Hybrid lines
Hybrid lines
Considering the importance of reducing water consumption and power consumption, the evaluation plan for the construction of a combined dry and wet concentrate production plant was defined with the following goals:
1. Maximum reduction of water consumption per ton of produced concentrate
2. Feedability in the range of magnetite and hematite feeds
3. The ability to use low grade stones and mine tailings as feed
4. Reduction of harmful environmental effects
5. Achieving the technology of producing concentrate by hybrid method
6. Reduction of pellets consumed per ton of concentrate produced
7. Reducing the required power consumption in the grinding section due to the combination of HPGR and special magnetic separation and finally reducing the total power consumption per ton of concentrate produced
8. Removing a major part of waste in a dry form
9. Reducing the cost of investment in the dewatering sector
Water consumption
Liter / ton of product
The grade of the final product
Percent
Concentrate production capacity
tons/year
Sizing of incoming feed
0-30 mm
Input feed grade
35-50%
Factory operation
hours / year
In general, three feed samples with different characteristics were considered as samples for the experiments. The selection criteria of these samples were:
Variety of iron content in feed
Variation of iron oxide grade in the feed (hematite or magnetite of the feed)
Extracted feed from the mine and such dry processing tailings
Therefore, the following feeds were selected with the specifications mentioned in the following table:
| Description | Oxide grade | Grade | Sample source | Sample |
|---|---|---|---|---|
| 6-8 | 48.7% | Tail of the second stage of processing | Sample number 1 | |
| The initial grade is 26% with a magnetite grade of 10%, which was upgraded to 43.5% after crushing to 10 mm and magnetic separation | 6 | 26%, after pre-processing 43.5% | Final tail | Sample number 2 |
| After a step of crushing to 15 mm and magnetic separation, the grade was upgraded from 41 to 46.75 | 9-11 | 41% after pre-processing 75.46% | Extracted feed from placer mine after pre-processing | Sample number 3 |
Two general arrangements were used to perform the tests in the dry section.
1. Magnetic separation in one step
2. Magnetic separation of waste obtained from the separation of the first stage and returning the product as feed to HPGR (use of Sconger design)
These two modes were investigated for all three samples. Finally, layout 1 for the first and third samples and layout 2 for the second sample were selected as the optimal flowcharts.
The results are summarized in the following table:
| Weigh-dry recovery | Iron recovery | Tail grade | Product grade-dry | Feed grade | Sample |
|---|---|---|---|---|---|
| %73.56 | %94.40 | %10.30 | %62.50 | %48.70 | Sample number 1 |
| %64.39 | %89.11 | %13.20 | %60.20 | %43.50 | Sample number 2 |
| %67.37 | %88.34 | %11.79 | %61.30 | %46.75 | Sample number 3 |
Results and block diagram of sample number 1 + Scavenger
| Sample number 1 + Scavenger | Sample number 1 | Sample |
|---|---|---|
| %48.70 | %48.70 | Feed grade |
| %60.50 | %62.50 | Product grade-dry |
| %4.51 | %10.30 | Tail grade |
| %95.46 | %94.40 | Iron recovery |
| %76.86 | %73.56 | Weigh-dry recovery |
Results and block diagram of sample number 2 + Scavenger
| Sample number 2 + Scavenger | Sample number 2 | Sample |
|---|---|---|
| %43.50 | %43.50 | Feed grade |
| %60.20 | %63.0 | Product grade-dry |
| %10.89 | %22.30 | Tail grade |
| %89.11 | %75.44 | Iron recovery |
| %64.39 | %52.09 | Weigh-dry recovery |
Implementation of Hybrid Iron Ore Beneficiation Plant
Process Equipment list with main specification for samples 2 & 2 + Scavenger
| Power of single item(kW) | Remarks | Quantity | Type | Equipment name | NO. |
|---|---|---|---|---|---|
| 15kw | Pre processing | 6set | Dia.=1200mm, L=2000mm , MF=3500GS | Magnetic Separators | 1 |
| 1200kw | For preliminary grinding | 1set | Dia.=1700mm, L=1200mm | HPGR | 2 |
| 45kw | 2set | Aps=3mm, W=3000mm, L=9000mm | Vibrating screen | 3 | |
| 45kw | For dry separation | 6set | Dia.=1200mm, L=2000mm, MF=3500GS | Magnetic separator | 4 |
| 22kw | Scavenging | 6set | Dia.=900mm, L=2000mm, MF=3500GS | Magnetic separator | 5 |
| 3300kw | For secondary grinding | 1set | Dia.=4600m, L=7800, P=3350kW | Ball mill | 6 |
| 8set | D=20 | Hydrocyclone | 7 | ||
| 66kw | For wet separation-in two lines | 6set | Dia.=1200mm, L=3000mm, MF=2700GS | Magnetic separator | 8 |
| 270kw | De-watering of concentrate | 2set | W=2500mm, L=25000mm | Vaccum belt filter | 9 |
| 3.3kw | De-watering of tailing | 1set | Dia=16000mm | Thickener | 10 |
| 400kw | De-watering of tailing | 2set | Plate=2000×2000mm, Number of plate=260 | Filterpress | 11 |
| 180kw | Air filtration | 1set | Bag filter | 12 | |
| 90kw | Circulating load to HPGR | 2set | L= 12 mm Capacity | Bucket Elevator | 13 |
Conclusion
Using this method, in addition to significantly reducing the amount of water consumption, which is one of the most effective parameters in the production of concentrate in most regions of the country, it also reduces the amount of energy and bullets.
According to the tests carried out, the tailings sample of the second stage of the placer crushing and granulation lines is one of the most potential samples for the production of concentrate in this way. In the dry part and in one separation step, this sample reaches from 48.7% to 5.62% with iron recovery equal to 4.94% and weight recovery 56.73%. The resulting waste grade is also 10.3%.
Another sample on which the processing tests were performed was the tailings of the crushing and granulation line, which due to the high grade of the tailings with a magnetic separation stage, it was necessary to use a scavenger separator to reach the final grade of the tailings to 13.3%. . The grade of the primary feed increased from 26% to 5.43% after a crushing and pre-processing step, and then in the dry cobbing line, the product grade was equal to 2.60%. In this stage, hen recovery was equal to 11.89% and weight recovery was equal to 39.64%.
The use of the second magnetic separator in the role of a buffer leads to an increase in the load in plants and a decrease in the feeding capacity of the line with fixed equipment, or an increase in the need for initial investment to achieve the same product production rate, of course, this possibility is also provided. that different samples can be imported into the line as feed.
