Non-scale forming salts water quality

Non-hardness salts, such as sodium salts are also present, and are far more soluble than the salts of calcium or magnesium and will not generally form scale on the surfaces of a boiler, as shown in Figure 3.9.6.

Fig. 3.9.6
The effects of heat

Comparative units

When salts dissolve in water they form electrically charged particles called ions.

The metallic parts (calcium, sodium, magnesium) can be identified as cations because they are attracted to the cathode and carry positive electrical charges.

Anions are non-metallic and carry negative charges - bicarbonates, carbonate, chloride, sulphate, are attracted to the anode.

Each impurity is generally expressed as a chemically equivalent amount of calcium carbonate, which has a molecular weight of 100.