Method for treating high-iron bauxite

Abstract

A method for treating high-iron bauxite, comprising: carrying out selective crushing treatment and grading treatment on high-iron bauxite to respectively obtain coarse-fraction bauxite and fine-fraction bauxite; carrying out first gravity separation and impurity removal, and second gravity separation and impurity removal on the coarse-fraction bauxite to respectively obtain a gravity-separated concentrate, a gravity-separated middling, and a gravity-separated tailing; carrying out ore grinding and magnetic separation treatment on the gravity-separated concentrate to respectively obtain a magnetically separated concentrate and a magnetically separated tailing; carrying out impurity removal treatment on the fine-fraction bauxite by means of centrifugal separation to respectively obtain a centrifuged concentrate and a centrifuged tailing; mixing the gravity-separated middling, the magnetically separated tailing, and the centrifuged concentrate to obtain a product concentrate; and mixing the gravity-separated tailing and the centrifuged tailing to obtain a product tailing.

Description

A method for processing high-iron bauxite

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310877679.1, filed on July 17, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of mineral processing, and in particular to a method for processing high-iron bauxite. Background Art

[0004] With the rapid development of the economy and the alumina industry, the domestic demand for bauxite resources is growing rapidly. However, domestic bauxite reserves only account for 3.3% of the global reserves, and the quality is poor, far from meeting the demand for alumina production. As a result, the demand for imported ores has continued to rise in recent years and has shown a trend of sustained growth, which has gradually increased the dependence on foreign ores and made the risks faced by domestic alumina production increasingly greater.

[0005] At present, the direct Bayer process for producing alumina from high-iron bauxite will cause scaling, increased alkali consumption and ore consumption in the alumina process, thereby increasing the cost of alumina production, increasing the amount of red mud, and affecting the quality of alumina. Therefore, the development of impurity removal technology for bauxite is particularly important. At present, the conventional impurity removal technologies for high-iron bauxite are mainly acid leaching + roasting process, magnetic separation + flotation desiliconization process, but due to the high cost of these mineral processing processes and poor adaptability to the ore, the ore processing process is too long, which cannot cope with the current tense ore situation, nor can it meet the current economic and technical requirements of alumina companies for high-iron bauxite. Therefore, how to provide a short process and low-cost high-iron bauxite processing method is a technical problem that needs to be solved urgently.

[0006] Summary of the Invention

[0007] By utilizing one or more embodiments of the present disclosure, the technical problems of high cost and long process in the prior art processing methods for high-iron bauxite are solved.

[0008] According to some embodiments of the present disclosure, there is provided a method for processing high-iron bauxite, which comprises: subjecting the high-iron bauxite to selective crushing and grading to obtain coarse-grained bauxite and fine-grained bauxite, respectively; subjecting the coarse-grained bauxite to a first gravity separation and a second gravity separation to obtain a gravity concentrate, a gravity ore mine and a gravity tailings, respectively; subjecting the gravity concentrate to grinding and magnetic separation to obtain a magnetic concentrate and a magnetic tailings, respectively; subjecting the fine-grained bauxite to impurity removal by centrifugal separation to obtain a centrifugal concentrate and a centrifugal tailings, respectively; mixing the gravity ore mine, the magnetic tailings and the centrifugal concentrate to obtain a product concentrate; and, mixing the gravity tailings and the centrifugal tailings to obtain a product tailings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0010] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0011] FIG1 shows a schematic flow chart of a method for processing high-iron bauxite according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0013] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present disclosure can be purchased from the market or prepared by existing methods.

[0014] As shown in FIG1 , a method for processing high-iron bauxite according to some embodiments of the present disclosure includes:

[0015] S1. selectively crushing and classifying the high-iron bauxite to obtain coarse-grained bauxite and fine-grained bauxite;

[0016] S2. The coarse-grained bauxite is subjected to a first gravity separation and a second gravity separation to obtain a gravity concentrate, a gravity ore and a gravity tailings, respectively;

[0017] S3. Grinding and magnetic separation of the gravity concentrate to obtain magnetic concentrate and magnetic tailings, respectively;

[0018] S4. The fine-grained bauxite is subjected to impurity removal treatment by centrifugal beneficiation to obtain centrifugal concentrate and centrifugal tailings, respectively;

[0019] S5. mixing the gravity separation ore, the magnetic separation tailings and the centrifuged concentrate to obtain a product concentrate; and,

[0020] S6. Mixing the gravity separation tailings and the centrifuge tailings to obtain product tailings.

[0021] In some embodiments of the present disclosure, useful minerals in high-iron bauxite are aluminum minerals (diaspore, boehmite and gibbsite), gangue minerals are kaolinite, illite, pyrophyllite, chlorite, quartz and calcite, and iron minerals are hematite and limonite.

[0022] In some embodiments of the present disclosure, the crushing equipment in the selective grinding process may include a jaw crusher and a roller crusher, and the grading equipment in the grading process may include a classifier, a cyclone, a linear screen, and a high-frequency screen. The crushing equipment may be a combination of a jaw crusher and a roller crusher, with a two-stage, closed-circuit crushing process, and the crushed particle size is 100% of the particle size below 10 mm. The grading equipment may be a combination of a classifier, a cyclone, a linear screen, and a high-frequency screen, and the graded particle size may range from 0.074 mm to 1 mm.

[0023] In some optional embodiments, the target impurity of the first gravity separation is silicon minerals, and the separation density of the first gravity separation is 2.2 g / cm 3 ~2.8g / cm 3 The feeding pressure of the first gravity separation impurity removal is 0.1Mpa~0.5Mpa.

[0024] In some optional embodiments, the target impurities of the second gravity separation are iron minerals, and the separation density of the second gravity separation is 2.8 g / cm 3 ~3.5g / cm 3 The feeding pressure of the second gravity separation impurity removal is 0.15Mpa~0.5Mpa.

[0025] In some embodiments of the present disclosure, the target impurity removed by controlling the first gravity separation is silicon minerals, and the separation density is 2.2 g / cm 3 ~2.8g / cm 3The target impurities removed by controlling the second gravity separation are iron minerals, and the separation density is 2.8g / cm 3 ~3.5g / cm 3 , and the first gravity separation and the second gravity separation are carried out using a two-stage series heavy medium cyclone, which can completely separate the gravity separation concentrate, gravity separation middlings and gravity separation tailings; if the separation density is low, the aluminum minerals will remain in the selected middlings with undissociated minerals such as silicate minerals and iron minerals, resulting in a low grade of the selected middlings, thus affecting the separation indicators.

[0026] In some embodiments of the present disclosure, the heavy medium cyclone is a two-product heavy medium cyclone.

[0027] In some embodiments of the present disclosure, the feeding pressures of the first gravity separation and the second gravity separation are controlled to be 0.15 MPa to 0.5 MPa, respectively, so that the first gravity separation and the second gravity separation can be separated sufficiently. When the feeding pressure is insufficient, the centrifugal force of the first gravity separation and the second gravity separation will be reduced, and the separation of aluminum minerals and other impurity minerals cannot be achieved well, which will affect the separation index.

[0028] In some optional embodiments, the target impurity of the impurity removal treatment is silicon minerals, and the sorting density of the impurity removal treatment is 2.5 g / cm 3 ~3.2g / cm 3 .

[0029] In some embodiments of the present disclosure, the target impurity of the impurity removal process is silicon minerals, and the sorting density of the impurity removal process is controlled to be 2.5 g / cm 3 ~3.2g / cm 3 , which can ensure that the concentrate and tailings can be fully separated; if under conditions of lower sorting density, centrifugal separation can only bring out some completely monomer-dissociated silicate minerals with the tailings, while silicate minerals, aluminum minerals, iron minerals, titanium minerals and other undissociated minerals remain in the concentrate, resulting in a low concentrate grade.

[0030] In some optional embodiments, the medium for the first gravity separation and the second gravity separation respectively comprises at least one of water, a saturated calcium chloride solution and a sodium silicate solution; and / or,

[0031] The weighting media for the first gravity separation and the second gravity separation respectively include magnetic powder and / or ferrosilicon; and / or,

[0032] The particle sizes of the magnet powder and the ferrosilicon are respectively less than 0.038 mm.

[0033] In some embodiments of the present disclosure, by controlling the medium for the first gravity separation to include at least one of water, a saturated calcium chloride solution, and a sodium silicate solution, and the weighting medium for the first gravity separation to include magnetic powder and / or ferrosilicon, the mass ratio of the medium used in the first gravity separation to the weighting medium can be made 1:1.5 to 1:3.0.

[0034] In some embodiments of the present disclosure, by controlling the medium for the second gravity separation to include at least one of water, a saturated calcium chloride solution, and a sodium silicate solution, and the weighting medium for the second gravity separation to include magnetic powder and / or ferrosilicon, the mass ratio of the medium used in the second gravity separation to the weighting medium can be made 1.25 to 1:5.5.

[0035] Generally speaking, gravity separation concentrate mainly contains iron minerals (hematite and limonite); gravity separation middlings mainly contain aluminum minerals (diaspore and boehmite), which are suitable for the Bayer process to produce alumina; gravity separation tailings mainly contain kaolinite, illite, quartz and calcite, which can be used as ceramic materials and building cement raw materials.

[0036] In some optional embodiments, the impurity removal medium of the centrifugal beneficiation comprises at least one of water, a saturated calcium chloride solution and a sodium silicate solution; and / or,

[0037] The weighting medium of the centrifugal beneficiation comprises ferrosilicon; and / or,

[0038] The particle size of the ferrosilicon is less than 0.038 mm.

[0039] In some embodiments of the present disclosure, the medium for controlling centrifugal mineral processing includes at least one of water, a saturated calcium chloride solution, and a sodium silicate solution, and the weighting medium for centrifugal mineral processing includes ferrosilicon, so that the mass ratio between the medium and the weighting medium in the centrifugal mineral processing is 1:2.3 to 1:5.1.

[0040] The equipment used for centrifugal separation can be a water-jacketed centrifuge.

[0041] Generally speaking, centrifugal concentrate mainly contains aluminum minerals (diaspore and boehmite), which are suitable for the Bayer process to produce alumina; while centrifugal tailings mainly contain kaolinite, illite, quartz and calcite, which can be used as ceramic materials and building cement raw materials.

[0042] In some optional embodiments, the grinding may be performed by wet grinding, and the weight content of the ore with a particle size of ≤0.074 mm in the target bauxite of the grinding is 80% to 95%.

[0043] In some embodiments of the present disclosure, the weight content of the mineral material with a particle size of ≤0.074 mm in the target bauxite for grinding is controlled to be 80% to 95%, and the grinding method can be controlled to be wet grinding, which is beneficial to the better monomer dissociation of iron minerals and aluminum minerals in the bauxite and provides favorable conditions for magnetic separation; if the weight content of the mineral material with a particle size of ≤0.074 mm in the target bauxite for grinding is too large, the ore will be over-crushed, resulting in the inclusion of non-magnetic minerals during the magnetic separation process, thereby affecting the yield of the magnetic separation tailings, and at the same time increasing the energy consumption of grinding; if the weight content of the mineral material with a particle size of ≤0.074 mm in the target bauxite for grinding is too small, the iron-containing minerals and the useful aluminum-containing minerals will not be completely dissociated, which will result in poor magnetic separation and iron removal.

[0044] In some optional embodiments, the magnetic field strength of the magnetic separation is 0.2T to 1.2T, and the number of magnetic separations is 1 to 3 times.

[0045] In some embodiments of the present disclosure, the magnetic field strength of the magnetic separation is controlled to be 0.2T~1.2T, and the number of magnetic separations is 1~3 times, which can be beneficial to the magnetic separation of iron-containing minerals and reduce the iron content in the magnetic separation tailings as much as possible; if the magnetic field strength of the magnetic separation is too large, it will lead to a decrease in the yield of the magnetic separation tailings and the loss of aluminum minerals in the magnetic separation concentrate; if the magnetic field strength of the magnetic separation is too small, it will be insufficient to achieve magnetic separation of iron minerals and aluminum-containing minerals, resulting in a higher iron content in the magnetic separation tailings.

[0046] In some embodiments of the present disclosure, the equipment used for magnetic separation may include at least one of a CS-type wet electromagnetic induction roller strong magnetic field magnetic separator, a wet double vertical ring strong magnetic field magnetic separator, and a SLon-type vertical ring pulsating high gradient magnetic separator.

[0047] In some optional embodiments, the particle size D of the coarse-grained bauxite satisfies: n≤D≤10 mm;

[0048] The particle size d of the fine-grained bauxite satisfies: 0 mm ≤ d ≤ n;

[0049] Among them, the value of n is 0.074mm~1mm.

[0050] In some optional embodiments, n is the particle size dividing value between the coarse-grained bauxite and the fine-grained bauxite.

[0051] Due to the complex interpenetration of different minerals in bauxite, in coarse particle sizes, insufficient mineral dissociation can lead to a high aluminum-silicon ratio in the tailings and a low aluminum-silicon ratio in the concentrate during separation, directly impacting the separation efficiency. In some embodiments of the present disclosure, by controlling the particle size boundary between coarse and fine bauxite to 0.074 mm to 1 mm, the particle size entering the dense medium cyclone and centrifugal concentrator can be increased, directly impacting the performance of the final product.

[0052] The present disclosure will be further described below with reference to specific examples. It should be understood that these examples are intended to illustrate the present disclosure only and are not intended to limit the scope of the present disclosure. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national standards. If no corresponding national standards are available, the methods were performed in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0053] Example 1

[0054] High iron bauxite was selected, and its chemical composition, calculated by mass fraction, included: Al2O3: 48.51%, SiO2: 12.56%, Fe2O3: 20.23%, wherein the Al:Si ratio was 3.86.

[0055] As shown in Figure 1, the processing flow of the high iron bauxite processing method includes:

[0056] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a grading standard of 1 mm. The separation density of the crushed products with a particle size of -10 mm + 1 mm in the first gravity separation of water and ferrosilicon is 2.30 g / cm 3 The separation density of the second gravity separation is 2.90g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.1Mpa and 0.2Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0057] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 90% and a magnetic separation field strength of 0.3T to obtain magnetic separation concentrate and magnetic separation tailings.

[0058] The crushed product of -1mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 2.60g / cm 3 Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0059] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0060] Example 2

[0061] High iron bauxite was selected, and its chemical composition, calculated by mass fraction, included: Al2O3: 43.67%, SiO2: 15.32%, Fe2O3: 22.18%, wherein the Al:Si ratio was 2.85.

[0062] As shown in Figure 1, the processing flow of the high iron bauxite processing method includes:

[0063] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a grading standard of 0.5 mm. The separation density of the crushed products with a particle size of -10 mm + 0.5 mm in the first gravity separation of water and ferrosilicon is 2.20 g / cm 3 The separation density of the second gravity separation is 2.80g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.15Mpa and 0.25Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0064] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 85% and a magnetic separation field strength of 0.5 T to obtain magnetic separation concentrate and magnetic separation tailings.

[0065] The crushed product of -0.5mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 2.80g / cm 3 Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0066] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0067] Example 3

[0068] High iron bauxite was selected, and its chemical composition, calculated by mass fraction, includes: Al2O3: 41.87%, SiO2: 14.38%, Fe2O3: 25.76%, wherein the Al:Si ratio is 2.91.

[0069] As shown in Figure 1, the processing flow of the high iron bauxite processing method includes:

[0070] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a grading standard of 0.2 mm. The separation density of the crushed products with a particle size of -10 mm + 0.2 mm in the first gravity separation of water and ferrosilicon is 2.5 g / cm 3The separation density of the second gravity separation is 3.0g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.1Mpa and 0.2Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0071] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 90% and a magnetic separation field strength of 0.2T to obtain magnetic separation concentrate and magnetic separation tailings.

[0072] The crushed product of -0.2mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 2.95g / cm 3 Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0073] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0074] Example 4

[0075] High iron bauxite was selected, and its chemical composition, calculated by mass fraction, included: Al2O3: 38.47%, SiO2: 18.21%, Fe2O3: 23.18%, wherein the Al:Si ratio was 2.11.

[0076] As shown in Figure 1, the processing flow of the high iron bauxite processing method includes:

[0077] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a grading standard of 0.074 mm. The separation density of the crushed products with a particle size of -10 mm + 0.074 mm in the first gravity separation of water and ferrosilicon is 2.3 g / cm 3 The separation density of the second gravity separation is 3.30g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.1Mpa and 0.25Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0078] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 85% and a magnetic separation field strength of 0.2T to obtain magnetic separation concentrate and magnetic separation tailings.

[0079] The crushed product of -0.074mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 3.0g / cm 3Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0080] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0081] Comparative Example 1

[0082] Comparing Comparative Example 1 with Example 1, the difference between Comparative Example 1 and Example 1 is:

[0083] The composition of the high iron bauxite is the same as that in Example 1.

[0084] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a 3 mm grading standard. The separation density of the crushed products with a size of -10 mm + 3 mm in the first gravity separation of water and ferrosilicon is 2.30 g / cm 3 The separation density of the second gravity separation is 2.90g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.1Mpa and 0.2Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0085] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 90% and a magnetic separation field strength of 0.3T to obtain magnetic separation concentrate and magnetic separation tailings.

[0086] The crushed product of -3mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 2.60g / cm 3 Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0087] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0088] Comparative Example 2

[0089] Comparing Comparative Example 2 with Example 1, the difference between Comparative Example 2 and Example 1 is:

[0090] The composition of the high iron bauxite is the same as that in Example 1.

[0091] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a grading standard of 1 mm. The separation density of the crushed products with a size of -10 mm + 1 mm in the first gravity separation of water and ferrosilicon is 2.30 g / cm 3The separation density of the second gravity separation is 2.90g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.05Mpa and 0.15Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0092] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 90% and a magnetic separation field strength of 0.3T to obtain magnetic separation concentrate and magnetic separation tailings.

[0093] The crushed product of -1mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 2.60g / cm 3 Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0094] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0095] Comparative Example 3

[0096] Comparing Comparative Example 3 with Example 1, the difference between Comparative Example 3 and Example 1 is:

[0097] The composition of the high iron bauxite is the same as that in Example 1.

[0098] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a grading standard of 1 mm. The crushed products with a size of -10 mm + 1 mm are separated by the first gravity separation of water and ferrosilicon with a separation density of 2.00 g / cm 3 The separation density of the second gravity separation is 2.60g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.1Mpa and 0.2Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0099] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 90% and a magnetic separation field strength of 0.3T to obtain magnetic separation concentrate and magnetic separation tailings.

[0100] The crushed product of -1mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 2.60g / cm 3 Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0101] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0102] Comparative Example 4

[0103] Comparing Comparative Example 4 with Example 1, the difference between Comparative Example 4 and Example 1 is:

[0104] The composition of the high iron bauxite is the same as that in Example 1.

[0105] The raw ore is crushed and graded to obtain crushed products with a size of less than 10 mm. The crushed products are graded with a grading standard of 1 mm. The separation density of the crushed products with a size of -10 mm + 1 mm in the first gravity separation of water and ferrosilicon is 2.30 g / cm 3 The separation density of the second gravity separation is 2.90g / cm 3 Under the condition of , two-stage series heavy medium cyclones are used for separation, the feeding pressures of the first heavy medium cyclone and the second heavy medium cyclone are 0.1Mpa and 0.2Mpa respectively, to obtain gravity separation concentrate, gravity separation ore and gravity separation tailings;

[0106] The gravity separation concentrate is magnetically separated using a SLon vertical ring pulsating high gradient magnetic separator under the conditions of a grinding fineness of 80% and a magnetic separation field strength of 0.15T to obtain magnetic separation concentrate and magnetic separation tailings.

[0107] The crushed product of -1mm particle size is mixed with calcium chloride saturated solution and ferrosilicon to prepare a heavy liquid with a density of 2.60g / cm 3 Under the conditions of centrifugal concentrator, separation is carried out to obtain centrifugal concentrate and centrifugal tailings;

[0108] Gravity separation ore, magnetic separation tailings and centrifugal concentrate are combined into aluminum concentrate, gravity separation tailings and centrifugal tailings are combined into tailings, and magnetic separation concentrate is iron concentrate.

[0109] Related experiments and effect data:

[0110] The products obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were compared and analyzed, and the results are shown in Table 1.

[0111] Table 1: The product information of each embodiment and comparative example

[0112] From the data in Table 1, we can see that:

[0113] By comparing the data of Example 1 and Comparative Example 1, it can be seen that increasing the crushing particle size and increasing the particle size entering the heavy medium cyclone and centrifuge will directly affect the final gravity separation index. This is mainly because the interpenetration relationship between aluminum minerals, silicon minerals and iron minerals in bauxite is complex. Under coarser particle size conditions, the mineral dissociation is insufficient, the aluminum-silicon ratio of the tailings is high during the sorting process, and the aluminum-silicon ratio of the aluminum concentrate is low, which directly affects the sorting effect.

[0114] From the comparison of the data in Example 1 and Comparative Example 2, it can be seen that reducing the feeding pressure into the heavy medium cyclone will directly affect the separation index, mainly because the feeding pressure is insufficient and the centrifugal force is low, which cannot effectively achieve the separation of aluminum minerals and other impurity minerals.

[0115] From the comparison of the data in Example 1 and Comparative Example 3, it can be seen that reducing the sorting density entering the heavy medium cyclone and centrifuge will directly affect the sorting index. This is mainly because under the condition of lower sorting density, gibbsite will remain in the aluminum concentrate with the undissociated minerals of silicate minerals and iron minerals, resulting in a low grade of the aluminum concentrate.

[0116] From the comparison of the data in Example 1 and Comparative Example 4, it can be seen that reducing the grinding fineness and the magnetic field strength of the magnetic separator affects the separation indicators of the magnetic concentrate and the magnetic tailings. This is mainly because the grinding fineness is too low, which will lead to incomplete dissociation of iron-containing minerals and aluminum-containing useful minerals, and the magnetic separation and iron removal effect is poor; the magnetic field strength of the magnetic separator is too low, which is not enough to achieve magnetic separation of iron minerals and aluminum-containing minerals, resulting in a low iron content in the iron concentrate.

[0117] It should be noted that in the present disclosure, "particle size" can be measured as "particle diameter" and "equivalent particle diameter" according to whether the shape of the particles is spherical. When "particle diameter" in the present disclosure is used to describe non-spherical particles, it should be understood as the "equivalent particle diameter" of non-spherical particles. In the description of particle size in the present disclosure, the minus sign (-) before the specific numerical value indicates that the mesh of the particle size can pass through, and the positive sign (+) indicates that the mesh of the particle size cannot pass through. For example, "crushed product of -10mm+1mm particle size" means "crushed product that can pass through 10mm but cannot pass through 1mm particle size mesh"; "crushed product of -1mm particle size" means "crushed product that can pass through 1mm particle size mesh".

[0118] The high-iron bauxite processing method according to some embodiments of the present disclosure has the following advantages compared with the prior art:

[0119] According to the processing method of high-iron bauxite in some embodiments of the present disclosure, the high-iron bauxite is first subjected to selective crushing and classification to obtain coarse-grained bauxite and fine-grained bauxite, the coarse-grained bauxite is subjected to a first gravity separation and a second gravity separation to obtain gravity concentrate, gravity ore and gravity tailings, the gravity concentrate is then subjected to grinding and magnetic separation to obtain magnetic concentrate and magnetic tailings, the fine-grained bauxite is subjected to centrifugal separation to obtain centrifugal concentrate and centrifugal tailings, and the magnetic tailings, gravity ore and centrifugal concentrate are mixed to obtain the product aluminum concentrate. The product aluminum concentrate is obtained by mixing the gravity separation tailings and the centrifugal tailings to obtain the product tailings, and the magnetic separation concentrate is the product iron concentrate. Therefore, through the above steps, the high-iron bauxite can be processed briefly, and only selective crushing treatment, classification treatment, first gravity separation to remove impurities, second gravity separation to remove impurities, grinding, magnetic separation, and centrifugal separation are required. The product aluminum concentrate, product tailings and product iron concentrate can be obtained at a relatively low cost. Therefore, the overall method has the characteristics of short process, low energy consumption, low production cost, low investment, high mineral processing efficiency, etc., and the obtained aluminum concentrate is suitable for the production of alumina by the Bayer process.

[0120] In summary, according to the processing method of high-iron bauxite in some embodiments of the present disclosure, based on the process flow of "crushing-classification-coarse-grained heavy medium beneficiation desiliconization-magnetic separation deironization-fine-grained centrifugal beneficiation desiliconization", after processing the high-iron bauxite, tailings with high silicon mineral content and relatively low aluminum-silicon ratio, as well as aluminum concentrate with high alumina recovery rate and iron concentrate that can be sold directly can be obtained. It has the characteristics of short beneficiation process, low beneficiation cost, low investment, and high beneficiation efficiency. At the same time, the aluminum concentrate is suitable for the production of alumina by the Bayer process, and the iron concentrate is directly sold as a product, while the tailings are suitable as building materials and ceramic raw materials. Therefore, it can expand the available resource reserves of the bauxite industry and comprehensively improve the utilization rate of bauxite resources in the bauxite industry, and it is of great significance to the sustainable development of the aluminum industry.

[0121] Various embodiments of the present disclosure may be presented in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the present disclosure; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0122] In the present disclosure, unless otherwise specified, the directional words used, such as "upper" and "lower", specifically refer to the directions of the drawings in the accompanying drawings. In addition, in the description of the present disclosure, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" refers to one or more, and "plurality" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple.

[0123] The foregoing description is intended only to provide specific embodiments of the present disclosure, which will enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments shown herein, but rather to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for processing high-iron bauxite, comprising: The high-iron bauxite is selectively crushed and graded to obtain coarse-grained bauxite and fine-grained bauxite respectively; Performing a first gravity separation and a second gravity separation on the coarse-grained bauxite to obtain a gravity separation concentrate, a gravity separation middling and a gravity separation tailings, respectively; The gravity separation concentrate is subjected to grinding and magnetic separation treatment to obtain a magnetic separation concentrate and a magnetic separation tailings, respectively; The fine-grained bauxite is subjected to impurity removal treatment by centrifugal separation to obtain centrifugal concentrate and centrifugal tailings respectively; Mix the gravity separation ore, the magnetic separation tailings and the centrifugal concentrate to obtain a product concentrate; as well as, The gravity separation tailings and the centrifugal tailings are mixed to obtain product tailings.

2. The processing method according to claim 1, wherein: The target impurity of the first gravity separation is silicon mineral, and the separation density of the first gravity separation is 2.2 g / cm 3 ~2.8g / cm 3 The feeding pressure of the first gravity separation and impurity removal is 0.1Mpa~0.5Mpa.

3. The processing method according to claim 1, wherein: The target impurities of the second gravity separation are iron minerals, and the separation density of the second gravity separation is 2.8 g / cm 3 ~3.5g / cm 3 The feeding pressure of the second gravity separation and impurity removal is 0.15Mpa~0.5Mpa.

4. The processing method according to claim 1, wherein: The target impurity of the impurity removal treatment is silicon mineral, and the sorting density of the impurity removal treatment is 2.5g / cm 3 ~3.2g / cm 3 .

5. The processing method according to claim 1, wherein: The medium for the first gravity separation and the second gravity separation respectively comprises at least one of water, a saturated calcium chloride solution and a sodium silicate solution; and / or, The weighting media for the first gravity separation and the second gravity separation respectively include magnetite and / or ferrosilicon; and / or, The particle sizes of the magnetite and the ferrosilicon are respectively less than 0.038 mm.

6. The processing method according to claim 1, wherein: The impurity removal medium of the centrifugal beneficiation comprises at least one of water, a saturated calcium chloride solution and a sodium silicate solution; and / or, The weighting medium of the centrifugal beneficiation comprises ferrosilicon; and / or, The particle size of the ferrosilicon is less than 0.038 mm.

7. The processing method according to claim 1, wherein: The grinding includes grinding by wet grinding, and the weight content of the ore with a particle size of ≤0.074 mm in the target bauxite of the grinding is 80% to 95%.

8. The processing method according to claim 1, wherein: The magnetic field intensity of the magnetic separation is 0.2T to 1.2T, and the number of magnetic separations is 1 to 3 times.

9. The processing method according to claim 1, wherein: The particle size D of the coarse-grained bauxite satisfies: n≤D≤10 mm; The particle size d of the fine-grained bauxite satisfies: 0 mm ≤ d ≤ n; Among them, the value of n is 0.074mm~1mm.

10. The processing method according to claim 9, wherein: n is the particle size dividing value between the coarse-grained bauxite and the fine-grained bauxite.

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