Dissolution behavior of copper concentrate in acidic media using nitrate ions

Abstract

This study was conducted to investigate the dissolution process of copper concentrate using sodium nitrate (NaNO 3 ) in a sulfuric acid (H 2 SO 4 ) medium under various controlling parameters, including dissolution temperature, time, particle size, solid/liquid (S/L) ratio and concentration of NaNO 3 and H 2 SO 4 . The thermodynamic probability of mineral dissolution (CuFeS 2 , Cu 2 S, CuS, FeS 2 ) reaction in the concentrate was estimated by standard Gibbs energy. The activation energy (E a ) for the dissolution of copper concentrate was calculated as 15.96kJ/mol. Batch experimental results show that about 89.9% of copper in the intact concentrate have been leached and it increased to 96.5% at the fraction with <25.4µm particle size. Copper leaching rate has direct correlation with increase in time, temperature, solid/liquid (S/L) ratio and H 2 SO 4 concentration. The XRD and XRF analyses of the solid residue after leaching revealed the presence of elemental sulfur.

Caliche and Seawater, Sources of Nitrate and Chloride Ions to Chalcopyrite Leaching in Acid Media

“…Figure 6b shows that almost all tests show correlations close to 1:1. by the increase of acid concentration. This was also observed by Narangarav et al [31]. The final pH values were maintained near 0 in 0.7 M H2SO4, 0.3 in 0.5 M H2SO4 and 1 in 0.25 M H2SO4.…”

“…According to Sokić et al, [21] the oxidizing potential of nitrate ions is favored by the increase of acid concentration. This was also observed by Narangarav et al [31]. The final pH values were maintained near 0 in 0.7 M H 2 SO 4 , 0.3 in 0.5 M H 2 SO 4 and 1 in 0.25 M H 2 SO 4 .…”

“…The use of these nitrogenous species has several positive effects; they have the ability to partially or completely oxidize the sulfide contained forming elemental sulfur, the reaction speed is faster, reactors with less volume are needed, high temperatures or pressures are not necessary and the oxidation-reduction potential of the reaction is high. [21,24,[29][30][31][32][33]. Narangarav et al [31] studied the leaching of chalcopyrite concentrate in an acid-nitrate media.…”

“…[21,24,[29][30][31][32][33]. Narangarav et al [31] studied the leaching of chalcopyrite concentrate in an acid-nitrate media. They determined that copper extraction can reach over 85% by increasing the nitrate concentration from 0.2 to 1 M, and that the reaction has an activation energy of 15.96 kJ/mol indicating that the kinetics are chemically controlled.…”

Copper Recovery from Chalcopyrite Concentrate by Oxidative Roasting and Acid Leaching

“…The mechanism of copper extraction from sulphide concentrate is highly complex. In particular, the most operated mineral as chalcopyrite requires a powerful oxidizing agent to break its strong crystal lattice [3][4][5]. Nowadays, the combined technology for processing copper concentrates is investigated intensely to the pretreatment roasting before leaching method, which is a non-negative influence on the environment and the economic importance [6].…”