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Click to add WeChatThe flotation machine is one of the commonly used equipment in mineral processing plants and is the main equipment of the flotation process. The impeller plays an important role in the flotation operation and is equivalent to the "heart" of the flow parts. In daily operations, the impeller of the flotation machine is the most frequently worn and replaced component of the flotation machine due to long-term contact with the slurry and chemicals. Therefore, in order to ensure the normal operation of the flotation machine, it is necessary to reduce the wear of the flotation machine impeller. Let’s briefly understand the main causes of flotation machine impeller wear and some countermeasures!
During the working process of the flotation machine, the solids mixed in the slurry for a long time in the impeller operation The particles impact the flow-passing surface, causing elastic deformation and plastic deformation on the surface of the material in sequence. After repeated impact of solid particles, the material undergoes fatigue damage and the surface material falls off.
When the wear is slight, there will be concentrated scratches and pitting along the flow direction; when the wear is severe, the surface will be corrugated or grooved, and when the wear is severe, the parts may be perforated and fall off in pieces.
Improvement method: It can be solved by changing the outlet angle of the impeller blade. Generally, the thickness of the blade inlet edge is larger. For a highly abrasive medium such as flotation feed, a smaller blade outlet angle can minimize particle collision with the blade working surface. The blade outlet angle is generally 30°-40°.
When the impeller of the flotation machine rotates to discharge the slurry, air pressure will be generated and bubbles will be generated. After the bubbles are formed, they will move with the slurry and come into contact with the slurry. The bubbles that reach the inner wall of the impeller collapse due to the increase in pressure, thus forming a micro-jet toward the wall. This microjet completes the directional impact on the material surface in a very short time, and the force generated is equivalent to the effect of "water hammer".
In addition, the metal surface gradually fatigued and peeled due to impact, causing material loss. The solid particles in the slurry are driven by cavitation and impact the metal surface. This damage includes both the impact of micro-jet and the impact of solid particles. It is the combined effect of cavitation wear and impact wear.
Improvement methods:There are two methods, one is to improve the blade width, and the other is to reduce the number of blades.
Improve blade width:In order to reduce wear, increase the blade outlet width, which on the one hand reduces the relative speed at the impeller outlet, reduces impeller wear, and on the other hand reduces It eliminates the jet-wake effect at the impeller outlet and makes the exit slurry flow velocity evenly distributed.
Reduce the number of blades: The number of blades in a flotation machine is generally 4 to 7. Fewer blades reduce crowding at the impeller inlet, thereby reducing pump wear.
The above are the main reasons for the serious wear of the impeller of the flotation machine and the corresponding improvement methods. In fact, there are other improvement methods by controlling the mineral particle size and hardness. Solved, generally, the particle size and hardness of the solid particles in the slurry are important factors affecting the wear behavior of the impeller material. The increase in particle size and hardness will lead to a continuous increase in erosion particle size. Therefore, during the daily operation of the flotation machine, the particle size of the flotation feed should be strictly controlled to avoid "coarse" situations, so as to reduce the wear of the impeller of the flotation machine.