Determination of pore structures and adsorption properties of activated iron sulfide ores

Abstract

To better reveal the pore structures and adsorption characteristics of iron sulfide ores after the mechanical activation, the raw sulfur-rich ore obtained from a sulfide mine was activated into several samples under different billing conditions. Both the scanning electron microscopy (SEM) and low-temperature N2 gas adsorption/desorption (LT-N2GA) methods were used to understand the features of the pore structures, such as the pore volume, specific surface area (SSA), and pore size distribution (PSD). Moreover, the Frenkel-Halsey-Hill (FHH) model was applied to determine corresponding fractal dimensions. The research results indicate that the N2 adsorption of the activated samples mostly takes place in the mesopores ranging from 2 to 30 nm. The change order of the SSA and pore volume for the activated samples with different sample-ball ratios is as follows: a (1:2)< b (1:4)< c (1:6); and that with diverse milling rates is as follows: d (200 r/min)< e (400 r/min)< f (600 r/min). The transformations in the fractal dimensions agree with those in SSA and pore volume development, while the alterations are on the contrary in average pore diameter. The mechanical activation can increase the fractal dimensions of iron sulfide samples and alters their oxygen adsorption properties, so it promotes the tendency of iron sulfide ores to oxidation and spontaneous combustion.