A REFLECT team from the İzmir Institute of Technology (IZTech) visited the Germencik and Tuzla geothermal sites in Turkey. Both geothermal power plants are located in the Western part of Turkey. Stibnite scaling is the major problem in the Germencik site, while silica-based scaling is observed in the Tuzla site. Samples were taken from the wellhead in injection wells, production wells, and vaporiser of both sites at different dates.

The REFLECT team aims to fully understand scaling problems and fluid reactions considering physical and chemical properties. That is why physical and chemical properties of the geothermal waters were analysed by IZTech’s laboratories. Samples were also taken for isotopes 34S on sulphide and sulphate, and δ18O on sulphate and δ13C-CO2. These samples will be analysed by Hydroisotop (HI). Also, in the next coming period, gas sampling will be taken from the geothermal sites. Additionally, an experiment will be performed to investigate precipitations at various temperatures and pressures.


About the experimental set-up

Stibnite is seen in both Sb2S3 and Sb2S5 form in geothermal systems. However, Sb2S3, which is a black-greyish form, is commonly observed in Turkey. At first, the gathered scale is analysed, and the chemical composition of the deposit is generated. Then, the artificial scale is synthesised by a high-pressure reactor, which can reach a high temperature (140°C) and pressure (5 bar). After the black-greyish scale forms, various water-soluble antiscalants are used for the inhibition process.

High pressurised autoclave

The next step is to synthesise the stibnite in the new reactor, which allows to reach 300°C and up to 200 bar pressure, which means that under high pressure, well-shaped and organised crystals are obtained. Then, water-soluble polymers with different functional groups will be tested for inhibition.

Total volume of 100 ml autoclave


All the data collected during the project life will be implemented in a European geothermal fluid atlas and in predictive models allowing to provide recommendations on how to best operate geothermal systems for sustainable use.