catalogue
1. Product introduction
2. Features
3. The principle and use of the equipment
4. Process requirements
5. Description of application technology (taking JQR- Circuit -389 as an example)
6. Types and introduction
7. The meaning of eliminating qi
8. Equipment drawings
Product introduction
The degasser is a pollution-free green aluminum liquid purification treatment equipment, and its principle is as follows:
The rotary degasser breaks large bubbles of inert gas into small bubbles through a rotor rotating at high speed and injecting inert gas, and makes them uniformly dispersed in molten metal. By reducing the bubble diameter, the total surface area of these bubbles increases sharply, which makes more inert bubble surfaces contact with hydrogen and impurities in molten metal, thus bringing these harmful substances to the liquid surface.
The key to degassing of rotary degasser is that the rotor can break large bubbles of inert gas into small bubbles and make them spread throughout the molten metal. By reducing the bubble diameter, the surface area of inert gas increases sharply, which makes more inert gas surface contact with hydrogen and impurities in molten metal, and removes hydrogen or impurities from molten aluminum with the rise of bubbles.
The flow control of inert gas into molten aluminum can adjust the flow of gas according to the volume of molten aluminum to be treated, adjust the speed of rotating rod and rotor, and generate bubbles with appropriate size to facilitate the diffusion of inert gas.
Both argon and nitrogen can be used as inert gases to remove gas from molten aluminum. The purity of inert gas must be higher than 99.99%.
Degassing is to inject inert gas into molten aluminum to remove hydrogen. In addition, degassing is also considered to be a very effective method to make impurities float. Two main theoretical models have been proposed to explain the principle of degassing. The macro model holds that the removal of impurities is essentially similar. Microscopic mode, that is, according to this theory, due to the high vapor pressure of hydrogen, dissolved hydrogen diffuses into the gas injected into aluminum liquid. Theoretically, the inclusions with a diameter of 10 micron will be adsorbed on the bubbles, and will float to the surface after contacting with the bubbles.
Schematic diagram of rotating gas jet degassing (omitted)
There are four factors that affect the removal rate of hydrogen and inclusions in molten aluminum:
1) metal flow or volume
2) inert gas flow rate
3) Diffusion of inert gas
4) Contact between inert gas and impurities.
The research shows that the shorter the distance that hydrogen needs to move to reach the bubble, the faster the degassing speed. In addition, the longer the contact time between bubbles and molten metal, the greater the possibility of improving degassing efficiency. For these reasons, the narrow and deep degassing container can make the degassing effect better.
In addition to adsorbing hydrogen, degassing also makes more oxides adsorbed on bubbles. This reduces the amount of refining agent and production cost.
trait
1, the rotary refining degasser can be divided into two modes: mobile and fixed, which are suitable for different operating environments.
2. The degassing rate is above 50%, which shortens the smelting time and reduces the production cost.
3. It is suitable for purifying molten aluminum in crucible furnace, ladle and static box.
Principle and application of equipment
The principle of the equipment is that the rotating graphite rotor breaks inert gases (argon and nitrogen) blown into aluminum liquid into a large number of dispersed bubbles, which are dispersed in aluminum liquid; Bubbles in the molten aluminum absorb hydrogen and oxide slag in the molten aluminum, and are taken out of the surface of the molten aluminum with the rise of bubbles, so that the molten aluminum can be purified. Because the bubbles are small and dispersed, they are evenly mixed with the rotating molten steel, and slowly float up in a spiral shape with this rotation, and when they contact with the molten aluminum, they will not form an airflow generated by continuous straight-line rise, and the purification effect is significantly improved. Both argon and nitrogen can be used as gases for degassing and slag removal of aluminum liquid. The purity of inert gas must be higher than 99.99%. It is suitable for hydrogen/slag removal and purification of molten aluminum in crucible furnace, pool furnace, launching furnace, ladle/tundish and static tank.
Process requirements
1. Gas flow 8 8-20 liters/minute
2. The rotating speed is 300-600 rpm (the greater the subcontracting, the greater the required rotating speed).
3. The degassing time is 6- 15min (the more recycled materials, the longer the degassing time).
4. The vertical speed is 4.0m/min
Application technology description
1.JQR- circuit -389 technology
1. 1 machinery and equipment
JQR- Yunnan Furnace -389 molten metal automatic treatment station consists of five parts: rotary degasser, hopper system, spiral feed spraying device, adjustable baffle and electrical control cabinet, and also includes consumables (slag crusher and rotor) specially developed for JQR- Yunnan Furnace -389.
Rotary degasser is the most basic component of JQR- Circuit -389, and it is also the fixed base of feeding system, treatment flux transmission unit and movable baffle. In principle, the rotary degasser can be used as the basic component of CQJ treatment station, but the degasser itself is too small to physically fix other components on it.
The hopper system contains one or two flux boxes, and at most two treatment fluxes (such as slag cleaning and deterioration) can be added at the same time. The closed hopper design can prevent the flux from absorbing moisture, and the sensor in the hopper is used to prompt the amount of flux.
The flux injection device is installed at the outlet of the hopper, and is used for automatically injecting the processing flux into the eddy current. The device is driven by a motor, so as to realize accurate control of magnetic flux transmission. The amount of flux added is controlled by the screw advancing time.
The movement of the adjustable baffle is also driven by the motor, and the alloy liquid can be immersed and pumped out at will during treatment. Placing the baffle outside the alloy liquid is helpful to form eddy current in the alloy liquid. Immersing the baffle in the alloy liquid can not only eliminate the eddy current, but also optimize the degassing and slag removal process.
The control cabinet contains a PLC, which is used to ensure a good treatment process and maintain a stable treatment process. PLC mainly controls the following functions of JQR- Circuit -389: the lifting of the rotor and the rotating rod, the degree of immersion in the alloy liquid, the rotating speed of the rotor and the rotating rod, the required spraying amount of the treatment flux, the flow rate of nitrogen introduced into the alloy liquid, etc.
1.2 consumables
XSR rotor and covered MTS series slagging agent products are the key to the performance of JQR electric furnace -389.
XSR high-performance rotor with patented unique design is helpful to form eddy current during flux addition, and then degas and remove slag efficiently. XSR rotor has a powerful pump function, which can pump molten aluminum into the rotor from the bottom of the rotor and immediately mix it with inert process gas. At the same time, the speed of throwing the aluminum liquid out of the rotor is also increased accordingly, so that inert gas bubbles are more evenly distributed on the cross section of the aluminum liquid in the treatment container, and finally the gas is degassed quickly and thoroughly.
COVERAL MTS series slagging agent products developed in cooperation with MTS include slag remover/slagging agent, sodium-containing modifier, grain refiner and flux for removing special elements, and the smoke generated in use is extremely low.
2.2 Environmental, Health and Safety Benefits
With the progress of environmental legislation, foundries are required to reduce pollution. ISO and other relevant documents provide necessary guidance for reducing emissions. JQR- EAF -389 can help foundries to perform better in environmental protection, such as using less consumables (treating agents and inert gases), reducing slag, reducing emissions, reducing treatment time, reducing superheat during smelting and saving energy.
Flux is needed in the process of molten metal treatment, which is usually powder flux in the market, and granular flux is used in conjunction with JQR- furnace -389. After testing and collecting the emissions from molten metal treatment, it is found that fluoride and sulfur oxides produced by flux reaction are the main health hazards. Although the substances released by powder flux are still at a normal level, the test results under various conditions show that the emission of particle flux is obviously lower than that of powder flux. The total number of particles is correspondingly reduced from 19 mg/m3 using powder flux to less than 0.46 mg/m3 using particle flux. After using granular flux, the total chlorine emission in the form of hydrogen chloride gas is reduced by more than half, while when using granular flux, the low chlorine emission of powdery flux is maintained. Most importantly, the use of granular flux can significantly reduce the fluoride emission from 19 mg/m3 to below 4 mg/m3.
When using traditional powder flux, the addition amount is 0.25% of the weight of aluminum liquid to be treated, while the particle flux is 0. 125%. Logically speaking, the reduction of addition will naturally reduce emissions, but according to the test results, the emissions of the two forms of flux are not directly proportional to the addition. When the weight of granular flux is 50% of powder flux, the emission is reduced by 85%, which makes us know more about flux.
At the same time, the use of JQR- Circuit -389 can have a very significant impact on health and safety. As the slagging agent is added into the molten metal and fully reacts, compared with the traditional flux, the emission of gas and smoke is significantly reduced. Because the direct participation of operators is reduced, the safety of operators is improved.
2.3 Economic benefits
After use, JQR circuit -389 reduces the processing cost, improves the performance, reduces the waste and saves a lot of costs.
The reduction of treatment cost is mainly due to the reduction of inert gas and slagging agent and the reduction of labor cost. The improvement of overall performance is reflected in: shorter treatment cycle, good reproducibility of molten metal quality, higher reliability and lower maintenance cost. See the following case for details.
Types and introduction
One: Ultrasonic degasser
According to foreign media reports, the Ultra-D degasser developed by Southwire Com. Has been listed, its trademark Ultra-D