In the countryside, many families can also find a few centuries-old green bricks, which are very smooth to the touch, and the thickness is only half of the current bricks, but the hardness can be compared with the stone, and this texture can be used to make brick carving.

Green bricks are fired from clay, which is the product of the long-term weathering of certain aluminosilicate minerals, which is named for its strong viscosity. The clay is mixed with water to make bricks, which are calcined in a brick kiln (0°C for 8-15 days) to make bricks.

Clay contains iron, and when it is completely oxidized during the firing process, it produces ferric oxide which is red, that is, the most commonly used red brick; However, if water is added to cool during the firing process, the iron in the clay is not completely oxidized (Fe3O4), and it will be cyan, that is, green bricks.

The hardness of green bricks and red bricks is about the same, but the cooling method is different after firing, while the red bricks are naturally cooled and simpler, so there are many red bricks produced, and the green bricks are water cooled (in fact, it is a kind of anoxic cooling), which is more troublesome to operate, so the production is relatively small.

Although the strength and hardness are similar, the performance of green bricks in anti-oxidation, hydration, atmospheric erosion and other aspects is significantly better than that of red bricks. The firing time of green bricks is generally determined according to the size of the kiln; Small kilns (about 2-25,000 bricks) generally take 20 days (excluding drinking water), drinking water is generally 5 days, and large kilns take about 30 days.

The green brick is made of natural clay, and the product after firing is blue-black, with high density, good frost resistance, no deformation, and no discoloration.

The black and white gray bricks are made of natural original oxygen-free firing, with water as the spirit, fire as the rigid, the five elements are combined, the home is warm in winter and cool in summer, and the health and environmental protection: the green bricks contain trace amounts of sulfur elements that can be sterilized, balance the formaldehyde and other chemical gases that are not conducive to the human body in the decoration, maintain indoor air humidity, and integrate the characteristics of "air permeability, water absorption, anti-oxidation, and air purification", which has become one of the products highly recommended by the designer.

The surface of the product is smooth, the corners are at right angles, the structure is three-dimensional, compressive and wear-resistant, and it is an ideal material for house wall and pavement decoration.

Green bricks give people a plain, calm, simple, quiet beauty, black, white and gray bricks in 09 years of innovation to launch a hundred years of green brick series products, bas-relief, high relief and modern mechanism bricks, the art form is based on traditional Chinese allusions, exquisite patterns, meaningful, novel design techniques, blended with the essence of Chinese culture, can be appreciated and collected, can be decorated and appreciated, can carry the warmth and simplicity of life, not imported, not copied, is the true civilization of the return to the basics.

The art of green bricks can not only be decorated, can inherit history, but also is a work of art for appreciation, the golden mean, in the harmony of the traditional one, moisten the heart of the brick.

Blue-gray is also the most rare and best of bricks, and the visible color changes. If you often caress it, you will absorb the breath, taste, and liquid of its body and moisten it, and your feet will be light. The natural change of water is simple and natural.

Tea is like brown and tea fragrance. The runway of Danqing nourishes its artistic heart. Therefore, it is advocated to play with its collection, which can be self-cultivation and self-cultivation to integrate its five elements, and all things are one.

Green bricks belong to sintered bricks; The main raw material of ancient green bricks is clay, which is mixed with water, extruded, and then baked to (about 1000 degrees) in the brick kiln, cooled with water, so that the iron in the clay is not completely oxidized, so that it has better weathering resistance, water resistance and other characteristics.

After testing, the compression resistance of ancient green bricks is greater than 10 megapascals, and the water absorption rate is less than 20%, antique green bricks are modeled after various styles of ancient green bricks, according to the firing method of ancient green bricks, and the clay materials used in ancient green bricks and antique cylinder tiles are used in modern firing of green bricks is a common kind of antique building materials.

In daily life, most people have a clear understanding of red bricks, but their understanding of green bricks is relatively vague. In fact, green bricks are made from clay, which is the product of the long-term weathering of certain aluminosilicate minerals.

Green bricks are fired from clay, which is the product of the long-term weathering of certain aluminosilicate minerals, which is extremely sticky. The clay is mixed with water to make bricks, which are calcined in a brick kiln (0°C for 8-15 days) to make bricks.

Clay contains iron, and when it is completely oxidized during the firing process, it produces ferric oxide which is red, that is, the most commonly used red brick; However, if water is added to cool during the firing process, the iron in the clay is not completely oxidized (Fe3O4), and it will be cyan, that is, green bricks.

So what is the difference between green bricks and red bricks?

The main difference is that green bricks are much stronger than red bricks. The blue bricks used in ancient buildings are far greater than the hardness and strength of red bricks, the green bricks have high density, no deformation, good frost resistance, anti-oxidation, waterproof foam, wear resistance, wind and rain erosion, and no corrosion for thousands of years.

Moreover, the green brick is extremely breathable, has good water absorption, and can maintain indoor air humidity. The ancient Chinese "Qin bricks and Han tiles" can still be preserved well after thousands of years, which is the best proof of the excellent performance of green bricks.

As for the process of firing green bricks by hand, first find suitable arable land, and the clay layer should be thick, and generally such land must be good arable land. After removing some of the thin mud from above, the clay is dug up and transported to a large pond.

After adding water in proportion, drive the cow into the large pond and keep trampling, which is the same as the effect of constantly beating the soil to remove debris and bubbles and enhance the viscosity when making clay sculptures.

When they had almost stepped on it, the man jumped into the pool and stepped on it, picking out some of the stones he had stepped on. Seeing how relaxed they looked, when I was a child, I also naughtily jumped into the pool, but my legs were stuck and I couldn't pull them out.

The clay is then put into a brick mold and extruded. After the bricks are dried to a certain extent, they are burned in the brick kiln, and after they are burned, they are watered and cooled, and the kiln is stuffed to reduce the red high-valent iron oxide in the brick to blue-gray low-valent iron oxide.

When burning the cellar, you have to stare at it day and night, and you can't sleep, otherwise a drowsiness will ruin a kiln of bricks.

The blue bricks are sharp and angular, the walls are clearly lined, and the white and gray are very beautiful after the joints. However, the clay layer of cultivated land is only one or two meters thick, and firing green bricks to extract clay will destroy many farmlands.

Moreover, the process of making kilns, firing kilns, and stuffy kilns during firing is very complicated; High energy consumption to burn a large amount of firewood; The output is small, the cost is high, and it is difficult to realize automation and mechanized production. In order to protect arable land, the government restricted brick cellar factories from taking soil from cultivated land, and many brick cellar factories switched to burning red bricks.

The red bricks are made of red clay on the mountain, which is crushed and mixed, pressed and formed by manual or mechanical pressing, and then burned inside and out with a large fire after drying, and then turned off the fire to cool the kiln and the bricks.

Because the air in the kiln is relatively smooth and there is plenty of oxygen, eventually the iron element of the brick is oxidized to ferric oxide, so its color is red.

The production process of red bricks is simpler than that of green bricks, and it can be mechanized production, and its production efficiency is also very high, and it is widely used.

However, the surface of the red bricks is full of potholes, and the slag will fall off as soon as you grab it. A cart of red bricks fell to the ground, and there were no more edges and corners to find. When the red brick is lifted to a height of one person, it will basically break when it is let go of the ground, and the blue brick will only break in two if it is thrown hard. Therefore, the red bricks are now used by the folk masters who perform one-handed brick splitting.

Red bricks are not resistant to blisters, and red brick houses are only better than earthen walls in floods, and they are prone to collapse after being blistered for a long time. Red bricks are not frost-resistant, easy to freeze and crack, and easy to be eroded by wind and rain, so now houses built with red bricks and reinforced concrete can only be used for decades.

With such a texture, if people used it to build houses in the past, where would there be ancient buildings now?

At the same time, the performance of green bricks is steady, solemn, rich in cultural heritage, which is in line with ancient Chinese Confucianism, which is another reason why most ancient buildings use green bricks instead of red bricks.

The raw materials of green bricks and red bricks are the same, but the brick kiln in the past is the same as the porcelain kiln, all in and all out, in order to shorten the cycle, the annihilation water cools down after burning, and the bricks become cyan, and the water is red without annihilation.

My hometown has always used lake mud to burn green bricks, which is better than the soil in the ground, and dredged the lake without encroaching on the land, killing two birds with one stone.

The early stage of green bricks is an oxidation reaction, and the later stage is a reduction reaction, which is particularly fuel-intensive and costly. It is equivalent to porcelain, the porcelain of the oxidation atmosphere of each kiln is cheap and easy to do, and the porcelain of Jingdezhen is to restore the atmosphere, the cost is high and difficult, but the porcelain is the highest.

Green bricks and red bricks are made of the same soil. After the green bricks are burned, the kiln door should be closed with thin mud, and the top of the kiln should also be made with thin mud to make a paddy field sample, and all the bricks should be sealed in the kiln. It was opened a few days later, and I can't remember the time of opening. Red bricks should not be sealed. The intensity should be the same. The sealing kiln is not good, and there are green bricks and red bricks when it comes out.

The firing process of traditional fired green bricks can be divided into two parts, one is to fire red bricks, and the other is to make red bricks into green bricks. The difference between green bricks and red bricks is that the bricks are naturally cooled into red bricks after firing, and the red bricks become green bricks, the following processes are carried out, and the first process is called "kiln".

The traditional operation is like this: when it is judged that the bricks in the kiln are fired, two tasks should be carried out, one is to add coal, and the other is to seal the kiln body.

The purpose of sealing the kiln body is to isolate the air (oxygen) input from outside the kiln through the sealing of the kiln body; Coal addition is to deplete the oxygen in the kiln and bricks through coal combustion, and the combination of the two methods can quickly deplete the oxygen in the kiln, that is, reduction sintering.

When the reduction sintering is reached, how to isolate the invasion of external air and continue this state until it is completely cooled, the ancestors used the simple principle that water becomes steam when it encounters high temperatures, that is, the water drinking kiln.

Because the water infiltrates into the kiln and encounters high temperature, the water becomes vapor and expands in volume, forming positive pressure in the kiln, which isolates the invasion of external air and ensures that the bricks and tiles are cooled in the oxygen-deficient atmosphere until the temperature that cannot be oxidized again, and the whole rejuvenation work is completed.

From the sealing of the kiln to the drinking kiln, and then to the opening of the kiln to produce bricks, the first two processes are completed in one go, and the changes in the color of the bricks and tiles in the kiln are completed under the condition that people cannot observe.

In terms of operation, due to the short time of the kiln, people often think that the kiln is a preparation for the kiln, and the water work lasts for several days, and requires a lot of skills.

For example, the amount of water in the initial stage is different from that of the subsequent water, and at the same time, it is necessary to prevent a large amount of water from entering the kiln in a short period of time, and the continuity of drinking water, etc., these tasks and requirements can be seen by people, and there is a lot of hard work to operate, so the concept of green bricks is formed after drinking the kiln.

After this concept was formed, the brick-burners did not clarify it, which may have something to do with conservative concepts, after all, there are concerns about the church apprentices starving to death of the master. This set of continuous process brick and tile people is very vividly called "stuffy green", a stuffy word, the technology of green brick firing is described to the extreme, and the technical conservative psychology of brick burners can be vaguely observed.

The discoloration of green bricks begins in the early stage of restoration, and after the restoration is over, the process of rejuvenation has been completed, and the beginning of the drinking kiln also indicates the end of regreening. The water only remained in this state until the kiln was finally opened, rather than the water drinking kiln process created the green bricks.

Due to some kind of mistake caused by the failure of the return to green, the bricks and tiles in the kiln are different degrees of cyan, red, blue-red, etc., the brick burner is called "flower kiln", and the brick and tile is called "green and red bricks".

The firing of green bricks into green and red bricks is generally caused by three types of mistakes, one is that the reduction and sintering time is not enough, and the reducing atmosphere and concentration do not meet the requirements of complete oxygen depletion, resulting in some parts of the brick stack or the inside of the brick being red under the oxidation atmosphere to varying degrees.

For example, if the kiln can form an oxygen-deficient reducing atmosphere in the kiln, it is affected by factors such as the concentration, time, and temperature of the reducing atmosphere, and the reducing atmosphere is unstable, which will lead to the appearance of green and red bricks.

This also confirms that the key to the formation of green bricks is the firing reduction process rather than the launching process, for example: if it takes 3 hours for a kiln to completely reduce, the time is compressed to 2.5 hours, and the launching time remains unchanged, the kiln product will appear "green brick red heart" phenomenon, the brick outside has completed the regreening, and the brick is red due to the reduction time is not enough, although the launching time is not compressed, but due to the incomplete reduction and sintering before, the oxygen inside the brick body is not lost, and the phenomenon of green and red bricks appears.

The bricks that are often seen on some buildings are also blue and red bricks, but the reason for the formation is not necessarily due to insufficient restoration. If you carefully observe the blue and red bricks in different parts of the kiln, they generally appear regularly near the mouth of the exhaust flue, at the bottom layer, or at the location of the kiln door and the fire viewing hole.

In the reduction stage or the high temperature stage after reduction, due to the poor sealing of the kiln, there is air leakage, causing the outside air (oxygen) to enter the kiln, resulting in insufficient reduction atmosphere or oxygen return after reduction.

In addition, the amount of water in the high-temperature water stage after the reduction is completed, the positive pressure in the kiln with less steam is insufficient and unstable, and the outside air invades from the leakage point, which will also form the phenomenon of blue and red bricks. Therefore, another key point of the green brick kiln process is the sealing of the kiln body.

The third is that the re-oxidation caused by the high temperature out of the kiln will also form the phenomenon of green and red bricks, which is called "tempering" by brick burners. The ferric oxide in red bricks forms black (cyan, gray) ferrous oxide due to the loss of oxygen in the reducing atmosphere, which is the chemical reaction process of red bricks turning into green bricks.

However, ferrous oxide is very unstable, and it will oxidize rapidly when exposed to high temperatures, and then oxidize to red ferric oxide. From this conversion process, it can be observed that two basic conditions are required for red bricks to turn into green bricks and green bricks to red bricks, one is the sintering atmosphere, and the other is the temperature.

When the kiln is opened (open the kiln door is called the kiln), the high temperature is the culprit of this kind of green and red brick phenomenon, although it belongs to the low temperature stage relative to the high temperature of combustion, but due to the instability of ferrous oxide, easy to oxidize, the temperature of the brick body from low temperature to complete cooling to meet the conditions of oxidation, in this case, the color of the green brick is slowly lost, and gradually becomes red brick or gray brick.

The temperature at which the kiln is opened determines the degree of discoloration of the bricks, which is red at high temperatures and gray-red or gray at low temperatures.