Experimental Study on Beneficiation of a Coastal Iron-bearing Sand Mine in Indonesia

With the gradual expansion of iron ore resource development, iron sands seaside gradually being research units and enterprises attention. The development of iron-bearing sand mines on the seashore has its advantages, that is, the ore size is below -5mm, which eliminates the operation of the crushing section and can greatly reduce the investment cost of the enterprise. In addition, the coastal iron ore mine is mined by the sea, the technology is simple, and there is no need to consider the tailings pond problem. Indonesia, the Philippines, Malaysia and other countries have a large number of such resources. Due to their close proximity to China and low shipping costs, they can be used as an important supplement and source of iron ore resources in China.

A study on the nature and selectivity of ore in a coastal iron ore mine in Indonesia with a TFE grade of 30.52% was conducted to evaluate the development of such resources.

First, the nature of the ore

(1) Chemical analysis of ore. The results are shown in Table 1.

Table 1 Main chemical composition of ore

It can be seen from Table 1 that the original ore Fe grade is 30.52%, FeO16.75%, and the Ti grade is 4.78% in terms of TiO ₂ and V ₂ O ₅ 0.24%.

(2) Mineral composition of ore. Rock identification results showed that the main metal is vanadium and titanium mineral magnetite, the other containing a small amount of magnetite and hematite, limonite; non-metallic minerals pyroxene, feldspar, amphibole, biotite, Quartz, etc. The mineral content of various types is shown in Table 2.

Table 2 Mineral composition of ore %

(3) Analysis of ore size. The results are shown in Table 3.

Table 3 Raw ore particle size analysis results

(4) The monomer dissociation degree of the main iron minerals in the ore. The measurement results are shown in Table 4.

Table 4 Results of determination of monomer dissociation of main iron minerals in ore

As can be seen from Table 4, the monomers of the vanadium-titanium magnetite, hematite magnetite and limonite of +0.074 mm grade were 77.03%, 53.99% and 85.29%, respectively. If the monomer and >3/4 continuous organisms are combined, they are 99.41%, 98.06%, and 100.00%, respectively. It can be seen that the natural monomer dissociation degree of the mine is good.

According to the analysis of the ore sample, the natural monomer dissociation degree of the magnetite in the ore sample is high, and the semi-self-type-heger type particle has 15% magnetite with different degrees of hematite mineralization, and the limonite accounts for iron. 1% of minerals, gangue minerals have good crystallinity.

Second, the test process

The test flow is shown in Figure 1.

Figure 1 Test procedure

Third, the beneficiation test

(1) Direct tailing test

Since the natural monomer dissociation degree of the mine is good, the magnetic separation and tailing can be directly performed to reduce the amount of material processed by the ball mill . The magnetic separation equipment adopts the XCRS-74 type φ400×300 drum-shaped wet weak magnetic separator. Figure 2 shows the effect of magnetic field strength on various indexes of tailing concentrate.

Figure 2 Effect of magnetic field strength on concentrate index

● - concentrate Fe grade; ● - concentrate TiO ₂ grade;

- concentrate yield; â—‹ - concentrate Fe recovery; â–³ - iron concentrate TiO ₂ recovery

It can be seen from Fig. 2 that with the increase of the magnetic field strength, the concentrate yield also increases rapidly, and the iron recovery rate also increases rapidly. When the magnetic field strength reaches 62.30 kA/m, the iron recovery rate is about 94%. With the increase of magnetic field strength from 44.50kA/m to 62.30kA/m, the grade of iron concentrate decreased from 42.12% to 39.07%, and then stabilized above 38%. The TiO _{2 content of} iron concentrate also decreases with the increase of magnetic field strength, and the recovery rate of TiO ₂ increases gradually.

The results of the direct tailing test show that although the natural monomer dissociation degree of the test sample is good, the high-grade commercial iron concentrate (TFe≥56.0%) cannot be obtained without direct magnetic separation by grinding.

(2) Grinding fineness test

The test flow is shown in Figure 1. Different grinding fineness tests were carried out under the conditions of 1 rough selection and 1 selection of weak magnetic separation and magnetic field strengths of 125.0 kA/m and 111.5 kA/m, respectively. The results of the grinding fineness test are shown in Figure 3.

Figure 3 Effect of grinding fineness on concentrate index

â– -concentrate Fe grade; â—‹-concentrate TiO ₂ grade; ●-concentrate yield;

- Concentrate Fe recovery; â–³ - Concentrate TiO ₂ recovery

It can be seen from Fig. 3 that when the grinding fineness -0.074mm accounts for about 80%, the concentrate Fe technical index is the best. At this time, the iron concentrate yield is about 45%, the TFe grade is 57.50% to 58.00%, the TiO ₂ content is about 9.10%, the TFe recovery rate is about 86%, and the TiO ₂ recovery rate is about 87%.

(3) Magnetic field strength test

Under the condition that the grinding fineness -0.074mm accounts for about 80%, the magnetic field strength is changed to perform the magnetic separation test. One of the selected magnetic field strengths is 0.9 times the strength of the rough selected magnetic field. The test results are shown in Figure 4.

Fig. 4 Effect of weak magnetic separation magnetic field strength on concentrate index

â– -concentrate Fe grade; ●-concentrate TiO ₂ grade; â—‹-concentrate yield;

- Concentrate Fe recovery; â–³ - Concentrate TiO ₂ recovery

It can be seen from Fig. 4 that when the grinding fineness -0.074mm accounts for 80%, the first rough selection and the first selected magnetic field strength are 125.0kA/m and 111.5kA/m respectively, the best index is the concentrate TFe grade. 58.04%, the recovery rate was 86.27%, the TiO ₂ content was 9.20%, and the TiO ₂ recovery rate was 87.00%.

Fourth, the conclusion

(1) The TFe grade of an iron-bearing seashore sand mine in Indonesia is 30.52%, the grade of TiO ₂ is 4.78%, the natural monomer of the magnetite has high dissociation degree, and the semi-self-type-heavy particle has 15% magnetic Iron ore has different degrees of hematite mineralization, limonite accounts for 1% of iron minerals, and gangue mineral crystallinity is good.

(2) This coastal iron ore mine belongs to the easy-selected ore. When the grinding fineness is -0.074mm, it accounts for 80.0%. Once the rough selection and the selected magnetic field strength are 125.0kA/m and 111.5kA/m respectively, The yield was 45.00%, the TFe grade was 58.04%, the recovery rate was 86.27% iron concentrate, the TiO ₂ content in the iron concentrate was 9.20%, and the TiO ₂ recovery rate was 87.00%.

(3) The research results of this project provide a reliable basis for the development of such coastal iron ore resources.

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