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How to distinguish whether ceramic tableware is safe?

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judging the safety of porcelain tableware mainly depends on two points: ceramic raw materials and ceramic firing

1. Look at the raw materials of ceramics

the raw materials of ceramics include clay (body raw materials), glaze (glaze raw materials) and painting materials (decoration raw materials). The raw material of green body is usually kaolin or clay. Because it belongs to natural clay or minerals without chemical addition, it is basically safe

in the glaze, there is a layer of glass (glaze) wrapped in the underglaze color and underglaze color, which may contain heavy metal elements. The overglaze color, because its painting material will directly contact with food, is easy to release heavy metal elements at high temperature and cause harm to human body

in most cases, the painting materials are low-cost chemical materials, which are likely to contain heavy metals such as lead and cadmium

2. See the firing of ceramics

in addition to whether the painting material is in direct contact with food, it also depends on the firing temperature. The harmful substances disappear after the chemical reaction at high temperature

glaze is a glass body formed after high-temperature processing of glaze. Heavy metal elements will not remain after such high-temperature treatment (about 1200 ℃)

the color baking temperature of overglaze color is only about 800 degrees, which can not meet the “high temperature” conditions mentioned above. In this case, the safety depends on the quality of the drawing. The better the quality, the lower the content of lead and cadmium

extended data

ceramic tableware not only has a wide variety of designs and colors and different shapes, but also is delicate, smooth and beautiful; No rust, no decay, no water absorption, easy to wash and strong decoration

nowadays, people have new requirements for the performance and quality of ceramic tableware: the dissolution of heavy metal salts harmful to health such as lead and cadmium should not exceed the standard; It has a certain bearing capacity when subjected to cold and heat shock, that is, it has a certain service life; The style, design and appearance quality should meet the requirements of the times. For health reasons, people pay more attention to its safety

according to different decoration methods, ceramic products are divided into three types: overglaze color, underglaze color and in glaze color. The amount of lead and cadmium dissolved mainly comes from the overglaze decorative materials on the surface of products, such as ceramic decal paper and ceramic pigment for the production of decal paper

because these pigments generally contain a certain amount of lead, and some contain cadmium, the lead content in ceramic products has also been an unavoidable problem in the manufacturing process for a long time, especially the overglaze color and other inferior products

when people use these tableware for a long time to hold foods with high organic acid content such as vinegar, wine, fruit juice and vegetables, the lead and other heavy metals in the tableware will dissolve out and accumulate in the human body with the food, which will lead to chronic lead poisoning over time

reference source: People’s Daily – tableware safety

I. ceramic tableware is not always safe. Ceramic tableware is not always safe. Long term use of some tableware will cause chronic poisoning of heavy metals and damage the skin, teeth, eyes, brain, bones and fertility. These harmful substances are mainly heavy metals such as lead and cadmium contained in ceramic tableware. The degree of damage mainly depends on the amount of these heavy metals dissolved in use and absorbed by the human body

II. Which ceramic tableware has excessive heavy metal content? The heavy metal content of ceramic tableware should be determined through professional testing. The country and the world have extremely strict regulations. If the dissolution of heavy metals in a porcelain exceeds 0.0%, foreign countries will refuse to import it. However, there is no compulsory standard in China. In addition, some ceramic manufacturers are irresponsible, and the excessive dissolution of heavy metals in daily ceramic tableware is both common and serious in China. So we can only strengthen self-awareness and self-control

generally, the following ceramic tableware should be used less or not

1. There are large decorative patterns or painted colors in the tableware

2. Too many decorative patterns in tableware use dark colors such as bright red, dark yellow and dark green

3. The decorative pattern in the tableware lacks luster and the surface of the pattern is rough

Low-temperature porcelain, low bone white porcelain or other low-temperature porcelain

5. If not used for a long time, the porcelain pattern will deposit a layer of black gray and greasy tableware

6. In use, the porcelain pattern will be gradually corroded and the color will become lighter

III. how to avoid the harm of heavy metal dissolution from ceramic tableware to people

1. Try not to use ceramic tableware with large area patterns inside

2. Never use ceramic tableware with flowers inside and eat foods that are too sour and salty

3. Ceramic tableware placed for too long shall be cleaned and wiped with hot water before use

4. After cleaning, the ceramic tableware shall be dried or dried as much as possible for storage

5. Never use ceramic tableware with flowers inside to store food for a long time

6. Do not use ceramic tableware with flowers inside to cook food at high temperature

IV. misunderstanding about several ceramic tableware

1. “Bone China is made of cow bone and contains a large amount of calcium phosphate, which will be absorbed by the human body, so bone china is green tableware and health tableware”. This is wrong. Bone porcelain uses animal bone charcoal rich in calcium phosphate as raw material, but the chemical composition has changed after porcelain formation and can not transfer any calcium phosphate to the human body. Qualified Bone China is safe, but some low-quality and low-cost low-quality bone china products, even if they are pure white, have a high dissolution of heavy metals, which is extremely unsafe

2. “As long as the ceramic tableware with flowers inside is unsafe”, this is wrong. Generally speaking, underglaze pictures are very safe, such as underglaze blue and white tableware and underglaze blue and white exquisite tableware in Jingdezhen. The color of the overglaze picture is light, bright and clean, and it is also very safe. In short, the higher the temperature when making ceramics, the better the combination between the picture and the glaze, and the deeper the picture melts into the glaze, the safer it is

3, “as long as it is white porcelain, it is safe”. inaccurate. High temperature white porcelain, firing temperature above 1300 degrees, are safe. However, white porcelain below 1200 degrees should be distinguished if it has a smooth and bright glaze. When it is inconvenient to distinguish, it is best to use it as neutral food and cold meal to avoid being too sour and salty, or for high-temperature cooking

4. “Try to use less ceramic tableware”. This is an extremely fallacious view. Ceramic tableware is one of the most important manifestations of human civilization. Ceramic tableware is also the safest tableware. Only with the progress of modern industry, the decorative means of ceramic tableware are increasing, the use of lead, cadmium and other substances in ceramic processing are increasing, and some enterprises are shoddy, which leads to more unsafe hidden dangers of ceramic tableware. As long as we pay attention in life and use ceramic tableware correctly, there is no problem

v. the use of ceramic tableware should be regarded as a kind of enjoyment. It is a common custom all o
ver the world to take out the best ceramic tableware when entertaining distinguished guests. So is China. Eating with beautiful porcelain is really a pleasure

there is a jargon in Chinese catering industry: color, aroma and shape. Color, smell and shape refer to dishes, while utensils refer to tableware. Without good tableware to match, the best dishes are not perfect

pay attention to what kind of porcelain is used for any dish, square, round, long and flat, plates, dishes, pots and spoons. Especially the picture decoration is more important. The emperor of the Qing Dynasty often used a kind of “eternal life” Pastel tableware with magnificent decoration. It should be said that the content of heavy metals would seriously exceed the standard. However, these foods served in tableware, one is more “bedding”, the other is a lot of cold dishes, and the eaters are noble and exquisite. They will never sweep away the soup and dishes. Therefore, they are still very safe to a certain extent

from this point of view, good-looking ceramic tableware should not be rejected, and scientific and rational use is the most important

judge whether the porcelain tableware contains lead or is toxic:
1. At present, the ceramic utensils in circulation in the market can be divided into overglaze color, underglaze color, colored glazed porcelain and some uncolored white porcelain. Due to the different decoration methods of ceramic tableware, the possible impact on health is also different. Among them, the content of lead and cadmium in in glaze color, underglaze color and most colored glaze porcelain and white porcelain is very low. If the amount of pigment containing high lead and cadmium is too large during processing, or the temperature and ventilation conditions are not enough during baking, it is easy to cause the dissolution of lead and cadmium to exceed the standard. Another kind of bone ash porcelain is white, with transparent porcelain and smooth glaze, which is deeply loved by consumers. However, the production of this kind of porcelain is difficult, and most of them adopt high-temperature plain firing and low-temperature glaze firing technology. Its glaze adopts low-temperature lead containing glaze. If the production process is not properly controlled, the lead dissolution is also likely to exceed the standard
2. In order to avoid the possible adverse effects of tableware on health, experts warned that people should try to choose products with less decorative patterns and bright patterns on the inner wall of glazed and underglazed ceramic utensils and tableware
3. Never buy Tableware with patterns that can be wiped off by hand
4. For products that are not at ease, soak them in vinegar for several hours. If there is a significant change in color, they should be discarded
identify the quality of ceramic tableware as follows:
1. Hold the ceramic in your hand and observe it. The color of good ceramics is the unique natural milky white of natural bone powder. Observe the permeability of Ceramics against the bright light to see whether the composition of the cup is meticulous or not. Good ceramics should have good light transmission and uniform without impurities
2. Feel the delicacy and hardness of porcelain by hand. The addition of bovine bone powder makes the weight of ceramics lighter than other kinds of porcelain. It can be thinner than ordinary porcelain. The finished product is light, dense and hard (twice that of daily porcelain) and is not easy to crack
3. With a flick of your index finger and thumb, you can hear the “Ding” of ceramics. If you rub your hand with water at the mouth of the bowl, it will make a sound similar to that of an airplane flying by. Of course, the sound is relatively small, so you should listen carefully.

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