A: The screening operation before the ore enters the crusher is called pre-screening. It can pre-screen fine particles so that the crushed ore does not enter the crusher, thereby increasing the crusher's production capacity, preventing over-grain and reducing equipment wear and power consumption. When dealing with mud and wet ore, the use of pre-screening can avoid or reduce the blockage of the crusher discharge port, which is conducive to the normal operation of the crusher. The so-called inspection and screening operation is to screen the ore discharged from the crusher in a crushing section, so that the product on the sieve (greater than the specified particle size) is returned to the crusher and then crushed, and the sieved product is the section. Broken qualified products, inspection and screening can ensure the final product particle size, no large or small ore size, and have a direct impact on the stable production of the grinding machine. 2. What is the definition of screening? What is the meaning of screening? A: The operation of dividing the ore into several grades by particle size using a sieve is called screening. Significance is great sieving, screening operations can be sieved from the fine fraction of the ore in the crusher, the crusher can be increased productivity and to avoid excessive pulverization; jig before and dry magnetic beneficiation, often the ore According to the particle size sieve, it can be divided into several levels and treated separately, which can improve the sorting effect. In the concentrating plant, sometimes the screening operation can also be used as the screening, dewatering screening or beneficiation screening. In short, the screening operation is not in the mineral processing. A missing job. 3. What is the screening efficiency? How to calculate? Answer: Screening efficiency refers to the ratio of the weight of the under-slurry product actually obtained at the time of screening to the weight of the granules in the sifting material which is smaller than the size of the mesh, generally expressed as a percentage. 4. What kinds of screening machines are there? A: According to the structure diagram of the screening machine, there are roughly the following: 1. Fixed sieve; 2. Roller screen; 3. Cylindrical sieve; 4. Planar moving sieve (including shaking sieve and vibrating screen). 5. What are the factors that affect the screening operation? Answer: 1. Physical properties of the material to be screened, including coarseness composition, humidity, mud content and ore shape. 2, screen surface motion characteristics and its structural parameters: including the characteristics of the screen movement, the length and width of the screen surface, effective screen surface, mesh size and shape. 3. Operating conditions: including the size of the productivity and the uniformity of the ore. Among the above three types of factors, the first type of factors cannot be changed arbitrarily except for temperature. The second type of factors must be carefully considered when designing the sieve. Only the third type of factors can be adjusted in the actual production process. 6. Classification of vibrating screens? What kind of sieve is commonly used? Answer: 1. Self-centering vibrating screen; 2. Eccentric vibrating screen; 3. Inertial vibrating screen; 4. Linear screen; 5. Resonant screen, which is divided according to the mechanism of the movement of the sieve and the movement track of the screen surface. Due to the large vibrationality and low sieving rate of the eccentric and inertial vibrating screen, it is easy to cause clogging of the mesh hole, so it is generally not used. The self-centering vibrating screen overcomes the shortcomings of the first two kinds of sieves and is widely used. 7. What are the characteristics of the self-centering vibrating screen? A: The self-centering vibrating screen is also known as the universal hanging screen. It is caused by a vibrator with eccentric properties to vibrate the sieve. Its characteristics are as follows: 1. The material on the sieve can achieve good looseness and delamination under the action of vibration. 2. The weight of the vibrating screen can be adjusted, and the amplitude of the sieve can be adjusted according to the production requirements. 3. When the ore quantity changes, the amplitude changes; when the ore quantity is small, the amplitude increases and the vibration is aggravated; when the ore quantity is large, the amplitude becomes smaller; the change of the ore amount will affect the “power balanceâ€, so that the belt center is generated. Some vibrations. 4, suitable for medium and fine particle screening and not suitable for coarse grain screening. Counterbalance Valve,Vbcd Se,Vbcd De,Counterbalance Valve Vbcd De Jiangsu haohong hydraulic Co.Ltd , https://www.jshhhydraulic.com
1. What is the role of pre-screening and screening?