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Yan Xingrong Wang Quanming
Han River iron ore steel plant Yangjiaba
Abstract Experimental study on the nature of the iron ore tailings obtained from the appropriate process recovery of valuable gold mine tailings in the case of magnetite, proved to be viable, a certain economic and social benefits.
Key words iron tailings re-selection research practice
Yangjiaoba Iron Mine Xiakouyu Separation Workshop has a production scale of 800,000 tons. In 1996, the workshop actually processed 70,100,000 tons of iron ore, produced 230,000 tons of iron concentrate, discharged 470,100 tons of tailings, and 8.38% of iron tailings. There is a loss of 39,300 tons of metal. There is still a certain amount of magnetite and monomer in the metal minerals in the tailings. In order to make full use of the country's valuable mineral resources, the laboratory conducted an exploratory experiment on the re-election of the iron ore tailings. Research and application in production practice, producing 6310 tons of iron fine powder per year, reducing the grade of tailings from 8.38% to 7.70%, reducing by 0.68% and increasing benefits by more than 1.8 million yuan.
1 tailings nature
The Yangjiaba iron ore is a poor magnetite ore. The main metal mineral in the ore is magnetite. The gangue mineral is serpentine and talc . The magnetite is coarse-grained, with a small part of fine-grained structure and gangue minerals. It has a mesh or strip structure. The workshop selection process is staged, that is, the iron concentrate is obtained by two stages of grinding and three magnetic separations. The tailings are mainly serpentine, talc, tremolite , chlorite, etc., and contain fine-grained monolithic magnetite and lean continuous organisms. The iron-containing grade is generally 8~9%, and the ore concentration is 7~10. %, below is a multi-element analysis of tailings.
Table 1 Multi-element chemical analysis
Element name
TFe
FeO
SiO 2
Al 2 O 3
CaO
MgO
MnO
P
S
content(%)
8.51
2.93
34.81
3.13
8.85
21.07
0.29
0.077
0.412
The results in Table 1 show that the TFE in the workshop tailings is 8.51% and the FeO is 2.93%, and some of them are in the state of magnetite.
2 experimental exploration
Sampling and magnetic separation test, the magnetic separator is a laboratory small magnetic separator, the field strength is 1600 Oersted, and the test is carried out continuously for 6 days. The results of the sorting are shown in Table 2. The concentrate grade obtained is 36.67% and the yield is 3.94. %, recovery rate 17.17%, -0.074mm accounted for 24.30%. Viewed from the microscope, in addition to the monomeric magnetite and a small amount of monomeric gangue, there are 40% of the coarse-grained continuous body.
Table 2 Results of magnetic separation test of iron tailings
product
Sample tailings (%)
Coarse concentrate (%)
Tailings (%)
Yield(%)
Recovery rate(%)
data
8.42
36.67
7.26
3.94
17.17
In order to further improve the iron grade, the next process for processing coarse concentrates is grinding + weak magnetic separation.
In order to find the best process parameters for grinding and sorting, the comparative tests under different grinding conditions were carried out. The results show that the finer the grinding grain size, the lower the concentrate yield, the higher the iron grade and the higher the recovery rate, when -0.074mm At 90%, the iron grade can reach 64%, the concentrate yield is 47.75%, and the recovery rate is 83.70%. This grinding fineness is more suitable.
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3 process test
In view of the above test, the selected iron tailings re-election process is weak magnetic separation + grinding + weak magnetic process, and the process test is carried out. The test results are shown in Figure 1. The result is 63.97% iron concentrate, and the total tailings recovery. The rate was 14.58% and the yield was 1.91%, which reduced the total tailings grade from 8.38% to 7.30%, which was reduced by 1.08%.
4 tailings recovery equipment requirements
The tailings slurry has a low concentration (7~10%), a large flow rate (700m 3 /h), a fast flow rate (1.3m/s), and a low iron grade (8~9%).
This requires the required tailings re-election equipment to obtain coarse concentrate from the tailings, which has a large processing capacity, and has a large separation area and a magnetic field force suitable for the tailings slurry flow rate to fully recover the magnetic properties. mineral.
5 tailings re-election practice
Through the above-mentioned experimental research, we also went to the Angang Steel Plant for investigation, indicating that it is feasible to re-elect the tailings of Yangjiaba Iron Mine. For the selection of tailings recovery equipment, the YH2106-8 permanent magnet mineral recovery machine is selected by comparison. The magnetic field strength is 1500 Oe.
In view of the feasibility of re-election of tailings and suitable tailings recovery machine, the iron selection process of Yangjiaba is two-stage grinding and three-time magnetic separation. After the discussion of the technicians, it is decided to install the permanent magnet recovery machine in the main In the tailings chute of the factory, the recovered coarse-concentrated concentrate is directly pumped into the second-stage grading ball mill by the sand pump to form a medium-mineral re-grinding and re-selecting the large closed-circuit circulation process. The tailings treatment system is not separately established. Add any equipment, use only one tailings recovery machine, and use the current process equipment.
On April 7th, 1997, the tailings recovery machine was installed and successfully put into production at one time. The grade of coarse concentrate obtained is generally between 32% and 38%, from April 7 to June 18. The accumulated iron tailings grade was 7.70%, which was 0.68 percentage points lower than the 8.38% of the iron tailings grade before recycling. The metal recovery rate was increased by 2.01 percentage points and the yield of concentrate was 1240.85 tons. According to the annual treatment of 700,000 tons of iron ore, the annual recovery of more than 5,810 tons of concentrates will create a profit of more than 1.8 million yuan, and the service life of the tailings dam will be extended accordingly. The infrastructure cost of the tailings recovery equipment will be nearly 300,000 yuan. In two months, the investment can be recovered, with obvious social and economic benefits.