PROCESS FOR LEACHING OF METALS MAINLY VANADIUM FROM SLAG Russian patent published in 2012 - IPC C22B34/22 E21B43/28 

FIELD: metallurgy.

SUBSTANCE: method involves disintegration, heat treatment, leaching and precipitation of vanadium compounds. The slag is ground to a particle size from - 0.2 to - 0.3 mm, vanadium and other metals are transferred from the slag into a solution of sulphates of metals using the heat of exothermic chemical reactions, "vanadium slag - sulfuric acid aqueous solution," which is conducted at temperatures ranging from 75 to 85 °C, achieved by changing the acid concentration from 20 to 30% in proportion to the size of the leaching slag particles. Vanadium and other metals are precipitated as hydroxides by treating a sulphate solution with magnesium oxide at a ratio of MgO:H₂SO₄ from 1:2.6 to 1:2.7 and pH 10.0÷10.4 for reactions such as: MeSO₄ + MgO + H₂O → Me(OH)₂ ↓ +MgSO₄, (1) with a turnover of magnesium reagents in the interaction of MgSO₄ with NaOH: MgSO₄ + 2NaOH → Mg(OH)₂ ↓ +Na₂SO, (2) with a possibility of exchange of MgO in (1) Mg(OH)₂ by (3): MeSO₄ + Mg(OH)₂ → Me(OH)₂ ↓ +MgSO₄, (3) using the reaction: Na₂SO₄+Ca(OH)₂ ("lime milk")→2Na(OH)+CaSO₄·2H₂O (gypsum)↓, for turnover of the reagents of sodium and utilisation of gypsum obtained in the form of gypsum concrete, alabaster.

EFFECT: decrease in power consumption.

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