CN117599947A - Iron ore dressing process - Google Patents
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- CN117599947A CN117599947A CN202311611464.1A CN202311611464A CN117599947A CN 117599947 A CN117599947 A CN 117599947A CN 202311611464 A CN202311611464 A CN 202311611464A CN 117599947 A CN117599947 A CN 117599947A
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- iron ore
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 235
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 117
- 238000000034 method Methods 0.000 title claims abstract description 33
- 230000008569 process Effects 0.000 title claims abstract description 30
- 230000005291 magnetic effect Effects 0.000 claims abstract description 193
- 239000012141 concentrate Substances 0.000 claims abstract description 61
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 61
- 239000011707 mineral Substances 0.000 claims abstract description 61
- 238000007885 magnetic separation Methods 0.000 claims abstract description 39
- 239000000843 powder Substances 0.000 claims abstract description 39
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052595 hematite Inorganic materials 0.000 claims abstract description 27
- 239000011019 hematite Substances 0.000 claims abstract description 27
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000007873 sieving Methods 0.000 claims abstract description 23
- 238000005188 flotation Methods 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 238000005096 rolling process Methods 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 35
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 30
- 229910021646 siderite Inorganic materials 0.000 claims description 30
- 230000005294 ferromagnetic effect Effects 0.000 claims description 11
- 230000005415 magnetization Effects 0.000 claims description 10
- 239000006148 magnetic separator Substances 0.000 claims description 9
- 239000000725 suspension Substances 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims 3
- 239000000047 product Substances 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 238000012216 screening Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 229910052683 pyrite Inorganic materials 0.000 description 4
- 239000011028 pyrite Substances 0.000 description 4
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000007789 gas Substances 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000002390 adhesive tape Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000007667 floating Methods 0.000 description 2
- 239000006246 high-intensity magnetic separator Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000010408 sweeping Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- QKTVBYVYNHFKDG-UHFFFAOYSA-H C([O-])([O-])=O.[Fe+2].[Fe+2].[Fe+2].C([O-])([O-])=O.C([O-])([O-])=O Chemical compound C([O-])([O-])=O.[Fe+2].[Fe+2].[Fe+2].C([O-])([O-])=O.C([O-])([O-])=O QKTVBYVYNHFKDG-UHFFFAOYSA-H 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003034 coal gas Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000009851 ferrous metallurgy Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910001608 iron mineral Inorganic materials 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 238000005456 ore beneficiation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
Abstract
The invention provides an iron ore dressing process, which comprises the following steps: rolling the iron ore, and then delivering the iron ore into a micro powder sieve for sieving; feeding the micro powder sieve, grinding, and then delivering the micro powder sieve into a high-frequency fine sieve for sieving; mixing the micro powder screen blanking and the high-frequency fine screen blanking, and then performing weak magnetic rough concentration to obtain a strong magnetic mineral and a weak magnetic mineral; carrying out strong magnetic separation on the weak magnetic minerals to obtain strong magnetic concentrate and strong magnetic tailings; the tailings subjected to strong magnetic separation are dehydrated and then subjected to magnetizing roasting to obtain roasted strong magnetic minerals; the mixture of the strong magnetic minerals obtained by roasting and weak magnetic roughing is subjected to magnetite classification grinding and weak magnetic concentration to obtain magnetite concentrate with the grade of 68.5% and weak magnetic concentration tailings; and carrying out reverse flotation on the mixture of the weak magnetic concentration tailings and the strong magnetic concentrate after hematite grading grinding to obtain flotation concentrate with the grade of 69%. The iron ore dressing process provided by the invention can be used for most efficiently utilizing the iron ore and producing high-quality iron ore concentrate.
Description
Technical Field
The invention relates to the technical field of ore dressing in the ferrous metallurgy industry, in particular to an iron ore dressing process.
Background
Iron ore is an international commodity and belongs to strategic materials. China is the largest iron ore demand country in the world, and although the iron ore reserves in China are not small, the grade of the iron ore reserves in China is low, so that refractory iron ores are most. Therefore, more than half of iron ores in China are imported from abroad every year. The imported iron ores contain a plurality of imported refractory iron ores, and the refractory iron ores are mainly middlings or tailings obtained by crushing the iron ores to 12mm and then reselecting the middlings or the tailings in foreign crushing factories. It features 45-60% grade, complex composition, high content of impurities, fine granularity of embedded cloth and easy mud formation. The part of ore is used as unqualified concentrate at home and abroad, and is often sold as a byproduct only to home.
At present, strong magnetism and floatation processes are generally adopted for treating refractory iron ores, but the processes are often unreasonable for treating a plurality of imported refractory iron ores, and although the imported refractory iron ores are higher in grade, concentrate grade obtained through treatment is not greatly improved, recovery rate is also unsatisfactory, more iron is lost in tailings, resources cannot be fully utilized, and therefore economic benefit is low.
In particular, some iron ores, such as imported iron ores, are often aggregates of various iron minerals including magnetite, limonite, hematite, siderite, and the like. The properties of the iron ores are often changed along with the change of the components of the iron ores, the original single ore grinding and strong magnetic-flotation process can not meet the production requirements, a large number of iron ores can not be effectively selected, the resource waste is caused, and the economic benefit is low.
Meanwhile, with the development of the metallurgical industry, the downstream metallurgical industry has higher and higher requirements on the grade of iron ore for ironmaking, and the TFe grade of the fine iron powder produced by mineral separation must reach more than 68.5%.
Therefore, a stable and reliable iron ore dressing process is needed at present so as to adapt to the change of the properties of iron ore, so that iron ore resources can be effectively recovered, the grade of iron ore concentrate obtained by dressing can be effectively improved, and the problems of low dressing recovery rate of refractory iron ore and low quality of the obtained iron ore concentrate are solved.
Disclosure of Invention
The invention aims to provide an iron ore dressing process capable of efficiently utilizing iron ore and producing high-quality iron concentrate.
In order to solve the technical problems, the invention provides an iron ore dressing process, which comprises the following steps:
rolling the iron ore, and then delivering the iron ore into a micro powder sieve for sieving;
feeding the micro powder sieve, grinding, and then delivering the micro powder sieve into a high-frequency fine sieve for sieving;
mixing the micro powder screen blanking and the high-frequency fine screen blanking, and then performing weak magnetic rough concentration to obtain a strong magnetic mineral and a weak magnetic mineral;
carrying out strong magnetic separation on the weak magnetic minerals to obtain strong magnetic concentrate and strong magnetic tailings;
the tailings subjected to strong magnetic separation are dehydrated and then subjected to magnetizing roasting to obtain roasted strong magnetic minerals;
the mixture of the strong magnetic minerals obtained by roasting and weak magnetic roughing is subjected to magnetite classification grinding and weak magnetic concentration to obtain magnetite concentrate with the grade of 68.5% and weak magnetic concentration tailings;
and carrying out reverse flotation on the mixture of the weak magnetic concentration tailings and the strong magnetic concentrate after hematite grading grinding to obtain flotation concentrate with the grade of 69%.
Further, the iron ore is middlings or tailings with granularity below 12mm and grade between 45 and 60 percent after crushing, screening and re-selecting, and comprises magnetite, limonite, hematite and siderite.
Further, the method for obtaining the strong magnetic concentrate and the strong magnetic tailings from the weak magnetic minerals through strong magnetic separation comprises the following steps:
the weak magnetic mineral is subjected to strong magnetic roughing to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings;
the strong magnetic rough concentration concentrate is subjected to strong magnetic concentration to obtain the strong magnetic concentration concentrate and strong magnetic concentration tailings;
and mixing the strong magnetic rougher tailings and the strong magnetic concentrator tailings to obtain the strong magnetic concentrator tailings.
Further, a medium rod with a diameter of 1.5mm and a gap of 3mmm is used in the strong magnetic separator for strong magnetic separation; the magnetic field strength of the strong magnetic rougher is 7000-9000Oe, and the magnetic field strength of the strong magnetic rougher is 5000-7000Oe.
Further, the iron ore is fed into a micro powder sieve for sieving after being rolled, namely the iron ore is rolled by an open-circuit high-pressure roller, and then the rolled material is fed into the micro powder sieve for wet sieving of 0.5 mm.
Further, the fine powder sieve feeding is sent to a high-frequency fine sieve for sieving after being ground, namely, the fine powder sieve feeding is sent to a ball mill for grinding, and then, the fine powder sieve feeding is sieved by a closed-circuit high-frequency fine sieve with the mesh size of 0.5 mm.
Further, the weak magnetic roughing adopts a cylindrical magnetic separator, and the magnetic field strength is 1500-2500Oe.
Further, the high-intensity magnetic separation tailings are dehydrated by combining a high-efficiency concentrator for the high-intensity magnetic separation tailings with a filter press, so that the moisture of the high-intensity magnetic separation tailings is below 10%; the magnetization roasting is to oxidize and reduce the weak magnetic ore in the strong magnetic separation tailings into the roasted strong magnetic ore by adopting a suspension magnetization roasting furnace.
Further, the magnetite classifying grinding is to grind the mixture of the roasted ferromagnetic mineral and the ferromagnetic mineral obtained by weak magnetic roughing by using a ball mill to obtain a classifying product with 90% of the materials with granularity smaller than 0.075mm, and the classifying product is subjected to weak magnetic refining under the magnetic field intensity of 1000-1500Oe to obtain magnetite concentrate.
Further, the hematite grading grinding is to grind the mixture of the weak magnetic concentration tailings and the strong magnetic separation concentrate by using a vertical mill to obtain an overflow product with 90% of materials with granularity smaller than 0.045mm, and the overflow product is subjected to reverse flotation by using one-coarse, one-fine and two-sweep to obtain flotation concentrate.
Aiming at some refractory iron ores, particularly some imported refractory iron ores, the refractory iron ores are middlings or tailings obtained by crushing, screening and re-selecting mines, the granularity is below 12mm, the grade is 45-60%, and the refractory iron ores not only contain magnetite and hematite, but also contain minerals such as limonite, siderite and the like which are easy to mud. The method comprises the steps of rolling iron ore, sieving with a micro-powder sieve, feeding the micro-powder sieve, grinding, sieving with a high-frequency fine sieve, mixing the micro-powder sieve with the high-frequency fine sieve, performing weak magnetic concentration and rough concentration to obtain strong magnetic ore and weak magnetic ore, performing strong magnetic concentration and rough concentration to the weak magnetic ore to obtain strong magnetic concentrate and strong magnetic tailings, dehydrating the strong magnetic tailings, performing magnetization roasting to obtain roasted strong magnetic ore, mixing the roasted strong magnetic ore with the strong magnetic ore obtained by the weak magnetic rough concentration, performing magnetite classification grinding, performing weak magnetic concentration to obtain magnetite concentrate with the grade of 68.5% and weak magnetic concentration tailings, mixing the weak magnetic concentration tailings with the strong magnetic concentrate obtained by the strong magnetic concentration, and performing reverse flotation to obtain flotation concentrate with the grade of 69% after hematite classification grinding. Therefore, the grade of the two final iron concentrates can reach more than 68.5%, high-quality iron concentrates are produced, the requirements of downstream metallurgical industry on the grade of iron ores for iron making are met, the refractory iron ores can be utilized most efficiently, the utilization rate of iron ore resources is effectively improved, the production cost is saved, and the economic benefit is improved.
Drawings
Fig. 1 is a flow chart of an iron ore beneficiation process provided by an embodiment of the present invention.
Detailed Description
Referring to fig. 1, the iron ore dressing process provided by the embodiment of the invention comprises the following steps:
step 1) conveying the iron ore into a micro powder sieve for sieving after rolling. Iron ore is some refractory iron ore, for example, some refractory iron ore imported from countries such as australia, brazil, india, etc. The iron ores are middlings or tailings of mines subjected to crushing, screening and re-selecting, the granularity is often not more than 12mm, and the grade of the iron ores is 45-60%. Since iron ore contains limonite, siderite and other minerals which are liable to be muddy, excessive grinding of the iron ore must be prevented, in order to prevent the iron ore from being excessively ground, the iron ore is firstly conveyed to a high pressure roller through an adhesive tape, and the iron ore is rolled by adopting an open-circuit high pressure roller, namely, the iron ore is rolled by high pressure roller grinding at one time. And then feeding the rolled material into a micro powder sieve with the sieve pore size of 0.5mm for wet sieving to obtain micro powder sieve feeding with the granularity of 12mm-0.5mm and micro powder sieve discharging with the granularity of less than 0.5mm respectively.
And 2) feeding the micro powder sieve into a high-frequency fine sieve for sieving after grinding. The material with the granularity of 12mm-0.5mm is fed into the micro powder sieve, the effective components in the material are recovered by the subsequent magnetic separation, the micro powder sieve is fed into the ball mill for ore grinding, the granularity of the material discharged after the micro powder sieve is ground by the ball mill is very fine, the material discharged after the ball mill is fed into a closed-circuit high-frequency fine sieve with the sieve pore size of 0.5mm for sieving, namely the material discharged after the ball mill is ground by the high-frequency fine sieve with the sieve pore size of 0.5mm is returned to the ball mill for continuous ore grinding, the material after the ore grinding is fed into the high-frequency fine sieve with the size of 0.5mm, and the material fed into the micro powder sieve is repeatedly ground and sieved in a closed ore grinding and sieving system until the aim of ore grinding and high-frequency fine sieving is achieved, and the material discharged from the high-frequency fine sieve is obtained.
The forced classification of the iron ore is realized by rolling the iron ore by an open-circuit high-pressure roller and controlling the mesh sizes of the micro powder sieve and the high-frequency fine sieve, so that overgrinding of qualified materials in the ball mill is avoided.
And 3) mixing the micro powder screen blanking and the high-frequency fine screen blanking, and performing weak magnetic rough separation to obtain the ferromagnetic mineral and the weak magnetic mineral. The undersize of the micro powder sieve and the undersize of the high frequency fine sieve are mixed together, wherein the granularity in the mixed material can reach 40 percent below 0.075 mm. The mixture is subjected to weak magnetic rough concentration by a drum magnetic separator under the magnetic field intensity of 1500-2500Oe, and the strong magnetic mineral mainly comprising magnetite and the weak magnetic mineral mainly comprising hematite, limonite, siderite and the like are obtained.
As a best specific implementation mode of the invention, the magnetic field intensity of the mixed material subjected to weak magnetic roughing through the drum type magnetic separator is controlled to be 2000Oe.
And 4) carrying out strong magnetic separation on the weakly magnetic minerals to obtain strong magnetic separation concentrate and strong magnetic separation tailings. Wherein, the medium bar with the diameter of 1.5mm and the gap of 3mmm is used in the strong magnetic separator used for the strong magnetic separation. Wherein, the weak magnetic minerals mainly including hematite, limonite, siderite and the like are subjected to strong magnetic roughing under the magnetic field intensity of 7000-9000Oe to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings mainly including limonite and siderite. And then carrying out strong magnetic concentration on the strong magnetic roughing concentrate obtained by the strong magnetic roughing under the magnetic field intensity of 5000-7000Oe to obtain strong magnetic concentrate mainly containing hematite and strong magnetic concentration tailings mainly containing limonite and siderite. And mixing the strong magnetic roughing tailings and the strong magnetic concentrating tailings to obtain the strong magnetic concentrating tailings mainly comprising limonite and siderite. Because limonite and siderite are easy to mud, the fineness of the limonite and siderite is far higher than that of hematite, and the limonite and siderite of micro-fine particles enter the high-intensity magnetic separation tailings and the hematite enters the high-intensity magnetic separation concentrate through the selection of the magnetic field intensity of the high-intensity magnetic roughing and the high-intensity magnetic separation and the selection of the large-diameter and large-gap medium rods in the high-intensity magnetic separator.
As a best mode of the invention, the magnetic field intensity of the strong magnetic roughing of weak magnetic minerals such as hematite, limonite, siderite and the like is controlled to be 8000Oe. And controlling the magnetic field intensity of the strong magnetic roughing concentrate obtained by the strong magnetic roughing to 6000Oe.
And 5) dehydrating the strong magnetic separation tailings and magnetizing and roasting to obtain the roasted strong magnetic mineral. The strong magnetic separation tailings taking limonite and siderite as main components are dehydrated by a high-efficiency concentrator and a filter press in a combined way, and the moisture content of the tailings is below 10%. And then sending the dehydrated strong magnetic separation tailings into a suspension magnetization roasting furnace to roast and reduce the limonite, siderite and other weak magnetic ores in the strong magnetic separation tailings into roasted strong magnetic minerals. Wherein, gas or natural gas is adopted as gas for roasting reduction, and the temperature of roasting reduction is controlled to be more than 600 ℃.
And 6) mixing the roasted ferromagnetic minerals with the ferromagnetic minerals obtained by the weak magnetic roughing, carrying out magnetite classifying grinding operation on the mixture of the ferromagnetic minerals and the ferromagnetic minerals by using a ball mill to enable the mineral aggregate with the granularity of less than 0.074mm to reach 90%, carrying out weak magnetic concentration on the mineral aggregate obtained by the magnetite classifying grinding operation at the magnetic field intensity of 1000-1500Oe, and carrying out magnetic separation on the mineral aggregate with the grade of 68.5% by using the magnetic field intensity with lower magnetic field intensity. Meanwhile, the weak magnetic concentration tailings containing the dissociated weak magnetic minerals are also obtained.
As a best specific implementation mode of the invention, the magnetic field intensity of the weak magnetic concentration of mineral aggregate obtained by the magnetite classifying and grinding operation is controlled to be 1000Oe.
Step 7) mixing the part of the material containing the dissociated weakly magnetic concentration tailings of the weakly magnetic minerals with the strong magnetic concentrate mainly containing hematite, and then sending the mixed material into a hematite grinding classification system, wherein the system adopts a vertical mill to grind the mixed material into superfine ore, so that the ore with the granularity below-0.045 mm reaches 90%. And finally, carrying out primary coarse, primary fine and secondary sweeping flotation operation on the overflow product, and selecting flotation magnetite concentrate with the grade of 69% by carrying out a floating beneficiation process of the weakly magnetic mineral.
And finally, the grade of the two magnetite concentrates reaches more than 68.5%, so that refractory iron ores, particularly some imported refractory iron ores, are utilized most efficiently, and high-quality iron concentrates are produced.
The ore dressing process of the iron ore provided by the invention is further described in detail below by taking ore dressing of imported refractory iron ore in a certain port area as an example.
The ore sample in the example of the invention is taken from imported refractory iron ore in a certain port area, the iron grade of the iron ore is 52.83%, the iron ore mainly comprises magnetite, limonite, hematite, siderite, a small amount of pyrite and other minerals, and the iron sample belongs to typical refractory imported iron ore, and the iron phase composition of the refractory imported iron ore is shown in Table 1.
TABLE 1 iron phase composition of the imported iron ore
| Some import mine | All iron | Magnetic iron | Iron carbonate | Iron (Chifusc) | Pyrite (pyrite) | Iron silicate |
| Iron content, percent | 52.83 | 12.88 | 6.08 | 30.05 | 1.44 | 2.38 |
| Iron distribution percentage% | 100 | 24.38％ | 11.51％ | 56.88％ | 2.73％ | 4.51％ |
Because the limonite and siderite content in the imported refractory iron ore is higher, the grade of the finally produced iron concentrate is only 62% by adopting the current conventional beneficiation method, the requirements of downstream ironmaking enterprises on the grade of the iron concentrate cannot be met, the beneficiation effect is poor, the resource waste is caused, the production cost is improved, and the economic benefit is lower. But the ore dressing process of the iron ore provided by the invention can improve the grade of the final iron concentrate to 68.5%, improve the grade by about 7%, produce high-quality iron concentrate powder and greatly improve the economic benefit. The ore dressing process of the iron ore provided by the embodiment of the invention comprises the following specific ore dressing processes.
The imported refractory iron ore raw ore is a middling product obtained by crushing, screening and re-selecting foreign mines, the granularity is below 12mm, and the grade is 52.83%. The main minerals of the ore are magnetite, limonite, hematite, siderite and a small amount of pyrite. Because the ore contains limonite, siderite and other minerals which are easy to mud, the prevention of excessive ore grinding of the ore is the first key link. Therefore, the raw ore in the raw material pile is conveyed to a high-pressure roller through an adhesive tape to carry out rolling operation, and the raw ore is rolled at one time by adopting an open-circuit high-pressure roller mill. And feeding the rolled material into a micro powder sieve with the mesh size of 0.5mm for wet sieving. After sieving, the materials with the granularity of 12mm-0.5mm are left on a sieve, and the materials with the granularity of less than 0.5mm are sieved.
And (3) conveying oversize materials with the granularity of 12-0.5 mm into a ball mill for ore grinding, and conveying the ball mill ore discharge into a closed-circuit high-frequency fine screen with the screen mesh size of 0.5mm for cyclic ore grinding and high-frequency fine screen to obtain the material. And finally, combining the micro powder undersize material with the granularity smaller than 0.5mm with the undersize material of the high-frequency fine sieve to obtain undersize material with the granularity smaller than-0.075 mm accounting for 40 percent. Through open-circuit high-pressure roller rolling and forced classifying and screening according to the mesh size, excessive grinding of qualified materials in the ball mill can be avoided.
And (3) carrying out weak magnetic roughing operation on the undersize material, wherein a drum-type magnetic separator is adopted for weak magnetic roughing, the magnetic field intensity of the weak magnetic roughing is controlled at 2000Oe, and the strong magnetic minerals mainly containing magnetite in the undersize material are selected, so that the weak magnetic minerals mainly containing hematite, limonite, siderite and the like are left.
And then carrying out strong magnetic roughing operation on the rest weak magnetic minerals mainly comprising hematite, limonite, siderite and the like, wherein the magnetic field strength is controlled to be 8000Oe, so as to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings mainly comprising limonite and siderite. And then carrying out strong magnetic concentration on the strong magnetic roughing concentrate obtained by the strong magnetic roughing, wherein the magnetic field strength is controlled to be 6000Oe, so as to obtain the strong magnetic concentrate mainly containing hematite and the strong magnetic concentrate mainly containing limonite and siderite. Wherein, the medium bars with the diameter of 1.5mm and the gap of 3mmm are used in the strong magnetic separator used for the strong magnetic rough concentration and the strong magnetic concentration. And finally, mixing the strong magnetic rough tailings and the strong magnetic concentrating tailings to obtain the strong magnetic concentrating tailings mainly comprising limonite and siderite. Because limonite and siderite are easy to mud, the fineness of the limonite and siderite is far higher than that of hematite, and the limonite and siderite of micro-fine particles enter the high-intensity magnetic separation tailings and the hematite enters the high-intensity magnetic separation concentrate through the selection of the magnetic field intensity of the high-intensity magnetic roughing and the high-intensity magnetic separation and the selection of the large-diameter and large-gap medium rods in the high-intensity magnetic separator.
And (3) carrying out combined dehydration operation of a high-efficiency concentrator and a filter press on strong magnetic separation tailings mainly comprising limonite and siderite, and carrying out magnetization roasting operation after the moisture content of the tailings reaches 10%. Wherein, the magnetization roasting operation adopts a suspension magnetization roasting furnace, the gas used for roasting and reduction adopts coal gas or natural gas, and the temperature of roasting and reduction is controlled to be above 600 ℃. Weak magnetic ores such as limonite, siderite and the like in the strong magnetic separation tailings can be roasted and reduced into roasted strong magnetic ores through magnetization roasting.
And mixing the roasted ferromagnetic minerals with the ferromagnetic minerals mainly containing magnetite obtained by the weak magnetic roughing, carrying out magnetite classifying grinding operation on the mixed minerals with the magnetite by using a ball mill to enable the mineral with the granularity less than 0.074mm in the mixed mineral to reach 90%, carrying out weak magnetic concentration on the mixed mineral obtained by the magnetite classifying grinding operation, controlling the magnetic field intensity to be 1200Oe, and carrying out magnetic separation through lower magnetic field intensity to obtain the magnetite concentrate with the grade of 68.5%. Meanwhile, the weak magnetic concentration tailings containing the dissociated weak magnetic minerals are also obtained.
Mixing the weak magnetic concentration tailings containing the dissociated weak magnetic minerals with the strong magnetic concentrate mainly containing hematite obtained by strong magnetic separation, and then sending the mixed material into a hematite grinding classification system, wherein the system adopts a vertical mill to perform superfine grinding on the mixed material, and the ore material with the granularity below-0.045 mm in the obtained mixed material reaches 90%. And finally, carrying out primary coarse, primary fine and secondary sweeping flotation operation on the overflow product, and selecting flotation magnetite concentrate with the grade of 69% by carrying out a floating beneficiation process of the weakly magnetic mineral.
By the iron ore dressing process provided by the invention, the grade of the obtained two iron concentrates reaches 68.5%. Not only meets the requirement of downstream metallurgical industry on the grade of iron ore for iron making, but also makes the most efficient use of refractory iron ore, effectively improves the utilization rate of iron ore resources, saves production cost and improves economic benefit.
Finally, it should be noted that the above-mentioned embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications and equivalents may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention, and all such modifications and equivalents are intended to be encompassed in the scope of the claims of the present invention.
Claims (10)
1. An iron ore dressing process is characterized by comprising the following steps:
rolling the iron ore, and then delivering the iron ore into a micro powder sieve for sieving;
feeding the micro powder sieve, grinding, and then delivering the micro powder sieve into a high-frequency fine sieve for sieving;
mixing the micro powder screen blanking and the high-frequency fine screen blanking, and then performing weak magnetic rough concentration to obtain a strong magnetic mineral and a weak magnetic mineral;
carrying out strong magnetic separation on the weak magnetic minerals to obtain strong magnetic concentrate and strong magnetic tailings;
the tailings subjected to strong magnetic separation are dehydrated and then subjected to magnetizing roasting to obtain roasted strong magnetic minerals;
the mixture of the strong magnetic minerals obtained by roasting and weak magnetic roughing is subjected to magnetite classification grinding and weak magnetic concentration to obtain magnetite concentrate with the grade of 68.5% and weak magnetic concentration tailings;
and carrying out reverse flotation on the mixture of the weak magnetic concentration tailings and the strong magnetic concentrate after hematite grading grinding to obtain flotation concentrate with the grade of 69%.
2. The process according to claim 1, wherein the iron ore is middlings or tailings having a particle size of 12mm or less and a grade of 45 to 60% after crushing, sieving and re-selecting, and the iron ore comprises magnetite, limonite, hematite and siderite.
3. The iron ore dressing process according to claim 1, wherein the obtaining the strong magnetic concentrate and the strong magnetic tailings from the weak magnetic minerals through strong magnetic separation comprises:
the weak magnetic mineral is subjected to strong magnetic roughing to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings;
the strong magnetic rough concentration concentrate is subjected to strong magnetic concentration to obtain the strong magnetic concentration concentrate and strong magnetic concentration tailings;
and mixing the strong magnetic rougher tailings and the strong magnetic concentrator tailings to obtain the strong magnetic concentrator tailings.
4. The process for beneficiation of iron ore according to claim 3, wherein a medium bar with a diameter of 1.5mm and a gap of 3mmm is used in the strong magnetic separator for strong magnetic separation; the magnetic field strength of the strong magnetic rougher is 7000-9000Oe, and the magnetic field strength of the strong magnetic rougher is 5000-7000Oe.
5. The process for beneficiation of iron ore according to claim 1, wherein the iron ore is fed into a micro-powder sieve after being rolled, wherein the iron ore is rolled by an open-circuit high-pressure roller, and then the rolled material is fed into the micro-powder sieve for 0.5mm wet sieving.
6. The iron ore dressing process according to claim 1, wherein the feeding of the micro powder sieve is fed into a high frequency fine sieve for sieving after grinding, and the feeding of the micro powder sieve is fed into a ball mill for sieving after grinding by a closed circuit high frequency fine sieve with a mesh size of 0.5 mm.
7. The iron ore dressing process according to claim 1, wherein the weak magnetic roughing is a drum type magnetic separator, and the magnetic field strength is 1500-2500Oe.
8. The iron ore dressing process according to claim 1, wherein the high-intensity magnetic separation tailings are dehydrated by combining a high-efficiency concentrator for the high-intensity magnetic separation tailings with a filter press to enable the moisture content of the high-intensity magnetic separation tailings to be below 10%; the magnetization roasting is to oxidize and reduce the weak magnetic ore in the strong magnetic separation tailings into the roasted strong magnetic ore by adopting a suspension magnetization roasting furnace.
9. The ore dressing process according to claim 1, wherein the magnetite classifying grinding is grinding a mixture of the roasted ferromagnetic minerals and the ferromagnetic minerals obtained by the weak magnetic roughing by a ball mill to obtain a classified product with the particle size of less than 0.075mm accounting for 90%, and the classified product is subjected to weak magnetic concentration under the magnetic field strength of 1000-1500Oe to obtain magnetite concentrate.
10. The process according to claim 1, wherein the hematite classifying grinding is to grind a mixture of weakly magnetic concentration tailings and the strongly magnetic concentrate by a vertical mill to obtain an overflow product with a particle size of less than 0.045mm, wherein the overflow product is subjected to one-coarse, one-fine and two-sweep reverse flotation to obtain a flotation concentrate.
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