In gravity separation, the shaking table (gravity concentrating table) is the most widely used and efficient sorting equipment for fine ore separation.
The shaking table beneficiation can not only be used as an independent beneficiation method, but also is often combined with methods such as jigging, flotation, magnetic separation by centrifugal concentrator, spiral classifier, spiral chute and other beneficiation equipment.
What minerals can be processed by the shaking table?
The shaking table is mainly used for the separation of copper, tungsten, tin, tantalum, niobium, chromium, gold and other rare metal and precious metal ores. In addition, it is widely used in the separation of iron, manganese ore and coal. Before flotation, it was also used in the dressing of nonferrous ores.
Shaking table the most widely used sorting equipment for fine ore separation
It can be used for different operations such as roughing, concentration, sweeping, etc., to separate coarse sand (2-0.5 mm), fine sand (0.5-0.074 mm), sludge (-0.074 mm) and sand with other different particle sizes. It is very effective equipment for selecting fine-grained materials below 1 mm, especially below 0.1 mm.
What are the advantages of shaking table beneficiation?
- The enrichment ratio (the ratio of concentrate grade to raw ore grade) is higher than many other mineral processing methods, up to more than 100 times.
- Qualified concentrate and waste tailings can be obtained just by one separation process.
- The ore is fan-shaped in the bed surface for easy observation and adjustment.
- The products can be taken separately according to needs, so a variety of products can be obtained.
- It consumes no medicine and little power.
What is the structure of the shaking table?
The basic structure of the gravity concentrating table is divided into three main parts: the bed surface, the head of shaking table and the frame.
1. Bed surface
The bed surface can be made of wood, FRP (glass fiber reinforced plastic), metals (such as aluminum, cast iron) and other materials. Common shapes of the bed surface are rectangle, trapezoid and diamond.
Along the longitudinal direction, there are many parallel bed strips or grooves on the surface of the shaking table.
There is a feeding chute on the upper right of the bed surface, the length of which is about 1/3~1/4 of the total length. There are many small holes on one side of the feeding chute, so that the slurry can be evenly distributed on the bed surface.
Connected to the feeding chute is the flushing tank, which accounts for 2/3~3/4 of the total length of the bed surface. Many small holes are made on the side of the tank so that the flushing water can be evenly fed along the longitudinal direction of the bed.
Structure of the shaker table
2. Head of shaking table (driving mechanism)
The head of the shaking table is driven by an electric motor and connected with the bed surface by a pull rod to make the bed surface reciprocate asymmetrically along the longitudinal direction.
- When the bed surface advances, its speed changes from slow to fast and then quickly stops.
- When the bed surface retreats, its speed increases rapidly from zero to the maximum, and then decreases slowly to zero.
3. Frame or append framework
The supporting mode of bed surface can be divided into seated type or suspension type.
- The seated type means that the bed surface is directly connected to the bracket, and a slope adjustment device is installed on the bracket to adjust the lateral slope of the bed surface.
- The suspension type refers to hang the bed surface on the bracket with a wire rope. The bed surface is suspended in the air, and its slope is adjusted by adjusting the tightness of the wire rope.
How does a shaking table work?
When the material flows from the feeding chute to the bed surface, the ore particles are loosened and stratified by the action of water and bed surface vibration in the bed strips or grooves.
The light mineral particles in the upper layer are subject to great impact force, and most of them move downwardly along the bed surface to become tailings. Accordingly, this side of the bed surface is called the tailings side.
Working principle of a shaker table
The heavy mineral particles at the bottom of the bed move longitudinally by differential movement of the bed surface, and are discharged from the opposite of the transmission end to become concentrate. The corresponding position of the bed surface is called the concentrate end.
The horizontal and longitudinal effects of mineral particles of different densities and particle sizes on the bed surface are different. The materials finally spread out in a fan shape on the bed surface, and a variety of products of different quality can be obtained.
The following is a video using the shaking table for goldwire recovery:
How to operate the shaking table?
1. Feeding size
The upper limit of feeding size is 2~3 mm, and the lower limit is 0.037 mm.
2. The amount of feeding ore
The amount of feeding ore is related to the granularity of the feed. If the ore grains are relatively coarse, the required amount of feeding ore is large. However, if it is too large, it will cause zoning problems. In this case, it is necessary to move the concentrate intercepting plate to increase the flushing water and the horizontal slope of shaking table surface.
3. Feeding concentration
In general, the feeding concentration of coarse and fine-grained minerals is 20%-30% and 15%-25% respectively.
- When the rushing rapid occurs on the surface of the shaking table bed, the ore concentration can be appropriately increased.
- If there is a sand pile, the ore concentration needs to be reduced.
4. Partition of bed surface of shaking table
The bed surface is divided into concentrated mine area, middle mine area, tailings area and sludge area.
Bed surface of Fote shaker table
- The width of the sludge area is generally 0.9-1.4 m.
- The ore flow in the tailings area must be stable without rushing rapids, and the ore bed must be covered by water.
- The middle mining area is to separate the middle mine, which is mainly controlled by adjusting the flushing water and the lateral slope.
- The concentrated mine area requires obvious zoning of various specific gravity minerals, so a stable and obvious boundary should be formed between the selected area and the primary selection.
5. Horizontal and longitudinal slope of the bed surface
|Types||Slope of coarse sand area||Slope of fine sand area||Slope of sludge area||Slope of bead surface|
|Installation of equipment||1°～2° (lengthways)||0.5°～1.0°||Basically no||1.5°~5° (Tilt from the feeding side to the opposite side)|
|In actual operation||2.5°～4.5°||1.5°～3.5°||1°～2°||
1. 2 mm: 3. 5°~4°
2. 0. 5 mm: 2. 5°~3. 5°
3. 0. 1 mm: 2°~2.5°
6. Flushing water
The flushing water includes feeding water and washing water.
- During the operation of the shaking table, when the concentrate zone becomes narrow and the concentrate runs into the medium ore, the amount of flushing water shall be reduced.
- On the contrary, if the surface of the shaking table shows anhydrous films, it is necessary to increase the amount of flushing water.
7. Stroke and times of stroke
|Materials||Stroke||Times of stroke|
|Coarse grains in thick bed||Large||Small|
|Fine grains in thin bed||Small||Large|
Fote chromite beneficiation process by strong magnetic separation—shaking table
The Cr2O3 content in a certain lean chromite ore in Zimbabwe is only 8.19%. Fote has conducted research on the beneficiation technology and equipment of the lean chromite ore, finally decided to adopt the beneficiation method: tail discharging by the strong magnetic separation—full-grain separation by shaking table. The indicators are relatively good.
Fote shaking table on working site
- 1 The first step is to crush and grind the chromite ore by using the jaw crusher, cone crusher, ball mill and other equipment, so that the grinding particle size -200 mesh reaches 60%.
- 2 Then use Fote magnetic separator for strong magnetic separation to remove qualified tailings with a yield of 50.21%, and the tailing grade is only 2.19%. As a result, the amount of ore entering the shaking table is reduced by half, and the number of shaking tables is greatly reduced. At the same time, after throwing the tail, it creates favorable conditions for the sorting of the shaking table and further improves the sorting index.
- 3 Then use a shaking table for selection to improve the chromite grade. Finally, the ideal indexes of 39.98% concentrate grade, 13.28% yield, 64.74% chromium recovery and 4.07% SiO2 content can be obtained.