Stas N.F. 1
1 National Research Tomsk Polytechnic University
The iron ore calcium and magnesium acid sanding is a self-stopping selective-oxidation process (its activation energy is 12kJ/mol), therefore speed and reaction completeness increase could be expected in case of ore degradation in acid solution. The article describes results of such field research where 2-mm grade natural Krivorogsky red hematite with a particle size from +0.063mm to -0.074 mm was used. It was simultaneously under nitric acid treatment and pebbling in a lab-size machine with 5 l displacement, 0.8 kg roll mass, 60 rpm roll rate. Tumbling test was 3 hours long, F:S balance – 20, acid mass fraction – 5, 10, 20%. Fixed that 76.3% of calcium blooms out in 10% and 20°C acid solution whereas in the same conditions without milling only about 30% of calcium blooms out. At 80°C separation grade increases up to 83.4%. Activation energy is 53 kJ/mol, what points to diffusion resistance absence. The iron ore milling in acid condition passes more intensive than in neutral water condition.
science-review.ru