Method for deeply recovering iron from red mud
Through the combination technology of weak magnetic separator, vertical ring magnetic separator and flat ring magnetic separator, the problem of low recovery efficiency of fine-grained iron ore in red mud is solved, and efficient recycling and resource utilization of iron in red mud is achieved.
Patent Information
- Application Number
- CN202510349507.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-07-08
AI Technical Summary
The prior art is difficult to efficiently recover fine-grained iron minerals in red mud, resulting in low production indicators and difficult to achieve resource utilization of red mud.
The combination technology of weak magnetic separator, vertical ring magnetic separator and flat ring magnetic separator is adopted to achieve step-by-step recovery of iron ore in red mud through the synergistic effect of different gradient magnetic fields. Combined with the use of flocculant and multi-stage magnetic separator, the yield and recovery rate of iron concentrate are improved.
The recovery rate of iron in red mud is significantly improved, especially the recovery effect of fine-grained iron, and the better resource utilization of red mud is achieved.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of red mud magnetic separation iron, and specifically relates to a method for deeply recovering iron from red mud. Background Art
[0002] Red mud is an industrial solid waste of alumina, with extremely fine particle size (P 80 19µm). Most of its iron-containing minerals are limonite, which are mostly secondary developed, with a small specific magnetization coefficient and weak magnetism. Coupled with the high temperature and high alkalinity of the pulp, not only the production operation environment is harsh, but also safety production accidents are prone to occur. Due to the extremely fine particle size of red mud, it has far exceeded the lower limit of the recovery particle size of the vertical ring high-intensity magnetic separator, resulting in low production indexes, especially poor recovery effect of fine-grained iron. Therefore, the resource utilization of red mud is a worldwide problem.
[0003] In the past, the technical routes for comprehensive utilization of red mud were either brick-making or using a drum type weak magnetic separator to recover strongly magnetic iron minerals such as martite and magnetite, or using a vertical ring high-intensity magnetic separator to recover part of the coarse-grained limonite. The concentrate yield (less than 10%) and recovery rate are low (less than 20%), the separation index is poor, and it is difficult to meet the needs of large-scale reduction. Due to the low magnetic field intensity and magnetic field gradient of the vertical ring high-intensity magnetic separator, the recovery effect of fine-grained iron minerals is severely restricted. Therefore, it is necessary to develop a high-intensity magnetic separation technology with high magnetic induction intensity and magnetic field gradient to achieve efficient capture of fine-grained iron minerals. Summary of the Invention
[0004] The purpose of the present invention is to provide a method for deeply recovering iron from red mud, which can realize the cascade recovery and utilization of different types of iron minerals in red mud from weak to strong magnetism and from coarse to fine particle size, significantly improving the concentrate yield and recovery rate of iron separation from red mud.
[0005] The method for deeply recovering iron from red mud includes the following steps: A. Adjust the concentration of the red mud pulp to 20%-40% by mass, and feed it into a weak magnetic separator with a magnetic field intensity of 0.1T~0.2T for weak magnetic separation to obtain a weak magnetic separation product and a weak magnetic tailing pulp; B. The weak magnetic separation pulp is treated by a vibrating screen for coarse separation and slag removal to obtain a screened pulp A; C. The screened pulp A is coarsely selected by a roughing high-intensity magnetic separator A with a magnetic field intensity of 0.6T~1T to obtain a roughing product A and a roughing tailing pulp A; The roughing product A is finely selected by a high-intensity magnetic separator A with a magnetic field intensity of 0.5T~0.8T to obtain a fine selection product A and a fine selection tailing pulp A. The fine selection tailing pulp A is returned to be jointly input into the roughing high-intensity magnetic separator A with the screened pulp; D. Adjust the concentration of the roughly selected tailings slurry A to 20% - 40% by mass, then process it through a vibrating screen for coarse separation and slag removal to obtain the screened slurry B; E. The screened slurry B is roughly selected by a high-intensity magnetic separator B with a magnetic field intensity of 1T - 2T to obtain the roughly selected product B and the roughly selected tailings slurry B; The roughly selected product B is finely selected by a high-intensity magnetic separator B with a magnetic field intensity of 0.6T - 1T to obtain the finely selected product B and the finely selected tailings slurry B. The finely selected tailings slurry B is returned to be jointly input into the high-intensity magnetic separator B with the screened slurry; F. The weakly magnetic selected product, the finely selected product A, and the finely selected product B are the recovered iron concentrates, and the weakly magnetic selected product, the finely selected product A, and the finely selected product B are the washed slurries of the corresponding magnetic separator selected products.
[0006] It also includes the following steps: G. Add 20 - 40 g / t of flocculant to the weakly magnetic selected product, the finely selected product A, and the finely selected product B respectively, and obtain three kinds of concentrate products after sedimentation, steam pressure filtration, and concentration dehydration.
[0007] In the said step A, the method for adjusting the concentration of the red mud slurry is to add 20 - 50 / t of flocculant to the red mud slurry with a mass concentration lower than 20%, mix it into the thickening well for thickening, and then add water to adjust to the required mass concentration; In the said step D, the method for adjusting the concentration of the roughly selected tailings slurry A is to add 10 - 40 g / t of flocculant to the roughly selected tailings slurry A, mix it into the thickening well for thickening, and then add water to adjust to the required mass concentration.
[0008] The said weakly magnetic separator is a drum-type magnetic separator, the said high-intensity magnetic separator A is a vertical ring high-intensity magnetic separator, and the said high-intensity magnetic separator B is a horizontal ring high-intensity magnetic separator.
[0009] In the said step C, after the screened slurry A is adjusted to a mass percentage concentration of 20% - 40% by controlling the flushing water volume or concentration, it is sent to the roughing high-intensity magnetic separator A for roughing; after the roughly selected product A is adjusted to a slurry with a mass percentage concentration of 10% - 30% by adjusting the flushing water, it is sent to the high-intensity magnetic separator A for fine selection.
[0010] In the said step C, the working conditions of the roughing high-intensity magnetic separator A are: stroke 10 - 30 mm, stroke frequency 200 - 300 times / min; the working conditions of the fine selection high-intensity magnetic separator A are: stroke 10 - 30 mm, stroke frequency 200 - 300 times / min.
[0011] In the said step B, the screen hole specification of the vibrating screen through which the weakly magnetic selected slurry passes is 0.5 - 1 mm; In the said step D, the screen hole specification of the vibrating screen through which the roughly selected tailings slurry A passes is 0.1 - 0.5 mm.
[0012] In the step E, the operating conditions of the roughing high-intensity magnetic separator B are as follows: the flushing water pressure is 0.1~0.3 MPa; the operating conditions of the cleaning high-intensity magnetic separator B are as follows: the flushing water pressure is 0.1~0.3 MPa.
[0013] The magnetic system of the vertical-ring high-intensity magnetic separator adopts a semi-closed armored solenoid magnetic system, and the magnetic medium adopts rod-shaped magnetic concentrating media; the magnetic system of the horizontal-ring high-intensity magnetic separator adopts a double-ring orifice magnetic system, and the magnetic concentrating medium is a toothed-plate magnetic concentrating medium.
[0014] The flocculant is one or a mixture of more than one of anionic polyacrylamide, cationic polyacrylamide, non-ionic polyacrylamide, polyaluminum chloride, or polyferric sulfate.
[0015] The present invention has the following advantages: The method of the present invention forms a new technology for recovering iron from red mud with a new combination of weak magnetism + vertical-ring high-intensity magnetism + horizontal-ring high-intensity magnetism, effectively improving the recovery rate of iron in red mud, especially increasing the recovery effect of fine-grained iron, and realizing better resource utilization of red mud.
[0016] The method of the present invention develops a directional trapping technology with the synergistic effect of different gradient magnetic fields by applying a semi-closed armored solenoid magnetic system in the vertical-ring high-intensity magnetic separator, and applying rod-shaped magnetic concentrating media, a double-ring orifice magnetic system and a toothed-plate magnetic concentrating medium in the horizontal-ring high-intensity magnetic separator, strengthening the trapping of ultrafine-grained iron minerals in red mud and increasing the recovery efficiency of fine-grained iron. Description of the Drawings
[0017] Figure 1 It is a schematic structural diagram of the high-intensity magnetic separator A; The serial numbers in the figure and the structures and names of each part are as follows: 1 - Armored solenoid 1, 2 - Open end at the end. Detailed Embodiments
[0018] To better understand the present invention, it is illustrated by the following examples. These examples belong to the protection scope of the present invention, but do not limit the protection scope of the present invention. Example 1
[0019] A method for deeply recovering iron from red mud includes the following steps: A. Adjust the concentration of the red mud pulp to 20% by mass of the flushing water, and send it into a weak magnetic separator with a magnetic field intensity of 0.1 T for weak magnetic separation to obtain a weak magnetic separation product and a weak magnetic tailing pulp; The method for adjusting the concentration of the red mud pulp is to add 20 g / t of flocculant to the red mud pulp with a mass concentration lower than 20%, mix it into a thickening sump for thickening, and then add water to adjust to the required mass concentration; B. The pulp selected by weak magnetic separation is processed through a vibrating screen for rough separation and slag removal to obtain the screened pulp A. The screen aperture of the vibrating screen through which the pulp selected by weak magnetic separation passes is 0.5 mm. C. The screened pulp A is roughly separated by a rough separation high-intensity magnetic separator A with a magnetic field intensity of 0.6 T to obtain the rough separation product A and the rough separation tailing pulp A. The rough separation product A is finely separated by a high-intensity magnetic separator A with a magnetic field intensity of 0.5 T to obtain the fine separation product A and the fine separation tailing pulp A. The fine separation tailing pulp A is returned and jointly input into the rough separation high-intensity magnetic separator A with the screened pulp. After the screened pulp A is adjusted to a mass percentage concentration of 20% with flushing water, it is fed into the rough separation high-intensity magnetic separator A for rough separation; after the rough separation product A is adjusted with flushing water to form a pulp with a mass percentage concentration of 10%, it is fed into the high-intensity magnetic separator A for fine separation.
[0020] The operating conditions of the rough separation high-intensity magnetic separator A are: stroke 10 mm, stroke frequency 200 times / min; the operating conditions of the fine separation high-intensity magnetic separator A are: stroke 10 mm, stroke frequency 200 times / min.
[0021] D. The concentration of the rough separation tailing pulp A is adjusted to 20% by mass percentage, and then it is processed through a vibrating screen for rough separation and slag removal to obtain the screened pulp B. The method for adjusting the concentration of the rough separation tailing pulp A is to add 10 g / t of flocculant to the rough separation tailing pulp A, mix it in a thickening well for thickening, and then add water to adjust to the required mass concentration.
[0022] The screen aperture of the vibrating screen through which the rough separation tailing pulp A passes is 0.1 mm.
[0023] E. The screened pulp B is roughly separated by a high-intensity magnetic separator B with a magnetic field intensity of 1 T to obtain the rough separation product B and the rough separation tailing pulp B. The rough separation product B is finely separated by a high-intensity magnetic separator B with a magnetic field intensity of 0.6 T to obtain the fine separation product B and the fine separation tailing pulp B. The fine separation tailing pulp B is returned and jointly input into the high-intensity magnetic separator B with the screened pulp. The operating conditions of the rough separation high-intensity magnetic separator B are: flushing water pressure 0.1 MPa; the operating conditions of the fine separation high-intensity magnetic separator B are: flushing water pressure 0.1 MPa.
[0024] F. The weak magnetic separation product, the fine separation product A, and the fine separation product B are the recovered iron concentrate, and the weak magnetic separation product, the fine separation product A, and the fine separation product B are the flushing pulp of the corresponding magnetic separator products.
[0025] G. Add 20 g / t of flocculant to the weak magnetic separation product, the fine separation product A, and the fine separation product B, and obtain the concentrate product after sedimentation, steam pressure filtration, and thickening and dehydration.
[0026] The weak magnetic separator described is a drum magnetic separator, the strong magnetic separator A is a vertical ring high-intensity magnetic separator, and the strong magnetic separator B is a horizontal ring high-intensity magnetic separator.
[0027] In the strong magnetic separator A, a semi-closed armored solenoid magnetic system is combined with rod-shaped magnetic concentrating media. Figure 1 As shown, in the vertical ring high-intensity magnetic separator, an armored solenoid 1 with a spiral shape is adopted, and its tailing outlet is located at the end opening 2 of the armored solenoid. This opening is at the bottom of the magnetic system, and the magnetic concentrating media used are rod-shaped magnetic concentrating media. In the following embodiments, the strong magnetic separator A with this structure is used for operation.
[0028] In the strong magnetic separator B, a double-ring orifice magnetic system is combined with tooth plate magnetic concentrating media.
[0029] The flocculant is anionic polyacrylamide. Example 2
[0030] A method for deep recovery of iron from red mud includes the following steps: A. Adjust the concentration of the red mud slurry to 40% by mass percentage, and feed it into a weak magnetic separator with a magnetic field intensity of 0.2 T for weak magnetic separation to obtain weak magnetic separation products and weak magnetic tailing slurry. The method for adjusting the concentration of the red mud slurry is to add 50 / t of flocculant to the red mud slurry with a mass concentration lower than 20%, mix it in a thickening sump for thickening, and then add water to adjust to the required mass concentration. B. The weak magnetic separation slurry is treated by a vibrating screen for coarse separation and slag removal to obtain screened slurry A. The screen hole size of the vibrating screen through which the weak magnetic separation slurry passes is 1 mm. C. The screened slurry A is coarsely separated by a roughing high-intensity magnetic separator A with a magnetic field intensity of 1 T to obtain roughing product A and roughing tailing slurry A. The roughing product A is finely separated by a high-intensity magnetic separator A with a magnetic field intensity of 0.8 T to obtain fine separation product A and fine separation tailing slurry A. The fine separation tailing slurry A is returned to be jointly input into the roughing high-intensity magnetic separator A with the screened slurry. After the screened slurry A is concentrated to adjust the mass percentage concentration to 40%, it is fed into the roughing high-intensity magnetic separator A for roughing; after the roughing product A is adjusted with flushing water to make it a slurry with a mass percentage concentration of 30%, it is fed into the high-intensity magnetic separator A for fine separation.
[0031] The operating conditions of the roughing high-intensity magnetic separator A are: stroke 30 mm, stroke frequency 300 times / min; the operating conditions of the fine separation high-intensity magnetic separator A are: stroke 30 mm, stroke frequency 300 times / min.
[0032] D. Adjust the concentration of the rougher tailings pulp A to 40% by mass, then process it through a vibrating screen for coarse separation and slag removal to obtain the screened pulp B; The method for adjusting the concentration of the rougher tailings pulp A is to add 40 g / t of flocculant to the rougher tailings pulp A, mix it into the thickening sump for thickening, and then add water to adjust to the required mass concentration.
[0033] The screen hole size of the vibrating screen through which the rougher tailings pulp A passes is 0.5 mm.
[0034] E. The screened pulp B is roughly separated by a high-intensity magnetic separator B with a magnetic field strength of 2 T to obtain the roughly separated product B and the roughly separated tailings pulp B; The roughly separated product B is finely separated by a high-intensity magnetic separator B with a magnetic field strength of 1 T to obtain the finely separated product B and the finely separated tailings pulp B. The finely separated tailings pulp B is returned to be jointly input into the high-intensity magnetic separator B with the screened pulp; The operating conditions of the high-intensity magnetic separator B for rough separation are: the flushing water pressure is 0.3 MPa; the operating conditions of the high-intensity magnetic separator B for fine separation are: the flushing water pressure is 0.3 MPa.
[0035] F. The weakly magnetic separated product, the finely separated product A, and the finely separated product B are the recovered iron concentrate, and the weakly magnetic separated product, the finely separated product A, and the finely separated product B are the flushing pulp of the corresponding magnetic separator separated products.
[0036] G. Add 40 g / t of flocculant to the weakly magnetic separated product, the finely separated product A, and the finely separated product B, and obtain the concentrate product after sedimentation, steam pressure filtration, and thickening dehydration.
[0037] The said weakly magnetic separator is a drum type magnetic separator, the said high-intensity magnetic separator A is a vertical ring high-intensity magnetic separator, and the said high-intensity magnetic separator B is a horizontal ring high-intensity magnetic separator.
[0038] The magnetic concentrating medium used in the said high-intensity magnetic separator A is a rod-shaped magnetic concentrating medium, The magnetic concentrating medium used in the said high-intensity magnetic separator B is a tooth plate magnetic concentrating medium, The said flocculant is cationic polyacrylamide. Example 3
[0039] A method for deep recovery of iron from red mud includes the following steps: A. Adjust the concentration of the red mud pulp to 20% by mass, feed it into a weakly magnetic separator with a magnetic field strength of 0.15 T for weak magnetic separation to obtain the weakly magnetic separated product and the weakly magnetic tailings pulp; The method for adjusting the concentration of the red mud pulp is to add 30 / t of flocculant to the red mud pulp with a mass concentration lower than 20%, mix it into the thickening sump for thickening, and then add water to adjust to the required mass concentration; B. The weakly magnetic separated pulp is processed through a vibrating screen for coarse separation and slag removal to obtain the screened pulp A; The screen hole size of the vibrating screen through which the pulp selected by weak magnetic separation passes is 0.7 mm; C. The screened pulp A is roughly separated by a rough separation high-intensity magnetic separator A with a magnetic field intensity of 1 T to obtain a roughly separated product A and a roughly separated tailing pulp A; The roughly separated product A is finely separated by a high-intensity magnetic separator A with a magnetic field intensity of 0.5 T to obtain a finely separated product A and a finely separated tailing pulp A. The finely separated tailing pulp A is returned and jointly input into the rough separation high-intensity magnetic separator A with the screened pulp; After the screened pulp A is adjusted to a mass percentage concentration of 20% by controlling the flushing water volume, it is fed into the rough separation high-intensity magnetic separator A for rough separation; after the roughly separated product A is adjusted with flushing water to form a pulp with a mass percentage concentration of 10%, it is fed into the high-intensity magnetic separator A for fine separation.
[0040] The working conditions of the rough separation high-intensity magnetic separator A are: stroke 20 mm, stroke frequency 200 times / min; the working conditions of the fine separation high-intensity magnetic separator A are: stroke 20 mm, stroke frequency 300 times / min.
[0041] D. The concentration of the roughly separated tailing pulp A is adjusted to 20%-40% by mass percentage, and then it is treated by a vibrating screen for rough separation and slag removal to obtain a screened pulp B; The method for adjusting the concentration of the roughly separated tailing pulp A is to add 10-40 g / t of flocculant to the roughly separated tailing pulp A, mix it into a thickening well for thickening, and then add water to adjust to the required mass concentration.
[0042] The screen hole size of the vibrating screen through which the roughly separated tailing pulp A passes is 0.2 mm.
[0043] E. The screened pulp B is roughly separated by a high-intensity magnetic separator B with a magnetic field intensity of 1.8 T to obtain a roughly separated product B and a roughly separated tailing pulp B; The roughly separated product B is finely separated by a high-intensity magnetic separator B with a magnetic field intensity of 0.8 T to obtain a finely separated product B and a finely separated tailing pulp B. The finely separated tailing pulp B is returned and jointly input into the high-intensity magnetic separator B with the screened pulp; The working conditions of the rough separation high-intensity magnetic separator B are: flushing water pressure 0.1 MPa; the working conditions of the fine separation high-intensity magnetic separator B are: flushing water pressure 0.2 MPa.
[0044] F. The products selected by weak magnetic separation, the finely separated product A, and the finely separated product B are the recovered iron concentrates, and the products selected by weak magnetic separation, the finely separated product A, and the finely separated product B are the flushing pulps of the corresponding magnetic separator selected products.
[0045] G. Add 20-40 g / t of flocculant to the products selected by weak magnetic separation, the finely separated product A, and the finely separated product B, and obtain the concentrate product after sedimentation, steam pressure filtration, and thickening and dehydration.
[0046] The weak magnetic separator is a drum - type magnetic separator, the strong magnetic separator A is a vertical - ring high - intensity magnetic separator, and the strong magnetic separator B is a horizontal - ring high - intensity magnetic separator.
[0047] The magnetic concentrating medium used in the strong magnetic separator A is a rod - shaped magnetic concentrating medium. The magnetic concentrating medium used in the strong magnetic separator B is a toothed - plate magnetic concentrating medium. The flocculant is non - ionic polyacrylamide. Example 4
[0048] A method for deep recovery of iron from red mud includes the following steps: A. Adjust the concentration of the red - mud slurry to 20% - 40% by mass percentage, and feed it into a weak magnetic separator with a magnetic field intensity of 0.1T - 0.2T for weak magnetic separation to obtain weak magnetic separation products and weak magnetic tailing slurry. The method for adjusting the concentration of the red - mud slurry is to add 20 - 50 / t of flocculant to the red - mud slurry with a mass concentration lower than 20%, mix it into a thickening well for thickening, and then add water to adjust to the required mass concentration. B. The weak magnetic separation slurry is treated by a vibrating screen for rough separation and slag removal to obtain screened slurry A. The screen hole size of the vibrating screen through which the weak magnetic separation slurry passes is 0.5 - 1mm. C. The screened slurry A is roughly selected by a rough - selection high - intensity magnetic separator A with a magnetic field intensity of 0.6T - 1T to obtain rough - selection product A and rough - selection tailing slurry A. The rough - selection product A is finely selected by a high - intensity magnetic separator A with a magnetic field intensity of 0.5T - 0.8T to obtain fine - selection product A and fine - selection tailing slurry A. The fine - selection tailing slurry A is returned to be jointly input into the rough - selection high - intensity magnetic separator A with the screened slurry. After the screened slurry A is concentrated to adjust the mass percentage concentration to 20% - 40%, it is fed into the rough - selection high - intensity magnetic separator A for rough selection; after the rough - selection product A is adjusted with flushing water to form a slurry with a mass percentage concentration of 10% - 30%, it is fed into the high - intensity magnetic separator A for fine selection.
[0049] The working conditions of the rough - selection high - intensity magnetic separator A are: stroke 10 - 30mm, stroke frequency 200 - 300 times / min; the working conditions of the fine - selection high - intensity magnetic separator A are: stroke 10 - 30mm, stroke frequency 200 - 300 times / min.
[0050] D. Adjust the concentration of the rough - selection tailing slurry A to 20% - 40% by mass percentage, and then treat it by a vibrating screen for rough separation and slag removal to obtain screened slurry B. The method for adjusting the concentration of the rough - selection tailing slurry A is to add 10 - 40g / t of flocculant to the rough - selection tailing slurry A, mix it into a thickening well for thickening, and then add water to adjust to the required mass concentration.
[0051] The screen hole size of the vibrating screen through which the roughly selected tailings slurry A passes is 0.1 - 0.5 mm.
[0052] E. The screened slurry B is roughly selected by a high-intensity magnetic separator B with a magnetic field strength of 1 T - 2 T to obtain the roughly selected product B and the roughly selected tailings slurry B. The roughly selected product B is finely selected by a high-intensity magnetic separator B with a magnetic field strength of 0.6 T - 1 T to obtain the finely selected product B and the finely selected tailings slurry B. The finely selected tailings slurry B is returned to be jointly input into the high-intensity magnetic separator B with the screened slurry. The operating conditions of the high-intensity magnetic separator B for rough selection are: the flushing water pressure is 0.1 - 0.3 MPa; the operating conditions of the high-intensity magnetic separator B for fine selection are: the flushing water pressure is 0.1 - 0.3 MPa.
[0053] F. The weakly magnetic selected product, the finely selected product A, and the finely selected product B are the recovered iron concentrate, and the weakly magnetic selected product, the finely selected product A, and the finely selected product B are the flushing slurries of the corresponding magnetic separator selected products.
[0054] G. 20 - 40 g / t of flocculant is added to the weakly magnetic selected product, the finely selected product A, and the finely selected product B, and after sedimentation, steam pressure filtration, and concentration and dehydration, the concentrate product is obtained.
[0055] The described weak magnetic separator is a drum-type magnetic separator, the high-intensity magnetic separator A is a vertical ring high-intensity magnetic separator, and the high-intensity magnetic separator B is a horizontal ring high-intensity magnetic separator.
[0056] The magnetic concentrating medium used in the high-intensity magnetic separator A is a rod-shaped magnetic concentrating medium. The magnetic concentrating medium used in the high-intensity magnetic separator B is a toothed plate magnetic concentrating medium. The flocculant is a 1:1 weight ratio mixture of polyaluminum chloride and polyferric sulfate. Example 5
[0057] Iron selection from lime digestion red mud of a certain alumina ⑴ Chemical composition The chemical multi-element analysis results of the lime digestion red mud sample are listed in Table 1-1, and the chemical phase analysis results of iron are shown in Table 1-2.
[0058] Table 1-1 Chemical multi-element analysis results of lime digestion red mud / % Component TFe FeO <![CDATA[Fe2O3]]> <![CDATA[Al2O3]]> <![CDATA[Sc2O3]]> <![CDATA[Nb2O5]]> <![CDATA[Ta2O5 <!-- 6 -->]]> Content 25.62 0.54 36.04 18.50 0.013 0.034 0.010 Component <![CDATA[Cr2O3]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> CaO MgO MnO <![CDATA[Na2O]]> Content 0.23 10.31 4.64 10.59 0.35 0.12 5.16 Component <![CDATA[K2O]]> P S <![CDATA[CO2]]> Loss on Ignition TFe / FeO <![CDATA[Al2O3 / SiO2]]> Content 0.16 0.083 0.096 2.38 11.23 47.44 1.79
[0059] Table 1-2 Chemical phase analysis results of iron in the lime digestion red mud sample / % Iron Phase Iron in Magnetite Iron in Hematite (Limonite) Iron in Carbonate Iron in Sulfide Iron in Silicate Total Content 0.01 25.08 0.04 0.07 0.42 25.62 Distribution Rate 0.04 97.89 0.16 0.27 1.64 100.00
[0060] Table 1-3 Content of main minerals in the lime digestion red mud sample / % Mineral Hematite Limonite Titanium Mineral Diaspore Gibbsite Cancrinite Content 24.23 16.49 0.53 7.73 6.71 25.16 Mineral Hydrogrossular Calcite Dolomite Mica Kaolinite Garnet Epidote Rare Earth Mineral Others Content 12.06 5.56 0.61 0.37 0.05 0.50 The results show that the main iron minerals in the lime-leached red mud samples are hematite and limonite.
[0061] The mineral content ratio of hematite to limonite in the lime-leached red mud samples is approximately 60:40. Among them, hematite is euhedral, subhedral granular or irregular in shape. Limonitization is relatively common, and pores are well-developed. It mainly occurs as monomers or is closely intergrown with limonite to form iron mineral aggregates. Only a few are associated with gangue. The particle size is generally 0.01 - 0.08 mm, and some are even smaller than 0.005 mm. Limonite is cryptocrystalline - microcrystalline. Locally, it has oolitic, petaloid or serpentine structures due to the development of internal colloidal zonation. Microscopic pores are common. Locally, it is transformed into goethite due to dehydration, but most still retain the characteristics of the original limonite colloidal structure. In addition to occurring as monomers or replacing hematite, some limonite is also closely intergrown with diaspore and gibbsite in various forms. Its particle size is slightly coarser than that of hematite, generally ranging from 0.01 to 0.1 mm.
[0062] ⑵ Iron indexes of vertical ring - horizontal ring high-intensity magnetic separation Based on the method of Example 3, except that steps A and B are not adopted, the red mud slurry is directly fed into high-intensity magnetic separator A for operation. The specific parameters are as follows: The iron separation production of lime-leached red mud adopts a closed-circuit process of vertical ring (one roughing and one cleaning) - horizontal ring (one roughing and one cleaning) high-intensity magnetic separation. The magnetic field intensity of the vertical ring roughing is 1 T, and the stroke is 200 times / min. The magnetic field intensity of the vertical ring cleaning is 0.5 T, and the stroke is 300 times / min. The magnetic field intensity of the lower disk of the horizontal ring roughing is 1.8 T, and the magnetic field intensity of the lower disk of the horizontal ring cleaning is 0.8 T. The washing water pressure of the roughing middlings is 0.1 Mpa, and the washing water pressure of the cleaning middlings is 0.2 Mpa. The roughing feed concentration is 20%, and the cleaning feed concentration is 10%. The tooth pitch of the upper disk is 2 mm, and the tooth pitch of the lower disk is 0.8 mm. The results are shown in Table 1-4.
[0063] Table 1-4 Iron indexes of vertical ring - horizontal ring high-intensity magnetic separation process for lime-leached red mud separation / % Product Name Yield Grade of TFe Recovery Rate Remarks Iron Concentrate 21.13 55.51 45.78 Vertical Ring Slon-500 Tailings 78.87 17.61 54.26 Horizontal Ring ZH560 Feed 100.00 25.62 100.00
[0064] The results show that: By adopting a closed-circuit process of vertical ring - horizontal ring high-intensity magnetic (one roughing and one cleaning) separation for lime-leached red mud iron separation, technical indexes of iron concentrate yield of 21.13%, grade of TFe 55.51%, and recovery rate of 45.78% can be obtained.
[0065] Example 6 Iron separation of a certain alumina non-lime-leached red mud ⑴ Chemical composition The results of the chemical multi-element analysis of the non-lime-leached red mud samples are listed in Table 2-1, and the results of the chemical phase analysis of iron are shown in Table 2-2.
[0066] Table 2-1 Results of chemical multi-element analysis of non-lime-leached red mud samples / % Component TFe FeO <![CDATA[Fe2O3]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> CaO MgO Content 33.08 1.75 45.35 12.30 12.94 5.89 2.91 0.30 Component MnO <![CDATA[Na2O]]> <![CDATA[K2O]]> P S <![CDATA[CO2]]> Loss on Ignition Basicity Coefficient Content 0.10 8.43 0.31 0.04 0.22 2.13 8.19 0.13 Table 2-2 Chemical phase analysis results of iron in non-lime leached red mud samples / % Iron Phase Iron in Magnetite Iron in Martite Iron in Hematite (Limonite) Iron in Carbonate Iron in Sulfide Iron in Silicate Total Content 2.34 1.52 27.63 0.14 0.02 1.43 33.08 Distribution Rate 7.07 4.59 83.52 0.42 0.08 4.32 100.00 Table 2-3 Contents of main minerals in non-lime leached red mud samples / % Mineral Magnetite Martite Hematite Limonite Native Iron Pyrite Titanium Mineral Cancrinite Content 5.57 15.89 0.21 0.78 0.05 0.01 44.64 Mineral Hydrogrossular Aluminum Mineral Calcite Dolomite Mica Talc Zircon Rare Earth Mineral Others Content 0.76 0.21 0.49 0.12 0.04 0.03 0.05 The mineral content ratio of magnetite (including martite), hematite and limonite in non-lime leached red mud samples is approximately 10:30:60. Compared with lime leached red mud samples, the occurrence forms of iron minerals in non-lime leached red mud have the following characteristics: ① The alteration of magnetite is relatively common, and different degrees of martitization or limonitization often occur along the edges, grain boundaries and fissures; ② The frequency of limonite appears significantly increased, while the content of hematite decreases significantly; ③ The particle size of iron minerals is finer, the coarser ones are only about 0.1 mm, mostly between 0.01 - 0.07 mm, and a few are even less than 0.005 mm; ④ The dissociation degree of iron minerals is higher, and the monomer output is 90.65%. Together with the rich associated bodies, the total distribution rate is as high as 94.84%; the rest is mainly manifested as fine iron mineral particles often wrapped in cancrinite, and a small number of crust-like cancrinite are distributed on the edge.
[0067] ⑵Weak magnetic - vertical ring - horizontal ring high-intensity magnetic separation for iron Using the method of Example 3 for operation, non-lime leached red mud is subjected to weak magnetic - vertical ring - horizontal ring high-intensity magnetic (one roughing and one cleaning) separation for iron, and the results are shown in Table 2-4.
[0068] Table 2-4 Indexes of weak magnetic - vertical ring - horizontal ring high-intensity magnetic separation for iron from non-lime leached red mud / % Product Name Yield Grade of TFe Recovery Rate Remarks Iron Concentrate 42.23 55.12 70.16 Weak Magnetic Tailings 57.77 17.14 29.84 + Vertical Ring Feed 100.00 33.18 100.00 + Horizontal Ring
[0069] The results show that: By subjecting non-lime leached red mud to weak magnetic + vertical ring + horizontal ring high-intensity magnetic (one roughing and one cleaning) separation for iron, technical indexes of iron concentrate yield of 42.23%, grade of TFe 55.12%, and recovery rate of 70.16% can be obtained.
[0070] The above are only specific embodiments of the present application, which enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A method for deeply recovering iron from red mud, characterized in that, It includes the following steps: A. Adjust the concentration of the red mud slurry to 20%-40% by mass, and feed it into a weak magnetic separator with a magnetic field intensity of 0.1T - 0.2T for weak magnetic separation to obtain weak magnetic separation products and weak magnetic tailing slurry; B. The weak magnetic separation tailing slurry is treated by a vibrating screen for rough separation and slag removal to obtain screened slurry A; C. The screened slurry A is roughly separated by a rough separation high-intensity magnetic separator A with a magnetic field intensity of 0.6T - 1T to obtain rough separation product A and rough separation tailing slurry A; The rough separation product A is finely separated by a high-intensity magnetic separator A with a magnetic field intensity of 0.5T - 0.8T to obtain fine separation product A and fine separation tailing slurry A. The fine separation tailing slurry A is returned to be jointly input into the rough separation high-intensity magnetic separator A with the screened slurry; D. Adjust the concentration of the rough separation tailing slurry A to 20%-40% by mass, and then treat it by a vibrating screen for rough separation and slag removal to obtain screened slurry B; E. The screened slurry B is roughly separated by a high-intensity magnetic separator B with a magnetic field intensity of 1T - 2T to obtain rough separation product B and rough separation tailing slurry B; The rough separation product B is finely separated by a high-intensity magnetic separator B with a magnetic field intensity of 0.6T - 1T to obtain fine separation product B and fine separation tailing slurry B. The fine separation tailing slurry B is returned to be jointly input into the high-intensity magnetic separator B with the screened slurry; F. The weak magnetic separation products, fine separation product A and fine separation product B are the recovered iron concentrates.
2. The method for deep recovery of iron from red mud according to claim 1, characterized in that: It also includes the following steps: G. Add 20 - 40g / t of flocculant to the weak magnetic separation products, fine separation product A and fine separation product B respectively, and after sedimentation, steam pressure filtration and concentration dehydration, three kinds of concentrate products are obtained.
3. The method for deep recovery of iron from red mud according to claim 1, wherein: In step A, the method for adjusting the concentration of the red mud slurry is to add 20 - 50g / t of flocculant to the red mud slurry with a mass concentration lower than 20%, mix it into a concentration sump for concentration, and then add water to adjust to the required mass concentration; In step D, the method for adjusting the concentration of the rough separation tailing slurry A is to add 10 - 40g / t of flocculant to the rough separation tailing slurry A, mix it into a concentration sump for concentration, and then add water to adjust to the required mass concentration.
4. The method for deep recovery of iron from red mud according to claim 1, wherein: The weak magnetic separator is a drum-type magnetic separator, the high-intensity magnetic separator A is a vertical ring high-intensity magnetic separator, and the high-intensity magnetic separator B is a horizontal ring high-intensity magnetic separator.
5. The method for deep recovery of iron from red mud according to claim 1, wherein: In step C, after the screened slurry A is adjusted to a mass percentage concentration of 20% - 40% by controlling the washing water volume or concentration, it is fed into the rough separation high-intensity magnetic separator A for rough separation; after the rough separation product A is adjusted with washing water to form a slurry with a mass percentage concentration of 10% - 30%, it is fed into the high-intensity magnetic separator A for fine separation.
6. The method for deep recovery of iron from red mud according to claim 1, wherein: In step C, the working conditions of the rough separation high-intensity magnetic separator A are: stroke 10 - 30mm, stroke frequency 200 - 300 times / min; the working conditions of the fine separation high-intensity magnetic separator A are: stroke 10 - 30mm, stroke frequency 200 - 300 times / min.
7. The method for deep recovery of iron from red mud according to claim 1, wherein: In the step B, the screen hole specification of the vibrating screen through which the weakly magnetic selected pulp passes is 0.5 - 1 mm; In the step D, the screen hole specification of the vibrating screen through which the rough - selected tailing pulp A passes is 0.1 - 0.5 mm.
8. The method for deep recovery of iron from red mud according to claim 1, wherein: In the step E, the working conditions of the high - intensity magnetic separator B for rough selection are: the flushing water pressure is 0.1 - 0.3 MPa; the working conditions of the high - intensity magnetic separator B for fine selection are: the flushing water pressure is 0.1 - 0.3 MPa.
9. The method for deep recovery of iron from red mud according to claim 4, wherein: The magnetic system of the vertical - ring high - intensity magnetic separator adopts a semi - enclosed armored solenoid magnetic system, and the magnetic medium adopts rod - shaped magnetic concentrating medium; The magnetic system of the horizontal - ring high - intensity magnetic separator adopts a double - ring orifice magnetic system, and the magnetic concentrating medium is a toothed - plate magnetic concentrating medium.
10. The method for deep recovery of iron from red mud according to claim 2 or 3, wherein: The flocculant is one or a mixture of more than one of anionic polyacrylamide, cationic polyacrylamide, non - ionic polyacrylamide, polyaluminum chloride, or polyferric sulfate.