The softening principle of the softened water equipment is that the raw water passes through the sodium ion exchanger (sodium cation exchange resin), and the calcium and magnesium plasma in the water is replaced by the sodium ion in the exchanger, so that the calcium and magnesium compounds that are easy to scale can be transformed into soluble sodium compounds that do not form scale, so that the water can be softened.
With the increase of treatment capacity, more and more impurities are adsorbed and the adsorption capacity decreases gradually. It is necessary to use salt to replace the calcium and magnesium ions adsorbed by the resin and restore the adsorption capacity of the resin. This process is the regeneration of the resin.
So, what salt is needed for regeneration? How to control the amount and concentration of salt?
Special soft water salt (high-purity iodine free refined salt) is used for regeneration, also known as ion exchange resin regeneration agent. The main component is sodium chloride, with a content of more than 99.5% and no impurities. It is very different from the edible salt and industrial salt we see.
The salt consumption of demineralized water equipment is determined according to the resin filling amount, which also determines the equipment regeneration cycle. The theoretical salt demand for resin regeneration is 160 ~ 260g per liter. When the salt demand is the lowest, the theoretical exchange capacity per liter of resin is 0.058kg; When the salt demand is the highest, the theoretical exchange capacity per liter of resin is 0.067kg. The specific salt dosage needs to be adjusted according to the actual inlet hardness and outlet water quality.
When adding salt to the salt tank, it should be noted that soft water salt with large particles should be selected. It is better to add more than less, otherwise the effluent quality will be affected.