MULTI-STAGE SUSPENSION MAGNETIZING ROASTING-MAGNETIC SEPARATION SYSTEM DEVICE AND METHOD FOR REFRACTORY IRON ORE

Abstract

The invention discloses a multi-stage suspension magnetizing roasting-magnetic separation system and method for refractory iron ore, which belongs to the field of mineral processing technology. This system comprises multistage suspension preheater, multistage suspension oxidizer, multistage suspension redactor, on-line grade analyzer, ore-like splitter, magnetic separator, dust remover, roots blower and other components and connection modes. The refractory iron ore treated by the present method can be produced to homogeneous magnetite or maghemite accurately, and through magnetic separation, on-line grade analyzer detection and ore-like splitter, the concentrate powder which reach the set grade can be obtained, and the unqualified ore powder enters the next stage of oxidation-reduction-magnetic separation-split treatment. Through the present system and method, products with different roasting quality can be obtained, and can avoid the phenomenon of over burning or under burning occurring in the past process and equipment.

Claims

1. A multi-stage suspension magnetizing roasting-magnetic separation system device for refractory iron ore, wherein the system device comprising a feed bin (1), a suspension preheater (2), a gas burner (3), a first-stage suspension oxidizer (4), a first-stage suspension reductor (5), a first-stage electromagnetic dry magnetic separator (6), a first-stage X-ray fluorescence online grade analyzer (7), a first-stage ore-like splitter (8), a second-stage suspension oxidizer (9), a second-stage suspension reductor (10), a first-stage tailings collector (11), a first-stage concentrate collector (12), a second-stage tailings collector (13), a second-stage concentrate collector (14), a second-stage middling ore collector (15), a cyclone separator (16), a dust remover (17), a dust collector (18), a roots blower (19), a second-stage electromagnetic dry magnetic separator (20), a second-stage X-ray fluorescence online grade analyzer (21) and a second-stage ore-like splitter (22); wherein the feed inlet of the suspension preheater (2) is connected to the discharge outlet of the feed bin (1), and the discharge outlet of the suspension preheater (2) is connected to the feed inlet of the first-stage suspension oxidizer (4); the top discharge outlet of the first-stage suspension oxidizer (4) is connected to the feed inlet of the cyclone separator (16), the bottom discharge outlet of the first-stage suspension oxidizer (4) is connected to the inlet of the first-stage suspension reductor (5); the bottom discharge outlet of the reductor (5) is connected to the feed inlet of the first-stage electromagnetic dry magnetic separator (6), and the first-stage electromagnetic dry magnetic separator (6) is equipped with the first-stage X-ray fluorescence online grade analyzer (7) at the concentrate discharge outlet, the first-stage electromagnetic dry magnetic separator (6) is equipped with the first-stage X-ray fluorescence online grade analyzer (7) at the concentrate discharge outlet and is connected to the split inlet of the first-stage ore-like splitter (8), the high-grade discharge outlet of the first-stage ore-like splitter (8) is connected to the first-stage concentrate collector (12), the low-grade discharge outlet of the first-stage ore-like splitter (8) is connected to the feed inlet of the second-stage suspension oxidizer (9), the tailings outlet of the first-stage electromagnetic dry magnetic separator (6) is connected to the first-stage tailings collector (11); the bottom discharge outlet of the second-stage suspension oxidizer (9) is connected to the feed inlet of the second stage-suspension reductor (10); the bottom discharge outlet of the second-stage suspension reductor (10) is connected to the feed inlet of the second-stage electromagnetic dry magnetic separator (20), the concentrate outlet of the second-stage electromagnetic dry magnetic separator (20) is equipped with the second-stage X-ray fluorescence online analyzer (21) and is connected to the split inlet of the second-stage ore-like splitter (22), the high-grade concentrate split inlet of the second-stage ore-like splitter (22) is connected to the second-stage concentrate collector (14), the low-grade concentrate split outlet of the second-stage splitter (22) is connected to the second-stage middling ore collector (15), the tailings outlet of the second-stage electromagnetic dry magnetic separator (20) is connected to the second-stage tailings collector (13); the dust gas outlet at the top of the cyclone separator (16) is connected to the dust gas inlet of the dust remover (17); the air outlet at the top of the dust remover (17) is connected to the roots blower (19), and the dust outlet of the dust remover (17) is connected to the dust collector (18).

2. A multi-stage suspension magnetizing roasting-magnetic separation system device for refractory iron ore according to claim 1, wherein the suspension preheater (2) is of a barrel-type structure with a discharge outlet at the top, a feed inlet at the lower sidewall, and an gas inlet at the bottom of the suspension preheater (2), the suspension preheater (2) is connected to the gas burner (3) through the gas inlet, and the gas burner (3) uses coal gas as a fuel.

3. A multi-stage suspension magnetizing roasting-magnetic separation system device for refractory iron ore according to claim 1, wherein electric heating devices are arranged separately at the outer walls of the first-stage suspension oxidizer (4), the first-stage suspension reductor (5), the second-stage suspension oxidizer (9) and the second-stage suspension reductor (10) so as to ensure that the temperatures in them are set at the relevant temperatures; and thermocouple temperature measuring devices are arranged separately in the furnaces of the oxidizers and the reductors, and the temperature distribution can be monitored in real time by a computer.

4. A multi-stage suspension magnetizing roasting-magnetic separation system device for refractory iron ore according to claim 1, wherein the first-stage suspension reductor (5) and the second-stage suspension reductor (10) are provided with reducing gas spray inlet and protective gas spray inlet.

5. A method for using the multi-stage suspension magnetizing roasting-magnetic separation system device for refractory iron ore, wherein the method for using the system device according to claim 1 is performed according to the following steps: (1) the material ore fines of the complex refractory iron ore is placed in the feed bin (1), then fed into the suspension preheater (2) by the feed bin (1), meanwhile, the combustion flue gas is discharged from the gas burner (3) to the gas inlet of the suspension preheater (2), control the temperature of the material at 600-1300 C. and keep the material in suspension state; (2) start the roots blower (19) to produce negative pressure to make the preheated material in the suspension preheater (2) into the first-stage suspension oxidizer (4), control the temperature of the material in the first-stage suspension oxidizer (4) at 800-1200 C. and stay for 10-60 min, control the air excess to ensure an oxidizing atmosphere; the oxidizing material enters the first-stage suspension reductor (5), the nitrogen N.sub.2, hydrogen H.sub.2, carbon monoxide gas CO are added into the first-stage suspension reductor (5) to control the reduction atmosphere, and the reducing gas is mixed gas of CO and H.sub.2 with N.sub.2, wherein the CO and H.sub.2 accounts for 10-40% of the total volume of reducing gas, and stay for 5-25 min, control the material temperature at 450-700 C., and the reduction reaction occurs at this temperature; (3) after the reaction in the first-stage suspension reductor (5), the material enters the first-stage electromagnetic dry magnetic separator (6) to carry out a first-stage electromagnetic separation, the magnetic field intensity of electromagnetic separation is 1000-5000 Oe; after the electromagnetic separation, the concentrate powder is detected by the first-stage X-ray fluorescence online grade analyzer (7), then enters the first-stage ore-like splitter (8), the concentrate with a grade higher than the preset value enters the first-stage concentrate collector (12) as a finished product, and the concentrate with a grade lower than the preset value enters the second-stage suspension oxidizer (9), and the tailings of the first-stage electromagnetic dry magnetic separator (6) are discharged by the outlet into the first-stage tailings collector (11) to discharge; (4) the concentrate with a grade lower than the preset value enters the second-stage suspension oxidizer (9), control the temperature of the low-grade concentrate in the second-stage suspension oxidizer (9) at 700-1100 C. and stay for 10-30 min, control the oxidizing atmosphere in the second-stage suspension oxidizer (9) by excess air; the oxidizing low-grade concentrate material enters the second-stage suspension reductor (10), the nitrogen N.sub.2, hydrogen H.sub.2, carbon monoxide gas CO are added into the second-stage suspension reductor (10) to control the reduction atmosphere, the reducing gas is mixed gas of CO and H.sub.2 with N.sub.2, wherein the CO and H.sub.2 accounts for 10-40% of the total volume of reducing gas, and stay for 5-15 min, control the material temperature at 450-700 C., and the reduction reaction occurs at this temperature; (5) after the reaction in the second-stage suspension reductor (10), the material enters the second-stage electromagnetic dry magnetic separator (20) to carry out a second-stage electromagnetic separation, the magnetic field intensity of the electromagnetic separation is 1000-5000 Oe; after the electromagnetic separation, the concentrate is detected by the second-stage X-ray fluorescence online grade analyzer (21), then enters the second-stage ore-like splitter (22), the concentrate with a grade higher than the preset value enters the second-stage concentrate collector (14), the concentrate with a grade lower than the preset value enters the second-stage middling ore collector (15) for subsequent third-stage oxidation-reduction roasting; the tailings of the second-stage electromagnetic dry magnetic separator (20) are discharged by the outlet into the second-stage tailings collector (13) to discharge; (6) the dust gas discharged from the second-stage suspension oxidizer (9) and the cyclone separator (16) enter the dust remover (17) through pipes for separation and purification, then the gas separated from the dust remover (17) is discharged into the atmosphere through the air outlet of the roots blower (19), and the solid ash separated from the dust remover (17) enters the dust collector (18) through the bottom outlet of the dust remover (17).

6. A method for using the multi-stage suspension magnetization roasting-magnetic separation system device for refractory iron ore according to claim 5, wherein the amount of reducing gas added in the first-stage suspension reductor (5) and the second-stage suspension reductor (10) is determined by the molar ratio of CO and H.sub.2 in the reducing gas to the Fe.sub.2O.sub.3 in the raw ore powder to be 1:1-1.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a structural schematic drawing of the system for a multi-segment suspension magnetizing roasting and magnetic separation of refractory iron ore; wherein reference numerals represent the following components, 1feed bin, 2suspension preheater, 3gas burner, 4first-stage suspension oxidizer, 5first-stage suspension reductor, 6first-stage electromagnetic dry magnetic separator, 7first-stage X-ray fluorescence online grade analyzer, 8first-stage ore-like splitter, 9second-stage suspension oxidizer, 10second-stage suspension reductor, 11first-stage tailings collector, 12first-stage concentrate collector, 13second-stage tailings collector, 14second-stage concentrate collector, 15second-stage middling ore collector, 16cyclone separator, 17dust remover, 18dust collector, 19roots blower, 20second-stage electromagnetic dry magnetic separator, 21second-stage X-ray fluorescence online grade analyzer, 22second-stage ore-like splitter.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

[0020] The system of multi-stage magnetizing roasting-magnetic separation for refractory iron ore is constructed in accordance with the structure and process described in the previous contents of the present invention, and two different raw ore powders are performed as follows:

Embodiment 1

[0021] The complex refractory ore used in embodiment 1 is raw ore fines, which particle size of 74 m accounts for more than 80% of the total weight of all fines. Analysis of the raw ore and the chemical phase are shown in table 1 and table 2.

TABLE-US-00001 TABLE 1 Analysis of raw ore composition (%) Composition TFe SiO.sub.2 Al.sub.2O.sub.3 CaO MgO S P Content 31.60 22.97 3.12 2.07 2.68 0.07 0.41

TABLE-US-00002 TABLE 2 Chemical phase of raw ore (%) Iron Phases Hematite/ Iron Iron Silicate Total Limonite Magnetite Carbonate Sulfide Iron Fe Content 21.54 0.29 8.28 0.87 0.58 31.56 Distri- 68.25 0.92 26.24 2.76 1.84 100.00 bution rate

[0022] Operate According to the Following Method:

[0023] 1. the material ore fines of complex refractory ore is placed in the feed bin (1), then is added into the suspension preheater (2) by the feed bin (1), meanwhile, the high temperature combustion flue gas provided by the gas burner (3) enters the gas inlet of the suspension preheater (2), control the temperature of the raw ore fines at 800 C. and keep the fines in suspension state;

[0024] 2. start the roots blower (19) to produce negative pressure to make the preheated raw ore fines in the suspended preheater (2) into the first-stage suspension oxidizer (4), control the temperature of the raw ore fines in the first-stage suspension oxidizer (4) at 860 C. and stay for 15 min, control the air excess to ensure an oxidizing atmosphere; the oxidizing raw ore fines enters the first-stage suspension reductor (5) which is filled with nitrogen N.sub.2 and carbon monoxide CO, wherein the CO accounts for 25% of the total volume of the mixture of N.sub.2 and carbon monoxide, and stay for 10 min, control the temperature of raw ore fines at 500 C., and the reduction reaction occurs at this temperature;

[0025] 3. after the reaction in the first-stage suspension reductor (5), the raw ore fines enters the first-stage electromagnetic dry magnetic separator (6) to perform a first-stage electromagnetic separation, the magnetic field intensity of electromagnetic separation is 1800 Oe; the concentrate powder obtained after electromagnetic separation is detected by the first-stage X-ray fluorescence online grade analyzer (7), then enters the first-stage ore-like splitter (8); the concentrate with a grade higher than the preset value of 56% enters the first-stage concentrate collector (12) as a finished product, and the concentrate with a grade under the preset value of 56% enters the second-stage suspension oxidizer (9), and the tailings of the first-stage electromagnetic dry magnetic separator (6) are discharged by the outlet into the first-stage tailings collector (11) to discharge;

[0026] 4. the low-grade concentrate powder enters the second-stage suspension oxidizer (9), control the temperature of the low-grade concentrate in the second-stage suspension oxidizer (9) at 700 C. and stay for 10 minutes, the oxidizing atmosphere in the second-stage suspension oxidizer (9) is controlled by excess air; the oxidizing low-grade concentrate powder enters the second-stage suspension reductor (10) which is filled with nitrogen N.sub.2 and carbon monoxide CO to control the reduction atmosphere, wherein the volume percentage of CO is 30%, stay for 5 minutes, and control the reduction temperature at 450 C.;

[0027] 5. after the reaction in the second-stage suspension reductor (10), the material enters the second-stage electromagnetic dry magnetic separator (20) to perform a second-stage electromagnetic separation, the magnetic field intensity of the electromagnetic separation is 3000 Oe; the concentrate powder obtained after the second-stage electromagnetic separation is detected by the second-stage X-ray fluorescence online grade analyzer (21), then enters the second-stage ore-like splitter (22); the concentrate with a grade higher than the preset value 50% enters the second-stage concentrate collector (14), the concentrate with a grade under 50% enters the second-stage middling ore collector (15) for subsequent third-stage oxidation-reduction roasting, the tailings of the second-stage electromagnetic dry magnetic separator (20) are discharged by the outlet into the second-stage tailings collector (13) to discharge;

[0028] 6. the dust gas discharged from the second-stage suspension oxidizer (9) and the cyclone separator (16) enter the dust remover (17) through pipelines for separation and purification, then the gas separated from the dust remover (17) is discharged into the atmosphere through the exhaust port of the roots blower (19), and the solid dust separated from the dust remover (17) enters the dust collector (18) from the bottom outlet of the dust remover (17);

[0029] The amount of reducing gas added into the first-stage and second-stage suspension reductors is determined by the molar ratio of the CO in the reducing gas to Fe.sub.2O.sub.3 in the raw ore fines to be 1:1.

[0030] The composition analysis of the obtained first-stage concentrate and second-stage concentrate are shown in Table 3 and Table 4.

TABLE-US-00003 TABLE 3 Composition analysis of the first-stage concentrate (%) Composition TFe SiO.sub.2 Al.sub.2O.sub.3 CaO MgO S P Content 60.71 5.66 0.76 0.84 3.11 0.04 0.24

TABLE-US-00004 TABLE 4 Composition analysis of the second-stage concentrate (%) Composition TFe SiO.sub.2 Al.sub.2O.sub.3 CaO MgO S P Content 52.71 9.35 1.36 1.24 2.98 0.05 0.35

Embodiment 2

[0031] The complex refractory ore used in embodiment 2 is raw ore fines, which particle size of 38 m accounts for more than 90% of the total weight of all fines. The analysis of the raw ore and the chemical phase are shown in table 5 and table 6.

TABLE-US-00005 TABLE 5 Composition analysis of raw ore (%) Composition TFe SiO.sub.2 Al.sub.2O.sub.3 CaO MgO S P Content 26.87 19.62 2.79 3.89 2.85 0.04 0.11

TABLE-US-00006 TABLE 6 Chemical phase of raw ore (%) Iron Phases Hematite/ Iron Iron Silicate Total Limonite Magnetite Carbonate Sulfide Iron Fe Content 24.52 7.78 7.11 0.15 0.12 39.68 Distri- 61.79 19.61 17.92 0.38 0.30 100.00 bution rate

[0032] Operate According to the Following Method:

[0033] 1. the material raw ore fines of complex and refractory ore is placed in the feed bin (1), then is added to the suspension preheater (2) by the feed bin (1), meanwhile, the high temperature combustion flue gas provided by the gas burner (3) enters the gas inlet of the suspension preheater (2), control the temperature of the raw ore fines at 850 C. and keep the powder in suspension state;

[0034] 2. start the roots blower (19) to produce negative pressure to make the preheated raw ore fines in the suspended preheater (2) into the first-stage suspension oxidizer (4), control the temperature of raw ore fines in the first-stage suspension oxidizer (4) at 860 C. and stay for 15 minutes, control the air excess to ensure an oxidizing atmosphere; the oxidizing raw ore fines enters the first-stage suspension reductor (5) which is filled with nitrogen N.sub.2 and carbon monoxide CO, wherein the CO accounts for 25% of the total volume of the mixture of N.sub.2 and carbon monoxide, and stay for 10 minutes, control the temperature of raw ore fines at 530 C., and reduction reaction occurs at this temperature;

[0035] 3. after the reaction in the first-stage suspension reductor (5), the raw ore fines enters the first-stage electromagnetic dry magnetic separator (6) to perform a first-stage electromagnetic separation, the magnetic field intensity of electromagnetic separation is 2000 Oe; the concentrate powder obtained after electromagnetic separation is detected by the first-stage X-ray fluorescence online grade analyzer (7), then enters the first-stage ore-like splitter (8); the concentrate with a grade higher than 60% enters the first-stage concentrate collector (12) as a finished product, the concentrate with a grade under the preset value of 60% enters the second-stage suspension oxidizer (9), and the tailings of the first-stage electromagnetic dry magnetic separator (6) are discharged by the outlet into the first-stage tailings collector (11) to discharge;

[0036] 4. the low-grade concentrate powder enters the second-stage suspension oxidizer (9), control the temperature of the low-grade concentrate in the second-stage suspension oxidizer (9) at 750 C. and stay for 10 minutes, the oxidizing atmosphere in the second-stage suspension oxidizer (9) is controlled by excess air; the oxidizing low-grade concentrate powder enters the second-stage suspension reductor (10) which is filled with nitrogen N.sub.2 and carbon monoxide CO to control the reduction atmosphere, Wherein the volume percentage of CO is 25%, stay for 5 minutes, and control the reduction temperature at 450 C.;

[0037] 5. after the reaction in the second-stage suspension reductor (10), the material enters the second-stage electromagnetic dry magnetic separator (20) to perform a second-stage electromagnetic separation, the magnetic field intensity of the electromagnetic separation is 3000 Oe; the concentrate powder obtained after the second-stage electromagnetic separation is detected by the second-stage X-ray fluorescence online grade analyzer (21), then enters the second-stage ore-like splitter (22); the concentrate with a grade higher than 50% enters the second-stage concentrate collector (14), the concentrate with a grade under the preset value of 50% enters the second-stage middling ore collector (15) for subsequent third-stage oxidation-reduction roasting, the tailing of the second-stage electromagnetic dry magnetic separator (20) are discharged by the outlet into the second-stage tailings collector (13) to discharge;

[0038] 6. the dust gas discharged from the second-stage suspension oxidizer (9) and the cyclone separator (16) enters into the dust remover (17) through pipelines for separation and purification, then the gas separated from the dust remover (17) is discharged into the atmosphere through the exhaust port of the roots blower (19), and the solid dust separated from the dust remover (17) enters the dust collector (18) from the bottom outlet of the dust remover (17);

[0039] The amount of reducing gas added into the first-stage and second-stage suspension reductors is determined by the molar ratio of the CO in the reducing gas to Fe.sub.2O.sub.3 in the raw ore fines to be 1:1.

[0040] The composition analysis of the first-stage concentrate and second-stage concentrate are shown in Table 7 and Table 8.

TABLE-US-00007 TABLE 7 Composition analysis of the first-stage concentrate (%) Composition TFe SiO.sub.2 Al.sub.2O.sub.3 CaO MgO S P Content 63.05 4.89 0.89 1.21 2.79 0.01 0.07

TABLE-US-00008 TABLE 8 Composition analysis of the second-stage concentrate (%) Composition TFe SiO.sub.2 Al.sub.2O.sub.3 CaO MgO S P Content 55.25 8.76 1.07 1.53 2.92 0.01 0.09