Optimization of Copper Leaching from Ore Containing Malachite

Abstract

In this study, selective leaching of copper with NH₃(aq) from ore containing malachite, SiO₂, Al₂O₃ and Fe₂O₃ was optimized by using the Taguchi method. After determining the parameters and their levels affecting the leaching efficiency, the experiments were planned using an orthogonal array technique in an L₂₅ array with six parameters. It was determined that aqueous ammonia is unsuitable for leaching ore containing malachite. The effect of CO₂, (NH₄)₂CO₃, (NH₄)₂SO₄ and NH₄CI on leaching malachite with NH₃ (aq) was investigated. It was determined that NH₃ (aq) + CO₂ (g) is suitable for leaching malachite. The second experimental design using NH₃ (aq) + CO₂ as a leaching reagent was planned by means of orthogonal array technique in an L₁₈ array with seven parameters. Optimum leaching conditions for the second step were obtained as follows: temperature 42 °C, solid to liquid ratio 0.1 g.mL⁻¹, concentration of NH₃ 2.5 M, mean particle size 0.3375 mm, stirring speed 600 rpm, flow rate of CO₂ gas 61.64 mL.s⁻¹ and a reaction time of 50 minutes. For these conditions, 97.3% of the leaching efficiency was obtained.

In this study, selective leaching of copper with NH₃(aq) from ore containing malachite, SiO₂, Al₂O₃ and Fe₂O₃ was optimized by using the Taguchi method. After determining the parameters and their levels affecting the leaching efficiency, the experiments were planned using an orthogonal array technique in an L₂₅ array with six parameters. It was determined that aqueous ammonia is unsuitable for leaching ore containing malachite. The effect of CO₂, (NH₄)₂CO₃, (NH₄)₂SO₄ and NH₄CI on leaching malachite with NH₃ (aq) was investigated. It was determined that NH₃ (aq) + CO₂ (g) is suitable for leaching malachite. The second experimental design using NH₃ (aq) + CO₂ as a leaching reagent was planned by means of orthogonal array technique in an L₁₈ array with seven parameters. Optimum leaching conditions for the second step were obtained as follows: temperature 42 °C, solid to liquid ratio 0.1 g.mL⁻¹, concentration of NH₃ 2.5 M, mean particle size 0.3375 mm, stirring speed 600 rpm, flow rate of CO₂ gas 61.64 mL.s⁻¹ and a reaction time of 50 minutes. For these conditions, 97.3% of the leaching efficiency was obtained.

Dans cette étude, on a optimisé la lixiviation sélective du cuivre avec du NH₃ (aq) d'un minerai contenant de la malachite, du SiO₂, de l'Al₂O₃ et du Fe₂O₃, en utilisant la méthode de Taguchi. Après avoir déterminé les paramètres et leurs niveaux affectant le rendement de la lixiviation, on a planifié les expériences en utilisant une technique de tableau orthogonal dans un tableau L₂₅ avec six paramètres. On a déterminé que l'ammoniac aqueux était inadéquat pour la lixiviation de minerai contenant de la malachite. On a étudié l'effet du CO₂, du (NH₄)₂CO₃, du (NH₄)₂SO₄ et du NH₄Cl sur la lixiviation de la malachite avec du NH₃ (aq). On a déterminé que le NH₃ (aq) + CO₂ (g) était adéquat pour la lixiviation de la malachite. On a planifié le second plan expérimental utilisant le NH₃ (aq) + CO₂ comme réactif de lixiviation au moyen d'une technique de tableau orthogonal dans un tableau L₁₈ avec sept paramètres. On a obtenu les conditions optimales de lixiviation pour la seconde étape comme suit: température de 42 °C, rapport solide/liquide de 0.1 g.mL⁻¹, concentration de NH₃ de 2.5 M, taille moyenne de particule de 0.3375 mm, vitesse d'agitation de 600 rpm, débit de gaz CO₂ de 61.64 mL.s⁻¹ et une durée de réaction de 50 minutes. Pour ces conditions, on a obtenu un rendement de lixiviation de 97.3%.