Experimental Study on Beneficiation of a Difficult-Selected Manganese-poor Iron Ore in Yunnan

China is a country rich in manganese ore resources of the country, the resources of manganese ore reserves ranked in the world. With the rapid development of industry, manganese metal increased demand, leading to the gradual depletion of high-grade ore resources; and our poor manganese ore manganese ore resources there is a complex structure, fine dissemination size characteristics and high harmful elements, to sorting and utilization of manganese Bring difficulties.

At present, domestic and foreign selection of low-grade manganese ore is difficult to use strong magnetic separation - flotation - re-election, washing - strong magnetic separation - flotation, roasting - re-election - weak magnetic selection, strong magnetic rough selection - jump Eliminate joint processes such as selection and strong magnetic sweeping.

Yunnan somewhere manganese iron-poor symbiotic ore, mineral fine dissemination size, ferromanganese mineral component complex, is hard mineral stone, has long been not been developed. In order to make full use of mineral resources, the company entrusted Guangxi University to conduct mineral processing experiments on the ore.

The experimental research shows that the ore is added to the carbon powder, then redoxed, calcined, and the calcined ore is ground until the mineral monomer is dissociated, and the weak magnetic separation is performed, and the iron grade is 49.7%, and the recovery rate is 53.5%. Iron concentrate; weak magnetic tailings reuse strong magnetic to improve the grade of manganese, can obtain grade 36.54%, recovery rate of 81.69% S concentrate.

First, the nature of the sample

The test sample was taken from a certain area in Yunnan. The ore is mainly composed of ferromanganese compound, rehydrated manganese ore and manganese ore. Manganese oxides are mainly composed of limonite, goethite, hematite and rhombohedrite. The ore is mainly composed of a small amount of magnetite. The impurity minerals are mainly quartz , dolomite and Carbonate minerals, and a small amount of shale minerals. The chemical element multi-element analysis is shown in Table 1. The manganese phase analysis is shown in the table. 2. The iron phase analysis is shown in Table 3.

Table 1 Multi-element analysis of sample chemical

SiO 2

Mn

Fe

Al 2 O 3

K 2 O

P

S

MgO

46

20.7

13.4

5.5

1.5

0.65

0.04

0.4

Pb

Ti

Ba

CaO

Zn

Co

Na 2 O

Sb

0.2

0.1

0.1

0.1

0.05

0.05

0.05

0.04

Table 2 Manganese phase analysis

Phase state

Manganese carbonate

Pyrolusite

Manganese ore

Rehydrated manganese ore

Ferromanganese compound

Total manganese

content/%

0.96

1.31

2.13

3.76

12.54

20.7

Distribution rate /%

4.64

6.33

10.29

18.16

60.58

100.0

Table 3 Iron phase analysis

Phase state

Siderite

Goethite

magnetite

Hematite

Limonite

All iron

content/%

2.04

3.97

1.57

2.17

3.65

13.4

Distribution rate /%

15.22

29.63

11.71

16.19

27.23

100.0

From chemical analysis of multi-element, manganese ore is a low high low iron Phosphate minerals, low-grade and high useful minerals include phosphorus, manganese ore was useful minerals and iron minerals. In addition, from the phase analysis, there is only a very small amount of manganese carbonate in the ore sample, most of which exists in the form of soft manganese ore, manganese ore, rehydrated manganese ore and ferromanganese, indicating that the recovery of manganese minerals is extremely difficult. Large; iron phase analysis shows that iron is mainly in the form of ferric hydroxide, and there are some hematite, limonite, and magnetite. From the above, it can be concluded that such a sample is difficult to choose. Manganese ore.

Second, selective magnetization reduction roasting - weak magnetic separation test

The magnetization reduction roasting-weak magnetic separation test is to add a reducing agent carbon powder to the ore to be calcined, to reduce the weak magnetic iron mineral such as iron-containing mineral into a ferromagnetic iron mineral, and then to sort out the iron fine by weak magnetic separation method. The mine achieves the purpose of separation of iron and manganese, and the tailings are further selected for manganese.

(1) Magnetization reduction roasting test

The effect of calcination temperature, calcination time and amount of carbon powder on the separation of iron and manganese was investigated by magnetization reduction roasting test. The test procedure is shown in Figure 1.

Figure 1 Flow chart of magnetization reduction roasting test

It can be seen from Table 4 that as the calcination temperature increases, the iron grade of iron concentrate increases continuously, and the manganese grade and recovery rate do not change much, but the iron recovery rate increases and then decreases. When the calcination temperature reaches 900 °C, The iron recovery rate of iron concentrate is up to 48.91%, and the iron grade is 50.37%; the manganese grade of tailings is 22.88%, so the calcination temperature is 900 °C.

(2) Calcination temperature test

10% of the carbon powder is added to the ore for roasting for 50 minutes. After calcination, the ore is ground to -200 mesh 80%, the magnetic field strength is 140 kA/m, the calcination is cooled by water cooling, and the calcination temperature is changed to carry out the magnetization reduction roasting test. The test results are shown in Table 4.

Table 4 Roasting temperature test results

Calcination temperature

(°C)

product

Yield(%)

grade(%)

Recovery rate(%)

manganese

iron

manganese

iron

800

Iron concentrate

11.42

8.79

45.37

4.86

40.27

Tailings

88.58

22.18

8.68

95.14

59.73

Raw ore

100.0

20.65

12.87

100.0

100.0

850

Iron concentrate

11.84

9.02

48.81

5.03

44.28

Tailings

88.16

22.87

8.25

94.97

55.72

Raw ore

100.0

21.23

13.05

100.0

100.0

900

Iron concentrate

12.77

8.48

50.37

5.15

48.91

Tailings

87.23

22.88

7.70

94.85

51.09

Raw ore

100.0

21.04

13.15

100.0

100.0

950

Iron concentrate

11.71

9.43

47.43

5.23

42.78

Tailings

88.29

22.66

8.41

94.77

57.22

Raw ore

100.0

21.11

12.98

100.0

100.0

(3) Roasting time test

10% of the carbon powder is added to the ore for roasting. The calcination temperature is 900 °C. After calcination, the ore is ground to -200 mesh 80%, the magnetic field strength is 140 kA/m, the calcination is cooled by water cooling, and the calcination time is changed to carry out magnetization reduction roasting. Test, the test results are shown in Table 5.

Table 5 Roasting time test results

time

(min)

product

Yield(%)

grade(%)

Recovery rate(%)

manganese

iron

manganese

iron

30

Iron concentrate

12.44

8.95

45.76

5.09

43.67

Tailings

87.56

23.72

8.38

94.91

56.33

Raw ore

100.0

21.88

13.04

100.0

100.0

50

Iron concentrate

12.77

8.48

50.37

5.15

48.91

Tailings

87.23

22.88

7.70

94.85

51.09

Raw ore

100.0

21.04

13.15

100.0

100.0

70

Iron concentrate

13.24

8.04

50.86

5.03

51.47

Tailings

86.74

23.18

7.32

94.97

48.53

Raw ore

100.0

21.17

13.08

100.0

100.0

90

Iron concentrate

13.20

8.73

49.32

5.48

49.33

Tailings

86.80

22.90

7.71

94.52

50.67

Raw ore

100.0

21.03

13.21

100.0

100.0

It can be seen from the results in Table 5 that with the extension of the roasting time, the iron grade of the iron concentrate does not change much, the iron recovery rate first increases and then decreases; when the roasting time reaches 70 min, the grade and recovery rate of the iron concentrate reaches the highest, and the tail The manganese manganese grade reached 23.18% and the manganese recovery rate reached 94.97%. Therefore, a baking time of 70 minutes is suitable.

(4) Toner consumption test

The carbon powder is added to the ore for roasting. The calcination temperature is 900 °C, the calcination time is 70 min. After calcination, the ore is ground to -200 mesh 80%, the magnetic field strength is 140 kA/m, and the roasting is cooled by water cooling to change the amount of carbon powder. The magnetization reduction roasting test was carried out, and the test results are shown in Table 6.

Table 6 Carbon powder dosage test results

Toner consumption

(%)

product

Yield(%)

grade(%)

Recovery rate(%)

manganese

iron

manganese

iron

5

Iron concentrate

12.68

9.44

48.37

5.73

46.75

Tailings

87.32

22.55

8.00

94.27

53.25

Raw ore

100.0

20.89

13.12

100.0

100.0

10

Iron concentrate

13.24

8.04

50.86

5.03

51.47

Tailings

86.74

23.18

7.32

94.97

48.53

Raw ore

100.0

21.17

13.08

100.0

100.0

15

Iron concentrate

13.78

7.65

51.49

4.97

53.46

Tailings

86.22

23.39

7.16

95.03

46.54

Raw ore

100.0

21.22

13.27

100.0

100.0

20

Iron concentrate

13.61

8.80

50.13

5.61

51.87

Tailings

86.39

23.32

14.36

94.39

48.13

Raw ore

100.0

21.34

13.15

100.0

100.0

It can be seen from the data in Table 6 that with the increase of the amount of toner, the iron grade and recovery rate of iron concentrate first increase and then decrease. When the amount of toner is 15%, the recovery rate and grade are the best, so the amount of toner is fixed at 1.5. %.

(5) Grinding fineness test

15% of the carbon powder is added to the ore for roasting, the calcination temperature is 900 ° C, the calcination time is 70 minutes, the magnetic field strength is 140 kA / m, the calcination cooling is performed by water cooling, and the grinding fineness is changed to carry out the magnetization reduction roasting test. Table 7.

Table 7 Grinding fineness test results

Grinding fineness

-0.074mm

product

Yield(%)

grade(%)

Recovery rate(%)

manganese

iron

manganese

iron

60

Iron concentrate

15.97

12.55

47.23

9.56

57.39

Tailings

84.03

22.56

6.66

90.44

42.61

Raw ore

100.0

20.96

13.14

100.0

100.0

70

Iron concentrate

14.82

11.38

48.29

7.72

54.38

Tailings

85.18

22.81

7.05

92.28

45.62

Raw ore

100.0

21.05

13.16

100.0

100.0

80

Iron concentrate

13.97

7.70

49.78

5.04

53.58

Tailings

86.03

23.56

7.00

94.96

46.42

Raw ore

100.0

21.34

12.98

100.0

100.0

90

Iron concentrate

13.70

7.52

50.37

4.89

52.95

Tailings

86.30

23.22

11.49

95.11

47.05

Raw ore

100.0

21.07

13.03

100.0

100.0

It can be seen from the results of Table 7 that with the increase of grinding fineness, the iron ore iron ore grade increases but the iron recovery rate decreases, the tailings manganese grade changes little and the manganese recovery rate increases continuously. Considering comprehensively, the fineness of the calcining grinding is preferably -200 mesh and 80%. At this time, the grade of iron concentrate is 49.78%, the recovery rate is 53.58%; the manganese grade in tailings is 23.56%, and the recovery rate is 94.96.

3. Strong magnetic separation test of magnetized reduction roasting weak magnetic separation tailings

After the ore is magnetized reduction roasting-weak magnetic separation, an iron concentrate with a yield of 13.79%, an iron grade of 49.78% and a recovery of 53.58% can be obtained, and manganese minerals such as goethite, pyrolusite and rehydrated manganese ore are accompanied by mica. The gangue minerals such as quartz are enriched in the iron ore tailings, so that the manganese grade of the iron ore tailings reaches 23.56%, and the manganese recovery rate reaches 94.96%. The manganese concentrate can be obtained by removing the gangue minerals in the tailings. In order to improve the grade of manganese concentrate, after obtaining iron concentrate by magnetization reduction roasting weak magnetic separation, the tailings are subjected to strong magnetic separation to obtain high-grade manganese concentrate. The test results are shown in Table 8.

Table 8 Test results of improving manganese grade under different magnetic field strengths

Magnetic field strength

(T)

product

Yield(%)

grade(%)

Recovery rate(%)

manganese

iron

manganese

iron

1.2

Iron concentrate

49.36

38.38

7.69

80.41

54.27

Tailings

50.64

9.11

6.18

19.59

44.73

Raw ore

100.0

23.56

7.00

100.0

100.0

1.4

Iron concentrate

51.19

37.76

7.70

82.36

55.29

Tailings

48.81

8.48

6.53

17.64

44.71

Raw ore

100.0

23.47

7.13

100.0

100.0

1.6

Iron concentrate

55.75

36.54

7.53

86.03

56.35

Tailings

44.25

7.48

7.35

13.97

43.65

Raw ore

100.0

23.68

7.45

100.0

100.0

1.8

Iron concentrate

56.97

35.77

7.31

87.28

56.86

Tailings

43.03

12.33

7.34

22.72

43.14

Raw ore

100.0

23.35

7.32

100.0

100.0

It can be seen from Table 8 that with the increase of magnetic field strength, the recovery rate of manganese concentrate is increasing, while the grade of manganese concentrate is gradually decreasing, but the decline is not obvious; the iron content in manganese concentrate is not much different, and the recovery of iron The rate also changed little. It is more appropriate to consider the magnetic field strength to be 1.6T. From the total recovery of manganese, the manganese concentrate grade can reach 36.54%, the iron content is 7.53%, the manganese operation recovery rate is 86.03%, and the total recovery rate can reach 81.69%.

Fourth, the conclusion

(1) The ore is mainly composed of ferromanganese compound, rehydrated manganese ore and manganese ore, and manganese oxide is rare; iron minerals are mainly limonite, goethite, hematite and siderite, and There are a small amount of magnetite; the impurity minerals are mainly quartz, dolomite and carbonate minerals, as well as a small amount of shale minerals.

(2) From the multi-element analysis of public school, the ore sample belongs to low-manganese low-iron and high-phosphorus minerals, and the useful minerals in the ore are manganese minerals and iron minerals. From the phase analysis, the manganese minerals in the ore samples exist in the form of pyrolusite, manganese ore, rehydrated manganese ore and ferromanganese minerals; the phase analysis of iron indicates that iron is mainly in the form of iron hydroxide, and There are some hematite, limonite, and less magnetite, which are difficult to select manganese ore.

(3) The redox roasting is carried out by adding the carbon powder to the ore, and then the ore obtained by roasting is ground until the mineral monomer is dissociated, and the iron mineral is recovered by weak magnetic separation, and the grade is 49.78%, and the recovery rate is 53.58%. The iron concentrate; weak magnetic separation tailings and strong magnetic separation to recover manganese minerals, can obtain manganese concentrate with a grade of 36.54% and a recovery rate of 81.69%.

(4) With the gradual depletion of ferromanganese and the increasing demand for raw materials for smelting, it will become more difficult to treat refractory manganese ore with simple physical beneficiation methods. It is particularly important to seek new beneficiation methods.

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