(I) Inflation mechanism The key components of the mechanical agitating flotation machine are the rotor and the stator. The rotor is also called an impeller. Its working parts can be rods or radial plates that are vertically arranged in a cage shape. They can also have the shape of a pump impeller—a turbine, a horizontal disc with upright blades, a mixed flow impeller, and the like. When the rotor rotates, holes are formed behind the blades to draw in air. The slurry bypassing the blades forms two rows of swirling swirls (Kamen vortex), and the air is drawn by these swirls to the center of the vortex to form bubbles. The formed bubbles may split into smaller bubbles under the dynamic pressure and shear force generated by the turbulent pulsation velocity. The farther away from the blade, the smaller the bubble splits. Figure 1 depicts the case where the impeller disperses air into bubbles, which is based on high speed photographic photographs. Experiments have shown that the ability of the rotor to disperse air is limited. The ability of a self-aspirating flotation machine to draw in air depends on the ability of the rotor to disperse and does not exceed this limit. The gas-pressing flotation machine can increase the gas filling amount by increasing the gas supply pressure. If a certain limit value is exceeded, a large air mass overflows the slurry surface, and the limit value is called an overflow value. Increasing the number of blades or increasing the speed increases the amount of inflation and increases the overflow value. The role of the stator is to destroy the rotational motion of the slurry, and also to convert the tangential velocity into a radial velocity, which is also called rectification. When the slurry is blocked by the stator and changes direction, a vortex is also generated. This is advantageous for the formation of small bubbles. For self-priming, self-aspirating flotation machines, there should also be an impeller cover on the stator to form the suction negative pressure zone. Smooth Powder Coating Smooth Powder Coating HLM Powder Coating CO,.Ltd , https://www.holymepowder.com
(Ii) trends Throughout the flotation machine history, 60 years ago beneficiation plant mainly in two self-priming method mechanical agitation flotation machine --- even Wald (Farenwald) flotation machine and Fagegulun (Fagergren )Flotation machine. These two long-established flotation machines are still used throughout the world.
Since the 1960s, to meet the processing plant, coal plant selected large-scale, automation and the need to save electricity, a lot of research work and achieved good results, production of many new high-efficiency mechanical agitation flotation machine, success Used for production. This technological advancement is closely related to the improvement and renewal of certain rotor substructures. Summary is as follows: [next]
(1) Large size The largest single tank volume has reached 85 m 3 (self-inhalation, Wimco 1+1 type) and 100 m 3 (compressed air type, OK type), and models with a volume exceeding 16 m 3 have been widely used. application.
(2) DCization According to the way in which the slurry flows from one flotation tank to the next, the flotation tank can be divided into two types: one is that the two tanks are separated by an intermediate chamber, and the slurry is from the middle chamber. The overflow enthalpy flows through the pipeline to the bottom of the next flotation tank and is sucked by the impeller, which is called a suction tank. Due to the large throughput of the large flotation machine, almost all types of large flotation tanks use DC tanks.
(3) Improve the design of certain rotor subsystems to increase the amount of aeration (the amount of inflation calculated according to the surface area of ​​the slurry is generally more than 1 m 3 /m 2 • min). The Humboldt flotation machine, similar to the Falengerwald flotation machine, uses an improved single yaw impeller (Fig. 2b), which is approximately one more efficient than the original horizontal disc impeller (Fig. 2a). Times. After using the double yaw impeller (Fig. 2c), the amount of inflation is increased by 50% compared to the single yaw impeller. The United States Wimco changed the cage rotor of the Fagguren flotation machine to a star rotor, and the cage stator to a porous cylinder with ribs. The new model is called Wimco 1+1. Large-scale operation has been achieved while maintaining the advantages of large gas filling, low power consumption, and self-inhalation. The largest model of the Fagerguren flotation machine has a single tank volume of 1.7 m3 , and the largest model of the Wimco 1+1 has a single tank volume of 85 m3 . Figure 3 illustrates the difference between the two rotor stators. [next]