water, "soft and hard" Unlike the naked eye solid material so intuitive, hard water is soft relative terms, then what is it hard water together with the small series and see it?.
The frequency of hard word appears more and more, but there are still a lot of people do not know what in the end is hard water, then what is it hard? Heres a look together with the small series it.
Hard water refers to water-soluble calcium and magnesium compounds containing more. Hard water does not pose a direct health hazard, but life will bring a lot of trouble, such as knot on the water apparatus scale, efficiency washing soap and detergents and other reduced.
Water hardness refers to the content of salts dissolved in water, i.e., how much calcium and magnesium content. High content of hardness, otherwise small. GPG water hardness units, 1GPG represents one gallon hardness ions (calcium and magnesium ions) in water content of a grain. U.S. press the WQA (Water Quality Association) standards, hardness of the water is divided into 6: 0 ~ 0.5GPG soft water, 0.5 ~ 3.5GPG as micro-hard, 3.5 ~ 7.0GPG is hard, 7 ~ 10.5GPG hard water, ~ 10.5 14.0GPG is very hard, 14.0GPG above is extremely hard. In Shanghai, for example, most parts of the domestic water tap water after each of the purification process water plant, the hardness range of 8 ~ 14 GPG, according to the standard belonging WQA hard or hard range.
hard water which has features
1, containing calcium, magnesium, potassium, sodium and other minerals rich;
2 proportional to the concentration of minerals, hard water with water; [ 123]
3, should not be as hard water and soft water "is healthy living and drinking water indicators."
Origin of hard water
When the water condensed in the atmosphere, it reacts with carbon dioxide in the air to form a weak acid carbonic acid is called. The acid rain falls to the ground with the final, then flows through the upper soil layer reaches the rock, carbonate dissolved lime (calcium and magnesium carbonate), and, at the same time and harden. Caves and caverns near the hard water in some areas is so formed. There are permanent and temporary hard points, usually related to the temporary hard water calcium and magnesium carbonates and bicarbonates, such long-term crystallization water may be present, until the air pressure or temperature changes, so thatWater becomes supersaturated, the resulting precipitate was attached to the hot surface or a rough surface, for example, in pipes and heat exchanger, i.e. the formation of hard scale; permanent hard water primarily to calcium sulfate and magnesium sulfate, is not subjected to a thermal impact and pressure changes, but if the water is evaporated, and still will leave to form a hard scale.
The above is what is hard water content of reports, and other small hard water For more information, please continue to focus on home safety knowledge column it.
Editor: Wang Xiaoli
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