The kettle has been used for a long time, and a thick layer of scale will grow on the inner wall. Usually, scale is mainly produced by the action of "hard water". We call water containing minerals such as calcium and magnesium salts "hard water". Rivers, lakes, wells and springs are hard water. Tap water is obtained after filtration, so it is also hard water. After the water is boiled, part of the water evaporates and precipitates the calcium sulfate that is not easy to dissolve. The original dissolved calcium bicarbonate and magnesium bicarbonate decompose in boiling water and release carbon dioxide. They become insoluble calcium carbonate and magnesium carbonate (they are the main components of limestone and dolomite) and precipitate. This is the origin of scale. Let's take a look with this website.
Hazards of scale
Scale does great harm to human body. Many people believe that scale only affects beauty; If the boiled water precipitates, the scale will not affect the taste; The scale in the thermos can't be seen anyway and won't have any impact. The scale was originally the sediment of heavy metals, calcium salts, dust, bacteria, insect eggs and corpses mixed in the water, which is not only unsanitary, but also seriously affects people's health. According to chemical analysis, there are a large number of heavy metals in scale. Facts have also proved that scale will not only cause a variety of stone diseases, but also cause diseases of digestive, nervous, urinary, hematopoietic, circulatory and other systems and cause aging. Long term intake will cause heavy metal poisoning in human body, and many heavy metals will cause canceration of human organs.
Scale affects human health. Tartar and periodontitis are often caused by scale; It can kill people. Legionella, which still has no vaccine to prevent, is hidden in scale. 2000 to 3000 people die of this pathogen in France every year. Scale has more hidden dangers. Washing your face and bathing with water containing scale will form calcium magnesium soap. It is as sticky as gum and sticks to your face and skin, making it difficult to remove the dirt. The dirt is not cleaned, blocking the opening of skin gland, forming embolism, affecting normal metabolism and premature atrophy and aging of skin.
How to produce scale
It is mainly related to water quality. If the water quality is hard, the oxygen content in the water is insufficient and the water molecules are unstable, the solubility of calcium and magnesium ions in the water will be reduced and the precipitation will be intensified, thus forming scale. As long as the water temperature exceeds 60 ℃, especially in the north where the water quality is relatively hard, scale will certainly occur, and scale will exist in daily kettles and boilers. The solution is to wash regularly.
How to remove scale?
1. Descaling with baking soda
When boiling water in an aluminum kettle, put a spoonful of baking soda and boil for a few minutes to remove the scale.
2. Removing scale with vinegar
If the kettle has soda, you can put a few spoons of vinegar into the water. After boiling, the soda can be removed.
3. Mask anti scaling
Put a clean mask in the kettle. When boiling water, the scale will be absorbed by the mask.
4. Egg descaling
A pot of boiling water has been used for a long time. The scale is hard and difficult to remove. In this regard, it can be used to boil eggs twice, which will have an ideal effect.
5. Potato peel descaling
Aluminum pot or aluminum pot will form a thin layer of scale after being used for a period of time. Put the potato peel inside, add an appropriate amount of water to boil, and cook for about 10 minutes to remove it.
6. Descaling by thermal expansion and cold contraction
Put the empty kettle on the stove to dry the water in the scale. When you see a crack on the bottom of the kettle or when there is a "bang" sound at the bottom of the kettle, remove the kettle and quickly inject cold water, or wrap the handle and spout with a rag, hold it with both hands, and quickly sit the dried kettle in cold water (do not let the water into the kettle). The above two methods need to be repeated for 2 ~ 3 times, and the scale at the bottom of the pot falls off due to thermal expansion and contraction.
7. Scale prevention of boiled potato in kettle
Put more than half of the potato in the new kettle, fill it with water and cook it. If you boil water later, there will be no water and scale. After boiling the potato in the kettle, do not scrub the inner wall, otherwise it will lose the anti scaling effect. For the old kettle with scale, after boiling potato for 1 ~ 2 times with the above method, not only the original scale will gradually fall off, but also the scale can be prevented from accumulating again.
8. A magnet in the kettle can remove scale
Put a magnet in the kettle. When boiling water, the thick scale at the bottom of the kettle will crack by itself, so it is easy to take out the scale block.
Prevention of scale
Ion exchange method
Ion exchange resins are divided into two categories. One is used to reduce the hardness of water to soft water for cleaning and bathing. This kind of ion exchange resin is called sodium ion exchange resin. The second type is hydrogen ion exchange resin used to reduce the hardness of water in an appropriate amount so that scale will not be formed after boiling drinking water.
1) Cleaning, bathing, etc.: sodium ion resin reacts with calcium and magnesium ions in water to quickly exchange sodium ions into water and adsorb calcium and magnesium ions in water, so as to completely soften hard water and turn it into water without calcium and magnesium ions. Suitable for washing clothes, bathing, etc. The product using this kind of resin is water softener or water softener.
2) Drinking: the hydrogen ion exchange resin reacts with some calcium and magnesium ions in the water to reduce the hardness. While retaining an appropriate amount of calcium and magnesium ions in the water, there will be no scale left in the boiled water. Products using this kind of resin, such as water purification equipment for infants and young children, water filtering kettle for infants and young children, etc.
Physical filtration
A membrane separation process that uses the pressure higher than the osmotic pressure as the driving force and uses the selective permeability of the selective membrane to extract fresh water from the water body. Reverse osmosis is also called reverse osmosis. It is commonly known as pure water machine.
Chemical treatment
A chemical agent that can prevent the formation of scale or inhibit its deposition and growth. Such as silicon phosphorus crystal and trisodium soft water agent (sodium hydroxide, trisodium phosphate and sodium humate). It can be selected according to different use conditions.