Sulphidizing reactions in the flotation of oxidized copper minerals, II. Role of the adsorption and oxidation of sodium sulphide in the flotation of chrysocolla and malachite

Sulfidation treatment of copper-containing plating sludge towards copper resource recovery

“…It can be seen from the figure that S 2− ions were almost completely consumed within the first 5 min, which indicated a high reaction rate of sulfidation of copper compounds to copper sulfides. Similar to this study, the high sulfidation rate has been reported for the sulfidation of brochantite [Cu 4 (OH) 6 SO 4 ] and chrysocolla [CuO·SiO 2 ·2H 2 O] with ammonium sulfide [13], further for the sulfidation of chrysocolla and malachite [CuCO 3 ·Cu(OH) 2 ] with sodium sulfide [14], and for the sulfidation treatment of malachite with sodium sulfide and sodium tetrasulfide [15]. However, in the reported research works, the sulfidation rate of oxidized copper ores was found to be the highest at mildly acidic or neutral pH, and the sulfidation rate significantly decreased when the pH value was increased to a value of about 11.0.…”

“…In this work, the sulfidation treatment of plating sludges was investigated in order to convert heavy metals to metallic sulfides and thus to overcome the difficulties resulting from the sludge heterogeneity. The sulfidation treatment is a method which has been used in the sulfidation treatment of various oxidized copper ores such as chrysocolla, brochantite [13], malachite [14,15] and copper oxide [16] in order to improve the metal recovery from natural resources. After the sulfidation treatment, the heavy metal sulfides are separated by means of flotation which is a commonly used separation technique in the process of refining metal resource from sulfide ores [17,18].…”

A comparative evaluation of the response of platinum and mineral electrodes in sulfide mineral pulps

“…Opening the cell to the atmosphere caused the departure of potentials of two electrodes from each other, Pt indicating higher potentials. Na 2 S and NaHS are commonly used in the flotation of oxidized base metal ores to sulfidize the mineral surfaces (Castro et al, 1974;Bessière et al, 1991;Herrera-Urbina et al, 1999). When Na 2 S is used as reducing agent, it is expected that the oxidized sulfide mineral surfaces should be restored as follows:…”

Studies on the Flotation of Chrysocolla

“…Apparently, the oxidation products formed during sulfidization, for example thiosulfate, playa destructive role and their presence results in the irreversible depression of chrysocolla (Castro el al. 27 ) . As opposed to the flotation behaviour of sulfidized chrysocolla, malachite floats best when high concentrations ofNa 2S are used for sulfidization.…”