Source and Behavior of Stibnite Scaling: Case Study: Büyük Menderes Graben (Western Turkey)

Abstract

Scaling in geothermal sites is one of the factors decreasing the efficiency of geothermal resources. Silica, calcium carbonate, and calcium sulfate are the most common types of scaling in geothermal fields. However, sulfides of antimony scaling are local to some geothermal areas such as Büyük Menderes Graben (BMG) where is one of the major graben systems with their geothermal capacities in Western Anatolia. The region has multi-reservoirs, and different reservoir temperatures may separate them. There are two main reservoirs in Miocene sediments; fractured and consisting of sandstone. The conglomerate is defined as the first reservoir, with a deep reservoir as the second one, represented by Menderes Metamorphic. Antimony sulfide, commonly known as stibnite (Sb2S3), forms in the heat-exchanger units and pipelines Büyük Menderes Graben (BMG), western Turkey. In the scope of this study, it aims to determine the source, type, and properties of the stibnite in the BMG. According to the mineral solubility diagram, stibnite starts to precipitate below ~90 °C. The result shows that the source of stibnite is calcschists. Also, pH and temperature change are the principal causes of stibnite deposition in the geothermal field. Acknowledgments This project has received funding from the European Union’s Horizon 2020 research and innovation programme under agreement No: 850626