The kiln is an important facility for clay to be fired into porcelain at high temperature. Today we will take the tunnel kiln of our LORY Ceramic Sanitary Ware Factory as an example to explain the firing technology of the kiln in detail.
1.Introduction to Tunnel Kiln
A tunnel kiln is a long, continuous kiln structure used for firing ceramic products. It consists of a tunnel-like chamber with a series of burners or heating elements positioned along its length.
Tunnel kiln is a modern kiln widely used in the sanitary ceramics manufacturing industry because of its high output, low fuel consumption, good working conditions, and easy mechanization and automation.
The kiln roof of the tunnel kiln is built with refractory bricks or prefabricated blocks with refractory castables. The kiln bottom is composed of multiple kiln cars. The kiln car moves along fixed guide rails. The billets are placed on the kiln car and pushed into the kiln by the kiln head, after preheating, firing and cooling, and finally exit the kiln from the kiln tail to obtain the finished product.
2.Kiln loading
After the kiln workers make the blanks, dry them, and apply glaze, they put the porcelain blanks into the kiln one by one for firing. This is called kiln loading. This is another critical step in the firing process of ceramic sanitary ware manufacturing.
Before installing the kiln, check the kiln, especially the integrity of the kiln wall, if any problems are found, repair them in time, and clean up the kiln to ensure that the product is clean and free of any pollutants or debris.
The products are then arranged in a suitable manner, taking into account factors such as product size, shape and stack arrangement, to maximize kiln capacity and ensure even heat distribution.
Use kiln furniture such as racks, posts and mounts to support and separate product during firing and prevent warping or sticking. At the same time, in order to ensure the stability at high temperature, a certain gap should be maintained between each column, and the gap should be even, and the sagger columns that are not stable enough should be firmly plugged with broken sagger pieces.
3.Firing
Precautions: Manufacturers of ceramic sanitary ware must ensure that the kiln is evenly charged to promote uniform heating. Additionally, the kiln atmosphere may need to be controlled by adjusting airflow or introducing specific gases to achieve the desired firing results.
Firing Temperature: The firing temperature depends on the type of ceramic material used and the desired properties of the final product. Different ceramics require different temperatures to achieve the desired strength, durability and aesthetic qualities. The firing temperature of ceramic toilets, pedestal basins and countertop basins produced by LORY is generally 1280 degrees.
Firing Duration: The firing duration is determined by factors such as the thickness and size of the ceramic products, the type of clay or glaze used, and the firing temperature. It can range from several hours to several days.
4.Kiln discharge
Precautions: Care should be taken when unloading the kiln to prevent damage to the ceramic products. Handling tools, such as gloves and tongs, should be used to protect against hot surfaces.
Product cooling time: Ceramic products should be allowed to cool gradually to room temperature to prevent thermal shock and cracking. The cooling time can vary depending on the thickness and size of the products but may typically take several hours or more.
5.Characteristics of ceramic bathroom products after firing
Increased strength and durability: Firing at high temperatures allows the clay or ceramic material to undergo physical and chemical transformations, resulting in increased strength and durability.
Stability: Firing removes excess moisture and volatile compounds, making the ceramic products stable and resistant to water absorption.
Color and texture: The firing process can alter the color and texture of the ceramic products, depending on the type of glaze or decoration used.
To sum up, firing technology plays a vital role in the production of ceramic sanitary products. Proper firing techniques ensure desired product characteristics such as strength, durability and aesthetics. It also allows for quality control, as the firing process corrects any flaws or flaws in the ceramic material. Overall, mastering firing technology is crucial for ceramic sanitary ware manufacturers to obtain high-quality ceramic bathroom products.
