Explosion means that during the bisque firing process, small chips are ejected from the interior of the ceramic body, or the surface of the body is broken into small chips. Through in-depth inspection of the holes in the green body, it can be found that such problems are usually caused by impurities in the mud. If the small nucleus in the center of the hole is white, you can drop a drop of diluted hydrochloric acid on the small white particles. When bubbling occurs, it means that the impurity contains lime-like substances. In fact, there is usually no clear reason for the explosion, or the small nucleus in the center of the hole is variable in color (gray, brown, and black), which indicates that the green body contains various impurities.
When the body contains pyrite particles, it can lead to spotting and popping on the outer surface of the vessel. When the firing temperature reaches 600°C, the pyrite particles begin to expand, especially when one-time firing is adopted or when the biscuit firing speed is fast, the expanded pyrite particles can easily cause the outer surface of the ceramic body to explode. For some once-fired vessels, the glaze debris will be sprayed far away and stick to the surface of the adjacent body, destroying the original body. The large centers of spots or holes sometimes do not reflect their original state, so they cannot be used to determine the exact cause of the problem.
We all know that ball soil contains several iron sulfide components, such as marcasite, iron disulfide (various pyrites) and their decomposition products. Although the content of marcasite is very small, almost any kind of ball soil contains fj iron ore. This substance usually appears in the form of small black particles. Diluted hydrochloric acid has no effect on it. When the firing temperature inside the kiln reaches a certain level, marcasite usually burns together with sulfur dioxide. Refractory clay also contains pyrite in the interior, usually in the form of grains or veins. Another common impurity in refractory clay is siderite (FeC03), also known as “mudirite”. Although siderite and pyrite are similar in appearance and heavy to the touch, the former will only form black Spots will not cause blasting. Siderite will melt into slag in a reducing atmosphere and spray or ooze out from the surface of the ceramic body.
Basalt particles with a diameter of up to 20 meshes will form black and dark chocolate vitrified spots in an oxidizing atmosphere; they will form black glassy substances in a reducing atmosphere, leaving holes in their precipitation sites and leaving holes under the holes. Flowing traces.
Post time: Dec-28-2022