Closed-path grading technology suitable for fine pea coal grading

Abstract

The invention discloses a closed-path grading technology suitable for fine pea coal grading. The closed-path grading technology is established according to characteristics of hydraulic classification hydrocyclone overflow products and underflow products, is adopted to improve a traditional fine pea coal hydraulic classification hydrocyclone technology to make the traditional fine pea coal hydraulic classification hydrocyclone technology suitable for the characteristics of the hydraulic classification hydrocyclone products, and is particularly suitable for the technological transformation of a fine pea coal classifying technology in coal preparation plants with extremely high fine particle material (<=1 mm) content.

Description

technical field [0001] The invention relates to a fine-grained coal grading process, in particular to a closed-circuit grading process suitable for fine-grained coal grading. Background technique [0002] China is the world's largest coal producer and consumer. In 2012, the national coal output was 3.66 billion tons. The environmental problems caused by coal utilization are becoming more and more prominent. Words such as smog, PM2.5 and inhalable particulate matter are often used It has been seen in the newspapers that the increase of suspended particulate matter in the air is closely related to the smoke and gas produced by coal-fired power plants, steel, cement and other coal-fired industries. This has aroused the great attention of the Chinese government and people and the concern of neighboring countries. In order to effectively utilize coal resources and reduce environmental pollution caused by coal burning, clean coal technology must be promoted. The source of clean c...

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Problems solved by technology

The lower limit of TBS sorting machine is 0.25mm, and the upper limit of sorting is 2-3mm. Therefore, high ash fine mud <0.25mm has no sorting effect in TBS, and the part of high ash fine mud in the feed enters the overflow of TBS with the rising water flow. In the process, the clean coal is polluted, and even the quality of the final clean coal product does not meet the requirements; ③The classification of the fine-grained coal by the hydraulic grading cyclone is not strictly classified according to the particle size, and some of the coarse-grained particles enter the overflow, and then into the flotation machine

The separation upper limit of the flotation machine is 0.25mm, so the particles >0.25mmd have no sorting effect in the flotation machine, and enter the tailings of the flotation machine, that is, the phenomenon of "running coarse", which causes clean coal The reduction of production rate; ④The technical improvement of replacing the hydraulic classification cyclone group with the cyclone classifying screen can improve the classification efficiency, but the cyclone classifying screen is still a combined equipment of centrifugal force classification and screening classification, centrifugal force classification It is still not possible to classify strictly according to the particle size, which cannot guarantee the efficient sorting of subsequent operations; ⑤ The coarse slime sorting equipment represented by the American Derek high-frequency vibrating fine screen can efficiently remove high-ash fine mud To ensure the ash content of the product, but because it is imported equipment with original packaging, there are problems such as huge capital investment and inconvenient equipment maintenance.

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