Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

A comprehensive study of the leaching behavior and dissolution kinetics of copper oxide ore in sulfuric acid lixiviant

“…According to this model, it can be concluded that the leaching process in H 2 SO 4 solution involves: (i) transport of H 2 SO 4 from the bulk solution to the particle surface, (ii) diffusion of H 2 SO 4 through the solid residual layer from the particle surface to the surface of unreacted core, (iii) reaction between H 2 SO 4 and oxide ore on the surface of the unreacted core, (iv) diffusion of the resultants through the solid residual layer from the reaction interface to the particle surface, and (v) transport of the resultants from the particle surface to the bulk solution [28,29,32]. Generally, this model expressed by below described equations [11,19,31]. This model assumes that the reaction between solid and liquid reactants occurs on the outer surface of the solid particle and the reacting particles are spherical, and their size does not change during reaction [23].…”

“…Researches on leaching behavior and kinetics of copper oxide ores have been extensively conducted by different lixiviants including mineral acids such as HCl, H 2 SO 4 and HNO 3 [7,[9][10][11]; organic acids such as citric acid and lactic acid [11][12][13]; chlorine [14], ammonium hydroxide or ammonium salts including ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium citrate and ammonium acetate, etc. (2,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) and alkaline glycine solutions [25].…”

A New Heterotrophic Strain for Bioleaching of Low Grade Complex Copper Ore

“…Malachite is easy to leach out, and the dissolution rate of malachite reached 69.4%. Chrysocolla is very difficult to leach out in ammonia medium owing to the dispersion of copper atoms in the crystal lattice of gangue ores [6]. However, 58.6% of chrysocolla was leached out in this bioleaching system.…”

“…Most of the chalcocite was leached out. However, chalcopyrite was leached out partly, with the oxygen dissolved in the solution as an oxidant [6]. Liu [11] has reported that the copper sulfides can be oxidized and dissolved effectively in ammonia solution with sodium persulfate as an oxidant, so we can infer that a more efficient oxidant will promote the dissolution of copper sulfides during bioleaching.…”

“…In recent years, due to the depletion of copper sulfides, low-grade copper ores with high contents of oxide ore and carbonate gangue gradually account for a high proportion in the copper extraction industry [6]. However, bioleaching in the acid condition becomes ineffective and uneconomical for these copper oxide ores due to the limited energy source in oxide ores for autotrophic bacteria [7], excessive acid consumption [8,9] and undesired impurity dissolution which causes some problems in the further processing of the leaching solution [10].…”