Abstract
The solubilities of CaSO4·2H2O (gypsum) have been determined in the acidic solutions of copper sulfate under the conditions such as those occurring in copper hydrometallurgical plants. The parameters investigated are the temperature (298–333 K) and the solution composition in terms of the concentrations of sulfuric acid (0–2 kmol·m−3 H2SO4) and copper sulfate (0–60 kg·m3 Cu).
The effects of temperature and solution composition on the solubility of calcium sulfate have been identified as follows. The increment in the solubility with temperature was found to be inversely proportional to the concentration of copper sulfate but directly proportional to the acid concentration at low acidity and constant at higher acidity. At constant temperature the solubility increases with acid concentration up to about 0.5 mol·m−3 H2SO4 but decreases with acid concentration at higher acidities. Copper sulfate decreases the solubility of calcium sulfate over the whole concentration range of copper sulfate investigated.
