High-frequency screens are widely used in the dry and wet screening, grading and dehydration of various materials in industries such as mineral processing, coal preparation, chemical industry, brick making, food, pharmaceuticals, alkali making, fertilizer, paper making, etc. Used for fine-grain classification in the grinding and grading process of the concentrator, at the appropriate feed concentration, feed size (-200 mesh content), and the difference between the required sieve particle size and the feed size is less than 30% Under these conditions, the screening efficiency is as high as 70%. Due to the high screening efficiency, the circulating load and the content of qualified particles in the screen can be greatly reduced, thereby improving the processing capacity of the mill (generally, it can be increased by 5-10%). The screening process strictly controls the particle size of the under-screen material, eliminating the adverse effect of coarse ore particles on the concentrate grade; in addition, under the action of high-frequency and small-amplitude oscillations on the screen surface, the pulp has the effect of layering according to density, and high-density small particles are easy to Settling down to the sieve surface to penetrate the sieve, so the quality of the under-sieve can be significantly improved.
Application in coal washing plant
The application of high-frequency screens in coal washing plants is a major advancement in coal slurry recovery technology in the coal preparation industry. Because of its low investment and operating costs, small and medium-sized coal preparation plants and simple coal preparation plants are also able to use high-frequency screens to recover coal slime, which is also conducive to the realization of closed-circuit coal washing cycles, improving the environment of the coal preparation plant, and is beneficial to the environment. For protection, the high-frequency screen used by the coal preparation plant to recover slime has obvious economic and social benefits. However, with the gradual enlargement of coal preparation plants, the requirements for technical indicators of high-frequency screens have gradually increased, including the requirements for use effect and processing capacity, so gradually improving and perfecting high-frequency screens is the goal that everyone has been pursuing.
Application in reducing silicon and raising iron
The main screening applications of Derek Fine Screen in iron ore separation are as follows:
(1) Reduce the silicon content. This application accounts for approximately 50%. Iron Ore in Minnesota, USA
Most stone concentrators use Derek fine screens to reduce the silicon content of the final iron concentrate. Through wet screening to remove the coarse-grained particles of 53-75 Pm (200-325 mesh), the silicon content of the iron concentrate can be reduced by about 1.0-1.5%. The application cost of fine sieve is much lower than the silicon reduction method using fine grinding or flotation. The following is an example effect of the application of Derek fine screen in iron ore dressing plant to reduce the silicon content: the capacity of the mill is increased by 8%-9%; the energy consumption of grinding is reduced by 9%-10%; the silicon content is reduced by 0.5-1.25 Percentage points. Fine sieve classification to reduce the silicon content by 0.5 to 4.5 percentage points is usually achieved on the basis of increasing the fineness of grinding. Another way to evaluate the performance of the fine sieve is to measure the total silicon removed by the fine sieve. In general, the fine sieve can screen out 50% to 70% of the total silicon content. Another advantage of the fine screen is that precise screening improves the classification efficiency.
(2) Control granularity. Approximately 25% of Derek's fine sieve is used to control the particle size of the product, or to create conditions for the production of high-quality iron concentrates in the subsequent sorting process, or to increase the metal recovery rate under the premise of ensuring the quality of the iron concentrate, mainly including: improving the float The particle size distribution of the selected ore; the particle size control of pellets and sintered ore; the improvement of the particle size distribution of the spiral chute. The coarser the silica particles, the more difficult the flotation. One of the application examples, the flotation process can only remove a small amount of silicon from the fraction larger than 150 mesh. In order to reduce the silicon content in iron concentrates, the amount of flotation reagents had to be increased, which resulted in the loss of a large amount of fine-grained iron concentrates. Before entering flotation, the removal of coarse particles will reduce the consumption of flotation reagents, reduce the loss of fine iron ore, and increase the flotation processing capacity. 40% to 70% of the silicon in the flotation feedstock of the Tieyingite Concentrator is in +325 mesh. For example, a flotation concentrate from a ferrite beneficiation plant contains 8% silicon at +325 mesh; -325 mesh only contains 1.75% silicon. As mentioned earlier, removing coarse materials before flotation will greatly improve the flotation effect.
(3) Grinding and classification. When the fine sieve is used for the grinding and classification of useful minerals and gangue minerals with a large difference in density, the benefits are very significant. The traditional method uses hydrocyclones or spiral classifiers to classify according to the difference in sedimentation speed. However, the density of the mineral itself is different. The sedimentation speed of coarse-grained gangue or conjoined body is similar to that of fine-grained concentrate, while gangue and conjoined body can not be effectively separated and enter the subsequent process. The fine, dissociated useful minerals return to the mill to cause overgrinding. The fine sieve is classified by the geometric size of the sieve holes, which can not only improve the efficiency of the mill and reduce the power consumption of grinding, but also realize the classification of gangue or conjoined body and monomer dissociated minerals. Cyclone classification efficiency is generally 45% to 70%, and spiral classifier is generally 40% to 60% or even lower. Research by authoritative organizations shows that the classification efficiency of most mineral classification equipment is around 50%. If the classification efficiency is increased to 80%, it is expected that the mill processing capacity can be increased by 20%, thereby reducing energy consumption by 15%.