261 / 2018-03-09 09:27:10

Characterization of pore structures and adsorption properties for mechanically activated sulfide ores

sulfide ores; mechanical activation; low temperature nitrogen adsorption; pore size distribution; fractal dimension; oxidation and spontaneous combustion

矿山职业健康与环境安全 > 防火

In order to uncover the fractal characteristics of adsorption-pores of mechanically activated sulfide ores, a representative sample collected from a typical sulfur-rich mine was activated into 6 groups under different mechanical activation conditions. Both scanning electron microscopy (SEM) and low-temperature nitrogen gas adsorption (LT-N2GA) were performed to gain insight into the nature of the pore morphology, including the pore volume, specific surface area (SSA), and pore size distribution (PSD). The FHH (Frenkel-Halsey-Hill) model was performed to calculate their fractal dimensions. The relationships of fractal dimension—pore-structure parameters and fractal dimension—adsorptive capacity were furtherly analyzed. The results show that gas adsorption of sulfide ores under mechanical activation mainly occurs in the mesopores varying from 2 to 30 nm. The order of SSA for samples under different sample to ball ratios is: a (1:3)< b (1:6)< c (1:10); and that of samples under different mill speeds is: d (300r/min)< e (400r/min)< f (500r/min). The order of samples’ fractal dimension is consistent with that of SSA, but average pore diameter is the exact opposite of that. Mechanical activation increases the fractal dimension of sulfide ores and improves the ability of oxygen adsorption, thus contributing to oxidation and spontaneous combustion.