The reaction of coke specimens in an environment where both the temperature and the gas composition are time dependent
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Mass Spectrometric Results
Heteronuclear Species Concentration Ratio Observed Temper~ure 573 K 673 K 773 K
In Sulfide System As4S6: As3SbS6: Sb4S6 500 : 10 : 1 As4S6: As3SbS6: Sb4S6 120 : 4 : l As4S6: AsSb3S6: Sb4S6: As2Sb2S6 9 : 3 :90: l
In Oxide System AS406 ."As3SbO6: 5b406 2 : 1 : 0 AS406 : As2Sb206 75 : 1
Mass to Charge Ratio
In Sulfide System
In Oxide System
M/e 506 - 508 + 552 + 556 + 598 + 604 + 426 - 428 § 472 + 476 § 518 § 524 +
heteronuclear compounds of arsenic and antimony were observed. Mass spectrometer experiments were not conducted with mixed antimony-bismuth compounds. The foregoing vaporization data could be considered the result of positive deviations of Raoult's law as shown in Figure 2 for the As2S3-Bi2S3 system and in Figure 4 for the As203-Sb203 system; however, this is unlikely as the chemical properties and the structure of the sulfides and of the oxides under consideration are quite similar. Similarly, the varporization curves up to 873 K for both the As2Sa-Sb2S3 system in Figure 1 and the orpiment-stibnite system in Figure 3 could be attributed to the depression of the vapor pressure, but the results are not consistent with the curves shown in the other figures and also neglect the heteronuclear compounds observed in the mass spectrometer. The only phenomenon common to all figures is the presence of heteronuclear compounds. During the roasting of copper ores, when both arsenic and antimony sulfides are present, the evolution of arsenic is retarded and the volatilization of antimony increased primarily because of the formation of heteronuclear compounds. These heteronuclear compounds exhibit vapor pressure different from those of their individual parent compounds. Because the arsenic and antimony content in copper ores and concentrates is generally a percent or less, the anomalous vaporization behavior of mixed arsenic and antimony oxides and sulfides may be of small magnitude. However, since the phenomenon of preferential antimony volatilization was noted in roasting studies of concentrates, and since high-arsenic flue dusts and antimony speiss are sometimes roasted together, the formation of heteronuclear compounds of arsenic and antimony is a factor that should be considered.
Observed Ionic Species As3SbS5
Proposed Molecular Species As3SbS6 As2Sb2S6
As2Sb2Ss
AsSb3S6
AsSb3S5 As3SbO5 As2Sb205 AsSb305
ms3SbO6
As2Sb206 AsSb306
The Reaction of Coke Specimens in an Environment Where Both the Temperature and the Gas Composition Are Time Dependent D. A. ADERIBIGBE and J. SZEKELY The purpose of this communication is to comment on the appropriateness of the currently employed testing procedures for evaluating the performance of coke in the iron blast furnace. In recent years there has been a growing interest in the development of alternative coking processes and in the modification of existing coke manufacturing operations in order to make the production of coke more cost effective. While the ultimate test of coke quality is its actual performance in the real operating blast furn
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