Showa-ku, Nagoya, Process TechnologyIn order to avoid sticking during a fluidized bed reduction of iron ores and elucidate its mechanism,their reduction tests using two types of easily sticked ores coated by a water-slurry consisting of each submicron reagent of gangue species were carried out at 900"C by N.

Gravimetric measurements were made for the kinetics of the carbide formation from reduced iron by preventing the decomposition of iron carbides and the deposition of carbon by utilizing the effect of sulfur. Particles of a hematite ore were completely reduced in the H 2 -H 2 S mixture and converted to iron carbide in a CO-H 2 -H 2 S-CO 2 -H 2 O-Ar or CO-CO 2 -COS-N 2 mixture at 873 to 1073 K. The carbide formation kinetics was drastically accelerated by the addition of a few percent H 2 to CO and reached the maximum at about 20 pct H 2 . From morphology observation, it was assumed that the carburization reaction on the surface of pores in the reduced iron determines the carbide formation kinetics, and the carburization rate, df /dt, is expressed as the product of a function of carburization rate, g( p i , T ), and the relative reaction surface area at the time t, 1 Ϫ f . Applying the integrated rate equation, Ϫln(1 Ϫ f ) ϭ g( p i , T )t, to the experimental results, the value of g( p i , T ) was obtained. By analyzing the carbide formation rate, it was assumed that the elementary reactions determining the carbide formation rate are CO ϩ H(ad) → [C] ϩ OH(ad) and OH(ad) ϩ H 2 ϭ H 2 O ϩ H(ad), except in the low ratio of p H 2 /p CO , where the rate determining elementary reaction shifts to O(ad) ϩ CO → CO 2 . The overall rate Eq. [22] has been proposed for the carbide formation from the reduced iron in CO-H 2 -H 2 S-CO 2 -H 2 O mixtures.

Un-ionized polyurethane was obtained by the reaction of an isocyanate-terminated urethane prepolymer, which was synthesized from 4,4Ј-diphenylmethane diisocyanate and poly(oxytetramethylene)-␣,-glycol, with 2,2-bis(hydroxymethyl)propionic acid. A carboxylate-based polyurethane anionomer was then derived from the polyurethane by the use of the sodium, potassium, or magnesium salt of acetic acid as a neutralizer. The ionomerization resulted in the following changes in the characteristics of the polyurethane: (1) an increase in the tensile strength, (2) a decrease in the glass-transition temperature, (3) an increase in the wettability and hygroscopicity with respect to water, and (4) susceptibility to thermal decomposition. A sulfonatebased polyurethane was also synthesized for comparison with the carboxylate-based polyurethane.

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