Planktonic election of coal, is currently the most effective method of fine coal sorting. The difference in surface properties of coal particles and mineral impurities is used as the basis for sorting. Coal slurry water treatment is an important and complicated process management system for coal preparation plants: it is related to the economic and technical indicators of coal preparation plants and also affects environmental protection. With the increasingly strict environmental requirements, higher standards have been proposed for wastewater treatment. Flotation and tailings treatment is one of the most effective ways to achieve a closed cycle of washing water in a coal preparation plant.

1 five elements in the flotation operation

This is the basic principle that the flotation driver must master. 1. Coal. First of all, we must be familiar with the characteristics of coal. The nature of coal is closely related to the difficulty of flotation. The hydrophobicity of coal surface and the degree of coal metamorphism are the internal factors for measuring the floatability of coal; the coal with good buoyancy has a faster flotation rate, good quality of clean coal and high yield. 2. Water. With water, the coal is moist. The quality of the slurry is directly affected by the level of the concentration of the float and the quality of the product. 3. Gas. Bubbles are carriers of hydrophobic ore movement. In order to increase the chance of collision between the ore particles and the bubbles, conditions for adhesion are formed, and the hydrophobic ore particles are carried to the liquid surface in time, and there must be sufficient gas-liquid interface in the flotation machine. Only the proper amount of aeration, the air dispersion is good, the bubbles are evenly distributed in the flotation cell, and the more chances that the ore particles will collide with the bubbles, the better the process performance of the flotation machine. 4. Medicine. Also known as flotation agent, it can be divided into foaming agent and collection. The foaming agent can reduce the surface tension of the liquid-gas interface to generate enough bubbles; the collection and collection is to improve the hydrophobicity of the mineral surface: one is to improve the adhesion of hydrophobic minerals and bubbles; the other is to increase the adhesion of hydrophobic ore particles to the bubbles. The degree of firmness. 5. Machine. The quality of flotation is inseparable from the performance of flotation machines. In order to make the ore particles have the energy required to fully contact the bubbles, the slurry should be fully agitated so that all the solid particles are in suspension; a relatively stable foam layer is formed on the flotation liquid surface and maintained at a sufficient thickness to make it more significant. The 2 times of enrichment, the foam is finally scraped out of the flotation machine.

2Floating scraping and adjustment of slurry level

(1) To make a bubble, it is necessary to master the change rule of foam ash in each room. The first two chambers have low foam ash and a thick foam layer, which should be scraped. As the flotation progresses, the foam ash increases and the foam layer becomes thinner, and the amount of foaming is reduced. It should be noted that when the foam ash is high, the medicine is not able to keep up, and the foam is after the string, do not take the operation method of the rear string less scraping. In doing so, it only delays the time of foaming; after the foam, the higher the ash, the higher the flotation of low-ash coarse coal, which causes the tailings to run coal.

(2) Scraping is to ensure 2 enrichment of the foam layer of each chamber. Its 2 enrichment helps to improve the dewatering and de-slurry effect of the foam layer and change the quality of the clean coal. The foaming speed is fast, the foam residence time is short, the mud removal and dehydration are sufficient; the foaming speed is slow, the foam is accumulated, the foam layer is thicker and thicker, the dehydration and desilting are not carried out, and the foam of the rear string is affected to float.

(3) Scraping should create conditions for the filtration and dehydration of the foam. Foam is the raw material for filtration and directly affects the working effect of the filter. The solids content of the foam has a great influence on the filtration effect. At the same time as the secondary enrichment in the foam layer, de-sludge, dehydration occurs, and the foam is concentrated. This creates conditions for the filtration and dehydration of the foam.

(4) When scraping, please listen carefully to the scraper. If there is rustling, the liquid level is normal; if there is a squeaking sound, the scraper is scraped to the slurry surface, and the liquid level should be adjusted immediately. The specific operation is: reduce the tailings discharge gate to ensure that the scraper can not scratch the liquid surface.

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