Beneficiation Research On A Mongolian Refractory Iron Ore

Abstract

The process of roasting-magnetic separation was used to treat a Mongolian refractory iron ore. The ore was roasted for20 min at a temperature of 800c, ground to 68% - 0. 074 mm and treated by magnetic separation at a magnetic field intensity of 96 kA/m. As a result, an iron concentrate grading 65. 03% at a recovery of 90. 49% was obtained. It provides a practical method for a wide application of hematite and siderite ores.

Introduction

In recent years the rising price of iron ore, severely restricted the development of steel production. To effectively solve the problem of iron ore resources, the utilization of refractory hematite and limonite with low efficiency becomes the attention focus. Many customers also call and write to ask the problems about beneficiation on the refractory hematite and limonite. This is a beneficiation research on a Mongolian refractory iron ore only for reference purposes.

1. The character of the Iron Ore

Table 1: Chemical Analysis Of Main Components Of The Ore

Table 2: The Results Of Phase Analysis

Table 1 shows the grade of TFe in the ore is 56.76%, in addition, the ore also contains a small amount of Mn with the grade of 1.39%. The main rock-forming elements are silicon and aluminum and a small amount of calcium, gangue should be With quartz and aluminum silicate-based.

Table 2 shows that the iron ore hematite mainly in the form of oxides, followed by the form of limonite is a small amount is based on pyrite, carbonate and silicate in the form, and The form of magnetite iron minimal.

Mineralogy Analysis shows that Hematite is closely associated with the gangue, or generally inclusions a fine gangue. This complex symbiotic relationship between hematite and gangue, seriously restricts the Milling quality. Moreover, in the ore 27.87% of Fu exists in limonite iron aggregates, these aggregates itself contain lower iron, in the grinding process they are too easy to become pelitization. Via magnetic method directly extract iron ore from the limonite is more difficult than from the hematite.

Mineral separation difficulties. If finely ground ore, part of the mill would be too coarse-grained hematite. if coarse grained, the fine-grained hematite in the package gangue minerals is very difficult of monomer dissociation, and in the grinding process a lot of limonite easy muddy brown iron ore. if use the method directly high intensity magnetic separation of iron ore, the final result is that any choice of grinding fineness would worsen the sorting process, resulting in a large number of Iron loss in the tailings.

2. Test Program Development

Process Mineralogy results show that fine grain size disseminated hematite, hematite and gangue are closely related, need to fine grinding to make it fully monomer dissociation, it will be possible to hematite and the effective separation of gangue . The brown iron ore in the grinding process are easy to clay, but the baking characteristics easily transformed into magnetite. To this end, according to the nature of the characteristics of ore, the proposed roasting - magnetic separation process for selection, in order to achieve the purpose of improving the iron grade.

3. Processing Test

Process mineralogy studies have shown that total iron ore mine-like brown 27.87%, magnetic separation and flotation of limonite sorting is not very effective, limonite most effective way is roasting - magnetic separation. To this end, for the roasting - magnetic flow test.

3. 1. Baking Time Test

Roasting tests carried out in a muffle furnace in laboratory, in the calcinations temperature of 800c.

Baking Time Test shows that after the magnetic ore by roasting and baking time extension, magnetic separation of iron ore grade decreased significantly reduce iron recovery. When baking time is 20 min, the iron concentrate iron grade was 67.01%, iron recovery was 75.82%. Description ore roasting - magnetic separation scheme can obtain high quality iron ore.

3. 2. Magnetic field strength test

In the calcination temperature of 800 C, 20min of roasting time, under the conditions of roasting, baking products for the magnetic field strength test.

Magnetic field strength test When the magnetic field strength from 64 kA / m to 128kA / m, Iron ore grade from 67.34% down to 65.76%, iron recovery from 70.58% up to 81.66%. Considering the iron concentrate grade and recovery, the magnetic field strength as 96 kA / m.

3. 3. Coal: Ore Ratio Test

In the calcination temperature of 800 C, baking time 20 min carried out the coal: ore ratio test.

Coal: Ore Ratio Test shows: when the coal: ore rises raised from 2.5% to 15%, the grade of iron ore rises from the 63.48% to 67.03%, while iron Recovery rate from 91.12% down to 37.07%, considering the grade and recovery of iron ore, coal: ore ratio set at 7. 5%.

3. 4. Calcination temperature test

under the conditions of baking time 20 min, coal: ore ratio of 7.5% carried out the calcination temperature test.
Calcination temperature test shows: when the calcination temperature from 600 C increased to 900 C, iron grade iron ore from the 64.53% to 69.24%, while iron recovery from 81.93% down to 22.74 percent. Comprehensive Consider the iron concentrate grade and recovery, calcination temperature set as 800 C.

3. 5. Grinding Fineness Test

under the conditions: the calcination temperature 800 C, baking time 20 min, coal: mining ratio 7.5% carried out the grinding fineness test.

Grinding Fineness Test: when the grinding fineness by the 60% -0. 074 mm increased from 99% -0. 074 mm, of iron concentrate grade by the 63.62% increase to 67.01 percent, while the iron recovery from the 97 . 38% to 77.35%. Considering the iron concentrate grade and recovery, grinding fineness as 68% -0. 074 mm, then iron ore grade 65.03%, iron recovery was 90.49%.

3. 6. Product inspection.

The main chemical composition of iron ore

Table 3: The main chemical composition of iron ore

4. Conclusions

The process of roasting-magnetic separation was used to treat a Mongolian refractory iron ore. The ore was roasted for20 min at a temperature of 800C, ground to 68% -0. 074 mm and treated by magnetic separation at a magnetic field intensity of 96 kA/m. As a result, an iron concentrate grading 65. 03% at a recovery of 90. 49% was obtained. It provides a practical method for a wide application of hematite and siderite ores.