Formation of a mineral layer during coke dissolution into liquid iron and its influence on the kinetics of coke dissolution rate

The formation and development of the mineral layer that forms between coke and liquid iron during carbon dissolution has been characterised. Coke particles (-2mm, +0.5mm) were added to the top surface of an iron 2 mass% C melt at representative ironmaking temperatures, for periods of time between 2 minutes and 120 minutes, before being quenched. The quenched samples were then sectioned and the solidified coke-melt interfacial region analysed in the SEM. Analysis showed that a mineral layer was present at the interface at all experimental temperatures (1450-1550oC) from 2 minutes and persisted beyond 120 minutes. The mineral layer was found to be composed of calcium aluminate phases, with the proportions of these phases dictating its morphology. Further, changes observed in the rate of carbon dissolution from the coke were related to the composition and morphology of the mineral layer. The effect of this mineral layer on the rate of carbon dissolution has been interpreted as a change in the reaction control mechanism

Normative data for an expanded set of stimuli for testing high-level influences on object perception: OMEFA-II

We present normative data for an expanded set of stimuli designed to investigate past experience effects on object detection. The stimuli are vertically-elongated "bipartite" displays comprising two equal-area regions meeting at an articulated central border. When the central border is assigned to one side, a shaped figure (i.e., an object) is detected on that side. Participants viewing brief masked exposures typically detect figures more often on thecriticalside ofIntactdisplays where a common ("familiar") object is depicted than on a matched critical side ofPart-Rearranged(PR) displays comprising the same parts arranged in novel configurations. This pattern of results showed that past experience in the form offamiliar configurationrather thanfamiliar parts is a prior for figure assignment. Spurred by research implicating a network involving the perirhinal cortex of the medial temporal lobe in these familiar configuration effects, we enlarged the stimulus set from 24 to 48 base stimuli to increase its usefulness for behavioral, neuropsychological, and neuroimaging experiments. We measured the percentage of participants who agreed on a single interpretation for each side ofIntact,Upright PR, andInverted PRdisplays (144 displays; 288 sides) under long exposure conditions. High inter-subject agreement is taken to operationally define a familiar configuration. This new stimulus set is well-suited to investigate questions concerning how parts and wholes are integrated and how high- and low-level brain areas interact in object detection. This set also allows tests of predictions regarding cross-border competition in figure assignment and assessments of individual differences. The displays, their image statistics, and normative data are available online ().Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The effect of sulfur concentration in liquid iron on mineral layer formation during coke dissolution

The effects of sulfur concentration in liquid iron on mineral layer development between coke and iron as coke dissolves in a 2 mass % carbon-iron liquid have been investigated at 1500°C. Initial sulfur in iron concentrations used ranged from 0.006 to 0.049 mass %. Key findings include that the two stage dissolution behavior exhibited in the carbon transfer from coke to iron as reported in a previous study by the authors, at low initial sulfur in iron contents, was also apparent at the higher values used in this study. This two stage behavior was attributed to a change in the mineral layer density, as a result of changes in mineral morphology at the interface. In addition to confirming the two stage behavior of the carbon transfer kinetics at the higher sulfur concentration in iron levels, it was also found that after a period of time a solid calcium sulfide layer formed on the mineral layer. The sulfide layer formed after approximately 40 minutes and the proportion of sulfide in the mineral layer increased with increased experimental time and initial sulfur concentration in iron. It was usually found at the iron side of the mineral layer and associated with calcium enriched calcium aluminates. Thermodynamic analysis of this layer confirmed that the sulfide is stabilized as the mineral layer is enriched by calcium