characteristics of relatively soft aluminum alloys. It begins by identifying alloy designations within the class and the types of extrusions made from them. It then explains how extruded shapes and cross-sections are defined and how to analyze and assess important process variables such as runout, extrusion pressure, ram speed, and butt thickness. It also provides best practices for various operations and explains how to identify and remedy common extrusion defects.

More on Mechanism and Some Important Properties of Chromate Ion Exchange

1988 ◽  
Vol 114 (1) ◽  
pp. 137-153 ◽  
Author(s):  
Arup K. Sengupta ◽  
Suresh Subramonian ◽  
Dennis Clifford
Keyword(s):  
Ion Exchange ◽  
Chromate Ion

The Effect of Phase Formation on Glass Leaching

1984 ◽  
Vol 44 ◽  
Author(s):  
Richard Haaker ◽  
Gonter Malow ◽  
Peter Offermann
Keyword(s):  
Ion Exchange ◽  
Phase Formation ◽  
Nuclear Waste ◽  
Linear Time ◽  
Release Mechanism ◽  
Important Process ◽  
Mass Losses ◽  
Congruent Dissolution ◽  
Saturation Effects ◽  
Glass Leaching

The leaching of nuclear waste glasses in aqueous solution is still considered to be the most important process when discussing a potential release of radionuclides. However, in the last few years it has become clear that the release mechanism under static leaching conditions is very complex involving several processes [1]. The kinetics gave no evidence for pure leaching (i.e. the alkali-ion exchange) which should result in a square root time law, or for pure corrosion (i.e. congruent dissolution of the glass) which should result in a linear time law. Moreover, fits using a combination of these two processes gave unsatisfactory results. This is certainly due to additional processes which are not considered by ion exchange and congruent dissolution. Some explanations may be the build up of alteration layers, saturation effects of some elements with phase formation due to solubility limits and disappearance of metastable phases. To describe such a complicated system thermodynamic data are needed and measurements of mass losses as well as analyses of leachates and surfaces layers have to be performed.

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