The colloid mill has multiple layers of cutter teeth along the radial direction, and the rotor and stator mesh with each other, so that the polymer can be ground around the cutter teeth at high speed and sheared at the side of the cutter teeth at high speed.
It has a unique "internal tooth" structure and patented design, and is suitable for processing various polymer modified asphalt, modified emulsified asphalt and common emulsified asphalt. Compared with similar products, it is more efficient. With the function of "cutting first and then grinding", it ensures super production capacity and is known as "super grinding" Schematic diagram
(1) Colloidal mill with unique internal tooth design, the turntable and the fixed disk are meshed with each other, and the asphalt mixture is ground and sheared through the high-speed operation of the turntable and the fixed disk of colloid mill.
(2) The grinding disc is radially distributed with multiple layers of cutter teeth, which can form circular flow and radial flow and realize multiple shearing and grinding.
(3) High-speed grinding is completed on the intersection surface of the top surface of the rotary table grinding gear, the bottom surface of the fixed table grinding gear and the four grinding gear side surfaces. The eight grinding sides of the turntable and the fixed table complete high-speed shearing.
(4) The colloid mill rotates at a high speed of 3000 rpm, and the direction and instantaneous speed of the fluid in the grinding area are constantly changing, resulting in high-speed shearing and high-speed grinding of the fluid.
(5) In the process of throwing the asphalt mixture from the center of the grinding disc to the edge, it moves in a spiral S-shaped path, which increases the length of the path, increases the cutting time and times, and is repeatedly cut and ground. Intense friction, extrusion, kneading and tearing between molecules break the molecular chain and redistribute the molecules of asphalt mixture with good combination. The modifier forms a stable network structure in asphalt under the chemical action of stabilizer. (1) patented design, internal tooth structure, small size and low energy consumption; The motor power is only 55KW.
(2) Imported parts, unique corrosion-resistant and wear-resistant materials, guarantee the service life of more than 200,000 tons.
(3) The colloid mill motor is controlled by frequency converter, with small current impact and adjustable speed.
(4) The clearance of colloid mill can be adjusted within the range of 0.65438 0 ~ 5mm. ..
(5) Various polymer asphalts, such as SBS, SBR, EVA, PE, waste rubber powder, etc., with a concentration as high as 20%, can be successfully ground at one time.
(6) The minimum particle size of polymer after one shear grinding can reach 0. 1um, and the shear grinding ability is 4- 10 times that of ordinary colloid mill, which greatly shortens the residence time of asphalt at high temperature and prevents asphalt from aging at high temperature. The continuous high shear degradation process of colloid mill is superior to the traditional hot melt method.
At present, there are two production processes of rubber asphalt: traditional hot-melt method and high-shear method, which are introduced respectively as follows:
Methods 1: traditional hot melt method
The traditional hot-melt method is to add the heated matrix asphalt and rubber powder into a mixing tank, and then pump them into a reaction tank for high-temperature swelling. The rubber asphalt produced by this method is usually called asphalt rubber. The traditional hot melt method has been applied in foreign countries as early as 30 years ago. This process is relatively simple, but the modification effect has a great relationship with the particle size of rubber powder used.
Because of its high viscosity, asphalt rubber has become the main asphalt binder of OGFC (open graded wear course) in the United States, and its viscosity at 60℃ can meet the requirements of high viscosity asphalt (20000Pa.s). The open graded wear layer is usually composed of a large number of coarse aggregates with a single size and a small amount of fine aggregates, and the porosity can be about 15% -20%. Because there is not enough fine aggregate to fill the gap between coarse aggregates, traditional low-viscosity asphalt is prone to vertical flow under the action of gravity, which can effectively resist this situation. The open graded wear layer has large friction resistance and a large number of pores, which can quickly remove the accumulated water on the road surface, ensure the anti-sliding ability of the road surface, enhance the durability of the road surface and effectively reduce the driving noise; However, due to its porosity, its service life is shortened, its gradation is fine, and its pores are easily filled with dust or sand, which reduces its water permeability. The water vapor carried by the pores blocked by sand accelerates the aging of asphalt binder, which leads to the peeling or even separation of OGFC from the lower concrete. Moreover, cleaning the road surface requires special cleaning equipment, which is expensive. Therefore, OGFC is not suitable for roads with heavy dust. Relatively speaking, it is suitable for countries with clean air, such as Europe and America, and should be selectively applied to some areas in China, especially those with more dust storms and sandstorms and heavier pollution.
In addition, this hot-melt process is only through simple mechanical stirring, and the rubber powder particles are coarse, which makes the pavement more elastic and difficult to crush. The negative effects of insufficient compaction on some pavements offset the performance improvement effect of asphalt rubber.
Method 2: High shear method
In order to solve the limitation of road performance of rubber asphalt, the production technology of rubber asphalt has been greatly improved with the in-depth research at home and abroad in recent years. After rubber powder is mixed with asphalt, it is not only by simple mechanical stirring, but also by shear grinding with colloid mill, which is called high shear method. The heated matrix asphalt, rubber powder and additives are stirred and mixed in a premixing tank, then pumped into a high-shear colloid mill, and finally uniformly swollen in a developing tank. The rubber asphalt produced by this method is usually called asphalt rubber. Because of the high shear colloid mill, rubber powder and asphalt particles are sheared and ground very finely, and rubber powder is dispersed more evenly in asphalt, which significantly improves the modification effect and the storage stability of finished products.
Our company's rubber asphalt equipment is suitable for both hot melt production and high shear production of rubber asphalt, which is a real "one machine with two functions" in the world at present.
The following is the difference of dispersion morphology of rubber asphalt samples prepared under two production processes.
The dispersion state of rubber asphalt samples prepared by continuous high shear degradation process is very different from that prepared by traditional hot melt process. The former is evenly distributed, while the traditional process is not evenly dispersed, and the rubber powder has obvious agglomeration phenomenon. The material price is generally around 4000 yuan /m3.