Application of Jaw Crusher in Mineral Processing Technology

Jaw crusher is a member of the large family of crushers. It is characterized by simple principle, convenience and outstanding cost performance. In the practice of many dressing plants, it is regarded as the first choice for coarse crushing in mineral processing equipment. Liming Heavy Industry has accumulated many years of experience in the production of jaw crushers. The design of its jaw plates and crushing bearings has fully adopted advanced wear-resistant materials and protection technologies.

Since the working chamber of the jaw crusher is composed of the movable jaw and the fixed jaw, it is easy to wear due to the huge crushing force and the friction of the material. Liner, this liner is also called crushing plate. The surface of the crushing plate is usually made into a tooth shape. The angle of the tooth peak of the crushing plate is 90°~120°, and its size depends on the nature and size of the material to be crushed. When the material is lumped, the angle can be smaller. The size of the tooth pitch depends on the particle size of the product, usually it is approximately equal to the width of the discharge port, and the ratio of the tooth height to the tooth pitch can be taken as 1/2 to 1/3. When working, the wear speed of the upper and lower parts of the crushing plate is different. The lower part wears faster than the upper part. When the jaw crusher is working, the crushing plate directly contacts with the material and bears huge crushing force and friction of the material. The service life of the crushing plate is directly related to the working efficiency and production cost of the jaw crusher. Therefore, it is particularly important to prolong the service life of the crushing plate of the jaw crusher. Enhancing the service life of the jaw crusher plate can be considered from the aspects of design, material selection, assembly and improvement during use.

When designing, the movable jaw of the jaw crusher and the crushing plate of the fixed jaw should have tooth peaks facing tooth valleys. In this way, in addition to the extrusion effect on the material during crushing, there is also a bending effect, and the material is easier to crush. In order to enhance the service life of the crushing plate, the crushing plate of the small and medium-sized crusher is designed to be symmetrical up and down, and can be used when the lower part is worn; Replace the breaker plate. The material of the crushing plate can be white cast iron. White cast iron has higher hardness, better wear resistance, easy source, and cheap price; the disadvantage is that it is brittle, easy to break, and has a short service life. In order to improve the service life of the crushing plate, it is better to use manganese steel with more than 12% manganese as the material, and ZGMn13 is commonly used. The toughness of manganese steel is good, although the hardness is not high (about 210HB), but because of the characteristics of cold work hardening, it will be continuously strengthened under pressure, so it will continue to wear and strengthen during work until it is worn out and cannot be used. It was scrapped. . After casting, manganese steel crushing plate should undergo water toughening treatment. The operation of water toughening treatment is basically the same as quenching, that is, the cast manganese steel crushing plate is heated to 1000-1100 ℃ and then cooled rapidly in water. After the water toughening treatment, a uniform metallographic structure can be obtained, and the metallographic structure can be fixed, avoiding the natural phase change during use and making the performance worse. The disadvantage of manganese steel is that it is more expensive, but in terms of service life and cost, ZGMn13 has a longer service life and lower cost than white cast iron. When assembling, the crushing plate of the jaw crusher must be firmly attached to the jaw plate, and the space between the two should be flat, and soft metal (such as lead, zinc, etc.) And fasten with bolts. When the crusher is working, the crushing plate should not be loose, otherwise it is easy to break or wear the crushing plate, which will reduce the service life of the crushing plate. Therefore, the crushing plate must be installed during assembly to prolong the service life of the crushing plate.

In the production process, the crushing plate directly interacts with the material, and the crushing force is very large, especially when crushing materials with high hardness, the bolts on which the crushing plate is installed vibrate and the nuts become loose, which intensifies the wear of the crushing plate and generates great noise. In severe cases, the broken plate falls off or breaks, causing the equipment to stop and affecting normal production. In this case, just tightening the bolts and nuts before starting the machine cannot solve the problem. It is necessary to analyze the specific problems according to the actual situation on site, and find ways to solve the problems with practical methods. For example, a spring anti-loosening and vibration damping device can be used to solve the loosening of the crushing plate during work, thereby prolonging the service life of the crushing plate and improving work efficiency. The specific method is to use the spring to make a bolt anti-loosening and self-tightening device. The device is composed of an inner spring gland, a spring, and an outer spring gland. Put this device on the bolt and tighten the nut, because the spring is compressed to a certain extent by the nut. Finally, a strong anti-vibration effect is produced. The bolt loosening force generated by the huge crushing force is automatically compensated by the spring tension force, so the bolts will not loosen, thereby prolonging the service life of the crushing plate and improving production efficiency. In short, in the process of use, we can find ways to solve specific problems according to specific situations, prevent the crushing plate from loosening, aggravated wear, and breaking, so as to prolong the service life of the crushing plate, reduce costs, and improve work efficiency.

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