1. Ceramic tableware: don't choose "overglaze" Ceramic […]
1. Ceramic tableware: don't choose "overglaze"
Ceramic tableware has various shapes, delicate and smooth, bright colors and easy to clean. It is the first choice for most families to buy tableware. However, the colored glaze on the ceramic surface may become a health killer. Lead, mercury, radium, and cadmium in the colored glaze are all harmful elements to the human body.
There are three methods for making ceramic tableware: overglaze, underglaze and underglaze. On-glaze colored ceramics are made of decorative paper made of pigments and attached to the surface of the glaze or painted directly on the surface of the product, and then baked at a low temperature. Because the baking temperature does not reach the level of melting of the glaze layer, the flower surface cannot be sunk. In the glaze, touch the on-glaze colored ceramics with your hands, and you will feel that the flower surface has obvious unevenness.
The firing temperature of the in-glaze ceramics can melt the glaze, and the pigments can sink into the glaze and be covered by the glaze layer after cooling. The surface of the product is smooth and there is no obvious unevenness to the touch. All the underglaze ceramics are decorated on the porcelain blanks. After glazing, they are fired at a high temperature at a time. The flower surface is covered by the glaze layer, which looks bright, flat and smooth to the touch.
Harmful metals mainly come from on-glaze pigments. The radioactive element radium will kill white blood cells. Cadmium, lead, and mercury are heavy metals. Cadmium and lead can cause liver or other internal organs poisoning, and mercury can cause liver and kidney cirrhosis. When over-glazed tableware is used for a long time to hold foods with high organic acid content such as vinegar, wine, fruit juice, vegetables, the heavy metals such as lead in the tableware will dissolve out and enter the human body with the food to accumulate, which will cause chronic heavy metal poisoning over time.
In order to reduce costs, some small ceramic manufacturers purchase cheap raw materials with high lead and cadmium content and unstable performance. In the production process, due to factors such as excessively large decorative area, insufficient baking temperature or improper processing by workers, the amount of lead dissolution of ceramic products will not meet the standard.
In order to make more profits, even some individual and private enterprises arbitrarily shorten the roasting time or lower the roasting temperature, and use old-fashioned roasting furnaces that rely entirely on worker experience, which seriously restricts the quality of ceramic tableware.