Recycling. Vaporization Kinetics of Tin as SnS from Carbon Saturated Liquid Fe-Sn-S Alloy under Reduced Pressure.

Abstract

The recycling of valuable resources has currently became a major worldwide subject in the industries from the viewpoint of saving energy and protection of environment. Since the accumulated amount of steel product is reaching almost one billion ton in Japan, it is very important to develop the technology for the removal of tramp-elements such as tin, copper and zinc from steel scrap. In the present work, the rate of tin removal by the evaporation from carbon saturated liquid Fe-Sn-S alloy has been studied at 1,673 K under reduced pressure.Tin evaporates from molten iron and equimolar amount of sulfur is also removed together with tin. The evaporation rate of tin increases with increasing initial sulfur content in the melt. It is confirmed that tin dissolved in liquid iron is removed in the form of SnS under the presence of sulfur in the metal. The rate of tin evaporation becomes faster with reducing the pressure in the reaction chamber. This indicates that the rate is controlled mainly by the mass transfer of SnS in the gas phase.

Effect of Oxygen on the Evaporation Rate of Lead from Liquid Copper under Reduced Pressure.

“…The evaporation rate of Zn was mostly limited by liquid phase mass transfer, and they suggested that tens ppm of Zn could remain in liquid iron during typical operation period for refining in spite of high vapor pressure of Zn if initial Zn content in steel scrap was as high as hundreds ppm. Ito et al 6) and the present authors 7) demonstrated that Sn in liquid Fe-C-S alloy could be removed by the evaporation of SnS under the reduced pressure. Li et al 8) studied the evaporation rates of Pb and Zn from liquid Fe-4 mass%C alloy at 1 873 K under 10 kPa to 5 MPa of Ar pressure.…”

“…[1][2][3][4][5][6][7][8][9][10] Ward and coworker 1,2) first investigated the kinetics of Mn evaporation from inductively stirred liquid iron under vacuum. They reported that evaporation rate of Mn was the first order with respect to its concentration in liquid iron and the measured first order rate constant agreed with the free evaporation rate constant.…”

Impurity Removal from Carbon Saturated Liquid Iron using Lead Solvent

“…A number of suggestions have been proposed and studied for removal of copper and tin from steel scrap: vacuum distillation, evaporation using ammonia, urea or chlorine, sulfide fluxes and extraction by metal solvent. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] However, no economical process has been established because of their low efficiency, requirements for high cost, or high-energy consumption.…”