Common vacuum filters include a cylindrical external filter vacuum filter, a folding belt type vacuum filter, a cylindrical internal filter vacuum filter, a magnetic vacuum filter and a disc vacuum filter. The selection should be based on the particle size characteristics, specific gravity, concentrate content, pulp properties and required water content of the product.
The cylindrical outer filter has a large vacuum angle and a long dehydration time, and is mainly used for dehydration of flotation concentrate which is relatively fine in size and difficult to precipitate. Due to the low utilization factor of the filter, the filter cake is relatively hydrated. The disadvantage of the external filter vacuum filter is that the equipment is cumbersome and it is difficult to replace the filter cloth.
The belt-type vacuum filter does not discharge the blast, but causes the filter cloth to bypass the discharge roller, and the filter cake is automatically dropped by changing the curvature. Not only is the unloading safer, but it does not require blasting, which avoids the increase in filter cake moisture caused by backwater. The folding belt vacuum filter cleans the filter cloth more thoroughly. Therefore, the belt-type vacuum filter is suitable for the fine-grained concentrate with more mud, especially the filtration of the more viscous flotation concentrate, the efficiency is higher than other types, and the concentrate product has lower moisture. However, the structure of the device is complicated, and operation and maintenance are troublesome.
The cylindrical internal filter vacuum filter filters materials with large particle size, large specific gravity and easy sedimentation, and can obtain thick filter cake and faster filtration speed. The cylindrical internal filter type vacuum filter is mainly used for dehydration of magnetically selected iron concentrate, and the utilization coefficient of the filter is high, and the moisture of the filter cake is low.
The cylindrical magnetic vacuum filter is specially used for dehydration of a class of strong magnetic concentrates of magnetically selected iron concentrates, with high filtration efficiency, low concentrate water and large production capacity.
The disc type vacuum filter has the advantages of large filtration area, small occupied area, easy manufacture, strong adsorption capacity, and the like, and is suitable for processing fine-grain concentrate containing slime, but the product moisture is higher than that of the external filter.
The number of filter tables is calculated according to the following formula:
Where n - the number of filter tables;
Q--The amount of dry concentrate to be filtered, t/h;
F--Selected filter area, m 2 ;
q--Filter utilization factor (handling amount per unit area), t/m 2 • hour. It should be measured directly from industrial tests, semi-industrial tests, or calculated from filtered experimental data. If no test data, refer to similar beneficiation plant selection index, the following table may also be selected. [next]
| Filter unit area processing amount q value |
| Over filter Object material | q (ton / meter 2 · hour) | Prepare Note |
| Fine-grained sulfide ore, zinc oxide lead concentrate | 0. 1~0.15 | Small size when small granularity |
| Lead sulfide concentrate | 0.15 ~ 0.2 | |
| Zinc sulfide concentrate | 0.2 to 0.25 | |
| Copper sulfide concentrates | 0.1 to 0.2 | |
| Copper oxide, nickel oxide concentrate | 0.05~0.1 | |
| Pyrite concentrate | 0.2 to 0.5 | |
| Copper-bearing pyrite concentrate | 0.25~0.3 | |
| Nickel sulfide concentrate | 0.1 to 0.2 | |
| Phosphate concentrate | 0.4 to 0.5 | |
| Molybdenum sulfide concentrate | 0.1 to 0.2 | |
| Antimony concentrate | 0.1 to 0.2 | |
| Manganese concentrate | 1 | |
| Fluorite concentrate | 0.1 to 0.15 | |
| Magnet concentrate | 1.0 to 1.2 | Particle size 0.2 to 0mm |
| Magnet concentrate | 0.8 to 1.2 | Particle size 0.2 to 0mm |
| Roasting magnetic separation concentrate | 0.65~0.75 | |
| Flotation of red iron concentrate | 0.2 to 0.3 | Particle size 0.1 ~ 0mm |
| Magnetic flotation mixed concentrate | 0.4 to 0.6 |
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