Beneficiation method for refractory iron ore with symbiotic hematite, limonite and siderite

Abstract

The invention discloses a beneficiation method of refractory iron ore with symbiotic hematite, limonite and siderite, which comprises the following steps of: crushing weakly magnetic refractory iron ore to below 100mm in a closed circuit, then sequentially carrying out three times of dry screening to obtain four particle fractions of 0-6mm, 6-15mm, 15-40mm and 40-100mm, pre-selecting the particle fractions of 6-15mm by adopting a dry high-intensity magnetic separator, pre-selecting the particle fractions of 15-40mm by adopting a chunk jigger, pre-selecting the particle fractions of 40-100mm by adopting a photoelectric intelligent separator, and pre-selecting the particle fractions of 40-100mm by adopting a high-intensity magnetic separator; photoelectric intelligent pre-selected concentrate is crushed to 0-40 mm through a fine crushing closed circuit, then jigging pre-selected concentrate is combined, then the photoelectric intelligent pre-selected concentrate is crushed to 0-6 mm through an ultra-fine crushing closed circuit, an ultra-fine crushing product is combined with the 0-6 mm fraction, then wet type strong magnetic pre-selection is conducted through a coarse grain wet type strong magnetic separator, the pre-selected concentrate is subjected to ore grinding-fine grain wet type strong magnetic one-coarse one-scavenging one-coarse one-scavenging one-fine one-scavenging reverse flotation, and the final concentrate is obtained. And final concentrate is obtained. The invention has the advantages of large raw ore selection granularity, large tailing discarding amount, low energy consumption, good separation effect and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of weakly magnetic refractory iron ore beneficiation, and specifically relates to a weakly magnetic refractory iron ore beneficiation process, which is particularly suitable for the efficient separation of weakly magnetic refractory iron ore with a TFe grade between 25% and 35% and iron minerals mainly being hematite and siderite. Background Art

[0002] Iron ore is the main raw material of the steel industry, mainly distributed in Australia, Brazil, Russia, China and other countries; among them, the average total iron grade of Australian and Brazilian iron ore is relatively high, above 50%; while the average total iron grade of Chinese iron ore is only 34.5%, far below the world average. China's complex and difficult-to-select iron ore resources reserves exceed 20 billion tons, mainly including fine-grained hematite, siderite, limonite and hematite. At present, limonite, siderite and their paragenetic ores (red ore) are iron ores with large reserves but difficult to be separated. They are typical low-grade and difficult-to-select iron ores. Due to their poor, fine and mixed characteristics, they are difficult to beneficiate and have extremely low utilization rates. It is difficult to obtain good technical and economic indicators for the above-mentioned complex and difficult-to-select iron ore resources through traditional beneficiation methods. The iron concentrate recovery rate and concentrate grade obtained by conventional gravity-magnetic-flotation ore separation technology are both low, with serious waste of resources and poor concentrate quality, which is difficult to meet the requirements of concentrate smelting.

[0003] At present, the utilization rate of siderite and limonite in my country is extremely low, and most of them are not recycled or mined at all. Since the theoretical grade of siderite is low and it often coexists with calcium, magnesium and manganese, it is difficult to achieve an iron concentrate grade of more than 45% using physical beneficiation methods. In addition, since limonite is rich in crystal water, it is also difficult to achieve an iron concentrate grade of more than 60% using physical beneficiation methods.

[0004] For a long time, mineral processing researchers have conducted a lot of research on the separation of iron ore in my country, and successfully developed processes such as stage grinding-coarse and fine grading-gravity separation-magnetic separation-anion reverse flotation, rotary kiln roasting-magnetic separation, etc. However, the above processes have many disadvantages when processing complex and difficult-to-select iron ores, such as complex process flow, high energy consumption, high reagent cost, and low equipment productivity. In recent years, the developed suspended magnetization roasting-magnetic separation technology is an effective technical means to process complex and difficult-to-select iron ores. It has the advantages of good roasting product quality, low energy consumption, and high automation level. However, compared with physical mineral processing methods, the suspended magnetization roasting-magnetic separation technology still has relatively high energy consumption, high production cost, and the flue gas generated has a great impact on the environment. In addition, the iron grade of the final iron concentrate is not high, especially it is highly sensitive to the price of iron concentrate powder. Once the price of iron concentrate powder falls, it is possible to suffer losses and stop production. For example, the article "Suspended Magnetic Roasting Test and Mechanism Research of Jiugang Iron Ore" published in the 4th issue of "Metal Mine" in 2022 carried out suspended magnetic roasting tests and mechanism research. The test results showed that under the conditions of roasting time of 10 minutes, roasting temperature of 570°C, and CO concentration of 20%, suspended magnetic roasting was carried out. After magnetic separation, only the best indicators of concentrate iron grade of 52.98% and iron recovery rate of 83.92% were obtained.

[0005] In addition, pre-selection is an important operation in the beneficiation of low-grade iron ore. By discarding qualified tailings in advance through pre-selection, not only can the grade of selected iron ore be improved, but also the amount of subsequent processing can be greatly reduced, thus achieving the purpose of energy saving and consumption reduction. For a long time, for strongly magnetic minerals, a single magnetic separation process is usually used to obtain satisfactory pre-selection indicators. However, for weakly magnetic minerals such as hematite, limonite, and siderite, if only a single magnetic separation process is used, the separation effect is much worse than that of strongly magnetic minerals.

[0006] Therefore, it is urgent to develop new methods for efficient pre-selection, separation and enrichment of difficult-to-select weakly magnetic iron ore with coexisting hematite, limonite and siderite. Summary of the invention

[0007] The purpose of the present invention is to provide a method for beneficiating refractory iron ore containing coexisting hematite and siderite, in order to address the technical difficulties in the prior art, such as the inability to pre-select and discard weakly magnetic iron minerals, poor separation effect for coarse particles of 50 mm and fine particles of less than 6 mm, and small processing capacity.

[0008] To achieve the above-mentioned object of the present invention, a refractory iron ore beneficiation method of hematite and siderite coexisting in the present invention is implemented by the following steps:

[0009] S1 crushes the weakly magnetic refractory iron ore with TFe content between 25% and 35% and mainly hematite and siderite into smaller than 100mm in a closed circuit, and then dry screens the ore three times to obtain four particle sizes of 0-6mm, 6-15mm, 15-40mm and 40-100mm.

[0010] S2 uses different pre-selection equipment to pre-select and discard tailings for the three particle sizes of 6-15mm, 15-40mm, and 40-100mm obtained in step S1, wherein the 6-15mm particle size is pre-selected by a dry strong magnetic separator to obtain a dry strong magnetic pre-selected concentrate and discharge the dry strong magnetic tailings, the 15-40mm particle size is pre-selected by a large block jig to obtain a jig pre-selected concentrate and discharge the jig pre-selected tailings, and the 40-100mm particle size is pre-selected by a photoelectric intelligent separator to obtain a photoelectric intelligent pre-selected concentrate and discharge the photoelectric intelligent pre-selected tailings;

[0011] In step S3, the photoelectric intelligent pre-selected concentrate obtained in step S2 is crushed to 0-40 mm by fine crushing in a closed circuit, and then combined with the jigging pre-selected concentrate obtained in step S2, and then crushed to 0-6 mm by ultra-fine crushing in a closed circuit, and then the ultra-fine crushed product is combined with the 0-6 mm particle size obtained in step S1, and then wet strong magnetic pre-selection is performed using a coarse wet strong magnetic separator to obtain a wet strong magnetic pre-selected concentrate and discharge a wet strong magnetic tailings;

[0012] S4 combines the dry strong magnetic pre-selected concentrate obtained in step S2 with the wet strong magnetic pre-selected concentrate obtained in step S3 as the final pre-selected concentrate, and combines the dry strong magnetic tailings, jigging pre-selected tailings, photoelectric intelligent pre-selected tailings discharged in step S2 and the wet strong magnetic tailings discharged in step S3 as the final pre-selected tailings;

[0013] S5 grinds the final pre-selected concentrate obtained in step S4, and then separates the ground product through fine-grained wet strong magnetic roughing and sweeping separation, and discharges fine-grained wet strong magnetic roughing tailings and fine-grained wet strong magnetic concentration tailings respectively, to obtain fine-grained wet strong magnetic concentration concentrate;

[0014] S6 feeds the fine-grained wet strong magnetic concentration concentrate obtained in step S5 into a first roughing, a first fine, and a second scavenging reverse flotation operation to obtain a final iron concentrate, and discharges the reverse flotation scavenging tailings; the reverse flotation scavenging tailings are combined with the fine-grained wet strong magnetic roughing tailings and the fine-grained wet strong magnetic concentration tailings discharged in step S5 to form the final fine-grained tailings.

[0015] Preferably, in step S1, the secondary crushing equipment is a jaw crusher, and the screen forming a closed circuit with the secondary crushing equipment is a linear vibrating screen with a sieve hole size of 100 mm; the sieves for the three dry screenings are also linear vibrating screens with sieve hole sizes of 40 mm, 15 mm, and 6 mm, respectively; the dry high-intensity magnetic separator is a permanent magnet roller-type high-intensity magnetic powder ore dry separator with a maximum feed particle size of 20 mm; the magnetic field strength of the drum surface is 11000-13000 Oe, 12000Oe is preferred; the frequency of the drum inverter is 28-32HZ, preferably 30HZ; the large block jig machine is a diaphragm large block jig machine, the jig stroke is 130-150 times / min, and the jig stroke is 90-110mm; the photoelectric intelligent sorting machine is an XNDT-104 fully automatic intelligent online sorting machine, the belt width is 1.5-1.7m, preferably 1.6m; the belt speed is 3-4m / s.

[0016] In addition, in step S2, the photoelectric intelligent sorting machine can also be a HOT intelligent X-ray sorting machine.

[0017] Preferably, in step S3, the fine crushing equipment is a jaw crusher, and the screen forming a closed circuit with it is a linear vibrating screen with a sieve hole size of 40 mm; the ultra-fine crushing equipment is a high-pressure roller mill, and the sieve forming a closed circuit with it is a linear vibrating screen with a sieve hole size of 6 mm; the coarse-grained wet high-intensity magnetic separator is a Slon coarse-grained vertical ring pulsating high-gradient magnetic separator, with a maximum feed particle size of 6 mm, a magnetic field strength of 954-1194KA / m, a rotating ring speed of 2-4 rpm, and a pulsation frequency of 40-80 times / min.

[0018] Preferably, in step S5, the grinding operation adopts a wet ball mill, and the grinding fineness is -0.076mm80%~95%; the fine-grained wet strong magnetic roughing and fine-grained wet strong magnetic sweeping both adopt a fine-grained pulsating high-gradient magnetic separator, the roughing magnetic field strength is 0.8~1.2T, and the roughing magnetic field strength is 1.0~1.4T.

[0019] Preferably, in step S6, the reagent system for reverse flotation roughing is: NaOH dosage 800-1200g / t flotation feed, CaO dosage 200-400g / t flotation feed, starch dosage 800-1200g / t flotation feed, sodium oleate dosage 1000-1500g / t flotation feed; the reagent system for reverse flotation cleaning is: sodium oleate dosage 500-1000g / t flotation feed; no reagent is added in the reverse flotation scavenging operation.

[0020] In addition, in step S6, the reagent system for reverse flotation roughing can also be: NaOH dosage 500-800g / t flotation feed, starch dosage 500-800g / t flotation feed, collector dosage 300g / t-600g / t; the reagent system for reverse flotation fine selection is: collector dosage 100-250g / t flotation feed; the reagent system for reverse flotation fine selection is: collector dosage 120g / t-200g / t flotation feed; reverse flotation sweeping operation does not add reagents. The collector is made of dodecylamine and glacial acetic acid solution in a mass ratio of 4:0.9-4:1.1 and heated at 80-100°C hot water.

[0021] In addition, in order to further realize the resource utilization of tailings and reduce the final discharge of fine tailings, the photoelectric intelligent pre-selection tailings and jigging pre-selection tailings discharged in step S2 are sold as building aggregate products; in this case, the dry strong magnetic tailings discharged from step S2 and the wet strong magnetic tailings discharged from step S3 are combined and then fed into dry screening and wet screening in turn to obtain

[0022] There are three particle sizes of tailings: +4.75mm, 0.5-4.75mm, and -0.5mm. The +4.75mm tailings are sold as construction aggregate products, and the 0.5-4.75mm particle size tailings are sold as construction sand products; the reverse flotation sweeping tailings discharged from step S6 are combined with the -0.5mm particle size tailings discharged from step S4 to form the final fine-grained tailings.

[0023] Compared with the prior art, the ore dressing method of the refractory iron ore containing symbiotic hematite and siderite of the present invention has the following beneficial effects:

[0024] (1) The combined pre-selection process of the present invention can achieve precise classification, and organically integrates different pre-selection methods and pre-selection equipment, so as to achieve effective pre-selection of all particle sizes of weakly magnetic and difficult-to-select iron ore under wide particle size (0-100 mm) conditions, wherein: 6-15 mm particle size is pre-selected by dry strong magnetic separator, 15-40 mm particle size is pre-selected by large block jig, 40-100 mm particle size is pre-selected by photoelectric intelligent separator, and 0-6 mm particle size is pre-selected by coarse wet strong magnetic separator. The present invention organically integrates multiple pre-selection methods (magnetic separation, gravity separation, photoelectric separation), so as to achieve effective pre-selection of all particle sizes of weakly magnetic iron ore under wide particle size (0-100 mm) conditions, and solves the problem of narrow effective pre-selection particle size of traditional single pre-selection method, and greatly improves the sorting accuracy. Finally, the iron grade of the final pre-selected concentrate is more than 9 percentage points higher than the iron grade of the selected weakly magnetic and difficult-to-select iron ore.

[0025] (2) The combined pre-selection process of the present invention adopts different pre-selection methods according to the characteristics of ores of different particle sizes, which can give full play to the performance of various pre-selection equipment and effectively improve the sorting effect. For example, the present invention adopts photoelectric intelligent pre-selection for large pieces of ore of 40 to 100 mm, which solves the problem that if strong magnetic pre-selection is used for this particle size, the centrifugal force on the mineral is much greater than the magnetic force, resulting in a significantly low metal recovery rate. At the same time, since photoelectric intelligent pre-selection requires a single layer of cloth, photoelectric intelligent pre-selection is used for large pieces of ore of 40 to 100 mm, which also effectively improves the hourly processing capacity of photoelectric intelligent pre-selection. For another example, for fine particles of 0 to 6 mm, because of its fine particle size and easy agglomeration, the effect of dry strong magnetic pre-selection is very poor. Therefore, the present invention uses a coarse-grained wet strong magnetic separator for wet strong magnetic pre-selection.

[0026] (3) The combined pre-selection process of the present invention adopts intelligent pre-selection and jigging pre-selection to discard large pieces of tailings, achieving the purpose of "discarding as early as possible", thereby effectively reducing the energy consumption of subsequent crushing. At the same time, the concentrates obtained by intelligent pre-selection and jigging pre-selection are crushed again and then wet strong magnetic pre-selection is used to discard tailings, which further increases the amount of tailings discarded and also improves the grade of the final pre-selected concentrate.

[0027] (4) Compared with the traditional single pre-selection process, the combined pre-selection process of the present invention has the advantages of large selected particle size, wide particle size, large tailings discarding amount, high concentrate grade and low energy consumption.

[0028] (5) Compared with the traditional single pre-selection process, the combined pre-selection process of the present invention has the advantages of large selected particle size, wide particle size, large tailing amount, low energy consumption, etc., and the tailing yield is as high as more than 33%.

[0029] (6) The final pre-selected tailings are fed into dry screening in sequence, and finally +4.75mm building aggregate products, 0.5-4.75mm building sand products, and -0.5mm particle size are obtained.

[0030] (7) The present invention adopts a pure physical mineral processing process of grinding-strong magnetic separation-reverse flotation to obtain qualified concentrate for pre-selected concentrate. Compared with the traditional roasting-magnetic separation process of siderite and limonite, it has the advantages of low production cost, low energy consumption, and less environmental pollution.

[0031] (8) In addition, the photoelectric intelligent pre-selection tailings and jigging pre-selection tailings discharged by the method of the present invention are sold as building aggregate products; the dry strong magnetic tailings discharged in step S2 and the wet strong magnetic tailings discharged in step S3 are combined and successively fed into dry screening and wet screening to obtain building aggregate products with a particle size of +4.75 mm and building sand products with a particle size of 0.5-4.75 mm, respectively, thereby greatly improving resource utilization. The yield of the obtained building aggregate products - jigging pre-selection tailings, photoelectric intelligent pre-selection tailings, +4.75 mm tailings and 0.5-4.75 mm building sand products accounts for more than 28% of the selected original ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart of the pre-selection process principle of a refractory iron ore beneficiation method in which hematite and siderite coexist.

[0033] Figure 2 The present invention is a flow chart showing the quality of an embodiment of the pre-selection process of a method for beneficiating refractory iron ore containing coexisting hematite and siderite.

[0034] Figure 3 The present invention discloses a process flow chart of the final pre-selected concentrate grinding - high-intensity magnetic separation - reverse flotation principle of a refractory iron ore beneficiation method containing symbiotic hematite and siderite. DETAILED DESCRIPTION

[0035] To further describe the present invention, a method for beneficiating refractory iron ore containing symbiotic hematite and siderite is further described in detail below in conjunction with the accompanying drawings and embodiments. However, the present invention is not limited to the embodiments.

[0036] The ore sample used in this embodiment is a weakly magnetic iron ore from an iron mine in western China. The iron minerals of the ore are mainly hematite and siderite, which account for more than 95% of the iron minerals, and are typical weakly magnetic and difficult to select iron ore. The results of multi-element analysis and iron phase analysis of the ore are shown in Tables 1 and 2.

[0037] Table 1 Results of multi-element analysis of raw ore (%)

[0038] element TFe <![CDATA[SiO2]]> <![CDATA[Al2O3]]> CaO MgO S P MnO content 32.51 26.05 2.85 1.14 1.07 1.18 0.025 1.07 element <![CDATA[K2O]]> <![CDATA[Na2O]]> ZnO NiO <![CDATA[TiO2]]> <![CDATA[V2O5]]> <![CDATA[Cr2O3]]> Burning content 0.881 0.047 0.040 0.005 0.195 0.008 0.003 12.92

[0039] Table 2 Analysis results of iron phase of raw ore (%)

[0040] Phase Name magnetite Hematite Siderite Iron silicate Pyrite Pyrrhotite total Iron content 0.50 21.41 9.68 0.52 0.31 0.0022 32.42 Iron distribution rate 1.54 66.04 29.85 1.60 0.96 0.01 100.00

[0041] Depend on Figure 1 The pre-selection process principle flow chart of the present invention is a method for beneficiating refractory iron ore with coexistence of hematite and siderite. Figure 2 , Figure 3 It can be seen that the specific implementation steps adopted in the embodiment of the ore dressing method for refractory iron ore in which hematite and siderite coexist are as follows:

[0042] (1) The ore is crushed in a closed circuit to a size of less than 100 mm, and then dry-screened three times to obtain four particle sizes of 0-6 mm, 6-15 mm, 15-40 mm, and 40-100 mm.

[0043] (2) The 6-15 mm particle size in step (1) is subjected to dry strong magnetic preselection using a permanent magnetic roller strong magnetic powder ore dry separator, the 15-40 mm particle size is subjected to jigging preselection using a diaphragm large block jigger, and the 40-100 mm particle size is subjected to photoelectric intelligent preselection using a photoelectric intelligent separator. The discharged jigging preselection tailings and photoelectric intelligent preselection tailings can be sold as building aggregate products.

[0044] (3) The photoelectric intelligent pre-selected concentrate obtained in step (2) is finely crushed in a closed circuit to 0-40 mm and then combined with the jigging pre-selected concentrate obtained in step (2), and then ultra-finely crushed in a closed circuit to 0-6 mm, and then the ultra-fine crushed product is combined with the 0-6 mm particle size in step (1) and subjected to wet strong magnetic pre-selection.

[0045] (4) The dry strong magnetic pre-selection concentrate obtained in step (2) and the wet strong magnetic pre-selection concentrate obtained in step (3) are combined as the final pre-selection concentrate, and the dry strong magnetic pre-selection tailings, jigging pre-selection tailings, photoelectric intelligent pre-selection tailings obtained in step (2) and the wet strong magnetic pre-selection tailings obtained in step (3) are combined as the final pre-selection tailings.

[0046] (5) grinding the final pre-selected concentrate obtained in step (4), and then subjecting the ground product to fine-grained wet strong magnetic roughing and sweeping separation, respectively discharging fine-grained wet strong magnetic roughing tailings and fine-grained wet strong magnetic concentrating tailings to obtain fine-grained wet strong magnetic concentrating concentrate;

[0047] (6) The fine-grained wet strong magnetic concentration concentrate obtained in step (5) is fed into a first roughing, a first fine, and a second scavenging reverse flotation operation to obtain a final iron concentrate, and the reverse flotation scavenging tailings are discharged; the reverse flotation scavenging tailings are combined with the fine-grained wet strong magnetic roughing tailings and the fine-grained wet strong magnetic concentration tailings discharged in step S5 to form the final fine-grained tailings.

[0048] The secondary crushing equipment in step (1) is a jaw crusher, and the screen forming a closed circuit with it is a linear vibrating screen with a screen hole size of 100 mm; the screens for the three dry screenings are also linear vibrating screens with screen hole sizes of 40 mm, 15 mm, and 6 mm, respectively.

[0049] The dry strong magnetic pre-selection equipment in step (2) is a permanent magnet roller strong magnetic powder ore dry separator, with a maximum feed particle size of 20 mm, a drum surface magnetic field strength of 12000 Oe, and a drum inverter frequency of 30 Hz.

[0050] The jig pre-selection equipment in step (2) is a diaphragm type large block jig, the jig stroke is 135 times / min, and the jig stroke is 105mm; the photoelectric intelligent sorting machine is an XNDT-104 intelligent pre-selection machine, the belt width is 1.6m, and the belt speed is 3.5m / s.

[0051] The fine crushing equipment in the step (3) is a jaw crusher, and the screen forming a closed circuit with it is a linear vibrating screen with a sieve hole size of 40 mm; the ultra-fine crushing equipment is a high-pressure roller mill, and the screen forming a closed circuit with it is a linear vibrating screen with a sieve hole size of 6 mm; the wet strong magnetic pre-selection equipment is a Slon coarse-grained vertical ring pulsating high-gradient magnetic separator, with a maximum feed particle size of 6 mm, a magnetic field strength of 1114KA / m, a rotating ring speed of 3 rpm, and a pulsation frequency of 60 times / min.

[0052] In the step (5), the grinding operation adopts a wet ball mill, and the grinding fineness is -0.076mm90%; the fine-grained wet strong magnetic roughing and fine-grained wet strong magnetic sweeping both adopt a fine-grained pulsating high-gradient magnetic separator, and the roughing magnetic field strength is 1.0T and the roughing magnetic field strength is 1.2T.

[0053] In the step (6), the reagent system for reverse flotation roughing is: NaOH dosage is 1000g / t flotation feed, CaO dosage is 300g / t flotation feed, starch dosage is 1000g / t flotation feed, and sodium oleate dosage is 1300g / t flotation feed; the reagent system for reverse flotation cleaning is: sodium oleate dosage is 600g / t flotation feed; no reagent is added in the reverse flotation scavenging operation.

[0054] After the above-mentioned process treatment, the weakly magnetic iron ore with an original ore iron grade of 32.60% can be discarded in advance with qualified tailings with a yield of 33.31% and an iron grade of 14.49%. The iron grade of the obtained pre-selected concentrate is 41.64%, which is more than 9 percentage points higher than that of the original ore, and the iron recovery rate of the concentrate is 85.19%. The pre-selected concentrate is subjected to grinding-fine-grained wet strong magnetic one roughing and one sweeping-one roughing, one fine, two sweeping reverse flotation, and the final concentrate iron grade is 63.12%. The iron recovery rate of the grinding operation is 80.52%, and the iron grade of the grinding tailings is 17.30%.

[0055] In addition, a new type of high-efficiency iron ore reverse flotation collector is also used. In the embodiment, the new type of high-efficiency iron ore reverse flotation collector is made by heating dodecylamine and glacial acetic acid solution at a mass ratio of 4:1 with hot water at 90°C. In step (6) of using the new type of high-efficiency iron ore reverse flotation collector, the reagent system for reverse flotation roughing is: NaOH dosage 600g / t flotation feed, starch dosage 700g / t flotation feed, collector dosage 450g / t flotation feed; the reagent system for reverse flotation concentration is: collector dosage 100-250g / t flotation feed; the reagent system for reverse flotation concentration is: collector dosage 120g / t-200g / t flotation feed; no reagent is added in the reverse flotation sweeping operation. The final concentrate iron grade obtained is 63.52%, and the iron recovery rate of the grinding operation is 81.63%.

[0056] In addition, in the embodiment, the dry strong magnetic tailings discharged from step S2 and the wet strong magnetic tailings discharged from step S3 are combined and then fed into dry screening and wet screening in sequence to obtain tailings of three particle sizes of +4.75mm, 0.5-4.75mm, and -0.5mm, respectively. The +4.75mm tailings are sold as building aggregate products, and the 0.5-4.75mm particle size tailings are sold as building sand products. The yield of the obtained building aggregate products - jigging pre-selected tailings, photoelectric intelligent pre-selected tailings, +4.75mm tailings, and 0.5-4.75mm particle size building sand products accounted for 28.5% of the original ore yield.

[0057] The above are only preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined by the claims.

Claims

1. A method for beneficiating refractory iron ore containing symbiotic limonite and siderite, characterized in that This is done using the following steps: S1 crushes the weakly magnetic refractory iron ore with TFe content between 25% and 35% and mainly hematite and siderite into smaller than 100mm in a closed circuit, and then dry screens the ore three times to obtain four particle sizes of 0-6mm, 6-15mm, 15-40mm and 40-100mm. S2 uses different pre-selection equipment to pre-select and discard tailings for the three particle sizes of 6-15mm, 15-40mm, and 40-100mm obtained in step S1, wherein the 6-15mm particle size is pre-selected by a dry strong magnetic separator to obtain a dry strong magnetic pre-selected concentrate and discharge the dry strong magnetic tailings, the 15-40mm particle size is pre-selected by a large jig to obtain a jig pre-selected concentrate and discharge the jig pre-selected tailings, and the 40-100mm particle size is pre-selected by a photoelectric intelligent separator to obtain a photoelectric intelligent pre-selected concentrate and discharge the photoelectric intelligent pre-selected tailings; In step S3, the photoelectric intelligent pre-selected concentrate obtained in step S2 is crushed to 0-40 mm by fine crushing in a closed circuit, and then combined with the jigging pre-selected concentrate obtained in step S2, and then crushed to 0-6 mm by ultra-fine crushing in a closed circuit, and then the ultra-fine crushed product is combined with the 0-6 mm particle size obtained in step S1, and then wet strong magnetic pre-selection is performed using a coarse wet strong magnetic separator to obtain a wet strong magnetic pre-selected concentrate and discharge a wet strong magnetic tailings; S4 combines the dry strong magnetic pre-selected concentrate obtained in step S2 with the wet strong magnetic pre-selected concentrate obtained in step S3 as the final pre-selected concentrate, and combines the dry strong magnetic tailings, jigging pre-selected tailings, photoelectric intelligent pre-selected tailings discharged in step S2 and the wet strong magnetic tailings discharged in step S3 as the final pre-selected tailings; S5 grinds the final pre-selected concentrate obtained in step S4, and then separates the ground product through fine-grained wet strong magnetic roughing and sweeping separation, and discharges fine-grained wet strong magnetic roughing tailings and fine-grained wet strong magnetic concentration tailings respectively, to obtain fine-grained wet strong magnetic concentration concentrate; S6 feeds the fine-grained wet strong magnetic concentration concentrate obtained in step S5 into a first roughing, a first fine, and a second scavenging reverse flotation operation to obtain a final iron concentrate, and discharges the reverse flotation scavenging tailings; the reverse flotation scavenging tailings are combined with the fine-grained wet strong magnetic roughing tailings and the fine-grained wet strong magnetic concentration tailings discharged in step S5 to form the final fine-grained tailings.

2. A method for beneficiating refractory iron ore containing symbiotic limonite and siderite, characterized in that This is done using the following steps: S1 crushes the weakly magnetic refractory iron ore with TFe content between 25% and 35% and mainly hematite and siderite into smaller than 100mm in a closed circuit, and then dry screens the ore three times to obtain four particle sizes of 0-6mm, 6-15mm, 15-40mm and 40-100mm. S2 uses different pre-selection equipment to pre-select and discard the tailings of the three particle sizes of 6-15mm, 15-40mm, and 40-100mm obtained in step S1, wherein the 6-15mm particle size is pre-selected by a dry strong magnetic separator to obtain a dry strong magnetic pre-selected concentrate and discharge the dry strong magnetic tailings, the 15-40mm particle size is pre-selected by a large block jig to obtain a jig pre-selected concentrate and discharge the jig pre-selected tailings, and the 40-100mm particle size is pre-selected by a photoelectric intelligent separator to obtain a photoelectric intelligent pre-selected concentrate and discharge the photoelectric intelligent pre-selected tailings, and the discharged jig pre-selected tailings and photoelectric intelligent pre-selected tailings are sold as building aggregate products; In step S3, the photoelectric intelligent pre-selected concentrate obtained in step S2 is crushed to 0-40 mm by fine crushing in a closed circuit, and then combined with the jigging pre-selected concentrate obtained in step S2, and then crushed to 0-6 mm by ultra-fine crushing in a closed circuit, and then the ultra-fine crushed product is combined with the 0-6 mm particle size obtained in step S1, and then wet strong magnetic pre-selection is performed using a coarse wet strong magnetic separator to obtain a wet strong magnetic pre-selected concentrate and discharge a wet strong magnetic tailings; S4 combines the dry strong magnetic pre-selected concentrate obtained in step S2 with the wet strong magnetic pre-selected concentrate obtained in step S3 as the final pre-selected concentrate, combines the dry strong magnetic tailings discharged in step S2 and the wet strong magnetic tailings discharged in step S3, and sequentially feeds them into dry screening and wet screening to obtain tailings of three particle sizes of +4.75mm, 0.5-4.75mm, and -0.5mm, respectively; the +4.75mm tailings are sold as construction aggregate products, and the 0.5-4.75mm tailings are sold as construction sand products; S5 grinds the final pre-selected concentrate obtained in step S4, and then separates the ground product through fine-grained wet strong magnetic roughing and sweeping separation, and discharges fine-grained wet strong magnetic roughing tailings and fine-grained wet strong magnetic concentration tailings respectively, to obtain fine-grained wet strong magnetic concentration concentrate; S6 feeds the fine-grained wet strong magnetic concentrate obtained in step S5 into a coarse, fine and two-sweep reverse flotation operation to obtain the final iron concentrate, and discharges the reverse flotation sweeping tailings; the reverse flotation sweeping tailings are combined with the -0.5mm particle size tailings discharged in step S4 to form the final fine-grained tailings.

3. The ore dressing method for refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S1, the secondary crushing equipment adopts a jaw crusher, and the screen forming a closed circuit with the secondary crushing equipment adopts a linear vibrating screen with a screen hole size of 100 mm; the screens for the three dry screenings are also linear vibrating screens, and the screen hole sizes are 40 mm, 15 mm, and 6 mm respectively.

4. The ore dressing method for refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S2, the dry-type strong magnetic separator is a permanent magnet roller-type strong magnetic powder ore dry separator, with a maximum feed particle size of 20 mm, a drum surface magnetic field strength of 11000-13000 Oe, and a drum inverter frequency of 28-32 Hz; the large block jig is a diaphragm large block jig, with a jig stroke of 130-150 times / min and a jig stroke of 90-110 mm; the photoelectric intelligent separator is an XNDT-104 fully automatic intelligent The online separator has a belt width of 1.5 to 1.7 m and a belt speed of 3 to 4 m / s; the dry strong magnetic separator is a permanent magnet roller strong magnetic powder ore dry separator, with a maximum feed particle size of 20 mm, a drum surface magnetic field strength of 11000 to 13000 Oe, and a drum inverter frequency of 28 to 32 Hz; the large block jig is a diaphragm large block jig, with a jig stroke of 130 to 150 times / min and a jig stroke of 90 to 110 mm.

5. The ore dressing method for refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S3, the fine crushing equipment is a jaw crusher, and the screen forming a closed circuit with it is a linear vibrating screen with a sieve hole size of 40 mm; the ultra-fine crushing equipment is a high-pressure roller mill, and the screen forming a closed circuit with it is a linear vibrating screen with a sieve hole size of 6 mm; the coarse-grained wet high-intensity magnetic separator is a Slon coarse-grained vertical ring pulsating high-gradient magnetic separator, with a maximum feed particle size of 6 mm, a magnetic field strength of 954-1194KA / m, a rotating ring speed of 2-4 revolutions / minute, and a pulsation frequency of 40-80 times / minute.

6. A method for beneficiating refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S5, the grinding operation adopts a wet ball mill, and the grinding fineness is -0.076mm80%~95%; the fine-grained wet strong magnetic roughing and fine-grained wet strong magnetic sweeping both adopt fine-grained pulsating high-gradient magnetic separators, and the roughing magnetic field strength is 0.8~1.2T, and the roughing magnetic field strength is 1.0~1.4T.

7. The ore dressing method for refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S6, the reagent system for reverse flotation roughing is: NaOH dosage is 800-1200g / t flotation feed, CaO dosage is 200-400g / t flotation feed, starch dosage is 800-1200g / t flotation feed, sodium oleate dosage is 1000-1500g / t flotation feed; the reagent system for reverse flotation cleaning is: sodium oleate dosage is 500-1000g / t flotation feed; no reagent is added in the reverse flotation scavenging operation.

8. The ore dressing method for refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S6, the reagent system for reverse flotation roughing can also be: NaOH dosage 500-800g / t flotation feed, starch dosage 500-800g / t flotation feed, collector dosage 300g / t-600g / t flotation feed; the reagent system for reverse flotation cleaning is: collector dosage 100-250g / t flotation feed; the reagent system for reverse flotation cleaning is: collector dosage 120g / t-200g / t flotation feed; no reagent is added in the reverse flotation scavenging operation; the collector is made of dodecylamine and glacial acetic acid solution in a mass ratio of 4:0.9-4:1.1 and heated at 80-100°C hot water.

9. The ore dressing method for refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S2, the dry-type strong magnetic separator is a permanent magnet roller strong magnetic powder ore dry separator, the maximum feed particle size is 20mm, the magnetic field strength of the drum surface is 11000-13000Oe, and the drum inverter frequency is 28-32HZ; the large block jig is a diaphragm large block jig, the jig stroke is 130-150 times / min, and the jig stroke is 90-110mm; the photoelectric intelligent sorting machine is an XNDT-104 fully automatic intelligent online sorting machine, the belt width is 1.5-1.7m, and the belt speed is 3-4m / s; In step S3, the fine crushing equipment is a jaw crusher, and the screen forming a closed circuit with it is a linear vibrating screen with a screen hole size of 40 mm; the ultra-fine crushing equipment is a high-pressure roller mill, and the screen forming a closed circuit with it is a linear vibrating screen with a screen hole size of 6 mm; the coarse-grained wet high-intensity magnetic separator is a Slon coarse-grained vertical ring pulsating high-gradient magnetic separator, with a maximum feed particle size of 6 mm, a magnetic field strength of 954-1194 KA / m, a rotating ring speed of 2-4 rpm, and a pulsation frequency of 40-80 times / min; In step S5, the grinding operation adopts a wet ball mill, and the grinding fineness is -0.076mm80%~95%; the fine-grained wet strong magnetic roughing and fine-grained wet strong magnetic sweeping both adopt fine-grained pulsating high-gradient magnetic separators, and the roughing magnetic field strength is 0.8~1.2T, and the roughing magnetic field strength is 1.0~1.4T. In step S6, the reagent system for reverse flotation roughing is: NaOH dosage is 800-1200g / t flotation feed, CaO dosage is 200-400g / t flotation feed, starch dosage is 800-1200g / t flotation feed, sodium oleate dosage is 1000-1500g / t flotation feed; the reagent system for reverse flotation cleaning is: sodium oleate dosage is 500-1000g / t flotation feed; no reagent is added in the reverse flotation scavenging operation.

10. The method for beneficiating refractory iron ore containing symbiotic hematite and siderite as claimed in claim 1 or 2, characterized in that: In step S2, the dry-type strong magnetic separator is a permanent magnet roller strong magnetic powder ore dry separator, the maximum feed particle size is 20mm, the magnetic field strength of the drum surface is 11000-13000Oe, and the drum inverter frequency is 28-32HZ; the large block jig is a diaphragm large block jig, the jig stroke is 130-150 times / min, and the jig stroke is 90-110mm; the photoelectric intelligent sorting machine is an XNDT-104 fully automatic intelligent online sorting machine, the belt width is 1.5-1.7m, and the belt speed is 3-4m / s; In step S3, the fine crushing equipment is a jaw crusher, and the screen forming a closed circuit with it is a linear vibrating screen with a screen hole size of 40 mm; the ultra-fine crushing equipment is a high-pressure roller mill, and the screen forming a closed circuit with it is a linear vibrating screen with a screen hole size of 6 mm; the coarse-grained wet high-intensity magnetic separator is a Slon coarse-grained vertical ring pulsating high-gradient magnetic separator, with a maximum feed particle size of 6 mm, a magnetic field strength of 954-1194 KA / m, a rotating ring speed of 2-4 rpm, and a pulsation frequency of 40-80 times / min; In step S5, the grinding operation adopts a wet ball mill, and the grinding fineness is -0.076mm80%~95%; the fine-grained wet strong magnetic roughing and fine-grained wet strong magnetic sweeping both adopt fine-grained pulsating high-gradient magnetic separators, and the roughing magnetic field strength is 0.8~1.2T, and the roughing magnetic field strength is 1.0~1.4T. In step S6, the reagent system for reverse flotation roughing is: NaOH dosage 500-800g / t flotation feed, starch dosage 500-800g / t flotation feed, collector dosage 300g / t-600g / t flotation feed; the reagent system for reverse flotation cleaning is: collector dosage 100-250g / t flotation feed; the reagent system for reverse flotation cleaning is: collector dosage 120g / t-200g / t flotation feed; no reagent is added in the reverse flotation scavenging operation; the collector is made of dodecylamine and glacial acetic acid solution in a mass ratio of 4:0.9-4:1.1 and heated at 80-100°C hot water.

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