How to choose ceramic dinnerware? When purchasing, you must first decide the purchase grade, and then choose your favorite color. Then, in the pending varieties, first check whether the shape is straight, and then check each piece for damage, spots, bubbles, etc.
How to choose ceramic dinnerware? We are concerned about how to ensure health in diet every day, but few people pay attention to dinnerware. dinnerware is an indispensable tool for eating, it is closely related to our health, let’s take a look at how to choose healthy, beautiful and practical ceramic dinnerware!
How to choose ceramic dinnerware 1. From the perspective of porcelain
When purchasing ceramic daily necessities, bone china and reinforced porcelain are better, both of which are the materials of high-quality dinnerware. Bone china is recognized as a high-grade porcelain in the world. It is not pure white, but a natural milky white, with high transparency and light texture. The molding and color formation of bone china itself mainly depend on silica, alumina and calcium oxide. The higher the content of calcium oxide, the better the color. In nature, there are not many sources of calcium oxide, so animal bone meal is selected as the source of calcium oxide. When the bone powder content reaches a certain proportion, the porcelain will be greatly improved, which is mainly reflected in the gloss and moisturizing of the utensils. However, if the content exceeds a certain proportion, the porcelain will become softer, it will be difficult to shape during the production process, and it will be difficult to fire, and if the process is not properly controlled, it is easy to cause excessive lead dissolution, so the price is also the highest. Reinforced porcelain contains magnesium components and has outstanding features such as high whiteness, high strength, and high thermal stability.
How to choose ceramic dinnerware 2. From the perspective of flower decoration
According to the characteristics of the flower surface, it can be divided into on-glaze color, in-glaze color, under-glaze color and color-glazed porcelain, as well as some uncolored white porcelain. What is glaze? Glaze is a powerful substance. The glaze is applied to the ceramic body. After passing through the kiln, the ceramic product can obtain a glossy and non-absorbent surface, that is, water. Unglazed ceramics can be fired. After finishing, the surface will be rough and dull, such as purple sand pottery.
On-glaze color: On-glaze color ceramics is a product made by sticking the flower paper made of ceramic pigments on the glaze or directly painting the surface of the product with pigments, and then roasting at a high temperature of 700 ℃ ~ 850 ℃. Because the baking temperature did not reach the melting temperature of the glaze layer, the flower surface could not sink into the glaze, but could only stick to the surface of the glaze layer. If you touch it with your hand, the surface of the product has a bumpy feeling, and it is uneven when observed with the naked eye.
In-glaze color: The firing temperature of in-glaze color ceramics is higher than that of on-glaze color, reaching the melting temperature of the product glaze. The ceramic pigment sinks into the glaze when the glaze is melted, and is covered by the glaze layer after cooling. The surface of the product is as smooth as glass when touched by hand, and there is no obvious unevenness.
Underglaze color: Underglaze color ceramics is a traditional decoration method in my country. All the color decoration of the product is carried out on the porcelain blank, and it is fired at a high temperature after glazing. This product is the same as the in-glaze color, the flower surface is covered by the glaze layer, the surface is bright and smooth, and there is no uneven feeling.
Color-glazed porcelain: Color-glazed porcelain is a high-temperature coloring agent added to the glaze of ceramics, so that the glaze of the fired product shows a certain color, such as yellow, blue, bean blue, etc.
White Porcelain: White Porcelain usually refers to ceramics without any color decoration, and the sales of this kind of products in the market are generally not large.
Compared with the above decoration methods, the underglaze colors are mostly traditional blue and white and exquisite blue and white colors, the colors are relatively monotonous, and the price is moderate; the underglaze colors are richer than the underglaze colors, and the product grades are higher, but the process requirements are strict, and The cost is high and the price is also high. The on-glaze ceramics have rich colors, strong three-dimensional effect but low surface smoothness, and convenient processing, so the cost is correspondingly low.
In addition to the different artistic effects, the main difference between the above different decoration methods is the content of heavy metal elements such as lead and cadmium. Among them, the content of lead and cadmium in underglaze color, underglaze color and most of the color glaze porcelain and white porcelain is very low, and if the on-glaze color uses inferior pigments in the processing of ceramic flower paper, or in the design of flower surface If the amount of pigments containing high lead and cadmium is too large, or the temperature and ventilation conditions are not enough during roasting, it is easy to cause excessive lead and cadmium dissolution.
How to choose ceramic dinnerware 3. Quality standard of ceramic dinnerware
Appearance quality standard:
Appearance quality is an important indicator for product classification. my country’s current product standards divide products into three categories: superior products, first-class products, and qualified products. The first-class products are equivalent to the international advanced level, the first-class products are the domestic advanced level, and the qualified products are the domestic general level. The appearance quality of high-quality products basically meets the requirements of “five nos and one small”, that is, no spots, no slag, no color and dirt, no pinholes, no glaze scratches, and small deformation. Spots (black spots) are commonly known as fly droppings. If there are spots on the product, it will always give people an unclean feeling, thus affecting the appetite. First-class products and qualified products have more relaxed requirements than superior products in terms of allowable defects.
Lead and cadmium dissolution standard:
The amount of lead and cadmium dissolved is an important safety and health indicator for ceramic products. The existence of lead and cadmium is due to their components in the ceramic pigments in the decorative patterns on the surface of the product. The existence of lead may also be caused by the addition of lead-containing components to reduce the firing temperature of the surface glaze of the product. If the production process is not properly controlled, it is very easy to cause excessive dissolution of lead and cadmium in the process of use. Frequent use of such products can easily lead to heavy metal poisoning of lead and cadmium. The national standard GB12651-2003 “Lead and Cadmium Dissolution Allowable Limits of Ceramic Products in Contact with Food” is a national mandatory standard, and its scope of application covers all daily ceramic eating utensils. The standard stipulates that the dissolved lead and cadmium of any single product shall not exceed the specified allowable value. Among them, the specified value of flat products (products whose depth from the inner lowest plane of the product to the level of the mouth edge is less than 25mm) is: lead dissolution amount 7mg/l, Cadmium dissolution amount 0.50mg/l; small hollow products (products whose depth from the inner lowest plane of the product to the level of the mouth edge is greater than or equal to 25mm, and the capacity is less than 1.1L) specified values: lead dissolution amount 5.0mg/l, cadmium dissolution amount 0.50mg/l; large hollow products (products whose depth from the inner lowest plane of the product to the level of the mouth is greater than or equal to 25mm, and whose capacity is greater than or equal to 1.1L) are specified as: lead dissolution amount 2.5mg/l, cadmium dissolution amount 0.25mg /l.
Thermal Stability Criteria:
Thermal stability means that the product does not crack or break during the exchange of cold and heat. The quality of thermal stability can reflect the service life of ceramic products. The greater the temperature difference between cold and heat exchange, the longer its service life. The standard generally stipulates that it is heated to 180 ℃ and then put into 20 ℃ water. Take it out and observe whether there is damage. There is no damage at this temperature, and its service life can generally reach more than 2 to 3 years.
How to choose ceramic wareware 4. How to choose
The first is to “look”, which is to observe the porcelain up and down, inside and outside, to see if the product has major defects such as deformation and black spots, and then look at the whiteness, light transmittance and glaze gloss of the product.
The second is “listening”, which is to listen to the sound made when tapping the porcelain lightly. If the sound is crisp and pleasant, it means that the porcelain body is fine and dense, without cracks and damage, and the porcelain is completely transformed when fired at high temperature. If the sound is hoarse, it can be concluded that the porcelain body is cracked or damaged, or the porcelain is not complete. This kind of porcelain is easy to crack after the change of heat and cold.
The third is “comparison”, that is, comparison. For matching porcelain, it is necessary to compare the accessories to see whether the shape and picture decoration are consistent.
The fourth is “trial”, which is to test the cover, test the installation, and test. Some porcelain has a lid, and some porcelain is composed of several components. When choosing porcelain, don’t forget to try to cover the lid and try to assemble the components to see if they are suitable.
How to choose ceramic dinnerware 5. Purchase precautions
The content of lead and cadmium in the glaze color, underglaze color and most color glaze porcelain and white porcelain in ceramic eating utensils is very low. In the design, the amount of pigments with high lead and cadmium content is too large, or the temperature and ventilation conditions are not enough when baking flowers, which can easily lead to the dissolution of lead and cadmium exceeding the standard. Some white china, mainly unpainted bone china, use lead-containing frit glaze. If the process conditions of bone ash china are not strictly controlled during firing, the possibility of lead dissolution exceeding the standard is also very high.
In addition, the blue pigment in ceramic pigments has a high amount of lead leaching. If the amount is too large in product decoration, it will easily lead to excessive lead content in the product. In order to reduce the influence of lead content in products, special attention should be paid when purchasing ceramic dinnerware: for utensils containing food, attention should be paid to the decoration of the surface in contact with food. For utensils containing acidic food, products with less decorative patterns on the surface should be used as much as possible. When purchasing, you should also pay attention to whether the color of the pattern is bright. If it is not bright, it may be that the temperature does not meet the requirements when baking flowers, and the amount of lead and cadmium dissolved in such products is often high. Special attention should be paid to products that can be wiped off by hand, which have high levels of lead and cadmium leaching. For products that are not assured, soak them in vinegar for a few hours. If there is a significant change in color, they should be discarded.
How to choose ceramic dinnerware 6. Misunderstandings in purchasing
Products containing lead and cadmium leaching are not safe. Products that contain lead and cadmium are not unsafe. A small amount of lead and cadmium enters the human body and will be excreted through normal excretion, and if it exceeds a certain amount, it will deposit in the human body and cause heavy metal poisoning. All products that meet the requirements of national standards can generally be used safely.
Glazed products are not safe. The idea that “on-glaze products are not safe” is wrong. As long as the production process of on-glaze color products is properly controlled, the amount of lead and cadmium leaching will generally not exceed the standard. However, in order to save costs, some small enterprises have excessive bulk density during roasting, the temperature does not meet the requirements, and the speed is too fast.
White porcelain must be absolutely safe. Generally speaking, white porcelain is relatively safe, but some porcelains add lead flux to the glaze to reduce the firing temperature of the glaze, which may cause the hidden danger of excessive lead dissolution.
How to choose ceramic dinnerware? After reading the introduction of this article, I believe that everyone has a certain understanding of the purchase of set dinnerware, and these skills must be mastered clearly!
Post time: Jun-16-2022