CN103464272A - Coarse coal slime two-section water medium sorting method - Google Patents

Abstract

The invention relates to a two-stage water-medium separation method for coarse coal slime, which can be used for the separation and recovery of coarse coal slime in desliming and washing, eliminating the need for traditional coal desliming and washing and the currently popular coarse coal slime separation method. Selecting the link of hydraulic grading simplifies the technological process and saves costs.

Description

A two-stage water media separation method for coarse coal slime

technical field

The invention belongs to the technical field of coal preparation, and in particular relates to a two-stage water-medium separation method for coarse coal slime.

Background technique

In coal preparation technology, according to the way of coal washing, it can be divided into washing with desliming and washing without desliming. The separation and recovery of 2-0.2mm coarse coal slime produced by desliming and washing is the focus and difficulty of coal preparation technology research. It is urgent to select effective separation equipment and formulate a reasonable coarse coal slime separation process. A problem solved.

The process flow for sorting the coarse coal slime in the present invention can be respectively used for sorting and recovering the coarse coal slime in desliming and washing.

The traditional desliming and washing process is that after the raw coal is classified by a 1-2mm sieve, the material under the screen enters the hydraulic grading cyclone for further classification, the overflow in the hydraulic grading cyclone enters the slime water system, and the bottom flow is dehydrated by the high frequency sieve After that, it is mixed into the material on the raw coal grading sieve and fed to the dense medium cyclone for separation. The disadvantages of the above sorting process are: 1. The classification and desliming effect of the hydraulic classifying cyclone is not ideal, because the hydrocyclone has obvious concentration effect while grading, so that a large amount of fine mud is mixed into the underflow and re-enters the heavy 2. Due to the unsatisfactory desliming effect, the dense medium system has high mud content, which not only affects the normal operation of the dense medium system, but also reduces the separation effect, and also affects the magnetic separator. The working effect is that the heavy medium cannot be recovered efficiently, and the medium loss is relatively serious.

The current mainstream desliming and grading washing process is that after the material under the grading sieve is subjected to hydraulic grading, the coarse coal slime is separately treated with a coal slime dense medium cyclone or TBS and other sorting equipment. The disadvantage of the first process is that the introduction of a new dense medium system and medium recovery system makes the coal preparation process more complicated. Not only does the construction investment increase, but also the production management is complicated, the medium recovery is more difficult, the medium consumption increases, and the production cost increases. . The disadvantage of the second process is that the separation accuracy of TBS or spiral chute, which is the main separation equipment for coarse coal slime, is not high enough. The economic benefit of the choice is not ideal.

Contents of the invention

The purpose of the present invention is to solve the two main problems existing in the current coarse coal slime sorting, that is, the hydraulic classification efficiency is not high and the sorting accuracy of the coarse coal slime main sorting equipment is low or the follow-up treatment process is complicated.

Starting from solving the two problems mentioned above, the present invention proposes a two-stage water media separation method for coarse coal slime, comprising the following steps:

In the first step, the raw coal is classified through the desliming sieve with a sieve hole of 0.75mm to 3mm, and the material under the sieve enters the slime tank, and is directly pumped into the coarse coal slime main separation equipment for separation; the material on the grading sieve is fed into the main Sorted in a dense medium cyclone.

In the second step, the main separation equipment for the coarse coal slime is a three-cone water-medium separation cyclone, and after the coarse coal slime is sorted by the three-cone water-medium separation cyclone, the underflow and overflow are processed separately , the Ep( value of the three-cone water-medium separation cyclone in processing materials above 0.2 mm can reach 0.1.

In the third step, the overflow of the three-cone water-medium separation cyclone is dehydrated through the curved screen and the high-frequency screen in turn, and the material on the screen enters the coal slime centrifuge for further dehydration and becomes low-ash clean coal, which is mixed into the clean coal, and the centrifuge The centrifugal liquid enters the slime bucket and returns to the three-cone hydrocyclone for separation; the material under the screen of the curved sieve and the high-frequency sieve enters the slurry preparation device and is further flotation to recover the particle size of less than 0.2mm clean coal. When the clean coal moisture requirement is not strict, the material on the high-frequency sieve can also be directly mixed into the clean coal. The underflow of the cyclone enters the water-medium separation equipment such as TBS or spiral chute for re-separation. The light products produced by TBS or spiral chute pass through the curved screen, high-frequency screen and slime centrifuge in turn to obtain high ash concentrate. Coal, slime water under the curved screen and high-frequency screen, and centrifuge liquid are returned to the slime bucket to enter the three-cone water-medium separation cyclone for further separation. The heavy products produced by TBS or spiral chute, etc. are dehydrated by high-frequency sieve, the material on the screen is used as medium coal, and the material under the screen enters the thickener for processing.

In the fourth step, the under-screen slime water obtained by the overflow of the three-cone water-medium separation cyclone through the curved screen and the high-frequency screen enters the slurry preparation device, and enters the flotation machine for flotation recovery, of which less than 0.2mm Clean coal in particle size fraction. Flotation tailings and heavy products produced by TBS or spiral chute, etc., the under-screen slime water obtained by high-frequency sieve enters the thickener for concentration treatment, and then undergoes pressure filtration dehydration to obtain high-ash slime filter cake. Slime centrifuge centrifuge and light products produced by TBS or spiral chute pass through curved screen and high-frequency sieve, and the under-screen slime water is returned to the slime bucket due to insufficient material self-flow into the flotation position, and then the three-cone water The overflow of the hydrocyclone enters the flotation system for separation.

The sieve hole of the raw coal desliming grading sieve in the first step is 1-2mm; the diameter of the three-cone water-medium separation cyclone is 300mm-750mm.

The sieve hole size of the curved sieve is 0.3mm-0.7mm; the sieve hole size of the high-frequency sieve is 0.15mm-0.45mm; the sieve mesh size of the coal slime centrifuge is 0.20-0.45mm.

The ash content of the low-ash clean coal is less than 9%; the ash content of the high-ash clean coal is less than 13%; the feeding concentration of the three-cone water-medium separation cyclone is lower than 25%; the feeding of TBS (interference bed) and spiral separator The coal slime content of less than 0.2mm particle size is less than 30%. Description of the first step: This step saves the traditional coarse coal slime treatment process and the current popular coarse coal slime treatment process before the coarse coal slime is sorted or processed. It not only avoids the step of hydraulic classification The impact on subsequent processing caused by low efficiency, and it simplifies the process and saves costs.

The second step description: the most critical step, the main separation equipment of coarse coal slime chooses the three-cone water-medium separation cyclone, which can effectively separate the coarse coal slime with a particle size of 3-0.2mm. The test verifies that the possible deviation Ep value of the three-cone water-medium separation cyclone can reach 0.1 when processing materials larger than 0.2mm, and it is a kind of efficient coarse coal slime separation equipment. Even when dealing with extremely difficult coarse coal slime, by changing the size of the cone angle of the conical section, the ash content greater than 0.2mm in the overflow can reach about 8%, so that qualified clean coal can be obtained.

The third step is explained: the overflow of the three-cone water-medium separation cyclone passes through the curved screen and the high-frequency screen for dehydration and desliming, and then the clean coal on the screen is selected according to the actual situation. ) to continue dehydration; for the underflow of the three-cone water-medium separation cyclone, select TBS or spiral chute as the water-medium separation equipment for underflow re-sorting according to the actual situation.

The fourth step description: This step is mainly to classify the under-screen material of the overflow grading sieve (curved sieve and high-frequency sieve) of the three-cone water-medium separation cyclone and the light products produced by the secondary water-medium separation equipment. The sieve (curved sieve and high-frequency sieve) is subjected to flotation to recover the fine-grained clean coal in the particle size of less than 0.2mm.

Beneficial effect:

1. The traditional coal desliming and washing and the current popular coarse coal slime sorting and hydraulic classification are omitted, which simplifies the process and saves costs.

2. The three-cone water-medium separation cyclone was selected as the main separation equipment for coarse coal slime. The three-cone water-medium separation cyclone has the function of classification and separation. With the help of the fine mud in the particle size below 2-3mm and its unique three-cone angle structure, it can effectively separate the materials above 0.2mm in the feed. , so that the materials above 0.2mm in the coarse coal slime do not need to enter the dense medium system for sorting, which is beneficial to the management and normal operation of the dense medium system, and also reduces the load of the dense medium system, leaving room for increasing the washing amount of raw coal. Its separation accuracy is higher than other water media separation equipment, and qualified clean coal products can be obtained;

3. The clean coal separated by the three-cone water-medium cyclone is recovered separately, which reduces the load of the clean coal de-medium sieve, improves the de-medium effect, reduces medium consumption, and reduces production costs;

4. By making the underflow enter the water-medium separation equipment such as TBS or spiral chute, high-ash clean coal is obtained from the underflow, and the high-ash clean coal can be sieved with the overflow grading sieve (curved sieve and high-frequency sieve) The low-ash clean coal is mixed to obtain clean coal with qualified ash content, which further improves the economic benefits of the coal preparation plant.

5. The process of recovering coarse coal slime by the three-cone hydrocyclone is simple and the arrangement is convenient. The cost of technical transformation is low, and the system has been formed, which is more suitable for the technical transformation of old coal preparation plants with compact process layout.

6. The process of overflow grading sieve (curved sieve and high frequency sieve) is introduced into the process, and the flotation process under the sieve is combined with the advantages of low gravity separation cost and low particle size limit of flotation treatment, and the coarse coal is fully recovered The clean coal in the mud maximizes the economic benefits.

7. The two-stage separation can minimize the content of clean coal in coarse and medium coal slime to increase the recovery rate of clean coal. Under the premise of ensuring the ash content of clean coal, the maximum recovery of clean coal is to make reasonable use of limited coal resources and improve the efficiency of enterprises. economic benefits.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail:

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

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention.

As can be seen from Fig. 1, a kind of coarse coal slime two-stage water medium separation method is characterized in that comprising the following steps:

In the first step, the raw coal is classified through the desliming sieve with a sieve hole of 0.75mm to 3mm, and the material under the sieve enters the slime bucket, and is directly pumped into the main separation equipment for separation; the material on the grading sieve is fed into the main separation heavy medium sorted in a cyclone.

In the second step, the main separation equipment for coarse coal slime is the three-cone water-medium separation cyclone. After the coarse coal slime is sorted by the three-cone water-medium separation cyclone, the underflow and overflow are treated separately. The possible deviation Ep value of the above-mentioned three-cone water-medium separation cyclone can reach 0.1 when processing materials larger than 0.2 mm.

In the third step, the overflow of the three-cone water-medium separation cyclone is dehydrated through the curved screen and the high-frequency screen in turn, and the material on the screen enters the coal slime centrifuge (or sedimentation filter centrifuge) for further dehydration and then mixed with clean coal (ie The centrifugal dehydration part in the figure), the centrifuge liquid enters the slime bucket and then returns to the three-cone hydrocyclone for separation; the materials under the arc screen and high-frequency screen enter the slurry preparation device for further flotation To recover the clean coal which is less than 0.2mm in size. When the clean coal moisture requirement is not strict, the material on the high-frequency sieve can also be directly mixed into the clean coal. The underflow of the cyclone enters the water-medium separation equipment such as TBS or spiral chute for re-separation. The light products produced by TBS or spiral chute pass through the curved screen, high-frequency screen and slime centrifuge (or sedimentation filter centrifuge) in turn. machine) to obtain high-ash medium coal, and the slime water under the curved screen and high-frequency screen enters the slurry preparation device for flotation to recover the clean coal in the particle size of less than 0.2mm; the centrifugal liquid of the centrifuge is returned to The slime barrel is sorted again in the three-cone water-medium sorting cyclone. The heavy products produced by TBS or spiral chute, etc. are dehydrated by high-frequency sieve, the material on the sieve is used as high-ash medium coal, and the material under the sieve enters the thickener for processing.

In the fourth step, the under-screen slime water obtained from the overflow of the three-cone water-medium separation cyclone passes through the curved screen and high-frequency screen, and the light products produced by TBS or spiral chute pass through the curved screen and high-frequency screen. The lower coal slime water enters the slurry preparation device, and after being treated with a reasonable chemical system, it enters the flotation machine for flotation recovery of clean coal with a particle size of less than 0.2mm. Flotation tailings and heavy products produced by TBS or spiral chute, etc., the under-screen slime water obtained by high-frequency sieve enters the thickener for dehydration treatment, and then press filter dehydration to obtain high-ash slime filter cake.

The sieve hole of the raw coal desliming grading sieve in the first step is 1-2mm; the diameter of the three-cone water-medium separation cyclone is 300mm-750mm.

The sieve hole size of the curved sieve is 0.3mm-0.7mm; the sieve hole size of the high-frequency sieve is 0.15mm-0.45mm; the sieve mesh size of the coal slime centrifuge is 0.20-0.45mm.

The ash content of the low-ash clean coal is less than 9%; the ash content of the high-ash clean coal is less than 13%; the feeding concentration of the three-cone water-medium separation cyclone is lower than 25%; the feeding of TBS (interference bed) and spiral separator The -0.2mm content is less than 30%.

It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (4)

1. two sections water Jie method for separating of a coarse slime is characterized in that comprising the following steps:

The first step, raw coal is through sieve aperture 0.75mm～3mm desliming screen classification, and undersize material enters the coal slime bucket, directly is driven into coarse slime master screening installation through pump and carries out sorting; The classifying screen on-the-sieve material feeds main separation and heavily is situated between in cyclone and carries out sorting;

Second step, described coarse slime master screening installation is third hand tap water Jie cyclone separator, coarse slime is after the sorting of third hand tap water Jie cyclone separator, and underflow and overflow are processed respectively again, and at the Ep that processes the above material of 0.2mm, (value can reach 0.1 to described third hand tap water Jie cyclone separator;

The 3rd step, the overflow of third hand tap water Jie cyclone separator is successively after sieve bend and high-frequency screen dehydration, on-the-sieve material enters coal slime centrifuge further to be become low ash extract coal after dehydration and sneaks in cleaned coal, and the centrifugate of centrifuge is returned to the sorting of third hand tap water-only cyclone after entering the coal slime bucket; After the undersize material of sieve bend and high-frequency screen all enters into kaskad apparatus for pre-flotation pulp conditioning, further flotation is to reclaim the cleaned coal that wherein is less than the 0.2mm grade; When the moisture of cleaned coal requirement is strict, the on-the-sieve material of high-frequency screen can directly not sneaked into cleaned coal yet, the cyclone underflow enters into water Jie screening installation sortings again such as TBS or spiral chute, light product by generations such as TBS or spiral chutes obtains high grey cleaned coal successively after sieve bend, high-frequency screen and coal slime centrifuge, and under the sieve of sieve bend and high-frequency screen, the centrifugate of black water, centrifuge turns back to the coal slime bucket to enter sorting again in third hand tap water Jie cyclone separator; The heavy product produced by TBS or spiral chute etc. is by after the high-frequency screen dehydration, and on-the-sieve material is as middle coal, and undersize material enters into thickener and processes;

The 4th step, under the sieve that the overflow of third hand tap water Jie cyclone separator obtains through sieve bend and high-frequency screen, black water enters into kaskad apparatus for pre-flotation pulp conditioning, enters into flotation device and carries out the cleaned coal that the flotation recovery wherein is less than the 0.2mm grade; Under the sieve that the heavy product of the generations such as flotation tailing and TBS or spiral chute obtains through high-frequency screen, black water enters into after the thickener concentration and carries out filter-press dehydration again and obtain dirty coal mud filter cake, under the sieve that the light product of the generations such as coal slime centrifuge centrifugate and TBS or spiral chute obtains through sieve bend and high-frequency screen, black water returns and enters the coal slime bucket not because the material gravity flow enters the flotation position, then enters the floatation system sorting by the overflow of third hand tap water-only cyclone.

2. two sections water Jie method for separating of a kind of coarse slime as claimed in claim 1, is characterized in that in the described first step, raw coal desliming classifying screen sieve aperture is 1-2mm; The diameter of described third hand tap water Jie cyclone separator is 300mm-750mm.

3. two sections water Jie method for separating of a kind of coarse slime as claimed in claim 1, is characterized in that described sieve bend screen size is 0.3mm-0.7mm; The high-frequency screen screen size is 0.15mm-0.45mm; The coal slime centrifuge mesh size is 0.20-0.45mm.

4. two sections water Jie method for separating of a kind of coarse slime as claimed in claim 1, is characterized in that described low ash extract coal ash content is less than 9%; High grey cleans ash is lower than 13%; Third hand tap water Jie cyclone separator pan feeding concentration is lower than 25%; Be less than 0.2mm sized coal cement content lower than 30% in TBS (disturbing bed) and spiral pan feeding.

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