One of our customers doesn’t have pre leaching thickener, thus, he is not able to filter out the water added during the flotation. Without filtering the water, fresh raffinate added is huge and neutralizing the additional raffinate becomes impossible and not viable.
Then we are comparing different solutions, final solution is by Deep Cone Thickener for cost saving, fresh water saving and easy operation.
1. Acidic Grinding Modification of Ball Mill
If the ball mill is modified for acidic grinding, all downstream equipment in contact with the acidic slurry (including the spiral classifier, agitation tanks, pipelines, and pumps) will also need to be modified or replaced.
From the investment perspective, the cost of acidic grinding modification is relatively high. In terms of operational references, there are very few cases of acidic ball mill modification, and it is still uncertain whether there may be any additional adverse impacts.
Considering all factors comprehensively, we currently do not recommend carrying out acidic grinding modification for the ball mill.
2. Dewatering by Water Pond
Second, if a water pond settling system is adopted for dewatering, the required footprint will be relatively large, with at least 3–4 large settling ponds needed. Slurry is directed into the emptied pond by manually opening and closing valves. After the slurry in the corresponding pond is dewatered to a concentration of approximately 70%–75%, loaders are then used to repeatedly transfer the slurry among the ponds.
The overall production and operation process is relatively complicated; therefore, this solution is not recommended.
3. Dewatering by Thickener
Dewatering can be carried out using a thickener, which has a small footprint and a relatively simplified overall process. Slurry transfer between stages is handled by slurry pumps, making manual operation relatively easy and less labor-intensive.
4. Deep Cone Thickener Comparison
Compared with a conventional high-rate thickener, a deep cone thickener can achieve a higher underflow solids concentration, thereby reducing fresh water consumption and decreasing the generation of acidic process water in the hydrometallurgical system.
Assuming the feed slurry contains 60 t/h of solids at a solids concentration of 30 wt%, the comparison is shown below:
| Item | Conventional High-Rate Thickener | Deep Cone Thickener |
|---|---|---|
| Feed solids | 60 t/h | 60 t/h |
| Feed slurry concentration | 30 wt% | 30 wt% |
| Underflow solids concentration | 50 wt% | 60–65 wt% |
| Recovered water volume | 80 m³/h | 100–107.6 m³/h |
| Required fresh water make-up | 60 m³/h | 40 m³/h |
| Acidic process water generation | Higher | Lower |
| Operating cost impact | Higher | Lower |
| Overall performance | Standard | Recommended |
Calculation Basis
- Conventional High-Rate Thickener
Recovered water volume:
80 m³/h
Calculation:
60/0.3−60/0.5=80 m³/h
Required fresh water make-up:
60 m³/h
Calculation:
60/0.5−60=60 m³/h
- Deep Cone Thickener
Recovered water volume:
100–107.6 m³/h
Calculation:
60/0.3−60/0.6=100∼107.6 m³/h
Required fresh water make-up:
40 m³/h
Calculation:
60/0.6−60=40 m³/h
Overall Comparison
The comparison clearly demonstrates the advantages of a deep cone thickener in slurry dewatering and water recovery. A deep cone thickener increases recovered water volume from approximately 80 m³/h to 100–107.6 m³/h and reduces fresh water demand from 60 m³/h to 40 m³/h, achieving about a 33% reduction in fresh water consumption. Lower fresh water usage also decreases acidic process water generation in the hydrometallurgical circuit, reduces operating costs, and improves overall process efficiency. For SX-EW pre-leaching applications that require better water balance and lower operating costs, a deep cone thickener provides a more efficient and practical solution.
