Leaching behaviour of low-grade copper ore in the presence of organic acid

ABSTRACT

This study investigated the kinetics of copper leaching from malachite ore using formic acid as an organic leaching reagent. The analysis was carried out to determine the effect of the following parameters: particle size, acid concentration, leaching time, formic acid/malachite ratio, reaction temperature and stirring speed. Based on the experimental results, the optimum leaching parameters are as follows: particle size, +75−30 µm; formic acid concentration, 0.4 mol L⁻¹; leaching time, 90 min; formic acid (volume)/malachite (weight) ratio, 10 mL g⁻¹; temperature, 25°C; and stirring speed, 200 rev min⁻¹. Copper extraction was 70.25% under optimum experimental conditions. Furthermore, a kinetic model was used to indicate the effects of these parameters on the leaching of copper from malachite ore in formic acid solution. It was observed that the leaching process was controlled by film diffusion through a product layer. In conclusion, formic acid can be utilised as an organic leaching reagent in the leaching process of other ores that are similar in structure and composition to malachite.

RÉSUMÉ

Cette étude a examiné la cinétique de lixiviation du cuivre à partir du minerai de malachite en utilisant l’acide formique comme réactif de lixiviation organique. On a effectué l’analyse afin de déterminer l’effet des paramètres suivants: taille de particule, concentration d’acide, temps de lixiviation, rapport acide formique/malachite, température de réaction et vitesse d’agitation. Sur la base des résultats expérimentaux, les paramètres optimaux de lixiviation sont les suivants: taille de particule, +75−30 μm; concentration d’acide formique, 0.4 mol L⁻¹; temps de lixiviation, 90 min; rapport d’acide formique (volume)/malachite (poids), 10 mL g⁻¹; température, 25°C; et vitesse d’agitation, 200 tr min⁻¹. L’extraction du cuivre était de 70.25% dans des conditions expérimentales optimales. De plus, on a utilisé un modèle cinétique pour indiquer les effets de ces paramètres sur la lixiviation du cuivre à partir du minerai de malachite dans une solution d’acide formique. On a observé que le procédé de lixiviation était contrôlé par diffusion de film à travers une couche de produit. En conclusion, on peut utiliser l’acide formique comme réactif de lixiviation organique dans le procédé de lixiviation de d’autres minerais qui ont une structure et une composition similaires à la malachite.

KEYWORDS:

• Low-grade copper ore
• malachite
• leaching
• organic acid
• shrinking core model

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Ali Yaras gained his BS and MS in Chemical Engineering from Firat University, Elazig, Turkey in 2007 and 2010, respectively. In 2016, he received his Ph.D. degree in Chemical Engineering from Gazi University. During his Ph.D. studies, he worked on topics of boron technology and flame retardant materials. Now, he is serving as Associate Professor in Department of Metallurgy and Material Engineering in Bartin University. His main fields of interest are adsorption, hydrometallurgy, boron compounds and industrial wastes. He published a lot of international journal papers and presented international conference papers.

Hasan Arslanoglu was born in Elazig in 1983. Dr. Hasan Arslanoglu gained his BS and MS in Chemical Engineering from Firat University, Elazig, Turkey in 2005 and 2008, respectively. In 2016, he received his Ph.D. degree in Chemical Engineering from Firat University, Turkey. During his Ph.D. studies, he worked on topics of slow release fertilzers. Hasan Arslanoglu is a Research Assistant in the Department of Chemical Engineering at the University of Firat where he has been a faculty member since 2010. In a majority of education by taking various projects throughout the years, he had the opportunity to improve himself as successful. His research interests in the area of sugar technology, removal of heavy metals from waste water, metallurgical waste consideration, hydrometallurgy, slow release fertilzers.

Additional information

Funding

The authors would like to thank the coordinator of scientific research projects of Bartın University (grant no: 2017-FEN-B-003) for financial support.