Practical Application Case of TBS Coarse Slime Separator in Gujiao Coal Preparation Plant

With the development of science and technology, China's coal washing technology level has been significantly improved in recent years, and many coal washing processes have been developed very mature. The separation of coarse slime with particle size range of 0.5 ~ 1 mm is a technical problem faced by all coal preparation plants, but the TBS(teeter bed separator) has achieved very good results in the process of practical application, which effectively solved the separation problem of coarse slime.

Today, in this paper, I will share this typical case of TBS application, which helped the coal preparation plant increase its annual profit by $1.5 million.

1.Working principle of TBS coarse slime separator

TBS coarse slime separator is used for separation according to particle size and density. Separation principle: different particles and density of material in the interference of water flow, the sedimentation speed will be different. When the particle and density of the material are larger, the settling velocity is larger, while the settling velocity of the material with smaller particle and density is small.

2.Basic structure of TBS coarse slime separator

This structure of TBS is base on H-CSS series, which is manufactured by Beijing HOT Mining Tech Co Ltd. After upgrading the original TBS, H-CSS series TBS has the following features:

▶Backwater Self-stabilized System

▶Density Stabilizing System

▶Expert Control System

3.Case: H-CSS TBS application in Gujiao coal preparation plant

3.1 Coarse slime separation process and existing problems in Gujiao coal preparation plant

Gujiao coal preparation plant, Shanxi China

You can check the process flow chart of TBS Coarse Slime Separator in Gujiao coal preparation plant above. The slime with particle size less than 1 mm can be divided into two parts after being classified by hydrocyclone, which are slime with particle size less than 0.25 mm and slime with particle size between 0.25 ~ 1 mm. The former is recovered by flotation, while the latter is separated by TBS separator.

Existing problems: The experimental work was carried out on the products of TBS separator. Based on the experimental results, it is found that the recovery rate of some size fractions is relatively low, and the recovery rate of +0.90 mm fraction is 10.2%, which is the lowest among all the size fractions.

In addition, the recoveries of 0.90 ~ 0.45 mm and -0.125mm were 39.22% and 33.76%, respectively, which were at a relatively low level.

The proportion of different density grades in the tailings of TBS separator was further analyzed. The results showed that the cumulative yield and ash content of -1.5g/cm3 density grade were 41.20% and 15.92%, respectively. The results show that there are many combustibles in the tailings which have not been recovered, and there is a serious waste phenomenon.

3.2 Optimization and improvement of coarse slime separation process in Gujiao plant.

Optimized process flow after H-CSS 3600 in Gujiao plant:

The raw coal with particle size ranging from 0 to 50 mm is first deslimed by a desliming screen with 1 mm mesh size, and then separated by a non pressure three product dense medium cyclone. After separation, three kinds of products can be obtained, namely gangue, medium coal and clean coal. The above three products can be obtained by 1 mm demediation and dehydration respectively.

After the desliming screen, the material under the screen and the tailings of the medium coal magnetic separator are all treated by the classification cyclone, and the slime with particles less than 0.25 mm and 0.25 ~ 1 mm are obtained. The slime with particle size of 0.25 ~ 1 mm is separated by TBS interference bed separator, and the obtained clean coal is dehydrated by vibrating arc screen, and then dehydrated by clean coal centrifuge, so as to obtain clean coal products.

For coarse slime, it is first dehydrated by vibrating screen, and then treated by rod mill. The milled products are pretreated and then transported to the flotation machine for flotation. The clean coal products can be obtained by dewatering the flotation clean coal with pressure filter. The flotation tailings can be treated by concentration and pressure filtration process to obtain tailings products.

4.Economic benefits before and after process optimization design.

According to the current market situation of coal products, the price of clean coal and slime is $124/MT and $12/MT respectively.

Before the process optimization and improvement of Gujiao coal preparation plant, the market price of middling coal is about $28/MT because the quality of middling coal is not very good. After the optimization and improvement of the process, the quality of China coal has been significantly improved, and the corresponding selling price has increased to a certain extent, which is $38/MT.

Conclusion: 

According to the data in the table, after the optimization and improvement of the process, the annual sales can be increased by 2 million US dollars. However, after optimization and improvement, the annual production cost of the coal preparation plant is about $500,000.

Compared with before and after optimization, the annual extra income of the coal preparation plant is 1.5 million US dollars. The optimization and improvement of coarse slime separation process has created very good economic benefits for the plant.