The tin- iron ore processed by Kunming Baoyijia Co., Ltd. in the Pianma Concentrator has increased its tin grade from 0.2% at the time of construction to about 1% at the current stage. Therefore, it has become more urgent to strengthen the recycling of tin. To this end, the company provided 300 kg of mineral samples for mineral analysis and sorting tests of tin and iron to seek a more economical and reasonable tin-iron recovery process.

Before the experiment, the ore material was analyzed. 1. The ore material composition and its relative content analysis; 2. The occurrence state of tin and iron; 3. The main gangue mineral process (crystallization) grain size characteristics and process characteristics.

The experiment mainly carried out two pre-magnetic and first-weight and post-magnetic options. In the case of 1.01% tin content in the original ore and 33.4% iron content, the first magnetic re-weighting scheme, iron concentrate yield 45.11%, iron grade of 63.04%, Sn 1.57% grade, 85.64% recovery of iron, iron ore containing metallic tin was 70.23%, 0.88% of tin fine mineral, grade of 12.43% tin, tin recovery was 10.83%. When the tin concentrate rate is 5.29%, the tin grade is only 2.5%, the tin recovery rate is 12.02%, the iron concentrate yield is 41.55%, the iron grade is 61.46%, and the tin concentrate metal ratio of iron concentrate is 77.38%. .

The reason for the poor tin separation effect mentioned above is that except for 21.77% acid tin, the fine grain size of the cassiterite is fine, the cassiterite of less than 5um accounts for 31.46% of the cassiterite metal, and the bismuth metal amount of 5-20 um. 58.99%, less than 20um, accounting for 90.45% of the cassiterite metal, and tightly combined with iron and other gangue minerals.

First, the nature of the ore

(1) Chemical analysis

1, multi-element analysis

element

Sn

Fe

Pb

S

As

SiO2

CaO

content(%)

1.01

33.4

0.347

0.091

0.038

19.49

11.27

2, tin phase analysis

Different

Acid soluble tin

锡石锡

total

content(%)

0.246

0.884

1.13

Relative amount (%)

21.77

78.23

100

From the chemical analysis, the main recovery of the mineral is iron and tin, and lead can be recycled. The acid-soluble tin accounts for 21.77% of the total amount of tin.

(2) Particle size analysis

-2mm material particle size analysis

Size (mm)

Yield(%)

grade(%)

Metal rate (%)

Sn

Fe

Sn

Fe

+1.2

1.83

0.716

20.56

1.28

1.14

0.6-1.2

25.81

0.921

26.88

23.17

20.98

0.3-0.6

16.85

1.02

32.55

16.75

16.58

0.15-0.3

11.78

1.08

33.90

12.4

12.08

0.074—0.15

13.68

1.2

36.79

16

15.23

0.037—0.074

11.42

1.25

41.77

13.92

14.42

-0.037

18.63

0.907

34.76

16.48

19.58

total

100

1.03

33.07

100

100

-0.3mm material particle size analysis

Size (mm)

Yield(%)

Sn grade (%)

Sn metal rate (%)

+0.15

34.61

0.957

32.28

0.074—0.15

28.57

1.102

30.69

0.037—0.074

15.87

1.11

17.17

—0.037

20.95

0.972

19.86

total

100

1.026

100

From the particle size analysis, no matter the -2mm material or -0.3mm material, the tin grade difference is not large, while the iron is gradually thinner with the grain size, and the grade gradually increases, indicating that the iron is easily enriched as the grinding grain size becomes finer. Sorting, but tin is not obvious.

Second, mineral identification

(1) The composition of ore material and its relative content

(2) The state of occurrence of Sn and Fe

(III) Particle size characteristics and process characteristics of major gangue mineral processes

Please see the Minerals Report for the above studies.

Third, the beneficiation test

(1) Pre-magnetic re-scenario

The scheme is to perform magnetic separation rough selection in the grinding fineness of 0.3mm, the magnetic field strength is 1200 Oersted, the magnetic material is ground to -200 and accounts for 90%, and then the iron concentrate is selected by magnetic separation, and the non-magnetic material is selected. The shaker is tinned.

See the following figure for the quality process of selecting the number:

First magnetic after weight scheme number quality flow chart

The technical indicators for selection are shown in the following table:

product name

Yield(%)

grade(%)

Recovery rate(%)

Sn

Fe

Sn

Fe

Iron concentrate

45.11

1.57

63.04

70.23

85.64

Tin concentrate

0.88

12.43

10.83

Tin secondary concentrate

0.24

1.95

0.46

Tin mine

6.42

0.89

5.66

Tailings

47.35

0.27

12.82

total

100

1.01

100

From the number of quality processes and technical indicators, it can be seen that the iron concentrate grade can reach 63%, the concentrate yield is 45.11%, but the tin grade is up to 1.57%, the tin metal rate is 70.23%, and the tin concentrate yield is 0.88%. The tin grade is 12.43%, the recovery rate is 10.83%, and the tin recovery effect is poor.

Multi-element analysis of tin concentrate

element

Sn

Pb

Ag(g/t)

S

content(%)

12.43

2.84

85

7.46

From the above table, the silver concentrate and sulfur are higher in the tin concentrate. In the future production, lead and silver can be recovered by flotation, and sulfur is removed to further improve the tin grade.

(2) First heavy magnetic scheme

The scheme is to re-select the tin concentrate and part of the iron concentrate after the grinding fineness reaches -200 mesh accounted for 90%, and the middle and tailings are magnetically selected to produce the second iron concentrate. The magnetic field strength is 1200 Oster.

The selection of technical indicators is shown in the table below.

product name

Yield(%)

grade(%)

Recovery rate(%)

Sn

Fe

Sn

Fe

Shaker concentrate 1

5.29

2.5

63.57

12.95

10.01

Shaker concentrate 2

24.98

1.94

63.81

47.46

47.44

Magnetic separation concentrate

12.28

1.46

55.26

16.13

18.55

Tailings

58.45

0.41

13.8

23.46

twenty four

total

100

1.02

33.60

100

100

From the above table, tin can not be effectively enriched after the first heavy magnetic scheme, and the iron grade in the tailings is as high as 13.80%, and the loss rate of iron metal is 24.00%. At the same time, the grinding cost is high, and the scheme is not desirable.

Fourth, the conclusion

Cassiterite ore since the fine grain size, and containing 21.77% of acid soluble tin, is more difficult dressing stone, mainly magnetite iron minerals, the grain size 0.037-0.074 monomer accounted for 90%, ground to in - When 200 mesh accounts for 90%, iron can be recovered better, but the tin content in iron concentrate is as high as 1.57%, and the tin metal rate is 70.23%. Therefore, how to effectively recover tin metal in iron concentrate is to treat the ore. key.

In view of the above ore properties, it is recommended to perform magnetic separation in the case of coarse grinding (0.3-0.5mm), fine grinding of magnetic materials (-200 mesh accounted for 90%), and magnetically selected fine tin-bearing concentrates, magnetic separation On the tailings, the shaker is selected to produce part of the crude tin concentrate and the secondary concentrate, and the secondary concentrate is finely ground to try to recover the tin in the non-magnetic material. Iron concentrates are treated by fire to increase product value and efficiently recover tin metal.

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