クロマイトの硫酸浸出について

抄録

Leaching reaction of chromite in H₂SO₄ with K₂Cr₂0₇ as an oxidizing agent was studied.
Since it was found that for the dissolution of chromite in H₂SO₄, the oxidation of ferrous iron in the ore to ferric state was an important factor, the extraction of Cr was restricted by the ratio of FeO content in the ore to the theoretical amount derived from Cr₂0₃ content. The FeO ratio of the high grade ore (Cr₂O₃ 43.95%, FeO 18.70%) was 90% and the low grade ore (Cr₂O₃ 37.41%, FeO 11.66%) was 66%. The extraction of Cr of the high grade ore was 94.5%, but with the low grade ore, it was only 46.1% under the same conditions as the high grade ore, due to the low FeO ratio.
An experimental equation on the rate of leaching was given by
y= α√θ—βθ
where y is the extraction of Cr, θ is the leaching time and α, β are constants. It was considered that the rate process would be the diffusion in particles.