Ceramic tableware is the most commonly used tableware in our life. In the face of ceramic tableware with beautiful colors, beautiful patterns and elegant shapes on the market, we often love it. Many families will constantly add and update ceramic tableware. However, according to the testing results of ceramic products on the market by relevant testing institutions in recent years, the quality of ceramic products on the market is uneven, and some low-quality porcelain produced by irregular enterprises has the problem of excessive heavy metal lead dissolution.
Where does the heavy metal in ceramic tableware come from?
Kaolin, cosolvent and pigment will be used in ceramic production. These materials often contain heavy metals, especially pigments used in color tableware. Because of the good adhesion of metal lead, lead is widely added to these materials, especially those pigments with particularly bright colors.
That is to say, materials containing heavy metals, especially lead, must be used in the production of ceramic tableware. But it is not the lead it contains that brings harm to our health, but the lead that may dissolve and be eaten by us. The ceramic firing glaze is used as a protective film to prevent the release of heavy metals in pigments and porcelain clay. With this glaze protection, why is there a risk of lead precipitation in ceramic tableware? This has to mention the three processes of ceramic tableware: underglaze color, underglaze color and overglaze color.
1. Underglaze color
The underglaze color is to paint, color and then glaze at high temperature. This glaze covers the pigment well, and feels smooth, warm and smooth, without concave and convex feeling. As long as the glaze is intact, the risk of lead precipitation is very low, and heavy metals will not exceed the standard. As our daily tableware, it is very safe.
2. Underglaze color
Color in glaze is to glaze at high temperature first, then paint and color, and then apply a layer of glaze at high temperature. There is also a layer of glaze to isolate the pigment and prevent it from separating out into food. The ceramics fired at high temperature twice are more durable and wear resistant, and can be used as safe tableware.
3. Overglaze color
Overglaze color is first glazed at high temperature, then painted and colored, and then fired at low temperature, that is, there is no protection of glaze on the outer layer of pigment. It is fired at low temperature, and the color choices that can be adapted are very wide, with rich patterns and colors. The color changes little after firing, and it feels concave and convex.
How to distinguish whether heavy metals in ceramic tableware exceed the standard?
1. Choose ceramic tableware with regular manufacturers and channels. The state has strict quality standards for porcelain tableware, and the products of regular manufacturers can meet the standards.
2. Pay attention to the color of the ceramic tableware. The glaze is even, and the appearance pattern is fine and not rough. Touch the tableware surface to see if it is smooth, especially the inner wall. The tableware with good quality is free of uneven small particles. Porcelain with uniform and regular shape is generally the product of regular manufacturers.
3. Don’t buy ceramic tableware with bright colors and patterns because of the pursuit of beauty and novelty. In order to look better, this kind of tableware usually adds some heavy metals to the glaze.
4. It is better to choose ceramic tableware with underglaze color and underglaze color processes. These two processes are very strict. The glaze formed in the manufacturing process can isolate harmful materials and effectively prevent the dissolution of heavy metals in the use process.
5. Before using ceramic tableware, first boil it in boiling water for about 5 minutes, or soak it in vinegar for 2-3 minutes to dissolve the toxic elements in tableware.
Post time: Nov-06-2022
