Water purification information

What is the difference between softened water and other water

Update time : 2021-09-24 15:03:21

In daily life, we often see scale formation on the inner wall of the kettle after being used for a long time. What is the reason? It turns out that the water we take contains many inorganic salts, such as calcium and magnesium salts. These salts are invisible to the naked eye in water at room temperature. Once they are heated and boiled, a lot of calcium and magnesium salts will precipitate out as carbonates, and they will form scale when they cling to the kettle wall.

We usually use the index of "hardness" to express the content of calcium and magnesium ions in water. A hardness of 1 degree is equivalent to 10 mg of calcium oxide per liter of water. The water below 8 degrees is called soft water, the water above 17 degrees is called hard water, and the water between 8 to 17 degrees is called moderately hard water. Rain, snow, rivers, rivers, and lakes are all soft water, spring water, deep well water, and sea water are all hard water
Raw water refers to untreated water. In a broad sense, the water before entering the water treatment process is also called the raw water of the water treatment. For example, the water sent from the water source to the clarification tank is called raw water.
　　
Softened water refers to water whose hardness (mainly refers to calcium and magnesium ions in water) has been removed or reduced to a certain extent. In the process of water softening, only the hardness decreases, while the total salt content does not change.

Desalting water refers to water that has been removed or reduced to a certain extent by salts (mainly strong electrolytes dissolved in water). The electrical conductivity is generally 1.0～10.0μS/cm, the resistivity (25℃)(0.1～1.0)×106Ω˙cm, and the salt content is 1～5mg/L.

Pure water refers to the water that has been removed or reduced to a certain extent by the strong and weak electrolytes (such as SiO2, CO2, etc.) in the water. The electrical conductivity is generally 1.0～0.1μS/cm, and the electrical conductivity (1.01.0～10.0)×106Ω˙cm. The salt content is <1mg/L.

Ultrapure water refers to the water in which the conductive medium in the water is almost completely removed, and the non-dissociated gases, colloids, and organic substances (including bacteria, etc.) are also removed to a very low level. Its electrical conductivity is generally 0.1～0.055μS/cm, resistivity (25℃) ﹥10×106Ω˙cm, salt content ﹤0.1mg/L. Ideal pure water (theoretically) has a conductivity of 0.05μS/cm and a resistivity (25°C) of 18.3×106Ω˙cm.

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