Process Design to Obtain Copper Sulfate Crystals Using Solid-Liquid Equilibrium of Copper Sulfate-Sulfuric Acid-Seawater

摘要

In Chile, there are several mining companies that crystallize copper sulfate pentahydrate using freshwater; however, it would be interesting to know the effect of seawater in the process design of copper sulfate pentahydrate crystals, considering the low freshwater availability in the mining zones. In the present work, three different processes are proposed for obtaining copper sulfate pentahydrate crystals using seawater, by means of the addition of sulfuric acid. These were evaluated and compared in terms of their mass and energy balances. The first process (Case 1) is composed of crystallization, heating/mixing, recrystallization, centrifugation, and drying stages. In the second process (Case 2), the recirculation of the solution from the recrystallization to the crystallization stage is added. In the third process (Case 3), the heating/mixing and recrystallization stages are eliminated, considering one crystallization stage along with centrifugation and drying. The results of the Mass and Energy balances showed that there is high energy consumption associated with the heating/mixing and recrystallization stages, so the process that does not contain these stages (Case 3) is the most convenient from an energy point of view. On the other hand, the results indicated that the highest yield (97.17%) of the process is obtained when the recirculation of the solution is added from the recrystallization to the crystallization stages (Case 2), followed for the yield of 94.41% obtained in the process where the heating/mixing and recrystallization stages are eliminated (Case 3), which would make it the most convenient process from an energy and production point of view.Graphical Abstract