Effect of the electromagnetic water treatment on the carbonate scales. Determination of calcite and aragonite by the Meigen test

Poster submitted to the 14th Mediterranean Congress of Chemical Engineering, Virtual Event: 16-20 November 2020Carbonate scale in water systems is a very common problem, frequently associated with exchange heaters. The presence of deposits involves technical and economic problems that can be minimised using different treatments, such as electromagnetic (EM) techniques. However, there are few studies determining the scientific basis of this water treatment technique. With the application of EM treatment, aragonite becomes predominant with respect to calcite and does not produce scale, in contrast to calcite. The presence of calcite or aragonite could be determined by the Meigen test, which is applied to solid minerals. Hence, this study aimed to analyse the potential usefulness of the TK3K equipment in water treatment, as well as the applicability of the Meigen test to solid samples obtained from water evaporation. It was observed that the evaporation temperature is a fundamental factor in the crystalline form of calcium carbonate because at higher temperatures (70 and 105 °C) there was more aragonite formed than calcite, even when no treated water was evaporated. The application of EM techniques increased the concentration of aragonite in the samples at 25 and 40 °C, as well as the durability of the aragonite crystals, by reducing their reversion to calcite. On the other hand, it was observed that Meigen test could be an excellent option as a complementary technique to X-ray diffraction and microscopy in the determination of calcite and aragonite from water evaporation. It is a simple, cheap and quick analysis, prior to determination by instrumentals techniques