Linz-Donawitz steel slag for the removal of hydrogen sulfide at room temperature

Abstract

Slags collected from the basic oxygen furnaces of two Linz-Donawitz steel making plants were tested as adsorbents for H2S removal at room temperature (298 K). Two different particle size fractions, namely <212 and 212–500 μm, were selected from the original slag samples. Dynamic adsorption tests were carried out using a column-bed configuration and retention capacities were calculated after bed exhaustion. Retention capacities as high as 180 mg of H2S g–1 of slag were attained, in spite of the very low specific surface area of the steel slags. As expected, humidity played a crucial role in the removal of H2S. Particle size had also an important effect on the capacity of the adsorption beds. Analysis of the exhausted slags revealed considerable amounts of elemental sulfur on the surface of the particles. Sulfates were also found on the exhausted slags, especially on the 212–500 μm size fractions. The characterization of the slags prior and after the H2S adsorption experiments allowed us to postulate plausible mechanisms to understand the outstanding capacity of these steel byproduct for H2S adsorption