The hardness of water is mainly composed of calcium and magnesium ions. When the raw water containing hardness ions passes through the resin layer in the water softener, the calcium and magnesium ions in the water are exchanged and adsorbed by the tree fingers, and the sodium ions released by the substances are simultaneously discharged. The water flowing out of the water softener is the softened water from which the hardness ions are removed.
The main process of scale formation:
1.Decomposed by heat.
Under the action of high temperature and high pressure, some calcium and magnesium salts (such as bicarbonate) dissolved in water are decomposed by heat and become insoluble substances (such as CaCO3, MgCO3) to precipitate.
2.The solubility is reduced.
Under the action of high temperature and high pressure, the solubility of some salts (such as CaSO4, SiO32-, etc.) is greatly reduced with the increase of temperature. After reaching a certain level, precipitation will precipitate.
3.The pot water is evaporated and concentrated.
Under high temperature and high pressure, the concentration of salt in the boiler water will increase with evaporation and concentrate. When supersaturation is reached, precipitation will precipitate on the heated surface.
4.Mutual reaction and transformation.
Salts with a large solubility in the feed water react with other salts during operation to form a poorly soluble precipitate. If the reaction takes place on the heated surface, scale is formed directly. If the reaction takes place in the pot water, slag is formed. Some of the slag is sticky, and when it is not removed in time, it is converted into scale.