I. Overview
Blackstone Lizi iron ore deposits occur in the group Presinian Anshan metamorphic rocks central banded iron quartzite, ore types divided into three categories: oxidizing mineral magnetite, hematite, martite, limonite mine; siderite iron carbonate and iron with a rock dolomite; sulfide ore are pyrite mineral and trace brass. The ore grade of ore is generally 20% to 35%, and the content of iron carbonate is relatively high. The whole mine area is generally between 1% and 8%.
The test adopts continuous grinding, coarse subdivision, re-election-magnetic separation-middle-mine regrind process. Under the condition of 25.55% original ore grade and -63μm grinding ratio of 65.00%, the final index is 65.05% of concentrate grade. The tailings grade is 12.57% and the recovery rate is 63.46%.
Second, experimental research
(1) Phase and multi-element analysis results
The results of chemical multi-element and phase analysis are shown in Table 1.
As can be seen from Table 1, due to the higher iron carbonate ore containing, mineral binding Anshan plant experience a greater impact on reverse flotation, gravity separation and thus determines the two methods subjected to magnetic sorting tests .
(2) Grindability test
The results of relative grindability test show that the -74μm content of different grinding time products is better than that of Dagushan ore in comparison with Dagushan ore.
(3) Magnetic separation tube test results of different grinding sizes (Table 2)
It can be seen from Table 2 that the magnetic separation tube concentrate yield is between 20.50% and 24.00%, indicating that the ore contains other non-magnetic iron.
(4) Particle size and dissociation characteristics of grinding products
The test samples were ground to -74 μm in 60% and 90%, respectively. The particle size analysis and the monomer dissociation of iron minerals and gangue were determined. From the results, when -74μm accounts for 60.0%, the monomer dissociation degree of iron mineral is 53.93%, and the monomer dissociation degree of the grade-level iron mineral below -74μm is 77.73%, and the yield of -10μm is 20.27%. When the grinding particle size -74μm accounts for 90%, the monomer dissociation degree of iron mineral is 80.10%, and the monomer dissociation degree of the granular iron mineral below -74μm is 83.96%, the yield of -10μm 39.09%.
(5) Testing of mineral processing conditions
According to the above ore property analysis, re-election and weak magnetic separation conditions were tested to determine reasonable process conditions and processes.
- Re-election tests for different grinding sizes. The sample of the sample -74μm accounted for 63.00% and 73.50% of the two samples were subjected to a coarse and a fine two-stage spiral chute. The test results and flow charts are shown in Figures 1 and 2, respectively.
Comparing the test results of the two particle sizes of Fig. 1 and Fig. 2, the index of 73.50% of the particle size of 74μm is obviously better than the index of 63.00%. Therefore, the appropriate grinding size should be about 70.00%.
- Weak magnetic separation test. When the ore sample is ground to -74 μm and the content is 90.00%, the test result of the weak magnetic machine is shown in Fig. 3. Although the process is simple, the concentrate grade is low.
Third, laboratory re-election test
(1) Continuous grinding, coarse subdivision, heavy-magnetic-medium ore regrind process test
According to the test results of various ore dressing conditions, it is determined that the laboratory re-election test is carried out by continuous grinding, coarse subdivision, and heavy-magnetic-medium ore regrind process. In ore grade 25.76%, a grinding fineness -74μm accounted for 68.00% of the conditions, sorting index was: concentrate grade of 65.05%, a yield of 25.13%, 63.46% metal recoveries and tailings grade of 12.57% Selection indicators. The mass quality process is shown in Figure 4.
(II) Analysis of the characteristics of re-grinding process in heavy-magnetic-middle mine
- The heavy-magnetic combined process is suitable for ore-bearing properties, and can effectively recover magnetic iron and non-magnetic iron minerals in ore, and has strong adaptability to changes in ore properties.
- Using this process, under the condition of coarse grinding particle size (particle size -74μm 70%), a part of qualified concentrate can be obtained and some qualified tailings can be discarded, and the product which is not separated by monomer can be regrind as medium mine. In this way, while ensuring the degree of mineral dissociation, the degree of muddy is reduced, which is conducive to improving the metal recovery rate.
- coarse subdivision selection, coarse fraction partial re-election, fine-grain partial-stage magnetic separation, achieving narrow-level selection, which is beneficial to fully play the role of re-election and magnetic separation equipment .
- The heavy-magnetic combined process played an important role in the sweeping magnetic operation. The crude snail tailings grade was 16.05%. After sweeping the magnetic separation, the coarse tailings with a grade of 9.09% and a yield of 31.66% were discarded. The amount of re-grinding in the mine.
- The heavy-magnetic combined process has a higher grade of tailings (12.57%) and a low metal recovery rate (63.64%), mainly due to the high content of non-industrial iron (FeCO 3 ) in the ore. The recovery rate is calculated by industrially available iron (63.64÷77.48)×100%=82.14%.
Fourth, the conclusion
- The results show that the nature of ore Lizi Blackstone, the majority of the ore iron grade of between 25% to 30%, is a high silica, low sulfur-depleted acidic iron phosphorus, iron carbonate-containing high, between 1% Between 8%, and in a complex form throughout the ore body.
- Using continuous grinding, coarse subdivision, heavy-magnetic-sequential regrind process, the ideal beneficiation index is obtained under the condition of 25.76% of original ore grade and -78μm of primary grinding size of 74.
- Continuous grinding, coarse subdivision, heavy-magnetic-medium ore re-grinding process with good stability, easy operation and management, strong adaptability to changes in ore properties, especially for the change of iron carbonate. The coarse subdivision selection process can effectively exert the respective advantages of the re-election and magnetic separation processes, solve the different requirements for the ore-feeding granularity, and realize a reasonable sorting process for narrow-level selection, which is conducive to improving the beneficiation technical indicators, so it is recommended to The magnetic-middle mine regrind process is the industrial production design process. According to the process, the expected achievable index is 65.05% concentrate grade, 24.03% yield and 60.68% recovery rate.
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