Karbonathärte

Karbonathärte, often referred to as temporary hardness, is a measure of the concentration of carbonate and bicarbonate ions in water. These ions are primarily derived from dissolved carbon dioxide reacting with calcium and magnesium carbonate minerals in the earth's crust. Unlike permanent hardness, which is caused by sulfates and chlorides of calcium and magnesium, the hardness associated with carbonates can be removed by boiling. When water containing significant amounts of carbonate hardness is heated, the dissolved bicarbonates decompose, precipitating as insoluble carbonates, often forming scale. This is why kettles and boilers can accumulate a white deposit over time. The presence of carbonate hardness is common in many natural water sources, particularly those that have passed through limestone or chalk formations. It plays a role in various chemical processes in water, including buffering pH and influencing the solubility of other minerals. While not directly harmful to human health, high levels of carbonate hardness can affect the taste of water and lead to the formation of scale in plumbing and appliances, necessitating water treatment in some applications.