What is the Difference Between Carbonate and Non-Carbonate Hardness?

The main difference between carbonate and non-carbonate hardness lies in the anions responsible for the hardness and their solubility in water.

Carbonate hardness is primarily caused by the presence of carbonate and bicarbonate salts of calcium and magnesium (Ca(HCO3)2, Mg(HCO3)2, CaCO3, and MgCO3). Carbonate hardness can lead to scale problems but is easier to control, as it can be removed by boiling.
Non-carbonate hardness, also known as permanent hardness, is caused by salts other than carbonate and bicarbonate salts, such as calcium sulfate, CaSO4, or magnesium chloride, MgCl2. Non-carbonate hardness can lead to permanent water and equipment quality problems, as it cannot be easily removed by boiling.

Both carbonate and non-carbonate hardness contribute to the total hardness of water, affecting various industrial, household, and environmental factors. They can interfere with the action of soaps and detergents, reducing their effectiveness and lathering ability, and can lead to the formation of scale deposits in water, affecting pipes, heating elements, and appliances.

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What is the Difference Between Carbonate and Non-Carbonate Hardness?

Comparative Table: Carbonate vs Non-Carbonate Hardness

The main difference between carbonate and non-carbonate hardness lies in the sources of the hardness, which affects their behavior when heated and their impact on water quality. Here is a table summarizing the differences between carbonate and non-carbonate hardness:

Parameter	Carbonate Hardness	Non-Carbonate Hardness
Source	Bicarbonate and carbonate ions, primarily derived from the dissolution of bicarbonates and carbonates of calcium and magnesium.	Divalent metal ions, primarily calcium and magnesium, associated with ions other than bicarbonate and carbonate, such as sulfates (SO4²⁻) and chlorides (Cl⁻).
Precipitation	Exhibits a behavior of precipitation upon heating.	Does not exhibit a behavior of precipitation upon heating.
Removal by Boiling	Carbonate hardness cannot be removed by boiling because it can form precipitations.	Non-carbonate hardness can be removed by boiling because it does not cause precipitation.
Impact on Water Quality	Can lead to scale build-up in pipes and appliances.	Can cause more permanent deposits that are harder to remove.

Both carbonate and non-carbonate hardness contribute to the total hardness of water and can affect pipes, heating elements, and appliances, as well as interfere with the action of soaps and detergents, reducing their effectiveness and lathering ability.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.