Method for resource utilization of high-iron and high-silicon bauxite

Abstract

The invention provides a method for resource utilization of high-iron and high-silicon bauxite, which comprises the following steps: (1) grinding the high-iron and high-silicon bauxite, and roasting in an oxidizing atmosphere at 1000-1200 DEG C; (2) reducing the temperature of the oxidizing roasting material to 600-800 DEG C, and performing reduction roasting; (3) the reduction roasting product is subjected to alkaline leaching, and alkaline leaching residues and leachate are obtained; (4) leaching the alkaline leaching residues by adopting a sodium aluminate solution to obtain leaching residues and a leaching solution; and (5) the leaching residues are subjected to magnetic separation, and magnetite concentrate and tailings are obtained. According to the method, comprehensive extraction of iron, aluminum and silicon in the high-iron and high-silicon bauxite can be achieved under the condition that no additive is added, the process is good in silicon, iron and aluminum separation effect, efficient separation of Al, Fe and Si and efficient recovery of valuable metal are achieved, the amount of discharged slag is small, compatibility with an existing process is good, and the method is suitable for industrial production. The method is suitable for large-scale industrial treatment of difficult-to-treat high-iron high-silicon bauxite which is not developed and utilized at present

Description

Technical Field

[0001] This invention belongs to the field of mineral engineering technology, specifically relating to a method for the resource utilization of high-speed iron and high-silica bauxite. Background Technology

[0002] The severe shortage of bauxite resources has seriously hampered the sustainable development of my country's alumina industry. Large quantities of high-iron, high-silica bauxite exist in regions such as Jiangxi and Guangxi, but due to their high iron, high silicon, and low aluminum content, these bauxite resources have not yet been effectively developed and utilized.

[0003] Patent document CN117138967A proposes using flotation to separate aluminum and silicon in high-silica bauxite; patent document CN106902975A proposes using gravity separation and flotation in combination to separate aluminum and silicon in high-silica bauxite; patent document CN116651609A proposes using physical separation methods to separate iron and aluminum in high-iron bauxite; and patent document CN120575027A proposes a single-stage leaching-roasting-two-stage leaching process to separate aluminum and iron in high-iron bauxite. Patent documents CN120440918A propose a roasting activation-high-temperature calcification transformation treatment for high-iron bauxite; CN120311021A proposes an acid leaching process for effective iron-aluminum separation in high-iron bauxite; CN118979147A proposes direct reduction-electric furnace smelting-magnetic separation for iron-aluminum separation in high-iron bauxite; and CN107686886A proposes suspension roasting-magnetic separation for iron-aluminum separation in high-iron bauxite. These methods are single treatments for high-silica or high-iron bauxite and are difficult to directly apply to the treatment of high-iron, high-silica bauxite.

[0004] The patent document with publication number CN103614547A proposes to separate iron, aluminum and silicon in high-iron and high-silicon bauxite through roasting-mixed alkali leaching-magnetic separation, but the recovery rate of iron in this method still needs to be improved. Summary of the Invention

[0005] This invention aims to solve the aforementioned problems of the prior art, and its purpose is to provide a method for the resource utilization of high-iron, high-silica bauxite. This method achieves efficient separation and recovery of silicon, aluminum, and iron in refractory high-iron, high-silica bauxite, exhibits strong compatibility with existing processes, and demonstrates high resource utilization and strong economic benefits.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for the resource utilization of high-silica bauxite deposits along high-speed railways includes: (1) After grinding, the high-iron high-silica bauxite is roasted in an oxidizing atmosphere at 1000~1200℃; (2) The oxidative roasted material is cooled to 600~800℃ and then subjected to reduction roasting; (3) The reduced roasting product is subjected to alkaline leaching to obtain alkaline leaching residue and leachate; (4) The alkaline leaching residue was leached with sodium aluminate solution to obtain leaching residue and leachate; (5) The leaching residue is subjected to magnetic separation to obtain magnetite concentrate and tailings. Furthermore, the high-iron, high-silica bauxite contains, by mass percentage, 20-40% iron oxide, 30-55% alumina, and 10-15% silicon oxide.

[0007] Furthermore, in the high-iron, high-silica bauxite, the iron-bearing phases include one or more of hematite, goethite, and aluminous goethite; the iron, aluminum, and silicon elements in the high-iron, high-silica bauxite mainly exist in a dispersed form, and the main distribution mode of the iron, aluminum, and silicon elements in the bauxite is that they are dispersed together.

[0008] Furthermore, in step (1), the particle size of the ground high-iron high-silica bauxite is controlled to be below 200 mesh.

[0009] Further, in step (1), the calcination time is 30~120 min; the oxidizing atmosphere is air.

[0010] Further, in step (2), the reduction roasting time is 20~60min; the reducing agent in the reduction roasting is one or more of CO, coke, coal, and charcoal.

[0011] Further, in step (3), the alkali immersion time is 30~120min; the concentration of the alkali solution is 100~140g / L; the liquid-solid ratio of the alkali immersion is 5:1~10:1; and the alkali solution is NaOH solution.

[0012] Further, in step (4), the sodium aluminate solution, ρ (Na2O k The concentration of sodium oxide is 220~240 g / L, and the molar ratio of sodium oxide to aluminum oxide is 2.5~3.0; the liquid-to-solid ratio of the leaching is 4~6:1.

[0013] Furthermore, in step (4), the leaching temperature is 240~260℃; the leaching time is 30~120min.

[0014] Furthermore, in step (5), the intensity of the magnetic separation is controlled at 500~1500Gs.

[0015] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: This invention enables the comprehensive extraction of iron, aluminum, and silicon from high-iron, high-silicon bauxite without the addition of external additives. The process achieves good separation of silicon, iron, and aluminum, efficient separation of Al, Fe, and Si, and efficient recovery of valuable metals such as Fe and Al. It also produces less slag, is compatible with existing processes, and is suitable for large-scale industrial processing of difficult-to-process high-iron, high-silicon bauxite that is currently undeveloped and unutilized.

[0016] The clinker produced by this invention, after oxidation roasting and cooling reduction roasting, can achieve a silicon dioxide leaching rate of >60% through alkaline leaching; the relative aluminum leaching rate of the leaching residue during the high-temperature leaching of sodium aluminate can reach over 92%; and the iron recovery rate of the high-temperature leaching residue after magnetic separation can reach over 80%, and magnetite concentrate with an iron content of >55% can be obtained, which can be used as a raw material for ironmaking, resulting in good economic benefits. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a process flow diagram of the method for resource utilization of high-silica bauxite ore for high-speed rail, as described in this invention.

[0019] Figure 2 The XRD patterns of high-iron, high-silica bauxite used in the various embodiments and comparative examples of this invention are shown.

[0020] Figure 3 The images shown are SEM-EDS images of high-iron, high-silica bauxite used in the various embodiments and comparative examples of this invention.

[0021] Figure 4 The images show the XRD patterns of the intermediate products obtained in steps (2) and (3) and the SEM-EDS patterns of the intermediate products obtained in step (4) of Comparative Example 1 of the present invention. Detailed Implementation

[0022] Some embodiments of the present invention provide a method for the resource utilization of high-silica bauxite deposits along high-speed railways, comprising: (1) After grinding, the high-iron high-silica bauxite is roasted in an oxidizing atmosphere at 1000~1200℃. The oxidizing roasting temperature can be, for example, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, etc. (2) The oxidized roasted material is cooled to 600~800℃ for reduction roasting, for example, it can be cooled to 600℃, 650℃, 700℃, 750℃, 800℃ etc. for reduction roasting; (3) The reduced roasting product is subjected to alkaline leaching to obtain alkaline leaching residue and leachate; (4) The alkaline leaching residue was leached with sodium aluminate solution to obtain leaching residue and leachate; (5) The leaching residue is subjected to magnetic separation to obtain magnetite concentrate and tailings.

[0023] Research has shown that by employing the above-mentioned technical solution and a reasonable roasting mechanism, kaolinite in high-iron, high-silica bauxite can be decomposed into aluminum-containing spinel and free silica during roasting in an oxidizing atmosphere. During the cooling process, the addition of a reducing agent can directionally transform hematite into magnetite. The resulting roasted product can achieve selective removal of silica through alkaline leaching, while iron and aluminum-containing minerals remain intertwined in the leaching residue. Leaching the residue with sodium aluminate solution can achieve magnetite dissociation. The resulting leaching residue can achieve selective enrichment of magnetite through magnetic separation, yielding iron concentrate that meets the requirements for ironmaking. Ultimately, this achieves comprehensive extraction of iron, aluminum, and silicon from high-iron, high-silica bauxite, effectively reducing the amount of tailings generated.

[0024] In some preferred embodiments, the high-iron, high-silica bauxite contains, by mass percentage, 20-40% iron oxide, 30-55% alumina, and 10-15% silicon oxide.

[0025] In some preferred embodiments, the iron-bearing phases in the high-iron, high-silica bauxite include one or more of hematite, goethite, and aluminous goethite. It is worth noting that iron, aluminum, and silicon in the high-iron, high-silica bauxite mainly exist in dispersed forms, and their distribution in the bauxite is primarily characterized by mutual dispersion, making it difficult for traditional gravity separation, magnetic separation, and flotation processes to achieve efficient separation of iron and aluminum.

[0026] In some preferred embodiments, in step (1), the particle size of the high-iron high-silica bauxite after grinding is controlled to be below 200 mesh.

[0027] In some preferred embodiments, in step (1), the calcination time is 30~120min, for example 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.; the oxidizing atmosphere is air.

[0028] In some preferred embodiments, in step (2), the reduction roasting time is 20~60min, for example 20min, 30min, 40min, 50min, 60min, etc.; the reducing agent for reduction roasting is one or more of coke, coal, and charcoal. The amount of reducing agent can be adjusted according to actual needs, as long as it is sufficient to reduce the iron in high-iron high-silica bauxite to magnetite. Specifically, when using a solid reducing agent, the amount of reducing agent can be 100~130% of the theoretical amount, for example 100%, 110%, 120%, 130%, etc. Specifically, in theoretical calculations, it is assumed that all iron in high-iron high-silica bauxite is in a +3 valence state after oxidation roasting.

[0029] In some preferred embodiments, in step (3), the alkali immersion time is 30~120min, for example 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.; the concentration of the alkali solution is 100~140g / L, for example 100g / L, 110g / L, 120g / L, 130g / L, 140g / L, etc.; and the liquid-solid ratio of the alkali immersion is 5:1~10:1, for example 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0030] In a partially preferred embodiment, in step (4), the concentration of the sodium aluminate solution is ( ρ (Na2O k ()=220~240g / L, the molar concentration ratio of sodium oxide to aluminum oxide is 2.5~3); the liquid-to-solid ratio of the leaching is 4~6:1.

[0031] In some preferred embodiments, in step (4), the leaching temperature is 240~260℃, for example 240℃, 250℃, 260℃, etc.; the leaching time is 30~120min, for example 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.

[0032] In some preferred embodiments, in step (5), the intensity of the magnetic separation is controlled at 500~1500Gs, for example 500Gs, 600Gs, 700Gs, 800Gs, 900Gs, 1000Gs, 1100Gs, 1200Gs, 1300Gs, 1400Gs, 1500Gs, etc.

[0033] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0034] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0036] The chemical composition of the high-iron, high-silica bauxite used in the following examples and comparative examples is shown in Table 1. Its main components are iron, alumina, and silicon oxide, with mass contents of 19.56%, 39.89%, and 13.45%, respectively, and an aluminum-silica ratio of 2.97. The XRD pattern of the high-iron, high-silica bauxite is shown below. Figure 2 As shown, the main phases in high-iron, high-silica bauxite are gibbsite, goethite, and kaolinite, with iron, aluminum, and silicon elements mainly dispersed together. Their SEM-EDS images are shown below. Figure 3 As shown, iron, aluminum and silicon elements in high-iron high-silica bauxite are mainly dispersed together; when using traditional gravity separation, magnetic separation and flotation processes to process this mineral, it is found that it is difficult to achieve efficient separation of iron, aluminum and silicon.

[0037] Table 1 Example 1 This embodiment discloses a method for the resource utilization of high-silica bauxite ore from high-speed railways, and the process flow diagram is as follows: Figure 1 As shown, it includes the following steps: (1) The high-silica bauxite ore of high-speed rail was finely ground to -200 mesh, accounting for 85.46%; (2) The high-iron and high-silica bauxite after grinding in step (1) is roasted at 1000℃ in an oxidizing atmosphere for 60 minutes; (3) After cooling the oxidized roasted material in step (2) to 700℃, add coal for reduction roasting for 30 minutes. The amount of coal used is 1.2 times the theoretical amount. The theoretical amount is the amount of carbon used when hematite is reduced to magnetite. Coal can be replaced by coke, charcoal, etc. (4) The roasted material obtained in step (3) was placed in a sodium hydroxide solution with a concentration of 100 g / L at 100 °C and leached for 80 min at a liquid-to-solid ratio of 5:1. The silica dissolution rate was 61.25%. (5) Place the leaching residue obtained in step (4) into a sodium aluminate solution at 260°C ( ρ (Na2O kWith a concentration of 230 g / L (molar concentration of Na₂O) / 3 (molar concentration of Al₂O₃), the relative dissolution rate of alumina was 94.25% after 80 minutes of dissolution at a liquid-to-solid ratio of 5:1. (6) The iron recovery rate of the concentrate obtained by dissolving the slag obtained in step (5) under the condition of magnetic field strength of 1000 Gs is 81.56% and the iron grade is 57.45%.

[0038] Example 2 This embodiment discloses a method for the resource utilization of high-silica bauxite ore from high-speed railways, and the process flow diagram is as follows: Figure 1 As shown, it includes the following steps: (1) The high-silica bauxite ore of high-speed rail was finely ground to -200 mesh, accounting for 90.23%; (2) The high-iron and high-silica bauxite after grinding in step (1) is roasted at 1050°C in an oxidizing atmosphere for 60 min; (3) After cooling the oxidized roasted material in step (2) to 800℃, add coal for reduction roasting for 30 minutes. The amount of coal used is 1.2 times the theoretical amount. The theoretical amount is the amount of carbon used when hematite is reduced to magnetite. Coal can be replaced by coke, charcoal, etc. (4) The roasted material obtained in step (3) was leached in a sodium hydroxide solution with a concentration of 100 g / L at 100 °C for 60 min at a liquid-to-solid ratio of 10:1, and the silica dissolution rate was 63.45%; (5) The leaching residue obtained in step (4) is placed in a sodium aluminate solution at 260°C. ρ (Na2O k With a concentration of 230 g / L (molar concentration of Na₂O) / (molar concentration of Al₂O₃) = 3, the relative dissolution rate of alumina was 95.03% after 60 minutes of dissolution at a liquid-to-solid ratio of 5:1. (6) The iron recovery rate of the concentrate obtained by dissolving the slag obtained in step (5) under the condition of magnetic field strength of 1000 Gs is 84.86% and the iron grade is 58.12%.

[0039] Example 3 This embodiment discloses a method for the resource utilization of high-silica bauxite ore from high-speed railways, and the process flow diagram is as follows: Figure 1 As shown, it includes the following steps: (1) The high-silica bauxite ore of high-speed rail was finely ground to -200 mesh, accounting for 90.23%; (2) The high-iron and high-silica bauxite after grinding in step (1) is roasted at 1100℃ in an air oxidizing atmosphere for 60 min; (3) After cooling the oxidized roasted material in step (2) to 700℃, add coal for reduction roasting for 30 minutes. The amount of coal used is 1.2 times the theoretical amount. The theoretical amount is the amount of carbon used when hematite is reduced to magnetite. Coal can be replaced by coke, charcoal, etc. (4) The roasted material obtained in step (3) was leached in a sodium hydroxide solution with a concentration of 140 g / L at 100 °C for 60 min at a liquid-to-solid ratio of 10:1, and the silica dissolution rate was 64.05%; (5) The leaching residue obtained in step (4) is placed in a sodium aluminate solution at 260°C. ρ (Na2O k With a concentration of 230 g / L (molar concentration of Na₂O) / (molar concentration of Al₂O₃) = 3, the relative dissolution rate of alumina was 94.86% after 60 minutes of dissolution at a liquid-to-solid ratio of 5:1. (6) The iron recovery rate of the concentrate obtained by dissolving the slag obtained in step (5) is 80.25% and the iron grade is 58.42% under a magnetic field strength of 500 Gs.

[0040] Comparing Examples 1 and 3, it can be seen that increasing the oxidative roasting temperature is beneficial to increasing the dissolution rate of silicon dioxide and aluminum oxide. Analysis suggests that this phenomenon may be due to the following: Kaolinite decomposes into mullite and free silicon dioxide at 980℃. A slight increase in temperature is beneficial to the stability of the mullite phase, which does not react during the subsequent alkaline leaching process, thus improving the silicon dioxide dissolution rate. Furthermore, during the subsequent high-temperature leaching process, due to the secondary reaction of silicon dioxide dissolving and then re-precipitating, the aluminum oxide dissolution rate decreases. Therefore, the increase in the silicon dioxide dissolution rate reduces the silicon content in the leaching residue, and thus the aluminum oxide dissolution rate increases as the silicon dioxide content in the leaching residue decreases.

[0041] Example 4 This embodiment discloses a method for the resource utilization of high-silica bauxite ore from high-speed railways, and the process flow diagram is as follows: Figure 1 As shown, it includes the following steps: (1) The high-silica bauxite ore of high-speed rail was finely ground to -200 mesh, accounting for 90.23%; (2) The high-iron and high-silica bauxite after grinding in step (1) is roasted at 1150°C in an oxidizing atmosphere for 60 min; (3) After cooling the oxidized roasted material in step (2) to 700℃, add coal for reduction roasting for 30 minutes. The amount of coal used is 1.2 times the theoretical amount. The theoretical amount is the amount of carbon used when hematite is reduced to magnetite. Coal can be replaced by coke, charcoal, etc. (4) The roasted material obtained in step (3) was leached in a sodium hydroxide solution with a concentration of 120 g / L at 100 °C for 60 min at a liquid-to-solid ratio of 8:1, and the silica dissolution rate was 62.32%; (5) The leaching residue obtained in step (4) is subjected to a process at 260℃. ρ (Na2O k With a concentration of 230 g / L (molar concentration of Na₂O) / (molar concentration of Al₂O₃) = 3, the relative dissolution rate of alumina was 95.15% after 80 minutes of dissolution at a liquid-to-solid ratio of 5:1. (6) The iron recovery rate of the concentrate obtained by dissolving the slag obtained in step (5) under the condition of magnetic field strength of 1000 Gs is 80.11% and the iron grade is 56.53%.

[0042] Comparing Examples 3 and 4, it can be seen that as the oxidative roasting temperature is further increased, the leaching rate of silicon dioxide and the grade of magnetite will decrease. Analysis shows that this is because as the roasting temperature is further increased, the free silicon dioxide decomposed from kaolinite will combine with aluminum-containing minerals in the ore to form new aluminum-silicon compounds, thereby reducing the silicon dioxide leaching rate. After the aluminum-silicon compounds are leached in step (5), they form sodium-aluminum-silicon-hydrate compounds that enter the slag. The increase in the amount of sodium-aluminum-silicon-hydrate compounds is not conducive to the dissociation of magnetite particles, resulting in a decrease in the grade of the subsequently recovered magnetite.

[0043] Comparative Example 1 This comparative example discloses a method for the resource utilization of high-silica bauxite ore from high-speed railways, including the following steps: (1) The high-silica bauxite ore of high-speed rail was finely ground to -200 mesh, accounting for 90.23%; (2) The high-iron, high-silica bauxite ore ground in step (1) was oxidized and roasted at 1050℃ for 60 min by air introduction. The XRD pattern of the obtained product is shown in the figure. Figure 4 As shown in (a); (3) Switch the air oxidation atmosphere in step (2) to a CO reduction atmosphere and continue calcining at 1050℃ for 15 min. The XRD pattern of the obtained product is shown below. Figure 4 As shown in (b), the main phases in the reduction roasting product are metallic iron and ferrous aluminate, while silicon exists as amorphous silicon oxide. (4) The roasted material obtained in step (3) was leached in a sodium hydroxide solution at 100°C for 60 min at a liquid-to-solid ratio of 10:1. The silica dissolution rate was 61.23%. The SEM-EDS image of the resulting desiliconized leaching residue is shown in the figure. Figure 4 As shown in (c), it can be seen from the figure that iron and aluminum elements in the desiliconized slag are completely dispersed together; (5) When the leaching residue obtained in step (4) is subjected to a magnetic field strength of 1000 Gs, the iron recovery rate in the resulting concentrate is 43.21% and the iron grade is 32.33%. This indicates that the desilication leaching residue is difficult to effectively separate iron-containing and aluminum-containing minerals through magnetic separation.

[0044] Comparative Example 2 This comparative example discloses a method for the resource utilization of high-silica bauxite ore from high-speed railways, including the following steps: (1) The high-silica bauxite ore of high-speed rail was finely ground to -200 mesh, accounting for 90.23%; (2) The high-iron and high-silica bauxite ore ground in step (1) is oxidized and roasted at 1100℃ for 60 minutes by passing air through it; (3) After cooling the oxidative roasting material in step (2) to 700℃, add coal or coke for reduction roasting for 30 minutes; (4) The roasted material obtained in step (3) was leached in a sodium hydroxide solution at 100°C for 60 minutes at a liquid-to-solid ratio of 10:1, and the silica dissolution rate was 64.25%. (5) The iron recovery rate of the leaching residue obtained in step (4) was 52.65% and the iron grade was 30.22% under a magnetic field strength of 1000 Gs.

[0045] Comparing Example 3 with Comparative Example 2, it can be seen that when the sodium aluminate solution is leached at high temperature and high pressure in Example 3 without step (5), the iron recovery rate is significantly reduced, and the iron grade in the recovered concentrate is also significantly reduced. After analysis, the reason for this phenomenon is that after the treatment of steps (1) to (4), the iron-containing and aluminum-containing minerals in the desilication product are still embedded and dispersed together. It is difficult to effectively separate the iron-containing and aluminum-containing minerals by magnetic separation. This further verifies that the gibbsite, goethite, and kaolinite in the original minerals are embedded and closely coexisted in extremely fine particles (at the micron or even nanometer scale), and are mutually wrapped, embedded, and cemented together. It is difficult to effectively enrich the iron-containing minerals by grinding-magnetic separation.

[0046] Comparative Example 3 The only difference between this comparative example and Comparative Example 1 is that, between step (4) and step (5), the following step is also included: The leaching residue obtained in step (4) is subjected to a process at 260°C. ρ (Na2O k With a concentration of 230 g / L (molar concentration of Na2O) / (molar concentration of Al2O3) = 3, the relative dissolution rate of alumina was 20.26% after 80 min of dissolution at a liquid-to-solid ratio of 5:1.

[0047] The leaching residue obtained in step (4) was subjected to a magnetic field strength of 1000 Gs, and the iron recovery rate in the resulting concentrate was 44.14%, and the iron grade was 38.16%.

[0048] Comparing Comparative Example 1 and Comparative Example 3, it can be seen that although leaching with sodium aluminate solution before magnetic separation can leach out some aluminum, the leaching rate is low, resulting in low aluminum recovery. While it has some effect on the recovery of iron in subsequent magnetic separation and on improving the grade of the concentrate obtained from magnetic separation, the improvement effect is limited. This indicates that the roasted product is difficult to separate and recover Fe and Al through leaching, magnetic separation, or other methods, highlighting the significant impact of the roasting process on product separation.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the resource utilization of high-silica bauxite deposits for high-speed rail, characterized in that, include: (1) After grinding, the high-iron high-silica bauxite is roasted in an oxidizing atmosphere at 1000~1200℃; (2) The oxidative roasted material is cooled to 600~800℃ and then subjected to reduction roasting; (3) The reduced roasting product is subjected to alkaline leaching to obtain alkaline leaching residue and leachate; (4) The alkaline leaching residue was leached with sodium aluminate solution to obtain leaching residue and leachate; (5) The leaching residue is subjected to magnetic separation to obtain magnetite concentrate and tailings.

2. The method for resource utilization of high-speed rail high-silica bauxite as described in claim 1, characterized in that, The high-iron, high-silica bauxite contains, by mass percentage, 20-40% iron oxide, 30-55% alumina, and 10-15% silicon oxide.

3. The method for resource utilization of high-speed rail high-silica bauxite as described in claim 1, characterized in that, The iron-bearing phases in the high-iron, high-silica bauxite include one or more of hematite, goethite, and aluminous goethite. In the high-iron, high-silicon bauxite, iron, aluminum, and silicon elements mainly exist in a dispersed form, and the main distribution mode of iron, aluminum, and silicon elements in bauxite is that they are dispersed together.

4. The method for resource utilization of high-speed railway high-silica bauxite as described in claim 1, characterized in that, In step (1), the particle size of the high-iron high-silica bauxite after grinding is controlled to be below 200 mesh.

5. A method for the resource utilization of high-speed rail high-silica bauxite as described in claim 1, characterized in that, In step (1), the roasting time is 30~120 min; the oxidizing atmosphere is air.

6. The method for resource utilization of high-speed railway high-silica bauxite as described in claim 1, characterized in that, In step (2), the reduction roasting time is 20~60min; the reducing agent in the reduction roasting is one or more of CO, coke, coal and charcoal.

7. The method for resource utilization of high-speed railway high-silica bauxite as described in claim 1, characterized in that, In step (3), the alkali immersion time is 30~120min; the concentration of the alkali solution is 100~140g / L; the liquid-solid ratio of the alkali immersion is 5:1~10:1; and the alkali solution is NaOH solution.

8. A method for the resource utilization of high-speed rail high-silica bauxite as described in claim 1, characterized in that, In step (4), the sodium aluminate solution, ρ (Na2O k The concentration of sodium oxide is 220~240 g / L, and the molar ratio of sodium oxide to aluminum oxide is 2.5~3.0; the liquid-to-solid ratio of the leaching is 4~6:

1.

9. The method for resource utilization of high-speed railway high-silica bauxite as described in claim 1, characterized in that, In step (4), the leaching temperature is 240~260℃; the leaching time is 30~120min.

10. The method for resource utilization of high-speed rail high-silica bauxite as described in claim 1, characterized in that, In step (5), the intensity of the magnetic separation is controlled at 500~1500Gs.

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