Flame surface: refers to a rough surface finish made of high-temperature flame generated by acetylene, oxygen or propane, oxygen, liquefied petroleum gas and oxygen as fuel. There are a few stones that cannot be processed by fire or the processing effect is not good. Due to the action of fire, some impurities and low melting point components on the stone surface can be burned off, thus forming a rough finish on the surface, which will have a certain tingling sensation to the touch. The processing of burnt noodles has certain requirements on the thickness of stone to prevent the stone from being broken during processing. Generally, the thickness is required to be at least 2CM, and some stone materials are required to be higher. In addition, some materials will change color during combustion, such as rust stone (G682), and the burnt rust stone will show a certain reddish color instead of the original yellow rust color.
The combustion surface is characterized by rough and natural surface, no reflection, fast processing speed and so on. , often used for external wall dry hanging.
Burning surface treatment is mainly suitable for crystalline stone with timely components, such as granite and amphibole. This kind of stone, under the rapid injection of high-temperature flame, the crystalline part of the surface layer instantly expands and peels off, which is more natural. However, when the stone surface is treated by flame, there is no special flame treatment device, but the stone surface is treated by a flame cutter or piercer with the usual flame temperature of 300℃ and the injection speed of 1200m/s, so it is difficult to control the injection speed and flame temperature well. However, it is very difficult to heat only the surface layer of stone under the above-mentioned extremely fast jet speed and extremely high flame conditions, because not only the surface layer, but also the inner layer under the jurisdiction may be melted, deteriorated and discolored by high temperature heating, which will not only fail to achieve the expected effect of flame processing, but also destroy the inherent natural color of stone.
The key to the success or failure of granite burning surface technology lies in controlling spraying speed and flame temperature. Therefore, repeated experiments have proved that the spraying speed and flame temperature of stone surface are controlled in the range of 400 ~ 1000 m/s and 2000℃ ~ 2500℃ respectively.
This device is mainly composed of slender aluminum metal, fire holes for generating flame jet, combustion chamber function and nozzle, and the nozzle is installed at its rear end. Because the flame nozzle is at ultra-high temperature, there is no water-cooled annular cooling chamber (not marked in the figure) around it. When the stone surface is treated by the flame treatment device, the pressure vessel is adjusted to the required pressure, oxygen is supplied through the oxygen supply pipe, pressurized by the pump, fuel such as kerosene is supplied through the fuel supply pipe, compressed air pressurized by the compressor is supplied through the compressed air supply pipe, and then the mixture is ignited through the nozzle at the top of each supply pipe, burned in the nozzle, and a high-temperature flame is rapidly sprayed to keep a certain inclination and contact with the stone surface to be processed, and the surface layer is peeled off.
At this time, the volume ratio of fuel (kerosene), oxygen and inert gas (nitrogen in compressed air) is adjusted to1:1:kloc-0/,forming a flame with an injection speed of 400 ~ 1000 m/s and a temperature of 2000℃ ~ 2500℃.
When the flame is sprayed on the stone surface in italics, the crystal on the stone surface in contact with the flame expands instantly, and the lattice expands, which leads to vibration and peeling off from the crystal on the surface. Therefore, by moving the processing equipment or stone in parallel at an appropriate speed, microwave concavities and convexities can be formed on the entire surface of the stone, and pear-shaped veneers can be obtained. According to the mineral composition of the stone to be treated, under the conditions of injection speed of 400 ~ 1000 m/sec and flame temperature of 2000℃ ~ 2500℃, the stone surface is properly selected for treatment, which has good strippability and does not deteriorate and change color when heated.
It is very convenient to effectively heat the stone surface and peel it off under the conditions of suitable spray speed and flame temperature, and it will not deteriorate and change color due to high temperature, and it can form a very beautiful pear-shaped surface. Because only the surface layer of stone is heated, it will not have adverse effects on the whole stone, and there will be no phenomena such as thermal deformation, cracking and embrittlement.
The firing of stone is mainly used for stone with crystals, and the crystal particles are small. Most domestic granites can be fired, such as domestic 603, 602, Rhododendron, 654 and so on. However, imported stones with large lines and exaggerated lines cannot be burned, such as Naples, Bordeaux Red, Indian Golden Hemp and Persian Kenaf. And those with large crystal particles are not suitable for burning, such as Angola brown, brown beads and brown diamonds.
The color of the burned stone will be lighter than that of the smooth surface, and the grain after burning is very different from that of the smooth surface, or you can't see what kind it is at all (you can see the grain by spraying water), so if you want to dry the stone, you'd better choose domestic stone.
The reason is simple:
1, imported granite is more expensive than domestic granite;
2. Most stones with the same main color, whether imported or domestic, have similar surface effects, so it is better to choose imported stones with smooth surfaces, which is a bit wasteful to make fire or litchi noodles.