How does Sodium Hexametaphosphate Soften Hard Water

Sodium hexametaphosphate is a widely used additive in fine phosphate products. Not only plays an important role in life and food, but also in industry more widely use. Sodium hexametaphosphate is an important washing aid in washing powder. It can also be used in ceramics, refractory materials, and can also be used as a water softener for industrial and boiler water.

sodium hexametaphosphate
sodium hexametaphosphate

The principle of using sodium hexametaphosphate to soften hard water is that calcium ions Ca++ or magnesium ions Mg++ which cause hardness in water enter sodium hexametaphosphate molecules and become a very stable soluble complex: Na2 [Ca2 (PO3) 6] and Na2 [Mg2 (PO3) 6]. The Ca++ or Mg++ in this complex makes it not easy to run out again. So it will not make Ca++ or Mg++ encounter dyes or soap to produce precipitation or agglomeration. It can also save dyes and soap, to achieve a water purification effect.

In softened water, it is impossible to find the existence of calcium ion Ca++ even with sensitive reagents like ammonium oxalate. Sodium hexametaphosphate produced by Yucai Chemical Industry is widely used as a water softening agent. There are many softening methods for hard water to make dyes and soaps not precipitate or agglomerate. It can generally be selected according to water hardness and specific conditions.

As a manufacturer of sodium hexametaphosphate, we should tell you that when it is used as a water softener in dyeing or post-treatment, it can take away calcium ions and magnesium ions from the insoluble calcium soap, magnesium soap or calcium dye and magnesium dye precipitates, and make the precipitates redissolve. In other words, sodium soap can be regenerated by introducing sodium hexametaphosphate into the solution. And even when calcium soap or magnesium soap is formed, the coagulation of calcium soap or magnesium soap will disappear. When dyeing artificial cotton cloth with direct dyes, soft water is an important condition to ensure the quality, especially for some direct copper salt dyes.


I’m Rena, and happy to share my knowledge about phosphate products with you. Yucai Chemical factoty have summed up a lot of market experience and excellent teams to provide the best service and quality. Looking forward to working with friends from all over the world, YUCAI chemical can be a trustworthy partner for you.