Scale is a white block or powdery substance that is gradually formed when minerals contained in hard water are attached to the container after boiling. According to chemical composition, scale can be divided into carbonate scale, sulfate scale, silicate scale and mixed scale. The poor thermal conductivity of scale will lead to the deterioration of heat transfer on the heating surface, thus wasting fuel or electricity. If scale adheres to the heating surface of thermal equipment, it will endanger the safe and economic operation of thermal equipment. When the scale fragments enter the stomach, they will react with hydrochloric acid and release calcium and magnesium ions and carbon dioxide. The former is a necessary substance for the formation of stones.
Scale can be removed by baking soda, lemon, vinegar, ion exchange, membrane separation and scale remover.