The Comparasion of Traditional Teetered Bed Separator (TBS)  

and Three-product TBS

Author：

Heng Huang, MAusIMM, MD of HOT Mining

Dongxu Fu, Professor (Senior Engineer)

Application status of traditional TBS

Traditional teetered bed separator (TBS) is one major device of dealing with coarse slime nowadays, with a great appreciation of only circulating water used as power source without other medium, low investment, low operating cost, perfect automation control and easy layout.

Coal slime could be only separated into two products at a time using traditional TBS; when to-be-treated material contains more than 20% middle density fraction, the separation performance gets lower with high clean coal loss in underflow. These mentioned disadvantages limited the application of TBS. Meanwhile, due to effect of equal settling particles, when the feed has wide size fraction, mineral particle with high density and small size goes into overflow, which leads to stringent requirements of the following dewatering; sometimes it will determines the total separation performance of coarse slime separation.

Even so, TBS is still irreplaceable nowadays due to its advantages and has widely used to tackle raw coal slime, magnetic separation tailings, slime of jig clean coal and so on. The main advantages could be concluded into the following two aspects:

• 1) With the use of TBS, the flowsheet of “first classifying by size and then separating by density” is achieved to reduce the effect of size on the density-based separation to maximum extent, thus improving the total separation efficiency of whole size material. The flowsheet that the whole size raw coal without classification is separated using jig or heavy medium separation technique accounts for most in coal preparation plant in China before 2008[7]. Except some plants with high quality coal, under normal circumstance, slime of jig clean coal or magnetic separation tailings of clean coal has more ash content than total clean coal, average 2%, in worse case as high as 10%[2], which is called “carrying ash” phenomena. Reconstruction of these preparation plants with original technique is usually carried out with the use of TBS, or slime of jig clean coal and magnetic separation tailings is separated again using TBS, removing +1.6 kg/l fraction and eliminating “carrying ash” phenomena, thus improving clean coal quality and total benefit. In another case, pre-desliming of raw coal before separation is performed to achieve jig separation or heavy medium separation without coal slime. No matter which form is adapted, coarse slime separation is carried out by itself.

• 2) The flowsheet of desliming of raw coal + TBS separation of raw coarse slime+ heavy medium separation has been widely used in a lot of new-built separation plants. Comparing with original flowsheet, the new one has a great appreciation due to high magnetic material content and low viscosity in qualified medium, low separation size and obvious low medium loss with the same equipment of recycling medium.

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Introduction of three-product TBS

The parameters affecting separation performance of TBS could be summarized into four aspects, that’s, washability of coal, size range of feed, dewatering and desliming performance of the following procedures and performance of the device. Due to its intrinsic property of producing two products, when treating +1mm material with all the same four parameters above, TBS has lower separation efficiency than heavy medium cyclone, with the least probable error value (Ep) 0.071. Therefore, it’s important to develop coarse slime separator which utilizes all kinds of advantages and produces three or more products, leading to the perfection of the “irreplaceable technology at present” to maximum extent. Under the circumstance, three-product teetered bed separator comes into being.

Three-product or more-product teetered bed separator, developed on a basis of traditional TBS technology, is authorized to be manufactured by national invention patent with complete intellectual property, and is also called three products separator, labeling as TPS.

Two kinds of TPS were invented, type I and type II.

TPS with type I is comprised of two or more barrels with the same central axis. Taking two barrels as an example, it’s named inner barrel used for first stage of separation and outer barrel used for second stage. Feed goes into inner barrel via feed well, and the first upwards water is moving from the bottom of inner barrel, thus producing the first teetered bed layer with material from feed well.

High density particle settles through the first teetered bed layer and discharged from the outlet at the bottom of inner barrel as product (1), and the light particle goes upwards into the outer barrel. Meanwhile, the second upwards water is going up from the bottom of outer barrel and mixing with the particles in overflow of inner barrel and forming the second teetered bed layer. The heavy particle sinks and discharges from the outlet of outer barrel as product (2), and the light particle goes up and concentrates as product (3). After separation of first stage and second stage, three products are obtained, that’s, underflow of first stage, underflow of second stage and overflow of second stage, which is illustrated as Figure 1.

      1. Overflow tube;

2. Water spray nozzle; 

3. Feed well; 

4. Outer water feeding tube；

5. Outer water feeding circular belt;

6. Overflow box; 

7. Outer barrel; 

8. Guide barrel; 

9. Inner barrel; 

10. Discharge actuator; 

11. Handrail; 

12 Platform;

More information about TPS contact us：

Kira     email：kira.zhang@hot-mining.com     Tel/WA:+86 15281051932

Teresa   email: teresa.zheng@hot-mining.com   Tel/WA:+86 15281626323