A low-grade iron ore reserves, low grade iron, iron minerals disseminated granularity uneven thickness, with a high clay content, is a mud of severe refractory poor hematite. In order to characterize the ore, this study carried out a stage grinding-weakening magnetic refining-strong magnetic tailing-re-selection process (a grinding-weakening-strong magnetic, two-stage grinding-strong magnetic-re-selection ( shaker) The iron ore test study has achieved an ideal beneficiation index, which can provide a basis for the development and utilization of the ore.
First, the nature of the ore
Test genus ore Anshan poor hematite, red metallic minerals are limonite, magnetic ore dressing, semi martite, martite; gangue minerals are quartz. The results of multi-element analysis of the ore and iron phase analysis are shown in Table 1 and Table 2.
Table 1 Multi-element analysis results of ore (unit: %) | |||||
ingredient | TFe | FeO | SiO2 | AL2O3 | CaO |
content | 24.07 | 2.23 | 59.50 | 11.34 | 0.62 |
ingredient | MgO | S | P | TiO2 | MnO |
content | 1.17 | 0.021 | 0.045 | 0.27 | 0.09 |
Table 2 Analysis results of ore phase of iron ore (unit: %) | ||
project | Iron content | Iron distribution rate |
Magnetic iron mineral iron | 9.93 | 41.26 |
Iron in red brown iron ore | 9.40 | 39.05 |
Iron in iron sulfide minerals | 0.69 | 2.87 |
Iron in iron ore | 0.27 | 1.12 |
Iron in iron silicate mineral | 3.78 | 15.70 |
Full iron TFe | 24.07 | 100.00 |
Second, iron ore beneficiation test research
1. Iron ore beneficiation process
The purpose of this ore dressing is mainly the separation of quartz and iron minerals. Due to the uneven grain size of the iron mineral in the ore, the stage grinding-stage selection process is adopted, and some coarse-grained quartz is pre-discarded, and the iron minerals which have been dissociated by the monomer are recovered in advance, which can reduce the subsequent operation load and reduce the ore dressing cost. . According to the types of useful minerals in the ore, it is preferred to use the weak magnetic separation method to recover the magnetic ore in the ore, and then use the strong magnetic-re-selection to recover the weak magnetic iron minerals in the weak magnetic tailings. The test flow is shown in Figure 1.
2. Weak magnetic separation process to recover magnetite test
In the weak magnetic separation test, the magnetic separation experiment, the magnetic field strength test, the magnetic separation test and the flow test in the stage grinding stage were carried out under different grinding fineness conditions, and the first grinding fineness in the weak magnetic separation process was determined to be 0.074. Mm accounted for 50%, the second section of grinding fineness was 0.074mm accounted for 95%, and the flow test results are shown in Table 3.
Table 3 Test results of weak magnetic separation process | |||
product name | Yield/% | Grade (TFe) /% | Recovery rate/% |
Weak magnetic concentrate | 12.88 | 65.99 | 35.38 |
Weak magnetic III tailings | 0.81 | 51.39 | 1.73 |
Weak magnetic II tailings | 10.78 | 25.62 | 11.49 |
Weak magnetic I tailings | 75.53 | 16.35 | 51.40 |
total | 100.00 | 24.03 | 100.00 |
3, two magnetic tail (middle mine) re-election test
Due to the high magnetic tail (weak magnetic II tailings) grade obtained in the weak magnetic separation process, it cannot be used as the final tailings. Therefore, a shaker re-election test was carried out on the second-stage magnetic separation tailings, ie, the middle ore.
Adopt XCY-73 type 1100×500 slot shaker, stroke 12mm, punching times 320 times/min, bed slope 3°, ore concentration 30%, ore amount 0.38t/h, pair two magnetic tail ie middle mine A shaker re-election test was carried out. The test results are shown in Table 4.
Table 4 Two magnetic tail-shaker test results | |||||
product name | Yield/% | grade | Recovery rate/% | ||
operation | Raw ore | (TFe)/% | operation | Raw ore | |
Shaker concentrate | 15.88 | 1.71 | 64.20 | 39.96 | 4.59 |
Shaker in mine | 18.58 | 2.00 | 15.19 | 11.06 | 1.27 |
Shaker tailings | 65.54 | 7.07 | 19.07 | 48.98 | 5.64 |
total | 100.00 | 10.78 | 25.52 | 100.00 | 11.50 |
According to the experimental results of the two-magnetic tail (middle mine) shaker, it can be found that the weak magnetic tailings can be sorted by shaker to obtain better sorting, and the concentrate with higher grade can be directly obtained. In actual production, the mine can merge with the three magnetic tailings into the re-election in the strong magnetic-re-election process to recover the iron minerals.
4. Weak magnetic-strong magnetic-re-election process to recover weak magnetic iron minerals
1 section of strong magnetic field strength test
Since the main purpose of strong magnetic separation in a section of grinding operation is to throw away the gangue or lean body that has been dissociated by the monomer, the change of the strength of the strong magnetic field will have a certain influence on the grade and recovery rate of the iron concentrate in this operation. Therefore, under the condition that the first stage grinding fineness is 0.074mm and 50%, the influence of the strong magnetic field strength on the sorting index is examined through experiments.
In order to be close to the actual production in the field, the weak magnetic I tailings obtained in the weak magnetic separation process were tested by different magnetic field strengths using the slon-500 vertical ring pulsation high gradient magnetic separator . The background field strengths were 0.80T and 0.85T, respectively. , 0.90T, and 1.00T, the pulsating stroke is 20mm, the stroke is 120 times/min, and the ore concentration is about 30%. Considering that the strong magnetic operation in this section needs to ensure a certain iron recovery rate, the concentrate obtained by the strong magnetic machine and the middle mine are combined as a strong magnetic concentrate into the second-stage strong magnetic separation. The test procedure is shown in Figure 1, and the test results are shown in Table 5.
Table 5 Test results of a strong magnetic field strength | ||||||
Magnetic field strength / T | product name | Yield/% | grade | Recovery rate/% | ||
operation | Raw ore | (TFe)/% | operation | Raw ore | ||
0.80 | Concentrate | 44.35 | 33.50 | 25.67 | 69.78 | 35.86 |
Tailings | 55.65 | 42.03 | 8.86 | 30.22 | 15.53 | |
total | 100.00 | 75.53 | 16.32 | 100.00 | 51.39 | |
0.85 | Concentrate | 46.56 | 35.17 | 25.51 | 72.64 | 37.33 |
Tailings | 53.44 | 40.36 | 8.37 | 27.36 | 14.06 | |
total | 100 | 75.53 | 16.35 | 100 | 51.39 | |
0.90 | Concentrate | 49.21 | 37.17 | 24.56 | 74.28 | 38.17 |
Tailings | 50.79 | 38.36 | 8.24 | 25.72 | 13.22 | |
total | 100.00 | 75.53 | 16.27 | 100.00 | 51.39 | |
1.00 | Concentrate | 54.66 | 41.28 | 22.97 | 77.35 | 39.75 |
Tailings | 45.34 | 34.25 | 8.11 | 22.65 | 11.64 | |
total | 100.00 | 75.53 | 16.23 | 100.00 | 51.39 | |
The test results show that with the increase of magnetic field strength, the yield and recovery rate of strong magnetic concentrate are improved, but the grade is reduced. Considering the grade and recovery rate, combined with the actual production of strong magnetic field, the strength of a strong magnetic field is determined to be 0.85T.
2 two-stage strong magnetic grinding fineness test (strong magnetic-shaker)
A slon-500 vertical ring pulsating magnetic machine was used for the weak magnetic tailings obtained in the process, and a strong magnetic coarse concentrate was prepared under the condition of magnetic field strength 0.85T. The obtained strong magnetic concentrate is ground to different fineness, and the XCSQ tooth plate type strong magnetic separator (about 30% of the ore concentration, magnetic field strength 0.85T) is used for the two-stage strong magnetic separation test, and the obtained strong magnetic concentrate is directly Enter the shaker re-election and determine the fineness of the two-stage strong magnetic separation according to the test results. In order to ensure the re-election of the selected grade, the section of the strong magnetic selection only the operation concentrate into the shaker re-election, the medium ore obtained by the strong magnetic machine and the tailings merge into a strong magnetic tailings. The process is shown in Figure 1, and the test results are shown in Tables 6 and 7.
Table 6 Results of two-stage strong magnetic separation test under different grinding fineness conditions | ||||||
Grinding fineness / (0.074mm) | product name | Yield/% | grade | Recovery rate/% | ||
operation | Raw ore | (TFe)/% | operation | Raw ore | ||
72.94 | Concentrate | 57.04 | 20.06 | 36.92 | 82.55 | 30.82 |
Tailings | 42.96 | 15.1 | 10.36 | 17.45 | 6.51 | |
total | 100.00 | 35.17 | 25.51 | 100.00 | 37.33 | |
83.06 | Concentrate | 51.60 | 18.15 | 42.08 | 82.07 | 30.64 |
Tailings | 48.40 | 17.02 | 9.80 | 17.93 | 6.69 | |
total | 100 | 35.17 | 26.46 | 100.00 | 37.33 | |
91.80 | Concentrate | 46.02 | 16.19 | 45.59 | 78.57 | 29.33 |
Tailings | 53.98 | 18.98 | 10.60 | 21.42 | 8.00 | |
total | 100.00 | 35.17 | 26.70 | 100.00 | 37.33 | |
95.00 | Concentrate | 43.71 | 15.37 | 46.89 | 77.00 | 28.74 |
Tailings | 56.29 | 19.80 | 10.88 | 23.01 | 8.59 | |
total | 100.00 | 35.17 | 26.62 | 100.00 | 37.33 | |
Table 7 Test results of two-stage strong magnetic concentrate shaker under different grinding fineness conditions | ||||||
Grinding fineness / (0.074mm) | product name | Yield/% | grade | Recovery rate/% | ||
operation | Raw ore | (TFe)/% | operation | Raw ore | ||
72.94 | Concentrate | 26.79 | 6.37 | 64.50 | 46.80 | 14.42 |
Middle mine | 36.50 | 7.32 | 30.98 | 30.63 | 9.44 | |
Tailings | 36.71 | 7.36 | 22.70 | 22.57 | 6.96 | |
total | 100 | 20.06 | 36.92 | 100.00 | 30.82 | |
83.06 | Concentrate | 35.52 | 6.45 | 64.79 | 54.69 | 16.76 |
Middle mine | 29.60 | 5.37 | 31.43 | 22.11 | 6.77 | |
Tailings | 34.88 | 6.33 | 28.00 | 23.21 | 7.11 | |
total | 100 | 18.15 | 42.08 | 100.00 | 30.64 | |
91.80 | Concentrate | 41.98 | 6.80 | 64.79 | 59.66 | 17.50 |
Middle mine | 25.47 | 4.12 | 31.65 | 17.68 | 5.19 | |
Tailings | 32.55 | 5.27 | 31.73 | 22.66 | 6.64 | |
total | 100.00 | 16.19 | 45.59 | 100.00 | 29.33 | |
95.00 | Concentrate | 42.09 | 6.47 | 65.69 | 58.97 | 16.95 |
Middle mine | 25.27 | 3.88 | 35.53 | 19.15 | 5.50 | |
Tailings | 32.64 | 5.02 | 31.43 | 21.88 | 6.29 | |
total | 100.00 | 15.37 | 46.89 | 100.00 | 28.74 | |
The test results show that when the second-stage grinding fineness is 0.074mm 95.00%, the iron concentrate with a yield of 6.47% and a grade of 65.69% can be obtained by two-stage strong magnetic-re-election, but the ore in the shaker The tailings grade is also high and can be used as a middle mine for the entire process. In actual production, the location of the mine return process in this part should be adjusted according to the specific situation.
The two-stage ferromagnetic-re-selection of this part of the qualified concentrate is combined with the iron concentrate obtained by the weak magnetic separation operation as the final concentrate after the ore is selected. From the above results, the final integrated concentrate grade TFe65.89%, the yield was 19.35%, and the recovery was 52.33%. In the actual production, the recovery rate can be higher due to the return of the medium mine.
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