CN102211054B - Process for sorting coarse coal slime by utilizing heavy medium liquid-solid fluidized bed - Google Patents

Abstract

The invention provides a process for sorting coarse coal slime by utilizing a heavy medium liquid-solid fluidized bed. The process provided by the invention comprises the following steps: pouring a dilute medium of screenings screened by a clean coal medium-removing and dewatering screen and a part of the medium in a current divider box into a coarse coal slime sorting feed barrel; introducing a medium in a heavy medium system into the feedings of a liquid-solid fluidized bed coarse coal slime sorter; after the feedings are sorted by the liquid-solid fluidized bed coarse coal slime sorter, adding a magnetic separator recovery medium into overflows and underflows, wherein the added heavy medium can be used for weakening the influence of granularity to interference settlement, and strengthening the effect for sorting materials according to density, so that the sorting precision of the liquid-solid fluidized bed coarse coal slime sorter within a wide grain range can be improved, and the recovery ratio of coarse clean coals is greatly improved on the premise of ensuring the ash content of the coarse clean coals; simultaneously, the grain processing range of the liquid-solid fluidized bed coarse coal slime sorter is expanded; and the processing capacity of reselection is improved, and the flotation cost is reduced.

Description

Separation of Coarse Coal Slime in Dense Medium Liquid-solid Fluidized Bed

technical field

The invention relates to a dense medium liquid-solid fluidized bed separation process for coarse coal slime, and is especially suitable for ash reduction and desulfurization of 3-0.25mm coarse coal slime in the coal wet separation process.

Background technique

At present, most coal preparation processes use a combination of non-graded gravity separation + coarse slime separation + flotation. According to the national standard GB/T7186-1998, coarse coal generally refers to coal particles of 2mm-0.25mm, which are located between gravity separation and flotation. In the vicinity of the separation particle size limit (generally 0.5mm), this part of the slime is generally separated by a slime dense medium cyclone, a spiral separator and a liquid-solid fluidized bed coarse slime separator. When the dense medium cyclone sorts coarse coal slime, it is greatly affected by the working conditions of the large-diameter cyclone, the separation effect is poor, and the feeding pressure of the equipment is high, and the equipment wears seriously. When the spiral separator sorts coarse coal slime, the sorting density is high and cannot be adjusted, and the sorted clean coal has a high ash content. The liquid-solid fluidized bed coarse slime separator relies on the low separation density and can be controlled and adjusted. The requirements for the feed concentration are generally not strict, and the advantages of low power consumption have become one of the equipments that can effectively separate coarse slime.

The liquid-solid fluidized bed coarse slime separator is a kind of coal slime fluidized by rising water flow, relying on the coal slime itself as a medium to form a bed with a certain density, and the coal slime is sorted according to a certain interference settlement speed. The interference settling velocity is related to the particle size and density properties of the particles. When the narrow particle size is sorted, the interference settling velocity is less affected by the particle size, the bed density is stable, the material is sorted according to the density, and the sorting accuracy is high. When sorting with a wide particle size, the disturbing sedimentation velocity is greatly affected by the particle size, the bed density is unstable, the materials cannot be sorted strictly according to the density, and the sorting accuracy is reduced. The general liquid-solid fluidized fluidized bed coarse coal separation process in actual production is that the clean coal magnetic separation tailings or the undersize of the desliming screen in the dense medium separation process enter the liquid-solid fluidization after being classified by a classifying cyclone. Bed coarse coal slime separator, in this process, the upper limit of the separator is determined by the sieve holes of the desliming sieve and the desliming sieve in the gravity separation process, and the lower limit of the separation is determined by the classifying cyclone Yes, due to the low classification efficiency of the classifying cyclone, the separation particle size range of this process is relatively wide. In the process of wide particle size separation, high-density fine particles will enter the overflow to pollute the clean coal, and low-density coarse particles will enter the underflow to become tailing coal, resulting in low recovery rate of clean coal, high ash content of clean coal, low separation accuracy, and low separation accuracy. At the same time, due to the poor separation effect of the liquid-solid fluidized bed separator in wide particle size, the processing capacity of re-election is limited, and the cost of flotation is high.

technical content

Technical problem: the purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a kind of heavy coal with low clean coal ash content, high sorting precision and good sorting effect when sorting 3mm-0.25mm coarse coal slime. Medium liquid-solid fluidized bed separation process for coarse coal slime.

Technical solution: The dense medium liquid-solid fluidized bed separation process for coarse coal slime of the present invention: including desliming or not desliming the raw coal, the raw coal after desliming or the raw coal without desliming and the medium in the medium barrel enter the three products Sorting is carried out in the dense medium cyclone, and the separated clean coal, medium coal and gangue are separated and dehydrated respectively. The clean coal dehydration screen is dewatered, and the medium under the screen enters the shunt box for diversion. The clean coal on the clean coal dehydration screen enters the clean coal dehydration equipment for dehydration and is discharged. The clean coal dehydration screen undersize The qualified medium and a part of the medium Ⅰ in the split box enter the combined media barrel together;

The thin medium of the undersieve of the clean coal de-intermediation and dehydration screen and another part of the medium II in the split box enter the coarse coal slime sorting into the bucket; the coarse coal slime sorting into the coal medium mixture into the bucket enters the classification Classification in a cyclone;

The overflow fine material classified by the grading cyclone enters the magnetic separator for magnetic separation, the concentrate after magnetic separation of the magnetic separator enters the mixing barrel, and the tailings after magnetic separation enters the flotation equipment for flotation;

The underflow coarse material classified by the classifying cyclone enters the liquid-solid fluidized bed coarse slime separator for separation, and the overflow from the liquid-solid fluidized bed coarse slime separator enters the clean coal magnetic separator Magnetic separation, the magnetic separation concentrate enters the mixing barrel, the magnetic separation tailings are dehydrated by the clean coal slime classification dehydration equipment, the dehydrated clean coal is discharged, and the clean coal slime water enters the flotation equipment for flotation;

The underflow from the liquid-solid fluidized bed coarse slime separator enters the China Coal Magnetic Separator for magnetic separation, and the magnetically separated concentrate enters the media barrel. The medium coal is discharged, and the medium coal slime water enters the concentrated filter press equipment for concentrated filter press.

Beneficial effects: the dilute medium of the clean coal de-intermediation and dewatering screen undersize and part of the medium in the splitter box enter the coarse coal slime sorting and feeding barrel, and pass through the liquid-solid fluidized bed coarse coal slime sorting machine. The medium in the dense medium system is introduced into the feed, and after liquid-solid fluidized bed separation, the corresponding overflow and underflow of the liquid-solid fluidized bed coarse slime separator increase the magnetic separation recovery medium, because the added heavy medium weakens the The effect of particle size on disturbing settlement, strengthening the separation of materials according to density, reducing the mismatch of high-density fine particles and low-density coarse particles, can improve the performance of liquid-solid fluidized bed coarse coal slime separator in a wide range of particle sizes The separation accuracy greatly improves the recovery rate of coarse and clean coal under the premise of ensuring the ash content of coarse and clean coal. At the same time, the processing particle size range of the liquid-solid fluidized bed coarse coal slime separator is extended. When the pre-sliming is used, the sieve hole of the desliming screen can be increased, and the desliming efficiency and the three-product dense medium cyclone can be improved. When using no desliming before selection, the sieve of the desliming sieve can be increased to reduce its media consumption; the liquid-solid fluidized bed coarse coal slime separator can improve the separation effect of fine particles, which can reduce the floating The upper limit of the effective separation particle size of the separation separation can reduce the amount of slime entering the flotation and reduce the cost of flotation.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Detailed ways

Embodiments of the present invention will be further described below in conjunction with the accompanying drawings:

Implementation 1. When the particle size of the raw coal is less than 0.5mm and the content is lower than 20%, it is not necessary to deslim the raw coal 1. The separation process steps are as follows:

a. The raw coal that is not deslimed and the medium in the medium barrel 22 enter the three-product dense medium cyclone 3 for separation, and clean coal, medium coal and gangue are selected respectively, and the medium coal that is sorted out enters the medium coal de-medium Dehydration equipment 4, the sorted gangue enters the gangue dehydration equipment 7;

b. The clean coal selected by the three-product dense medium cyclone 3 points into the clean coal arc screen 5 for pre-demediation, and the mixture on the arc screen 5 enters the clean coal de-intermediation and dehydration screen 7 for de-intermediation and dehydration, and the under-screen medium enters Shunt in the shunt box 8;

c. The clean coal on the screen of the clean coal dehydration screen 7 is dehydrated and discharged by the clean coal dehydration equipment 9. The qualified medium of the undersize of the clean coal dehydration screen 7 and a part of the medium I under the splitter box 8 enter the mediation barrel 22 Inside, the qualified undersize medium of the clean coal de-mediation and dehydration screen 7 and another part of the medium II under the shunt box 8 enter the coarse coal slime sorting into the material barrel 10;

d. Coarse slime is sorted into the coal-medium mixture in the material tank 10 and transported to the classifying cyclone 11 through the pump for classification;

f. The fine particles from the classification overflow of the classifying cyclone 11 enter the magnetic separator 15 for magnetic separation, the magnetically separated concentrate enters the joint barrel 22, and the magnetically separated tailings enter the flotation device 21 for flotation;

g. The fine particles from the classification overflow of the classifying cyclone 11 enter the liquid-solid fluidized bed coarse coal slime separator 12 for separation, and under the action of disturbing sedimentation, the low-density particles rise to overflow and enter the clean coal magnetic separator 14 Magnetic separation, the magnetic separation concentrate of the clean coal magnetic separator 14 flows back into the media barrel 22, the magnetic separation tailings enter the clean coal slime classification dehydration equipment 17 and discharge the clean coal 20 after dehydration, and the dehydrated clean coal slime water enters the buoy Flotation in the selection equipment 21;

h. After the fine particles in the classified underflow of the classifying cyclone 11 enter the liquid-solid fluidized bed coarse slime separator 12 for separation, under the action of disturbing sedimentation, the low-density particles settle and become the underflow, and enter the medium magnetic separator 13. The tailings through the medium coal magnetic separator 13 magnetic separation flow back to the joint barrel 22, and the magnetic separation tailings enter the medium coal slime classification dewatering equipment 16 for dehydration, and then discharge the medium coal 18, and the medium coal slime water after dehydration Enter the concentrated filter press equipment 21 to carry out concentrated filter press.

Implementation 2. When the particle size of the raw coal is less than 0.5mm and the content is greater than 20%, the raw coal 1 needs to be deslimed. Firstly, the raw coal 1 is introduced into the desliming screen 2 for desliming, and the raw coal on the sieve after desliming enters the tertiary heavy medium cyclone 3 for separation, and the undersieve coal slime water after desliming enters the coarse coal slime separation Enter in the material bucket 10; Subsequent technology is identical with implementation one, omits.

Claims (1)

1. A dense medium liquid-solid fluidized bed coarse coal slime separation process, including desliming or not desliming the raw coal (1), when the particle size of the raw coal is less than 0.5mm and the content is less than 20%, there is no need to deslim the raw coal (1) Desliming. When the particle size of the raw coal is less than 0.5mm and the content is greater than 20%, the raw coal (1) needs to be deslimed; the raw coal after desliming or the raw coal without desliming and the medium in the medium barrel (22) They enter the three-product dense-medium cyclone (3) for separation, and the separated clean coal, medium coal and gangue are separated and dehydrated respectively, and the clean coal enters the clean coal curved screen (5) for pre-dehydration. medium, the mixture on the sieve after de-intermediation in advance enters the clean coal de-intermediation and dehydration screen (7) for de-intermediation and dehydration, and the medium under the sieve enters the shunt box (8) for diversion, and the clean coal de-intermediation and dehydration screen (7) sieve The clean coal enters the clean coal dehydration equipment (9) and is discharged after dehydration, and the qualified medium of the undersize of the clean coal dehydration screen (7) and a part of medium I in the splitter box (8) enter the combined media barrel (22); It is characterized by: The dilute medium of the undersize of the clean coal de-intermediation and dehydration screen (7) and another part of the medium II in the split box (8) enter the coarse coal slime into the material bucket (10); Coarse slime sorted into the material tank (10) and the coal-medium mixture enters the classifying cyclone (11) for classification; the overflow fine material classified by the classifying cyclone (11) enters the magnetic separator (15) Magnetic separation, the concentrated ore after magnetic separation by the magnetic separator (15) enters the joint barrel (22), and the tailings after the magnetic separation enters the flotation device (21) for flotation; The underflow coarse material classified by the classifying cyclone (11) enters the liquid-solid fluidized bed coarse slime separator (12) for separation, and the liquid-solid fluidized bed coarse slime separator (12) separates The overflow of the overflow enters the clean coal magnetic separator (14) for magnetic separation, the magnetic separation concentrate enters the joint barrel (22), the magnetic separation tailings are dehydrated by the clean coal slime classification dehydration equipment (17), and the dehydrated clean coal is discharged , the clean coal slime water enters the flotation equipment (21) for flotation; The underflow from the liquid-solid fluidized bed coarse slime separator (12) enters the medium coal magnetic separator (13) for magnetic separation, and the magnetically separated concentrate enters the mixing tank (22), and the magnetic separation tailings pass through the medium coal The coal slime graded dehydration equipment (16) dehydrates, and the dehydrated medium coal is discharged, and the medium coal slime water enters the concentrated filter press (19) equipment for concentrated filter press.

Images