The sulfur partition ratio and the sulfide capacity of Na2O-SiO2 slags at 1200 °C

1986 ◽  
Vol 17 (3) ◽  
pp. 491-496 ◽  
Author(s):  
Allen H. Chan ◽  
R. J. Fruehan
Keyword(s):  
Sulfide Capacity ◽  
Partition Ratio

A New Approach for the Diffusion Coefficient Evaluation of Sulfur in CaO-SiO2-Al2O3 Slag

2011 ◽  
Vol 312-315 ◽  
pp. 626-634
Author(s):  
Luckman Muhmood ◽  
Nurini N. Viswanathan ◽  
Seshadri Seetharaman
Keyword(s):  
Diffusion Coefficient ◽  
Sulfide Capacity ◽  
Chemical Diffusion ◽  
Partition Ratio ◽  
Critical Parameters ◽  
New Approach ◽  
Matlab Program ◽  
Order Of Magnitude ◽  
Concentration Changes ◽  
Silver Metal

The Diffusion coefficient of sulfur in a ternary slag with composition of 51.5% CaO- 9.6% SiO2- 38.9% Al2O3 was measured at 1723 K by chemical diffusion from the variation of concentration of sulfur in silver metal. A MATLAB program was developed to find the concentration variation of sulfur in silver metal using various critical parameters like the diffusion coefficient of sulfur in slag available in literature, sulfur partition ratio, sulfide capacity of the slag and the its density. The PS2 and PO2 pressures were calculated from the Gibbs energy of the equilibrium reaction between CaO in the slag and solid CaS and confirming the same by using ThermoCalc. The density of the slag at 1723 K was obtained from earlier experiments. Initially the order of magnitude for the diffusion coefficient was taken from the works of Saito and Kawai but later was modified so that the concentration changes of Sulfur obtained from the program agreed with the experimental results. The diffusion coefficient of sulfur in 51.5% CaO- 9.6% SiO2- 38.9% Al2O3 slag at 1723 K was estimated as 4.14x10-6 cm2/sec.

scholarly journals A Novel Electrochemical Process for Desulfurization in the CaO-SiO2-Al2O3 System

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2478
Author(s):  
Sang Hoon Lee ◽  
Dong Joon Min
Keyword(s):  
Thermodynamic Stability ◽  
Electric Potential ◽  
Electrochemical Reaction ◽  
Sulfide Capacity ◽  
Partition Ratio ◽  
Electrochemical Process ◽  
Cathodic Potential ◽  
Potential Region ◽  
Anodic Potential ◽  
Co Gas

The effect of electric potential on the sulfide capacity of the CaO-SiO2-Al2O3 system was evaluated by applying voltages in the range of −1.5 to 1.5 V at 1823 K in a C/CO gas equilibrium. When the cathodic potential (−1.5 to 0 V) was applied, it was confirmed that the sulfur partition ratio increased based on the electrochemical reaction of sulfur (S + 2e− = S2−). However, the reversibility of the electrochemical resulfurization reaction (S2− = S + 2e−) in slag was not established in the reverse (anodic) potential region (0–1.5 V), yet the sulfur partition ratio increased. In particular, sulfur evaporation was observed in the anodic potential region. Therefore, in the present study, potential anodic electro-desulfurization mechanisms based on sulfur evaporation are proposed. To verify these mechanisms, sulfur evaporation is discussed in detail as a function of the thermodynamic stability of sulfur in the slag.

scholarly journals Sulfide Capacity of CaO–SiO2–MnO–Al2O3–MgO Slags at 1873 K

2012 ◽  
Vol 52 (5) ◽  
pp. 764-769 ◽  
Author(s):  
Joo Hyun Park ◽  
Geun-Ho Park
Keyword(s):  
Sulfide Capacity

scholarly journals Formal Synthesis of (±)-Allocolchicine Via Gold-Catalysed Direct Arylation: Implication of Aryl Iodine(III) Oxidant in Catalyst Deactivation Pathways

2017 ◽  
Vol 60 (8) ◽  
pp. 570-579 ◽  
Author(s):  
Tom J. A. Corrie ◽  
Guy C. Lloyd-Jones
Keyword(s):  
Catalyst Deactivation ◽  
Kinetic Modelling ◽  
Gold Catalyst ◽  
Side Reaction ◽  
Partition Ratio ◽  
Alkylation Reaction ◽  
Formal Synthesis ◽  
H Nmr ◽  
Diaryliodonium Salt ◽  
Deactivation Process

Abstract A concise formal synthesis of racemic allocolchicine has been developed, centred on three principal transformations: a retro-Brook alkylation reaction to generate an arylsilane, a gold-catalysed arylative cyclisation to generate the B-ring via biaryl linkage, and a palladium-catalysed carbonylation of an aryl chloride to generate an ester. 1H NMR monitoring of the key gold-catalysed cyclisation step reveals that a powerful catalyst deactivation process progressively attenuates the rate of catalyst turnover. The origins of the catalyst deactivation have been investigated, with an uncatalysed side-reaction, involving the substrate and the iodine(III) oxidant, identified as the source of a potent catalyst poison. The side reaction generates 1–4% of a diaryliodonium salt, and whilst this moiety is shown not to be an innate catalyst deactivator, when it is tethered to the arylsilane reactant, the inhibition becomes powerful. Kinetic modelling of processes run at two different catalyst concentrations allows extraction of the partitioning of the gold catalyst between the substrate and its diaryliodonium salt, with a rate of diaryliodonium salt generation consistent with that independently determined in the absence of catalyst. The high partition ratio between substrate and diaryliodonium salt (5/1) results in very efficient, and ultimately complete, diversion of the catalyst off-cycle. Graphical Abstract

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