Simulation of Sodium Bicarbonate Purification via the Sodium Sulfate Carbonation Route

The present work sought to study the mother water of the process and point out alternatives so that the water present in this solution can be recovered and the possibility of recycling it can be analyzed. The following alternatives were adopted: the evaporation of water without reaching the saturation point of the mother water and evaporation beyond the saturation point. For the first case, flash distillation was used to remove unwanted components, followed by an evaporation process. The second case was studied employing salt crystallization, for which crystallizers were used. This study was conducted with Aspen Plus® v12 software, which can represent the desired route, in addition to having data and tools that are suitable for the process modeling and simulation. For the evaporation without crystallization, it was noticed that it was possible to remove 23.89% of the water from the mother water. For the crystallization case, it was found that the mother water solution had dissolved ammonium sulfate for crystallization; however, it was necessary to first precipitate sodium sulfate. In the crystallization of sodium sulfate, it was possible to remove 85.62% of vapor from the mother water solution, containing water, ammonia, and carbon dioxide, thus inferring the possibility of recycling this current to the process. This study shows that it is not appropriate to insert evaporation equipment without thinking about the precipitation of by-products since there would be an increase in the price of the route, with little raw material for reuse.