What are the differences between antique grey bricks and red bricks?

The main difference between red bricks and ancient blue bricks lies in their raw materials and production processes. Red bricks are made from raw materials such as clay and shale, while the primary material for antique blue bricks is also clay. Red bricks are fired in high heat and then cooled after the fire is extinguished, whereas blue bricks are cooled inside the kiln after firing. The process of making blue bricks is more complex and produces fewer bricks, whereas the process for red bricks is simpler and more efficient.

The differences between the two are as follows:

1. Various processing materials

Red bricks are烧结型建筑砖, made from clay, shale, and coal gangue, which are crushed, mixed, dried, and then fired at high temperatures for oxidation.

Antique kiln-fired bricks are a type of烧结砖, primarily made from clay, which is mixed with water and then molded through extrusion.

Then, the bricks are fired in a kiln at approximately 1,000 degrees Celsius, followed by water cooling to prevent the iron in the clay from being fully oxidized, resulting in excellent resistance to weathering and water.

2. Different firing techniques

Red bricks are primarily fired by intense internal and external combustion, followed by cooling the kiln and bricks after the flame is extinguished.

Due to the smooth air inside the kiln and the abundance of oxygen, a very good oxidizing atmosphere is formed. Consequently, the iron elements in the bricks oxidize into ferric oxide, resulting in a red color.

Ancient-style blue bricks are directly poured into the kiln after firing, as the high temperature inside the kiln causes the moisture to instantly transform into steam upon contact, effectively blocking the air.

Under conditions of oxygen deficiency, the iron oxide in the bricks forms ferric oxide, which then turns the bricks blue.

3. Pros and Cons Comparison

The advantages of antique blue bricks include their superior durability, better alkali resistance compared to red bricks, but they have drawbacks such as high production costs, complex processes, low yield, and inability to be produced mechanically, leading to high prices. The benefits of red bricks are simpler production processes, mechanical production capabilities, high efficiency, and widespread application. However, the downside is that red bricks are solid, and their production process can damage a lot of farmland clay.

In summary, when selecting antique blue bricks and red bricks, it is essential to consider all factors and choose the appropriate product based on the actual situation.