Why can a kind of soil burn green bricks and red bricks?

During the firing process, one was drenched with water and turned into green bricks, and the other was dried and burned to the end and turned into red bricks. This is mainly due to the 'noisy' iron in the clay: the iron in the brick is dry-burned, and the iron inside it becomes fully oxidized ferric.

The color of the trivalent iron is red, so the bricks are also red. When water is poured during firing, the iron in the brick is limited, and only bivalent iron can be generated, and the brick becomes blue-gray.

This is a chemical reaction process, which can be seen as a solid-phase diffusion process, since the brick soil itself is a silica.

and various metal oxides.

When sintered at high temperatures, silica and metal oxides diffuse into each other's lattices, reforming binary or even poly oxides. When cooled, it's a hard brick.

Brick.

There are differences between cement bricks and ordinary fired red bricks in terms of raw materials, production methods and characteristics, and the specific differences are as follows: 1Raw materials Cement bricks are made of cement, and their main raw materials are fly ash, wild or cinder, coal gangue, tailings slag, chemical slag or natural sand and mud.

The main raw materials of ordinary red bricks are clay, shale, gangue and other materials. 2.Production method Ordinary firing red bricks or changing the crushed raw materials into the shape of bricks and then sintering, while cement bricks do not need to be forged at high temperatures, it mainly uses cement as a coagulant to form bricks.

3.Different characteristics Cement bricks are lighter than ordinary fired red bricks, have higher strength, and are more environmentally friendly than ordinary fired red bricks. However, ordinary fired red bricks are more suitable for plastering mortar, and are not as prone to cracks as cement bricks, so they are more beautiful than cement bricks.

Digging up the ground to dig up the green bricks, but the jujube burning is two situations: one is that it is possible to dig up ancient tombs. In our country, the practice of burial after death has been practiced for thousands of years. Therefore, it is also possible that tombs from thousands of years ago happened to be dug up when digging the ground.

The second is to dig up the ancient architectural traces of the rock site. Ancient buildings also used green bricks as a building material. Some ancient structures were buried deep underground for thousands of years for some reason, and happened to be dug up by farmers while plowing.

Sanzibi is a yaokou that dug up to the ancient firing of green bricks. This possibility is also very high.

Why did ancient China use a large number of blue brick buildings instead of red brick buildings?

Old-fashioned bricks are burned with straw (sorghum stalk), after the bricks are burned, people in order to save straw, so they are anxious to extinguish, and water is poured on the top of the kiln, at this time, the water vapor meets the red-hot charcoal at this time, CO reduces the red Fe2O3 to black Fe3O4 or Feo or Fe at high temperature, so that the original red bricks are reduced to blue-black green bricks, many people think that green bricks are alkali-resistant, in fact, it is not so, just people's intuitive imagination.

The strength is about the same, but the oxidation resistance is a little better. Red bricks were invented by the Romans, with low cost, and Chinese green bricks have a high cost and are not promoted