Application of Mathematical Modeling on Copper Recovery Optimization of Oxide Ores FATEMEH SADAT HOSEINIAN, 1,4 MOEIN BAHADORI, 2 MOHSEN HASHEMZADEH, 3 BAHRAM REZAI, 1 and SAEED SOLTANI-MOHAMMADI 2 1.—Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Islamic Republic of Iran. 2.—Department of Mining Engineering, University of Kashan, Kashan, Islamic Republic of Iran. 3.—Department of Materials Engineering, University of British Columbia, Vancouver, BC, Canada. 4.—e-mail: f_hoseinian@aut.ac.ir In this study, a mathematical modeling method was used to predict the optimum conditions of column leaching of copper oxide ore. Important parameters such as column height (m), particle sizes (m), acid rate (kg/ton) and leaching time (day) were studied and their impacts on copper recovery were investigated. Experiments were performed on samples with particle size distributions of 25.4 mm and 50.8 mm in six columns with the heights of 2 m, 4 m and 6 m. The results showed that the copper recovery has an inverse relation with column height and particle sizes, and direct relation with leaching time and acid rate. According to the results, the mathematical models based on the macro model predict the copper recovery based on operation conditions. The obtained values of determination coefficient (0.97), root mean square error (2.86) and relative error (0.089) testing datasets, showed the capability of the model in predicting the copper recovery. INTRODUCTION Heap leaching is a widely used hydrometallurgi- cal method to leach low grade minerals such as gold, copper, zinc, and nickel. Column leaching tests are commonly used to study the effect of process factors. 1–8 Many experimental and modeling studies have been carried out to gain a better understand- ing of the heap leaching process and its opera- tion. 9–13 However, little research has been conducted with the aim of optimizing the process. Recently, analytical models have been used for leaching processes in order to carry out planning, optimization, design and control of the heap leach- ing process. An analytical–numerical study was carried out to solve a heap leaching problem of one or more solid reactants from porous pellets. In this regard, an analytical model was used to optimize flow rates on copper heap leaching. 6,14 De Andrade Lima 15 introduced a mathematical model for the heap and column isothermal leaching processes. In this regard, the transient evolution of the dissolved chemical species was simulated and evaluated for an industrial gold heap leaching and a pilot column copper leaching. Veglio et al. 16 studied column leaching of a manganese dioxide ore to evaluate the effect of some main parameters on the process of leaching using fractional factorial design. Dixon and Hendrix 17 presented a mathematical model for heap leaching that was useful for designing and scaling up heap leaching processes. They also presented a general model for leaching processes to simulate reaction-zone and homogeneous kinetics through the use of effective factors. 18 In Mellado 19 was developed analytical models suitable for scaling up the heap leaching process of solid reactants from porous pellets. These models are appropriated for the scale-up of applications that allows obtaining the solutions for actual industrial heap leaching operations. A mathematical model for heap leaching of one or more solid reactants is presented by Dixon and Hendrix. 17,18 They developed an efficient ana- lytical–numerical scheme for solving differential equations that described the heap leaching process. The aim of the present study is to model the heap leaching process to optimize leaching conditions through the use of changing various parameters such as column height (m), particle size (m), JOM DOI: 10.1007/s11837-017-2476-6 Ó 2017 The Minerals, Metals & Materials Society