Geothermal energy is a renewable energy source by which heat is extracted from the subsurface. Due to changes in pressure and temperature and chemical reactions when the geothermal fluid is pumped through the wells and surface installations, scales can be formed. These scales can accumulate in different locations of the geothermal system and/or parts of the surface installation and cause clogging of the wells, pumps, pipes, heat exchangers and/or filter units. Consequently, the efficiency of the geothermal system can decrease. To obtain insight into the formation of scales in the surface installation of the Balmatt geothermal site, heat exchanger and filters scaling material was sampled after a circulation time of 240 h and 46 h respectively. This material was chemically, mineralogically and radiologically characterized. The scaling material found in the heat exchanger consists mainly of galena (PbS). Minor amounts of challacolloite (KPb₂Cl₅) and laurionite (PbClOH) were also observed. Additionally, in the filter scaling material carbonates such as witherite (BaCO₃), siderite (FeCO₃) and possibly rhodocrosite (MnCO₃) are present as well, together with an amorphous phase and elemental copper. Salt minerals such as sylvite (KCl), halite (NaCl) and challacolloite (KPb₂Cl₅) and iron oxides such as hematite (Fe₂O₃) were also observed in the scaling material. However, these minerals are thought to be formed during drying of the scalings after sampling. Together with these minerals, radionuclides such as ²²⁶Ra, ²¹⁰Pb and ²¹⁰Po are observed. ²²⁶Ra seems to predominantly co-precipitated with and/or sorb on witherite and hematite, while ²¹⁰Pb and ²¹⁰Po are rather accumulated in galena and laurionite. Equilibrium calculations, using the PhreeqC software were performed to gain insight into the geochemical processes. The calculations indicate that galena is one of the main oversaturated minerals. Precipitation of native copper and carbonates are also observed and supported by the equilibrium calculations. The formation of these precipitates is probably a result of electrochemical corrosion of carbon steel and/or corrosion by dissolved CO₂.

地热能是一种可再生能源，通过它可从地下提取热量。当将地热流体泵送通过井和地面设备时，由于压力和温度的变化以及化学反应，会形成水垢。这些水垢会积聚在地热系统的不同位置和/或地面设施的各个部分，并导致井，泵，管道，热交换器和/或过滤器单元堵塞。因此，地热系统的效率会降低。为了深入了解Balmatt地热站点地面设施中水垢的形成，分别在240 h和46 h的循环时间后对热交换器和过滤器中的水垢材料进行了采样。对该材料进行了化学，矿物学和放射学表征。热交换器中发现的水垢材料主要由方铅矿（PbS）组成。少量的黄铜矿石（KPb还观察到了₂ Cl ₅）和月桂石（PbClOH）。另外，在过滤器除垢材料中，还存在碳酸盐，例如钙铁矿（BaCO ₃），菱铁矿（FeCO ₃）和可能的菱锰矿（MnCO ₃），以及非晶相和元素铜。在结垢材料中还观察到了盐矿物，例如钾盐（KCl），盐岩（NaCl）和硅钙石（KPb ₂ Cl ₅）和氧化铁，例如赤铁矿（Fe ₂ O ₃）。但是，这些矿物被认为是在取样后的水垢干燥过程中形成的。与这些矿物质一起，放射性核素，例如²²⁶ Ra，²¹⁰观察到Pb和²¹⁰ Po。²²⁶ Ra似乎主要与堇青石和赤铁矿共沉淀和/或吸附，而²¹⁰ Pb和²¹⁰ Po则相当积累在方铅矿和月桂石中。使用PhreeqC软件进行平衡计算，以深入了解地球化学过程。计算表明方铅矿是主要的过饱和矿物之一。还可以观察到天然铜和碳酸盐的沉淀，并通过平衡计算得到支持。这些沉淀物的形成可能是碳钢的电化学腐蚀和/或溶解的CO ₂腐蚀的结果。