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Two jaw crusher factory pictures
The crusher is a crushing machine used in the processing of metal ores and non-metallic ores that can crush the mined raw ore into small particles by means of extrusion and bending. In the actual production process, the production efficiency of the crusher is often affected by various reasons, which directly affects the efficiency of the production enterprise and production line. This article discusses in detail the 8 specific factors that affect the production efficiency of the crusher.
Let's dive in!
The hardness of the ore is expressed by the compressive strength of the ore or the Platts hardness coefficient (The compressive strength divided by 100 is called the Platts hardness coefficient). In the process of ore beneficiation, obviously the harder the ore, the greater its compressive strength, so the more difficult to crush, resulting in low productivity. Conversely, the productivity is high.
When the amount of mud or fine ore in the material is large, the fine-grained minerals will agglomerate or stick to the coarse-grained materials due to the increase in humidity, thereby increasing the viscosity, reducing the discharge speed, and reducing the productivity. In severe cases, it may even cause blockage of the discharge port, affecting normal production of the crushing plant.
The proportion of ore is directly proportional to the productivity of the crusher. When the same crusher processes ores with different proportions, its productivity is bound to be different. When crushing ore with a large proportion, its productivity is high, and vice versa, the productivity is low.
The degree of ore cleavage also directly affects the productivity of the crusher. Since the ore tends to break along the decomposition surface during crushing, the productivity of the crusher must be much higher for crushing the ore with developed cleavage than for crushing the ore with dense structure.
When the content of coarse particles (larger than the size of the discharge port) in the crushed ore is high and the ratio of the largest ore block to the width of the feed port is large, the crusher needs to achieve a large crushing ratio, so the productivity is reduced. Conversely, if the content of fine particles (close to or smaller than the size of the discharge port) is large and the ratio of the largest ore block to the width of the feed port is small, the crushing ratio to be achieved is small, so the productivity is high.
Jaw crushers and cone crushers are called meshing angles by the angle between their two crushing working surfaces (when the two working surfaces are closest); roll crushers are called meshing angles by the angle of the two tangents leading from the contact point of the ore block and the roll.
The meshing angle of the crusher is an important condition to decide whether the crusher can crush the ore smoothly. The smaller the meshing angle, the larger the discharge port, the smaller the crushing ratio, the ore is easy to pass, and the productivity is large. If the meshing angle is too large, the ore will jump up and cannot be broken during crushing, and a safety accident may even occur. If the meshing angle is too small, the crushing ratio is too small to meet the requirements of the process. Therefore, the angle of the crusher should be appropriate. The maximum (limit) meshing angle of the crusher is determined by the friction coefficient between the crushed ore and the crushing working surface, which can be obtained by force analysis.
The friction angle of the ore to the steel plate is generally 17 degrees, so the meshing angle should not be greater than 34 degrees. In the actual production process, the size of the angle of the various crushers is far smaller than this limit value.
Crusher eccentric shaft rotation has a large impact on productivity. The rotation of various crushers should be within a certain range, otherwise, too high and too low rotation will reduce productivity.
Take jaw crusher as an example, its working process is composed of working stroke and empty return stroke. During the empty return stroke time, it should be fully ensured that the crushed ore can be discharged. If the number of swing of the moving jaw is large, i.e., the eccentric shaft speed is very fast, the crushed ore is not ready to be discharged from the crushing cavity within the time of the empty return stroke, thus being crushed again, causing the phenomenon of over-crushing, and also reducing the productivity. If the number of swing of the moving jaw is small, i.e. the speed of the eccentric shaft is too slow, the empty return stroke time is long and the crusher productivity is not high.
The size of the crusher discharge port is directly related to the meshing angle and crushing ratio of the crusher. Within the allowed range, if the discharge opening is increased appropriately, the meshing angle and crushing ratio will be reduced and the productivity will be increased. Conversely, if the discharge port is reduced, the meshing angle and crushing ratio increase, and the productivity decreases, and the productivity varies with the discharge port. The productivity of the same crusher increases with the increase of the discharge port.
In order to give full play to the production capacity of the crusher, it is necessary to correctly grasp the operating conditions of the crusher, strive to evenly feed the ore, and make the crusher work with a large crushing ratio and high load factor.
The above are 8 factors that affect the production efficiency of crushers. When purchasing a crusher, it is recommended that all mine owners purchase crushers from equipment manufacturers with the qualification of the concentrator，so as to ensure the grade and recovery rate of the concentrate. If you have other questions about the ore crushers, you can contact with our online service or submit a message, we will contact with you soon.