Purple clay pot "spit black" reasons and black methods

Purple clay pot "spit black" reasons and black methods

The black spit of purple sand pot refers to the black spots of the size of sesame and rice grains that appear separately on the surface of the pot during normal use.

Spit black is sometimes more uniform, distributed in the overall surface of the purple clay pot; Sometimes zonal distribution; Sometimes it is concentrated in local areas, the lid and the bottom of the pot are more common.

The main reason for black black is that there are defects in temperature control or time control in the firing process, insufficient sintering temperature, that is, the situation of insufficient fire, resulting in the shrinkage of the mud is not fully in place, and the density of the pores in the pot body is too loose and too large, resulting in iron ions in the tea, accumulation and precipitation in the loose and large pores, forming a different tone from the tire body.

Vomiting black also proves from a side that what you are using is a real purple clay pot, which is harmless to the body, but it is harmful to the quality of the purple clay pot.

The unique double porosity structure of the purple clay pot makes it breathable. In the process of long-term use, tea dirt will remain on the surface of the pot, invisible to the naked eye in the pores, and the iron ions in the tea are also easy to precipitate from these pores.

So purely theoretically, as long as it is a purple clay pot, it will generally spit black, unless the mud itself is not purple sand. Just because the teapot itself is different in color, different parts of the vomiting black, different tea leaves, and different experiences in raising the pot, the degree of vomiting black is not the same. Some are invisible to the naked eye, others are more obvious.

The darker the color of the pot, such as purple mud, spit black is not easy to see; Light-colored POTS, such as mud, spit black relatively obvious, coupled with the need for high temperature firing, so the mud pot spit black phenomenon is relatively obvious.

Is vomiting black harmful to the body?

I believe that by understanding the composition of "black", we will understand that "vomiting black" is completely harmless to the body. Just because it is damaging to the appearance, many people think it is a defect and do not like it, but conversely, "spitting black" proves from one side that you are using a real purple clay pot.

Can the "spit black" of the pot itself be eliminated?

Since "black" is tea dirt and iron ions, if you insist on removing "black", of course, there are ways.

Reheating the kettle can remove the "black", because at high temperatures, the tea scale and iron ions of these organic matter will be burned, and the purple clay pot can be restored to the original appearance.

But please note: first, the pot body must be fully dried before returning to the furnace, otherwise the pot will burn. Second, the furnace is risky, several senior national technologists reported that the burning rate of the furnace is about 5%-10%.

Does the obvious purple sand pot of "spitting black" mean that there is a problem with the production process?

There is an obvious local "spitting black" in the purple clay pot, which can only indicate that there may be flaws in temperature control or time control in the firing process, which has nothing to do with the ability of the craftsman to make the pot. Because the current purple clay pot firing kilns in Yixing are privately operated, under normal circumstances, craftsmen can only put forward the requirements of their own pot firing temperature and time, but can not control the firing process.

Moreover, a little temperature can't make a difference from the finished product itself. Therefore, even if the master level can not guarantee that their pot will not appear local "spit black" situation. It can only be said that the kiln cellar may be more attentive when firing master works.