A certain low-grade iron ore has large reserves, low iron grade, uneven particle size of iron minerals, and high mud content. It is a difficult-to-select poor hematite with severe mud formation. Based on the characteristics of the ore, this study carried out a staged grinding-weak magnetic extraction-strong magnetic tailing-gravity separation process (one-stage grinding-weak magnetic-strong magnetic, two-stage grinding-strong magnetic-gravity separation (shaking table) )’s iron beneficiation test research has achieved relatively ideal mineral processing indicators, which can provide a basis for the development and utilization of the ore.
1. Ore properties
The test ore is Anshan-style poor hematite, and the metallic minerals are mainly hematite, magnetic separation, semi-pseudo-hematite, and pseudo-hematite; the gangue minerals are mainly quartz. Raw ore multi-element analysis results and iron phase analysis results
2. Experimental research on iron ore beneficiation
1. Iron ore beneficiation process
The purpose of this ore beneficiation is mainly to separate quartz and iron minerals. Due to the uneven particle size of the iron minerals in the ore, the stage grinding-stage separation process is adopted to discard part of the coarse quartz in advance and recover the monomeric dissociated iron minerals in advance, which can reduce the subsequent operation load and reduce the cost of mineral processing. . According to the types of useful minerals in the ore, the weak magnetic separation method is preferred in the test to recover the magnetic minerals in the ore, and then the strong magnetic gravity separation is used to recover the weak magnetic iron minerals in the weak magnetic tailings.
2. Magnetite recovery test using weak magnetic separation process
In the weak magnetic separation test, magnetic separation experiments, magnetic field strength tests, stage grinding stage magnetic separation tests and process tests were conducted under different grinding fineness conditions, and it was determined that the grinding fineness of the first stage in the weak magnetic separation process was 0.074 mm accounts for 50%, and the second stage grinding fineness is 0.074mm accounting for 95%
3. Second magnet tail (medium ore) reselection test
Since the second magnetic tailings (weakly magnetic II tailings) obtained during the weak magnetic separation process are of high grade, they cannot be used as final tailings. Therefore, a shaking table re-selection test was conducted on the tailings of the second-stage magnetic separation, that is, the medium ore.
The XCY-73 type 1100×500 trough shaker is used, with a stroke of 12mm, a stroke of 320 times/min, a bed slope of 3°, a feeding concentration of 30%, and a feeding volume of 0.38t/h. The second magnetic tail is the middle ore. A shaker reselection test was conducted.
According to the results of the second magnetic tailing (medium ore) shaking table separation experiment, it is known that the weak magnetic tailings can be better separated after shaking table separation, and higher-grade concentrate can be directly obtained. In actual production, the ore can be combined with the three magnetic tailings into gravity separation in the strong magnetic gravity separation process to recover iron minerals.
4. Test on the recovery of weakly magnetic iron minerals through the weak magnetic-strong magnetic-gravity process
① A section of strong magnetic field strength test
Since the main purpose of strong magnetic separation in one-stage grinding and separation operation is to throw away the monomer dissociated gangue or poor conjoined bodies, changes in the strength of the strong magnetic field will have a certain impact on the grade and recovery rate of the iron concentrate in this operation. Therefore, under the condition that the grinding fineness of the first stage is 0.074mm accounting for 50%, the influence of the strong magnetic field intensity on the separation index was examined through experiments.
In order to be close to the actual production on site, the weak magnetic I tailings obtained in the weak magnetic separation process were tested with different magnetic field strengths using the slon-500 vertical ring pulsating high gradient magnetic separator. The background field strengths were 0.80T and 0.85T respectively. , 0.90T, and 1.00T, the pulsation stroke is 20mm, the stroke frequency 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, in the test, the concentrate obtained by the strong magnetic machine was combined with the medium ore as the strong magnetic concentrate and entered into the second stage of strong magnetic separation.
The test results show that with the increase of magnetic field intensity, the yield and recovery rate of strong magnetic concentrate increase, but the grade decreases. Considering the grade and recovery rate comprehensively, and combined with the actual production of strong magnetic field, the strength of a section of strong magnetic field is determined to be 0.85T.
②Second-stage strong magnetic grinding fineness test (strong magnetic – shaking table)
For the weak magnetic tailings obtained in the process, a slon-500 vertical ring pulsating strong magnetic machine is used to prepare a section of strong magnetic coarse concentrate under the separation condition of magnetic field strength 0.85T. Grind the obtained first-stage strong magnetic concentrate to different fineness, and use the XCSQ tooth plate type strong magnetic separator (the ore concentration is about 30%, the magnetic field strength is 0.85T) to conduct the second-stage strong magnetic separation test. The obtained strong magnetic concentrate can be directly Enter the shaking table gravity separation, and determine the fineness of the second stage of strong magnetic separation based on the test results. In order to ensure the selection grade of gravity separation, only the operating concentrate in this section of strong magnetic separation enters the shaking table gravity separation, and the medium ore and tailings obtained by the strong magnetic machine are combined into strong magnetic tailings. The process is shown in Figure 1, and the test results are shown in Tables 6 and 7.
The test results show that when the second-stage grinding fineness is 0.074mm 95.00%, an iron concentrate with a raw ore yield of 6.47% and a grade of 65.69% can be obtained through the second-stage strong magnetic gravity separation. However, the ore in the shaking table and The tailings are also of high grade and can be used as middlings in the entire process. In actual production, the position of this part of the ore return process should be adjusted according to specific conditions.
This part of the qualified concentrate obtained from the second-stage strong magnetic-gravity separation and the iron concentrate obtained from the weak magnetic separation operation together serve as the final concentrate after the separation of this type of ore. From the above results, the final comprehensive concentrate grade is TFe65.89%, the yield is 19.35%, and the recovery rate is 52.33%. In actual production, the recovery rate can be higher due to the return of mines.
Reprint Statement: If there are no special instructions, all articles on this site are original. Please indicate the source for reprinting:Alloy Wiki，thanks！^^