Fume Formation from Oxidation of Liquid SiMn Alloy

Abstract

Thermally generated fumes from the production of manganese ferroalloys are mostly composed of metallic oxides generated due to reaction between hightemperature molten metal and ambient oxygen in the air. In the current study, the fume characteristics (particle morphology, compositions and particle size distribution) from the exposure of a SiMn alloy under an impinging air jet, in the temperature range 1400-1700°C, were experimentally investigated. Combinations of manganese-and manganese/silicon oxide particles were found in the system, displaying both crystalline and amorphous structures. The governing generation mechanisms of fume from both a thermodynamic and a kinetic perspective are discussed.

Mechanisms of Toxicity of Industrially Relevant Silicomanganese Dust on Human 1321N1 Astrocytoma Cells: An In Vitro Study

“…The dust was collected in a filter fabric of industrial standard. The technical details of the laboratory set-up and the thermodynamics and kinetics which govern the dust generation process has been described in detail in previous publications [2,3].…”

“…Moreover, the smallest fractions of the fume had a larger dominance of Si than the larger fractions and the ultrafine sized particles contained a significantly smaller amount of Mn than the larger particles [1]. Similar dust was generated in a more controlled laboratory setting by Kero et al and Ma et al [2,3]. Characterization of such laboratory dust showed that the particles are oxides and very often amorphous.…”

Airborne Emissions from Mn Ferroalloy Production

“…110,114,115 This active oxidation fume generation mechanism has also been described by others. 63,[116][117][118] For ferromanganese (FeMn), the fume generation is dominated by the relatively high vapor pressure of Mn. The fume is mostly composed of metallic oxides, and as Mn is a transition metal, the PM may consist of different oxides.…”

“…Si oxidizes through a two-step reaction without vaporization. [125][126][127] The Mn vaporization is active simultaneously, and SiO (g) interacts with Mn (g) in a complex, temperaturedependent manner, postulated by Ma et al 116 The differences between fuming from FeMn and SiMn is highlighted by the effect of humidity. Certain FeMn smelters have successfully implemented a dustsuppression technology during casting, where an atomized water mist is sprayed around the casting beds.…”

Evaporation and Diffusion of Mn in Inert Systems

“…With silicomanganese, this leads to possible reactions between silicon oxides and manganese fumes, but can also cause a competition for oxygen close to the surface where if no oxygen reaches the surface, one might get no silicon in the dust at all. [12] Because of these reasons, the experimental study and subsequent modelling of evaporation rates of Mn is important.…”