Whether bone china contains lead and cadmium can be viewed from two aspects, one is the ceramic raw material, and the other is firing.
Bone china raw materials are mainly green body raw materials (kaolin, quartz, animal bone charcoal), glazed raw materials (glaze), decorative raw materials (namely flower paper).
The clay of the bone china body is mainly kaolin and quartz, which are basically considered safe, because there are generally no chemical additives, they are natural clay or minerals, and there is only a difference in grade and quality.
The problem is mainly on the glaze or flower paper. After the glaze is subjected to high temperature, it forms a glaze surface (vitrification) similar to glass. It does not matter if the raw ore of the formula contains a small amount of chemical elements. The health and safety of ceramics: high temperature porcelain > medium temperature > low temperature. High temperature generally refers to 1280 degrees Celsius to 1350 degrees Celsius. Calcined at such a temperature, through oxidation and reduction, generally harmful substances disappear or transform. Therefore, when conscientious manufacturers choose environmentally friendly glazes, they will choose safe glazes to minimize harmful substances as much as possible.
Therefore, pure white bone china dinnerware is still reassuring on the issue of whether the enamel layer contains harmful substances such as lead and cadmium.
For colored porcelain, it will be more troublesome. The baking process is the most critical for the safety and health of bone china dinnerware. Low-cost chemical pigments are likely to contain heavy metals (lead, cadmium, mercury, etc.). At present, on the issue of adding color to daily-use porcelain, it involves over-glaze color, in-glaze color, and under-glaze color. In fact, 99.9% of them belong to over-glaze color. Tangshan bone china manufacturer Win-Win Ceramics will try to choose mineral safe pigments On the basis of the specific high-temperature baking process, the glaze surface completely covers the pigment surface to form: nano self-cleaning glaze - mineral pigment layer - nano self-cleaning glaze - 45% bone china - nano self-cleaning glaze The hierarchical structure of the surface is sufficient to ensure the health and safety of products no matter in self-inspection or inspection by the Ministry of Light Industry.