Judgment on the safety of ceramic tableware materials

To determine the safety of ceramic tableware materials, one can comprehensively consider aspects such as raw materials, firing temperature, decorative techniques, testing and certification, as well as usage details. The following is a specific analysis:

Regarding raw materials

Natural minerals are superior to chemical clay glazes: High-quality ceramic tableware often uses natural mineral raw materials, such as kaolin and other natural clays or minerals. These raw materials have basically no chemical additives and are relatively safe. Inferior porcelain may add industrial waste to cut costs, and the glaze may contain harmful substances such as lead and cadmium. For instance, some traditional high-quality ceramic tableware is made only with local kaolin and natural plant ash glaze, and is safe and harmless after being fired at high temperatures.

Pay attention to the body and the painting material: The clay material for the body is generally porcelain clay (mainly kaolin), which is relatively safe. However, the main problem lies in the glaze or painting materials. Currently, low-cost painting materials are mostly chemical materials or coloring materials, containing heavy metals (such as lead and mercury), so underglaze painting is relatively much safer.

Firing temperature

High-temperature firing is safer: High-temperature porcelain is superior to medium and low-temperature porcelain. High temperature generally refers to the range between 1280 degrees Celsius and 1400 degrees Celsius. Under such high-temperature calcination, after being calcined by the oxidizing flame and the reducing flame, harmful substances will disappear or transform. Low-temperature porcelain (below 800℃) has large pores, is prone to color and water seepage, and has high residues of heavy metals. One can judge the quality by gently tapping the porcelain and listening to the sound. If the sound is clear and pleasant, it indicates that the porcelain body is fine and dense, without any cracks or damages, and has been fully vitrified during high-temperature firing, indicating good quality.

Decorative craftsmanship

Underglaze painting is highly safe: Underglaze painting involves first painting patterns on the body, then applying a glaze layer, and finally firing at a temperature above 1200° C. The painted layer is on the innermost layer and does not come into direct contact with food, making it relatively safe. The firing temperature of the painted layer of overglaze painting is low, and there is a wide variety of pigment color options. However, the painted patterns on the outermost layer come into direct contact with food, such as high-temperature food, heating, or contact with acidic food, which may accelerate the leaching of heavy metals. Moreover, the patterns are more prone to wear, peeling, or color fading during use, increasing the risk of heavy metal leaching.

Testing and certification

Check the test report and certification mark: Check the product's ingredient list and test report to ensure that the product does not contain harmful substances. Ceramic tableware that complies with relevant national standards will have corresponding labels, such as indicating compliance with standards like GB 4806.4-2016 "National Food Safety Standard - Ceramic Products". Some authoritative certifications, such as the "Geographical Indication Certification for Yue Kiln Celadon" by Shangyu Ceramic Research Institute, can control product quality throughout the entire chain from raw materials to firing.

Usage details

Avoid holding specific foods for a long time: Even for safe ceramic tableware, when used to hold acidic foods, products with fewer surface decorative patterns should be chosen as much as possible. Because acidic substances may accelerate the dissolution of heavy metals in ceramics.

Pay attention to the wear and tear of the patterns: If you find that the patterns on the ceramic tableware have fallen off or been scratched, they should be replaced in time to prevent the leaching of heavy metals and other harmful substances, which may endanger your health.