Method for recovering iron and titanium from low-iron low-titanium ultra-lean ore

Abstract

The invention provides a method for recovering iron and titanium from low-iron and low-titanium type ultra-lean ore, and belongs to the technical field of comprehensive recycling of minerals. According to the invention, two-stage dry waste throwing is adopted, the principle of'more crushing and less grinding, and complete throwing 'is followed, the grinding granularity is reduced, and the treatment capacity of the whole process is improved. Dry magnetic separation is adopted and is simple and easy to realize; the process flow is simplified, the whole process flow is simple and smooth, small in occupied area and environmentally friendly, return water can be completely recycled, and for water-deficient areas or areas where tailing ponds cannot be built, the process is high in practicability and very easy to apply to actual production; and the generated tailings can be used as building sandstone or cement ceramics, so that the tailing-free mine is realized. An effective method is provided for recycling the low-iron and low-titanium type ultra-lean ore, the comprehensive resource recycling rate of the low-iron and low-titanium type ultra-lean ore is greatly increased, and waste is turned into wealth.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive mineral recycling, and in particular to a method for recovering iron and titanium from low-iron and low-titanium ultra-lean ores. Background Art

[0002] At present, the low-grade titanium magnet beneficiation process includes dry tailings discarding, weak magnetic iron separation, strong magnetic titanium separation, strong magnetic regrinding and re-selection, gravity separation, flotation desulfurization, and flotation titanium selection. The main processes are as follows: (1) coarse dry tailings discarding first - stage grinding weak magnetic iron separation - strong magnetic titanium separation - flotation desulfurization - flotation titanium selection process; (2) coarse dry tailings discarding first - stage grinding weak magnetic iron separation - strong magnetic titanium separation - chute - shaking table titanium selection process. The disadvantages of the first process: the process is complicated, the process is too long, the cost is high, and the flotation agent has a certain impact on the environment; the second process has a large shaking table area, large water consumption, high cost, and poor applicability to water-scarce areas. For low-iron and low-titanium ultra-lean ores, the TFe content is 10-15%, and the TiO 2 The content is 3-4%. The above process is costly and not suitable for actual production. Usually this type of low-iron and low-titanium ultra-poor ore is abandoned due to geographical restrictions. Some mines only recycle magnetite and do not recycle ilmenite, which has caused a huge waste of mineral resources. Summary of the invention

[0003] The object of the present invention is to provide a method for recovering iron and titanium from low-iron and low-titanium ultra-lean ores, so that the low-iron and low-titanium ultra-lean ores can be fully recovered and utilized.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for recovering iron and titanium from low-iron and low-titanium ultra-lean ores, comprising the following steps:

[0006] The ultra-lean ore is first crushed to obtain ore particles; the ultra-lean ore has a TFe content of 12-16wt%, TiO 2 The content is 3-4wt%;

[0007] The raw ore particles are subjected to a first stage of dry disposal to obtain a rough concentrate and a stage of tailings; the first stage of dry disposal includes a roughing selection and a fine selection;

[0008] The roughing concentrate is subjected to a second crushing, and the obtained ore sample is subjected to a second stage of dry disposal to obtain a second stage of dry disposal concentrate and a second stage of tailings; the second stage of dry disposal includes a first roughing and a first concentrating;

[0009] After grinding the second-stage dry-throwing concentrate, wet weak magnetic separation is performed to obtain iron concentrate and weak magnetic separation tailings; the wet weak magnetic separation includes a roughing separation, a fine separation and a scavenging separation;

[0010] The weak magnetic separation tailings are subjected to wet strong magnetic separation to obtain strong magnetic separation titanium concentrate and strong magnetic separation tailings;

[0011] The high-intensity magnetic separation titanium concentrate is discarded by using a chute to obtain chute titanium concentrate and chute tailings; the tailing discarding includes one roughing selection, six cleaning selections and one scavenging selection;

[0012] The chute titanium concentrate is subjected to dry magnetic separation to obtain titanium concentrate.

[0013] Preferably, the particle size of the raw ore particles is ≤15 mm.

[0014] Preferably, in the first stage of dry waste disposal, the magnetic field strength for roughing is 0.5 to 0.68 T, and the magnetic field strength for fine selection is 0.5 to 0.68 T.

[0015] Preferably, a second crushing and screening is performed until the material particle size is ≤4 mm; in the second stage of dry waste disposal, the magnetic field strength of the roughing is 0.2-0.4 T, and the magnetic field strength of the fine selection is 0.2-0.4 T.

[0016] Preferably, the grinding is performed to a material content of 75-85% with a fineness of -0.074 mm.

[0017] Preferably, in the wet weak magnetic separation, the magnetic field strength for rough separation is 0.10-0.2T, the magnetic field strength for fine separation is 0.10-0.2T, and the magnetic field strength for scanning separation is 0.10-0.2T.

[0018] Preferably, the wet high-intensity magnetic separation includes a roughing separation, a fine separation and a scavenging separation, the magnetic field strength of the roughing separation is 0.4-0.69T, the magnetic field strength of the scavenging separation is 0.4-0.69T, and the magnetic field strength of the fine separation is 0.4-0.58T.

[0019] Preferably, the dry magnetic separation includes dry weak magnetic separation and dry strong magnetic separation performed sequentially, and the dry strong magnetic separation includes a roughing separation and a fine separation.

[0020] Preferably, the magnetic field strength of the dry weak magnetic separation is 0.08-0.12T; in the dry strong magnetic separation, the magnetic field strength of the roughing separation is 0.8-1.0T, and the magnetic field strength of the fine separation is 0.8-1.0T.

[0021] The present invention adopts a process flow of "two-stage dry waste disposal-weak magnetic iron separation-strong magnetic titanium separation-chute tailings disposal-dry magnetic separation". After the raw ore is crushed, a stage of dry waste disposal is carried out; after the coarse concentrate is crushed again, a second stage of dry waste disposal is carried out, and the titanium grade of the dry concentrate is enriched again, which is beneficial to subsequent experiments; then magnetite is pre-selected by weak magnetic iron separation, which not only reduces the influence of magnetite on titanium selection operation, but also recovers the useful mineral magnetite, and then strong magnetic titanium separation is carried out. According to the difference in physical properties between ilmenite and gangue minerals, ilmenite is selected by strong magnetic separation, so most of the tailings are directly discarded, and this part of the tailings can be used as raw materials for cement ceramics; then the chute tailings disposal is carried out, because the strong magnetic separation concentrate contains fine-grained mud, which affects subsequent operations, and the chute is used for tailings disposal; finally, the chute concentrate is subjected to dry magnetic separation to obtain titanium concentrate, which is simple and easy to implement.

[0022] The present invention adopts two-stage dry waste disposal, follows the principle of "more crushing, less grinding, and as much disposal as possible", reduces the particle size of the grinding, and improves the processing capacity of the entire process. The present invention adopts the second stage of dry waste disposal, which not only improves the titanium selection grade of the next level, improves the grade of coarse concentrate iron and titanium of dry magnetic separation, but also improves the processing capacity of the entire process; the tailings of dry waste disposal are directly recycled for sand and gravel aggregates, which greatly improves the comprehensive utilization rate of tailings in mines; the tailings produced can be comprehensively recycled and utilized, realizing the tailing-free mine. The present invention adopts dry magnetic separation instead of flotation process, simplifies the process flow, reduces production costs, reduces reagent pollution, saves a lot of water, and reduces floor space.

[0023] The present invention is practical: currently for low iron and low titanium type ultra-poor ores (TFe content 10-15%, TiO 2 The content is 3-4%). ​​Due to the complicated recycling process and high cost, the actual mines do not recycle them. The whole process provided by the present invention is simple and smooth; it occupies a small area, is green and environmentally friendly, and the return water can be fully recycled. For water-scarce areas and areas where tailings ponds cannot be built, the process is highly practical and can be easily applied to actual production; the tailings produced can be used as building sand and gravel or cement ceramics to achieve tail-free mines. Therefore, the method of the present invention allows low-iron and low-titanium ultra-poor ores to be recycled, greatly improves the comprehensive resource recycling rate of low-iron and low-titanium ultra-poor mines, realizes the transformation of waste into treasure, and provides an effective method for the recycling of low-iron and low-titanium ultra-poor ores. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of the method for recovering iron and titanium from low-iron and low-titanium ultra-lean ores. DETAILED DESCRIPTION

[0025] In the present invention, unless otherwise specified, the required raw materials or reagents are commercially available products well known to those skilled in the art.

[0026] The present invention provides a method for recovering iron and titanium from low-iron and low-titanium ultra-lean ores, comprising the following steps:

[0027] The ultra-lean ore is first crushed to obtain ore particles; the ultra-lean ore has a TFe content of 12-16wt%, TiO 2 The content is 3-4wt%;

[0028] The raw ore particles are subjected to a first stage of dry disposal to obtain a rough concentrate and a stage of tailings; the first stage of dry disposal includes a roughing selection and a fine selection;

[0029] The roughing concentrate is subjected to a second crushing, and the obtained ore sample is subjected to a second stage of dry disposal to obtain a second stage of dry disposal concentrate and a second stage of tailings; the second stage of dry disposal includes a first roughing and a first concentrating;

[0030] After grinding the second-stage dry-throwing concentrate, wet weak magnetic separation is performed to obtain iron concentrate and weak magnetic separation tailings; the wet weak magnetic separation includes a roughing separation, a fine separation and a scavenging separation;

[0031] The weak magnetic separation tailings are subjected to wet strong magnetic separation to obtain strong magnetic separation titanium concentrate and strong magnetic separation tailings;

[0032] The high-intensity magnetic separation titanium concentrate is discarded by using a chute to obtain chute titanium concentrate and chute tailings; the tailing discarding includes one roughing selection, six cleaning selections and one scavenging selection;

[0033] The chute titanium concentrate is subjected to dry magnetic separation to obtain titanium concentrate.

[0034] The present invention first crushes the super-lean ore to obtain ore particles;

[0035] In the present invention, the content of TFe in the ultra-lean ore is 12-16wt%, more preferably 15.61wt%, and the content of TiO 2 The content is 3-4wt%, more preferably 3.22wt%, that is, TFe:TiO 2 ≥4. The present invention has no special limitation on the source of the ultra-lean ore, which can be obtained in a manner well known in the art. The present invention has general applicability to ultra-lean ore. The ultra-lean ore with the above content in the present invention belongs to low-iron and low-titanium ultra-lean ore according to the ore industry type.

[0036] In the present invention, the particle size of the raw ore particles is preferably ≤15 mm, more preferably ≤12 mm. The present invention has no special limitation on the first crushing, and the desired particle size can be achieved according to a process well known in the art.

[0037] After obtaining the raw ore particles, the present invention performs a first stage of dry discarding on the raw ore particles to obtain a rough discard concentrate and a stage of tailings.

[0038] In the present invention, the first stage of dry waste disposal includes a roughing process and a fine separation process; in the first stage of dry waste disposal, the magnetic field strength of the rough separation is preferably 0.5-0.68T, more preferably 0.6-0.68T; the magnetic field strength of the fine separation is preferably 0.5-0.68T, more preferably 0.6-0.68T.

[0039] After obtaining the rough cast concentrate, the present invention performs a second crushing on the rough cast concentrate, performs a second stage dry cast waste on the obtained ore sample, and obtains a second stage dry cast concentrate and a second stage tailings.

[0040] The present invention preferably performs a second crushing and screening until the material particle size is ≤4 mm, more preferably ≤3 mm.

[0041] In the present invention, the second stage of dry waste disposal includes a roughing and a concentrating; in the second stage of dry waste disposal, the magnetic field strength of the roughing is preferably 0.2-0.4T, more preferably 0.3T; the magnetic field strength of the concentrating is preferably 0.2-0.4T, more preferably 0.3T. The purpose of the two-stage dry waste disposal of the present invention is to discard most of the tailings and enrich the waste concentrate at the same time; the first stage tailings and the second stage tailings are the discarded tailings, which can be used as sand and gravel for comprehensive utilization.

[0042] After obtaining the second-stage dry-cast concentrate, the present invention grinds the second-stage dry-cast concentrate and then performs wet weak magnetic separation to obtain iron concentrate and weak magnetic separation tailings.

[0043] The present invention preferably grinds the ore until the content of the material with a fineness of -0.074 mm is 75-85%, more preferably 79.7%. The present invention has no special limitation on the specific process of the grinding, and the desired fineness and content can be obtained according to the process known in the art.

[0044] In the present invention, the wet weak magnetic separation includes a roughing selection, a cleaning selection and a scavenging selection; the tailings of the cleaning operation and the concentrate of the scavenging operation are combined and returned to the roughing stage; in the wet weak magnetic separation, the magnetic field strength of the roughing selection is 0.10-0.2T, more preferably 0.12-0.15T; the magnetic field strength of the cleaning selection is preferably 0.10-0.2T, more preferably 0.12-0.15T; the magnetic field strength of the scavenging selection is preferably 0.10-0.2T, more preferably 0.12-0.15T.

[0045] The invention selects iron by wet weak magnetic separation, and selects and scavenges the minerals obtained by the primary roughing to obtain iron concentrate and weak magnetic separation scavenging tailings, and the weak magnetic separation scavenging tailings are used for the next step of titanium separation.

[0046] After obtaining the weak magnetic separation tailings, the invention performs wet strong magnetic separation on the weak magnetic separation tailings to obtain strong magnetic separation titanium concentrate and strong magnetic separation tailings.

[0047] In the present invention, the wet high-intensity magnetic separation preferably includes a roughing selection, a cleaning selection and a scavenging selection. The tailings of the high-intensity magnetic separation and cleaning operation and the concentrate of the high-intensity magnetic separation and scavenging operation are combined and returned to the high-intensity magnetic separation and roughing operation. In the wet high-intensity magnetic separation, the magnetic field strength of the roughing selection is 0.4-0.69T, more preferably 0.58T; the magnetic field strength of the scavenging selection is preferably 0.4-0.69T, more preferably 0.58T; the magnetic field strength of the cleaning selection is preferably 0.4-0.58T, more preferably 0.48T.

[0048] After obtaining the high-intensity magnetic separation titanium concentrate, the invention uses a chute to discard the high-intensity magnetic separation titanium concentrate to obtain chute titanium concentrate and chute tailings.

[0049] In the present invention, the tailings discarding includes one roughing selection, six fine selections and one scavenging selection; the present invention has no special limitation on the specific conditions of the roughing selection, fine selection and scavenging selection in the tailings discarding, and the process can be carried out according to the process well known in the art.

[0050] Since the high-intensity magnetic separation titanium concentrate contains fine-grained mud, the present invention adopts a chute to discard tailings to obtain chute titanium concentrate and chute tailings.

[0051] After obtaining the chute titanium concentrate, the present invention performs dry magnetic separation on the chute titanium concentrate to obtain the titanium concentrate.

[0052] In the present invention, the dry magnetic separation preferably includes dry weak magnetic separation and dry strong magnetic separation performed in sequence, and the dry strong magnetic separation preferably includes a roughing separation and a concentrating separation. The iron concentrate obtained by the dry weak magnetic separation is returned to the first grinding operation; the roughing tailings and the concentrating tailings of the dry strong magnetic separation are combined and returned to the chute roughing operation.

[0053] In the present invention, the magnetic field strength of the dry weak magnetic separation is preferably 0.08-0.12T, more preferably 0.1T; in the dry strong magnetic separation, the magnetic field strength of the roughing selection is preferably 0.8-1.0T, more preferably 0.85T; the magnetic field strength of the fine selection is preferably 0.8-1.0T, more preferably 0.85T.

[0054] The present invention has no special limitation on the specific operation process of roughing, fine selection and scanning selection in each step, and the operation can be carried out according to the process well known in the art.

[0055] The present invention has no particular limitation on the treatment method of the tailings obtained in each step, and the tailings can be treated in a manner well known in the art.

[0056] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0057] The following experimental methods and detection methods, unless otherwise specified, are conventional methods; the following reagents and raw materials, unless otherwise specified, are commercially available.

[0058] Example 1

[0059] The ultra-poor ore comes from low-grade ilmenite in Sichuan, hereinafter referred to as raw ore, with a TFe content of 15.61wt%, TiO 2 The content is 3.22wt%; SiO 2 The content is 39.96wt%; Al 2 O 3 The content is 15.35wt%; the CaO content is 8.87wt%; the MgO content is 5.53wt%;

[0060] The ultra-lean ore is first crushed to a particle size of -12 mm to obtain ore particles;

[0061] One-stage dry disposal: the raw ore particles are subjected to the first stage of dry disposal, including a roughing separation and a fine separation, the magnetic field intensity of the roughing separation and the fine separation is 0.68T, and a roughing concentrate and a stage of tailings are obtained;

[0062] Second stage dry disposal: the rough disposal concentrate is subjected to a second crushing and sieving to a material particle size of -3 mm, and the obtained ore sample is subjected to a second stage dry disposal, including a roughing selection and a fine selection, and the magnetic field intensity of the roughing selection and the fine selection is 0.3 T, to obtain a second stage dry disposal concentrate and a second stage tailings;

[0063] Weak magnetic iron separation: Grind the second-stage dry-throwing concentrate to a fineness of -0.074 mm with a material content of 79.7wt%, and perform wet weak magnetic separation, including a roughing separation, a fine separation and a scavenging separation. The magnetic field intensity of the roughing, fine separation and scavenging is preferably 0.15T to obtain iron concentrate and weak magnetic separation tailings;

[0064] Strong magnetic separation of titanium: the weak magnetic separation tailings are subjected to wet strong magnetic separation, including one roughing separation, one concentrating separation and one scavenging separation, the magnetic field intensity of the roughing separation and the scavenging separation is 0.58T, and the magnetic field intensity of the concentrating separation is 0.48T, to obtain strong magnetic separation titanium concentrate and strong magnetic separation tailings;

[0065] Chute tailings discarding: The strong magnetic separation titanium concentrate is subjected to tailings discarding in a chute, including one roughing selection, six cleaning selections and one scavenging selection, to obtain chute titanium concentrate and chute tailings;

[0066] Dry magnetic separation: the chute titanium concentrate is subjected to dry weak magnetic separation and dry strong magnetic separation in sequence, the magnetic field intensity of the dry weak magnetic separation is 0.1T, and the dry strong magnetic separation includes a roughing selection and a fine selection, and the magnetic field intensity of the roughing selection and the fine selection is 0.85T to obtain titanium concentrate.

[0067] The results show that the process of "two-stage dry tailings discarding - weak magnetic iron separation - strong magnetic titanium separation - gravity separation chute - dry magnetic separation" of the present invention can achieve a high TFe grade of 15.61% and a high Ti content of 1. 2 The yield of iron concentrate obtained from the ore with an O grade of 3.22% was 10.72%, the TFe grade was 60.21%, and the TFe recovery rate was 41.35%; 2 O grade is 5.46%, Ti 2 The recovery rate of O was 18.18% and the enrichment ratio of TFe was 3.86.

[0068] The yield of the titanium concentrate obtained was 2.22%, Ti 2 O grade is 40.12%, Ti 2 The recovery rate of O is 27.66%; the TFe grade is 35.15%, and the recovery rate of TFe is 5.00%; 2 The enrichment ratio of O is 12.46.

[0069] Comparative Example 1

[0070] The original ore in Example 1 is used, and the only difference from Example 1 is that the process of "one-stage dry tailings discarding - weak magnetic separation of iron - strong magnetic separation of titanium - gravity separation chute - dry magnetic separation" is adopted, that is, the two-stage dry tailings discarding in Example 1 is omitted.

[0071] The results showed that the yield of the iron concentrate was 11.80%, the TFe grade was 59.67%, and the TFe recovery rate was 45.11%. 2 O grade is 5.76%, Ti 2 The recovery rate of O was 21.11%;

[0072] The yield of the titanium concentrate obtained was 2.62%, Ti 2 O grade is 38.06%, Ti 2 The recovery rate of O is 30.97%; the TFe grade is 33.45%, and the recovery rate of TFe is 5.61%; 2 The enrichment ratio of O is 11.82.

[0073] The above results show that the grade of iron ore and titanium concentrate can be reduced by reducing the second-stage tailings.

[0074] Comparative Example 2

[0075] The original ore in Example 1 is used, and the only difference from Example 1 is that only the "two-stage dry tailings discarding-weak magnetic iron separation-strong magnetic titanium separation-dry magnetic separation" process is adopted, that is, the chute tailings discarding process in Example 1 is omitted.

[0076] The results showed that the yield of the iron concentrate was 10.54%, the TFe grade was 60.14%, and the TFe recovery rate was 40.61%. 2 O grade is 5.42%, Ti 2 The recovery rate of O was 17.74%;

[0077] The yield of the titanium concentrate obtained was 4.98%, Ti 2 O grade is 28.05%, Ti 2 The recovery rate of O is 43.38%; the TFe grade is 25.43%, and the recovery rate of TFe is 8.11%; 2 The enrichment ratio of O is 8.71.

[0078] The above results show that without the chute tailings discarding process, the mud content in the titanium concentrate is high, which is not conducive to improving the grade of the titanium concentrate.

[0079] Comparative Example 3

[0080] The original ore in Example 1 is used, and the only difference from Example 1 is that only the "two-stage dry tailings discarding - weak magnetic iron separation - strong magnetic titanium separation - gravity separation chute" process is used, that is, the dry magnetic separation process in Example 1 is omitted.

[0081] The results showed that the yield of the iron concentrate was 10.36%, the TFe grade was 60.27%, and the TFe recovery rate was 40.00%. 2 O grade is 5.40%, Ti 2 The recovery rate of O was 17.37%;

[0082] The yield of the titanium concentrate obtained was 3.54%, Ti 2 O grade is 32.24%, Ti 2 The recovery rate of O is 35.44%; the TFe grade is 30.15%, and the recovery rate of TFe is 6.84%; 2 The enrichment ratio of O is 10.01.

[0083] The above results show that without dry magnetic separation process, there are more impurities in the chute titanium concentrate, the grade of the chute titanium concentrate is low, and the Ti 2 The enrichment of O is relatively low.

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for recovering iron and titanium from low-iron and low-titanium ultra-lean ores, characterized in that: The following steps are involved: The ultra-lean ore is first crushed to obtain ore particles; the ultra-lean ore has a TFe content of 12-16 wt% and a TiO2 content of 3-4 wt%; The raw ore particles are subjected to a first stage of dry disposal to obtain a rough concentrate and a stage of tailings; the first stage of dry disposal includes a roughing selection and a fine selection; The roughing concentrate is subjected to a second crushing, and the obtained ore sample is subjected to a second stage of dry disposal to obtain a second stage of dry disposal concentrate and a second stage of tailings; the second stage of dry disposal includes a first roughing and a first concentrating; After grinding the second-stage dry-throwing concentrate, wet weak magnetic separation is performed to obtain iron concentrate and weak magnetic separation tailings; the wet weak magnetic separation includes a roughing separation, a fine separation and a scavenging separation; The weak magnetic separation tailings are subjected to wet strong magnetic separation to obtain strong magnetic separation titanium concentrate and strong magnetic separation tailings; The high-intensity magnetic separation titanium concentrate is discarded by using a chute to obtain chute titanium concentrate and chute tailings; the tailing discarding includes one roughing selection, six cleaning selections and one scavenging selection; The chute titanium concentrate is subjected to dry magnetic separation to obtain titanium concentrate.

2. The preparation method according to claim 1, characterized in that: The particle size of the raw ore particles is ≤15mm.

3. The preparation method according to claim 1, characterized in that: In the first stage of dry waste disposal, the magnetic field strength of the roughing is 0.5-0.68T, and the magnetic field strength of the fine selection is 0.5-0.68T.

4. The preparation method according to claim 1, characterized in that: The second crushing and screening is carried out until the material particle size is ≤4mm; in the second stage of dry waste disposal, the magnetic field strength of the rough selection is 0.2~0.4T, and the magnetic field strength of the fine selection is 0.2~0.4T.

5. The preparation method according to claim 1, characterized in that: The ore is ground to a fineness of -0.074 mm and the material content is 75-85%.

6. The preparation method according to claim 1, characterized in that: In the wet weak magnetic separation, the magnetic field strength of the rough separation is 0.10-0.2T, the magnetic field strength of the fine separation is 0.10-0.2T, and the magnetic field strength of the scanning separation is 0.10-0.2T.

7. The preparation method according to claim 1, characterized in that: The wet high-intensity magnetic separation includes a roughing separation, a fine separation and a scavenging separation. The magnetic field strength of the roughing separation is 0.4-0.69T, the magnetic field strength of the scavenging separation is 0.4-0.69T, and the magnetic field strength of the fine separation is 0.4-0.58T.

8. The preparation method according to claim 1, characterized in that: The dry magnetic separation includes dry weak magnetic separation and dry strong magnetic separation performed in sequence, and the dry strong magnetic separation includes a roughing separation and a fine separation.

9. The preparation method according to claim 8, characterized in that: The magnetic field strength of the dry weak magnetic separation is 0.08-0.12T; in the dry strong magnetic separation, the magnetic field strength of the roughing separation is 0.8-1.0T, and the magnetic field strength of the fine separation is 0.8-1.0T.

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