Influence of alkaline treatment on physicochemical properties of sulphide dust

The study of the alkaline medium effect on the physicochemical parameters of copper–pyrite ore dust (granulometric, chemical and phase compositions) is aimed at assessment of opportunities for the efficiency enhancement in dust suppression during drilling and blasting by means of spraying mine roadways with alkaline solutions. The grain size analysis of the test dust samples shows that alkaline treatment has no noticeable influence on the degree of dust dispersion. The alkaline medium effect on the chemical composition of the test dust shows up as the increase in the contents of silicon, iron and oxygen present in the dust in the greatest amounts. The change in the chemical composition of the dust treated with the alkaline solution correlates with the change in the phase composition of the dust. The mass fraction of quartz decreases, which leads to the re-distribution of the mass fractions of other components, including the increased content of pyrite. Thus, spraying of mine roadways can increase the concentration of pyrite in the accumulated dust, which implies an increase in the dust explosion risk. In this regard, alkaline solutions are not a special preventive means capable to ensure enhanced efficiency of explosible dust suppression as compared with water spraying.