Method for extracting ultra-low-ash-content pure coal from coal slime

Abstract

The invention discloses a method for extracting ultra-low-ash-content pure coal from coal slime. The method comprises the following steps: ball-milling slurrying, specifically, milling coal slime until particles with less than 200 meshes occupy more than 90%, and controlling the mass percent concentration of the coal slime slurry to be 10-35%; grading, specifically, conveying the particles with less than 200 meshes to a flotation step; flotation, specifically, adding a collecting agent, a foaming agent and an inhibitor in the obtained coal slime slurry, uniformly mixing, and carrying out one-time rough flotation, two sections of three-to-six-time fine flotation and one section of three-to-six-time scavenging to obtain refined coal slurry I, refined coal slurry II and tailing coal slurry respectively; and dehydration, specifically, adding a flocculant in the refined coal slurry I, the refined coal slurry II and the tailing coal slurry which are obtained through the flotation, carrying out flocculation settling, then dehydrating by virtue of an ultrahigh-pressure pressure filter, and controlling a pressure filter pressure to be 4.5-5.5Mpa, thus obtaining ultra-low-ash-content pure coal products, common refined coal products and tailing coal products. The method disclosed by the invention is simple in process flow, and capable of efficiently extracting the ultra-low-ash-content pure coal products from the coal slime; and moreover, the water contents of the obtained coal products are low and can achieve less than 15%, thus the coal products have remarkable economic benefits and environmental protection value.

Description

technical field [0001] The invention relates to the technical field of coal slime separation, in particular to a method for extracting ultra-low ash pure coal from coal slime. Background technique [0002] At present, the current situation of coal slime is that the coal washing process in my country is mainly jigging-flotation combined process, dense medium-flotation combined process and jigging-dense medium-flotation combined process. These washing processes generally produce about 15% coal slime. [0003] Coal slime is a viscous substance composed of fine-grained coal, pulverized bone stone and water. It has the characteristics of fine particle size, high particle content, high moisture and ash content, low calorific value, strong cohesiveness and strong cohesion. Due to its relatively high ash, sulfur and moisture content, it is difficult to be directly used, and even if it is used, it is difficult to obtain good economic benefits. It has been rejected by power users for...

AI Technical Summary

Problems solved by technology

Due to the long process flow, many steps, and chemical treatment involved in this method, the environmental protection cost is high, so the total cost is relatively high.

In addition, due to the needs of the process, the particle size of the clean coal products produced by the above methods is very fine, and dehydration is very difficult. The moisture content of the obtained clean coal products is generally about 30%, or even higher, resulting in a waste of transportation resources and increasing the cost of the enterprise. Coal Transportation Costs

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