Wudi shell porcelain, also known as shell porcelain and sea porcelain, belongs to high calcium porcelain and is produced in Wudi County, Shandong Province. Wudibei porcelain is a new kind of daily-use porcelain, which belongs to the Wudibei porcelain product display in figure 1.
International popular series of high calcium soft porcelain. Wudi county is the only producing area in the world. On February 22, 2008, the General Administration of Quality Supervision, Inspection and Quarantine issued an announcement to approve the protection of geographical indications of Wudi North Porcelain. ...
quality characteristic
Wudibei porcelain has fine texture, thin and soft wall, moist glaze and exquisite appearance. Compared with bone China and ordinary ceramics, Wudibei porcelain has the characteristics of high whiteness, high transparency, good thermal stability, high mechanical strength and light weight. What is particularly commendable is that Wudibei porcelain has a low content of heavy metal lead and almost zero cadmium, and is rich in natural pearls, which has a health care effect on human body and can be called "green and healthy porcelain". In addition, the application of nanotechnology in glaze can play a role in antibacterial activation of water, with an antibacterial rate of 97% and an activated water rate of 88%. .
manufacturing process
The so-called shell porcelain is made by mixing a certain amount of shells with ceramic raw materials and special processing. Fig. 2 shows the manufacturing process of shell porcelain.
And then firing twice by plain firing and glaze firing. As early as the Ming Dynasty, people found that colorful porcelain could be fired by mixing gold, silver, pearls and agate into porcelain tires. Shell porcelain is also rich in pearls, showing the elegance and charm that ordinary porcelain does not have. Calcium in shells can increase the hardness and transparency of porcelain, and react with impurities in kaolin during firing to eliminate impurities. Shell porcelain is very particular about materials, complicated technology, difficult molding and narrow firing temperature range, so the finished product is very precious. Wudibei porcelain has fine texture, thin and soft wall, moist glaze and exquisite appearance. Compared with bone China and ordinary ceramics, Wudibei porcelain has the characteristics of high whiteness, high transparency, good thermal stability, high mechanical strength and light weight. What is particularly commendable is that Wudibei porcelain has a low content of heavy metal lead and almost zero cadmium, and is rich in natural pearls, which has a health care effect on human body and can be called "green and healthy porcelain". .
Factory conditions
Wudi county has unique natural conditions for producing shellfish porcelain. Wudi County is located in the northernmost part of Shandong Province, bordering Wudi Shell Island in the east.
Bohai Bay in the north is the intersection of the Yellow River estuary, which belongs to shallow beach and is very suitable for the reproduction and growth of shellfish products, especially clam products. Shellfish products have high reproduction rate and fast growth in this area. With the movement of tides, they are constantly pushed to the coast, forming shell beaches. Wudi has two parallel rows of seashells along the coastline of Bohai Sea. The first column is at the southern end, with a length of 40 kilometers, a buried depth of 0.5 m ~ 1 m, a shell thickness of 3 m ~ 5 m and a history of more than 5,000 years. The second column is located at the northern end, with a length of 22 kilometers and a shell thickness of 3-5 meters. It is open, with a history of 2000 years, and its shell content is 100%. According to statistics, the total reserves of Wudi Bay reach 360 million tons, and increase by more than 654.38+10,000 tons every year with the tidal action, and it is known as one of the three largest Bay Islands in the world. Therefore, the production of Wudibei porcelain has unique geographical and natural resources conditions.
The production of Wudibei porcelain is also closely related to natural conditions. The geological soil in Wudi County is saline-alkali land, which is influenced by maritime climate, and the air humidity is humid all the year round. The average air humidity is above 65%RH for 300 days in a year, and the temperature difference and air humidity change little in one day. In the process of demoulding and drying of shell porcelain production, problems such as mucous membrane, cracking and deformation can be reduced, which becomes a necessary condition for large-scale production of shell porcelain. Even in winter with low temperature and summer with high humidity, Wudi's air humidity condition is suitable for shell porcelain. Due to the full use of local climatic conditions in production, the qualified rate of shell porcelain molding is over 90%. .
Production history
The activity of firing shellfish porcelain in Wudi County has existed since ancient times. According to the survey data of geographical names culture in Wudi County, in 1950s, archaeologists discovered an ancient well at Hanjiayao site in Wudi Town, Wudi County, from which a stone rammer, a stone mill, ceramic fragments and a relatively complete porcelain plate were unearthed. The porcelain of ceramics is exquisite, with high whiteness and good translucency. Later, a horizontal semi-elliptical ancient kiln was excavated at 1 km north of the ancient well. There are clear traces of stewed clay and blue bricks on the walls of the kiln. It is verified that this is the kiln site for firing shellfish porcelain in ancient times.
At the beginning of the founding of the People's Republic of China, there were sporadic folk kilns in Wudi County to produce shell porcelain, but the production technology and technology were very backward, with a single variety and a very low pass rate. After that, these folk kilns closed down one after another, and Wudibei porcelain almost disappeared.
After the Third Plenary Session of the Eleventh Central Committee of the Communist Party of China, Wudi County Party Committee and County 0 proposed to use the shell sand with local resource advantages to fire high-grade daily-use fine porcelain, and established Wudi County Shell Resources Development Company in 199 1. On the basis of absorbing folk production technology, Wudi County "collects the essence of famous kilns in China and porcelain-making skills" and cooperates with famous universities and research institutes in China, such as Tsinghua University. After three years of painstaking research, it was repeated hundreds of times. Wudibei porcelain was industrialized in 1994, won the national invention patent in 1999, won the second prize of national technical invention in 2000, and reached the production scale of more than 30,000 pieces of high-grade daily-use shellfish porcelain with an annual output of/kloc-0 in 2005. Products are exported to Korea, Germany, Australia, South Africa and other places. 20 1 1, Wudibei Porcelain was selected as the porcelain used by the central leading plane and the national gift porcelain. 20 1 1, 1, 18,-During the President's visit to the United States, four pieces of sea porcelain art were specially presented to President Obama as national gifts. .
The protection scope of geographical indication products of Wudi North Porcelain is subject to the scope proposed in the Request of People of Wudi County, Shandong Province on the Protection of Geographical Indications Products of Wudi North Porcelain (Lu Zi [2006] No.63), which is the administrative area under the jurisdiction of Wudi County, Shandong Province.