1. Appearance quality standard
Appearance quality is an important indicator of product classification.The current product standards in my country divide the products into three categories: superior quality products, first-class products and qualified products. The first-class products correspond to the international advanced level, the first-class products correspond to the national advanced level, and the qualified products correspond to the national general level. The aesthetic quality of the high-quality products basically meets the requirements of "five numbers and one small", that is, no stains, no dross, no paint and dirt, no holes, no enamel scratches and small deformations. Spots (black spots) are commonly known as fly droppings.When there are spots on the product, it always creates a dirty feeling and thus affects the appetite. First-class products and qualified products have less stringent requirements than superior products in terms of permissible defects.
2. Dissolution standards for lead and cadmium
The dissolution of lead and cadmium is an important indicator of the safety and health of ceramic products. The presence of lead and cadmium is due to their components contained in the ceramic pigments present in the decorative motifs present on the surface of the product.The presence of lead can also be caused by the addition of components containing lead to reduce the firing temperature of the product surface product polish. If the manufacturing process is not properly controlled, lead and cadmium can easily dissolve excessively during the process of use. Frequent use of such products can easily lead to lead poisoning and heavy metal cadmium.
The GB12651-2003 national standard "Permitted limits for the dissolution of lead and cadmium in ceramic products in contact with food" is a mandatory national standard, the scope of which covers all ceramic kitchen utensils for everyday use. The standard specifies that dissolved lead and cadmium in a single product must not exceed the specified permitted level, including flat products (products where the depth from the lowest innermost level of the product to the height of the finish is less than 25 mm) .
The reported values are: lead dissolution rate of 7 mg / l, cadmium dissolution rate of 0.50 mg / l; Small hollow products (products with a depth from the lowest internal level of the product to the height of the mouth edge greater than or equal to 25 mm and with a capacity of less than 1.1 l) are specified as follows: The amount of dissolution of lead is 5.0 mg / l, cadmium dissolution rate is 0.50 mg / l; Large hollow products (products whose depth from the innermost plane of the product to the height of the mouth edge is greater than or equal to 25 mm and whose capacity is greater than or equal to 1.1 l) are indicated as: Dissolution of lead The dosage is 2.5 mg / l and the cadmium dissolution rate is 0.25 mg / l.
3. Thermal stability standard
Thermal stability means that the product does not crack or break when cold and heat are exchanged. The quality of thermal stability can reflect the service life of ceramic products: the greater the temperature difference between heat and cold exchange, the greater the useful life. The standard generally states that it is heated to 180ºC and then placed in hot water at 20ºC. Take it out and see if there is any damage. Generally, if no damage occurs at this temperature, its service life can reach more than 2 ~ 3 years.