A method for preparing super iron concentrate containing RE and Nb

Abstract

The invention discloses a method for preparing super iron concentrate containing RE and Nb, and belongs to the technical field of iron ore beneficiation. The method for preparing super iron concentrate containing RE and Nb comprises: using Bayan Obo ore as a raw material, obtaining magnetite concentrate by magnetic separation, and then performing reverse flotation roughing on the magnetite concentrate to obtain roughing pulp, and performing reverse flotation fine separation on the roughing pulp to obtain super iron concentrate containing RE and Nb, wherein the iron grade of the super iron concentrate containing RE and Nb is 72.15%, and the content of SiO2 is 0.21%. The super iron concentrate prepared by the invention contains original niobium and rare earth, and is a high-quality base material for preparing multifunctional wave absorbing materials, magnetic materials, medical carrier materials, clean steel, etc.

Description

Technical Field

[0001] The invention relates to the technical field of iron ore dressing, and in particular to a method for preparing super iron concentrate containing RE and Nb. Background Art

[0002] The Bayan Obo mine is a large-scale polymetallic ore deposit with coexistence of iron, rare earths, niobium, etc. It is currently mainly used as ordinary iron concentrate for Baotou Steel's steel production. The utilization rate of valuable elements other than rare earths is not high. The production of super iron concentrate is one of the effective ways to improve the economic benefits of enterprises and promote the upgrading of mineral processing products. Compared with ordinary iron concentrate, super iron concentrate (TFe ≥ 71%, SiO2 < 0.25%, Fe3O4 purity > 98.5%), in addition to its own price increased by 4 to 5 times, can also be used as a high-quality raw material for powder metallurgy, magnetic materials, direct reduced iron and clean steel production, especially the Bayan Obo mine, which contains elements such as RE and Nb. The steel products and ceramic materials prepared with it show super wear resistance and corrosion resistance, and have good comprehensive performance. Therefore, the Bayan Obo mine should be developed as a mineral material, and it cannot be used only cheaply.

[0003] However, the Bayan Obo iron ore has the mineralogical characteristics of "poor, fine and mixed". The "grinding-magnetic separation" process can only obtain iron concentrate with an iron grade lower than 69.00% and a SiO2 content higher than 0.30%. This iron concentrate can only be used as a raw material for producing sponge iron; if you want to produce super iron concentrate base materials for powder metallurgy and magnetic materials, the iron grade must be ≥71% and the SiO2 content must be <0.25%. How to use Bayan Obo iron ore as a raw material to obtain an iron concentrate with a high iron grade, extremely low SiO2 content, and enriched RE and Nb elements has become a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing super iron concentrate containing RE and Nb to solve the problems existing in the above-mentioned prior art. The super iron concentrate containing RE and Nb with an iron grade (TFe) of ≥71.5% and SiO2 ≤0.25% is prepared by magnetic separation, roughing and concentrating. The super iron concentrate is different from conventional super iron concentrate in that it contains trace amounts of niobium and rare earths, and can be used to develop more advanced functional materials (such as military absorbing materials, medical drug carriers, etc.), and can be widely used in metallurgy, magnetic materials, medicine, military industry and other related fields.

[0005] To achieve the above-mentioned purpose, the present invention provides the following scheme: a method for preparing a super iron concentrate containing RE and Nb, comprising the following steps: using Bayan Obo ore as a raw material, obtaining a magnetite concentrate by magnetic separation, then subjecting the magnetite concentrate to reverse flotation roughing to obtain a roughing pulp, and reverse flotation roughing the roughing pulp to obtain the super iron concentrate containing RE and Nb.

[0006] Further, the iron grade in the Bayan Obo ore is 30-68%, the mass percentage of Nb element is 0.1-0.5%, the mass percentage of rare earth elements is 2-5%, and the content of SiO2 is 7.0-20.0%; the iron grade in the magnetite concentrate is 69-70.00%, the mass percentage of Nb element is 0.02-0.05%, the mass percentage of rare earth elements is 0.1-0.5%, and the content of SiO2 is 0.30-0.90%.

[0007] Further, the Bayan Obo ore is the original ore of the main east mine of Bayan Obo or the mixed magnetite concentrate of Bayan Obo.

[0008] Further, the magnetic separation specifically includes: grinding the Bayan Obo ore into original ore particles, where the particle size of at least 93% of the original ore particles ≤ 0.030 mm, and then performing magnetic separation on the original ore particles under a magnetic field intensity of 1900-3500 Oe.

[0009] The iron recovery rate of the magnetite concentrate obtained by magnetic separation is 65-90%.

[0010] Further, the rough reverse flotation specifically includes: preparing a magnetite concentrate pulp after adjusting the pulp of the magnetite concentrate, adding a roughing activator to activate in the magnetite concentrate pulp and then adjusting the pH value to 8, and then adding a roughing collector for collection to obtain a rough concentrate pulp; the mass fraction of magnetite concentrate in the magnetite concentrate pulp is 30-60%; the roughing activator includes ferric chloride and calcium chloride.

[0011] The roughing activator (Ca / Fe ion composite activator) can effectively remove SiO2 in the iron concentrate.

[0012] Further, the dosage of the roughing activator is 0.02-0.06% of the pulp mass; the dosage of the roughing collector is 0.01-0.03% of the pulp mass.

[0013] Further, the fine reverse flotation specifically includes: adding a fine flotation activator to activate in the rough concentrate pulp and then adjusting the pH value to 8, and then adding a fine flotation collector for collection to obtain the super iron concentrate containing RE and Nb; the fine flotation activator includes ferric chloride and calcium chloride.

[0014] Even further, an inhibitor is added during the rough reverse flotation and fine reverse flotation processes.

[0015] Even further, the inhibitor is water glass, and the addition amount is 0.01-0.04% of the mass of the magnetite concentrate pulp or the rough concentrate pulp.

[0016] Further, the dosage of the selected activator is 0.03% of the mass of the rough ore pulp; the dosage of the selected collector is 0.015% of the mass of the rough ore pulp.

[0017] Further, the molar ratio of ferric chloride to calcium chloride in the roughing activator and the selected activator is 1:1 to 10:1; the roughing collector and the selected collector include any one of sodium dodecyl sulfonate (SDS) or dodecylamine.

[0018] The roughing activator and the selected activator are the Ca / Fe ion composite activator.

[0019] The present invention discloses the following technical effects:

[0020] The present invention uses the Bayan Obo ore as a raw material, obtains magnetite concentrate through magnetic separation, then obtains rough ore pulp by reverse flotation roughing of the magnetite concentrate, and obtains the super iron concentrate containing RE and Nb by reverse flotation and selection of the rough ore pulp. The iron grade of the obtained super iron concentrate is 72.15%, the mass percentage of SiO2 is 0.21%, the recovery rate of iron is 87.45%, the purity is 99.6%, the mass percentage of Nb element is 0.01 - 0.05%, and the mass percentage of RE is 0.1 - 0.5%. It overcomes the technical problem that the Bayan Obo iron concentrate has the mineralogical characteristics of "poor, fine, and miscellaneous", and thus it is difficult to improve the iron grade, providing a method with a short process and high efficiency for producing niobium- and rare earth-containing super iron concentrate, and can realize the high-value utilization of the Bayan Obo iron ore.

[0021] The Ca / Fe ion composite activator of the present invention is a mixed solution containing Ca 2+ , Fe 3+ configured according to a certain stoichiometric ratio. Its main function is to effectively increase the chemical adsorption and physical adsorption of the collector and quartz minerals during the reverse flotation process under certain pH value conditions, that is: the O atoms on the quartz surface react with Ca 2+ , Fe 3+ simultaneously. Both a stable Fe-based six-membered ring chelate (Si-O-Fe bond) and a chain-like Ca-based complex (Si-O-Ca bond) are formed on the quartz surface, generating four active sites, and its adsorption structure is a stable "chelate ring + chain" enhanced adsorption structure, so that the anionic collector SDS is more likely to selectively adsorb the quartz minerals activated by Ca / Fe ions, and its adsorption strength is greater than that of using only Ca 2+ or Fe 3+The adsorption strength after activation effectively improves the effect of the collector on adsorbing the target mineral, thereby improving the recovery rate of reverse flotation quartz minerals, further reducing the SiO2 content in the super iron concentrate and improving the iron grade. Due to the "poor, fine and mixed" nature of the Bayan Obo mine, if the activator is not used for flotation, and only magnetic separation and conventional flotation processes are used, even if the quartz is finely ground to monomer dissociation, the collector cannot effectively capture the quartz due to the lack of adsorption activity of the fine quartz particles, that is, it is difficult to obtain super iron concentrate with an iron grade greater than 72.15%, a SiO2 content less than 0.25%, an iron recovery rate greater than 85.00% and a purity greater than 99.6%. Moreover, the super iron concentrate obtained by flotation using the activator of the present invention contains trace amounts of original RE and Nb elements (0.01-0.5%), compared with the super iron concentrate prepared from other iron ores, and is dispersed in the iron concentrate. It is a high-quality raw material for subsequent clean steel production and functional material research and development. Studies have found that the magnetic ferrite material prepared using this super iron concentrate has significantly improved magnetic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a desiliconization flow chart of Example 1 of the present invention;

[0024] Figure 2 This is a SEM image of the super iron concentrate containing RE and Nb prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0027] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to those documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0028] Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the specification of this invention, which are obvious to those skilled in the art. Other embodiments obtained from the specification of this invention are obvious to those skilled in the art. The specification and examples of this application are merely exemplary.

[0029] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0030] Example 1

[0031] A method for preparing super iron concentrate containing RE and Nb:

[0032] (1) Grind the original ore of the main east mine in Bayan Obo (iron grade is; the mass percentage of Nb element is 0.20%; the mass percentage of RE element is 2.50%) into original ore particles with a particle size of 0.030 mm (the 0.030 mm original ore particles account for 93.0% of the total amount of original ore particles).

[0033] (2) Conduct magnetic separation on the original ore particles prepared in step (1) under a magnetic field intensity of 750 Oe to obtain magnetite concentrate (iron grade is 70.5%, iron recovery rate is 97.4%; the mass percentage of SiO2 is 0.35%, the mass percentage of Nb element is 0.08%; the mass percentage of RE element is 0.85%).

[0034] (3) Rough selection: Mix the magnetite concentrate prepared in step (2) with water at a mass ratio of 1:2 to adjust the pulp, stir for 3 min to obtain pulp, and add a Ca / Fe ion composite activator to the pulp (in the Ca / Fe ion composite activator, ferric chloride and calcium chloride are in a molar ratio of 1:1, and the addition amount of the Ca / Fe ion composite activator is 0.04% of the mass of the pulp), stir for 3 min, adjust the pH value to 8 (according to the results of the single-factor test of the pH value, it is found that when the pH value = 8, the Ca / Fe ion composite activator has a strong activation effect and can greatly improve the flotation recovery rate), stir for 3 min, then add an SDS collector (the addition amount of SDS is 0.02% of the mass of the pulp), and stir for 3 min to obtain the rough-selected pulp.

[0035] Among them, the flotation foam mainly contains quartz minerals and is discharged as the rougher tailings. The pulp after rougher contains mainly magnetite concentrate and enters the next cleaning process for further flotation desilication (removing quartz) treatment.

[0036] (4) Cleaning: Add a Ca / Fe ion composite activator (in the Ca / Fe ion composite activator, ferric chloride and calcium chloride are in a molar ratio of 1:1, and the addition amount of the Ca / Fe ion composite activator is 0.03% of the pulp mass) to the rougher pulp prepared in step (3), stir for 5 min, then adjust the pH value to 8, and then add an SDS collector (the addition amount of SDS is 0.015% of the pulp mass), stir for 3 min, and finally obtain a super iron concentrate containing RE and Nb through flotation desilication, filtration, and drying.

[0037] Among them, the cleaning foam mainly contains quartz minerals and is discharged as the cleaning tailings. The pulp after cleaning mainly contains magnetite concentrate with a higher purity (compared to the rougher iron concentrate).

[0038] The flowcharts of rougher and cleaning (desilication) are shown in Figure 1 , and the SEM image of the super iron concentrate is shown in Figure 2 .

[0039] Example 2

[0040] Same as Example 1, the only difference is that the magnetic field strength in step (2) is 500 Oe.

[0041] Example 3

[0042] Same as Example 1, the only difference is that the magnetic field strength in step (2) is 900 Oe.

[0043] Example 4

[0044] Same as Example 1, the only difference is that in step (3), ferric chloride and calcium chloride in the Ca / Fe ion composite activator are in a molar ratio of 10:1.

[0045] Example 5

[0046] Same as Example 1, except that step (3) is specifically as follows: The magnetite concentrate prepared in step (2) is mixed with water at a mass ratio of 1:2 to form a pulp, and after stirring for 3 min, a pulp is obtained. Then, a Ca / Fe ion composite activator (in the Ca / Fe ion composite activator, ferric chloride and calcium chloride are in a molar ratio of 1:1, and the addition amount of the Ca / Fe ion composite activator is 0.04% of the mass of the pulp) is added to the pulp and stirred for 3 min, then sodium silicate (the addition amount of sodium silicate is 0.02% of the mass of the pulp) is added and stirred for 3 min, the pH value is adjusted to 8 and stirred for 3 min, and then sodium dodecyl sulfonate SDS (the addition amount of SDS is 0.02% of the mass of the pulp) is added and stirred for 3 min to obtain a rough beneficiation pulp.

[0047] Comparative Example 1

[0048] Same as Example 1, except that the operation of step (2) is not carried out.

[0049] Comparative Example 2

[0050] Same as Example 1, except that the operation of step (4) is not carried out.

[0051] Effect Example 1

[0052] Determine the iron grade, iron recovery rate, and mass percentage of SiO2 in the super iron concentrate containing RE and Nb prepared in Examples 1 to 5 and Comparative Examples 1 to 2.

[0053] Table 1

[0054]

[0055] As can be seen from Table 1, under certain weak magnetic separation conditions (magnetic field intensity 500 Oe - 900 Oe), the iron concentrate obtained can be further beneficiated by flotation (adding a Ca / Fe composite activator) to obtain a super iron concentrate with an iron grade greater than 71.5% and an SiO2 content < 0.25%. In Comparative Example 1, if magnetic separation is not carried out and only flotation is used directly, a super iron concentrate with an SiO2 content < 0.25% can also be obtained, but the consumption of flotation reagents increases, increasing the beneficiation cost; in Comparative Example 1, if the concentration by flotation is not carried out and the dosage of reagents is appropriately increased, a super iron concentrate with an SiO2 content < 0.25% can also be obtained, but the iron grade (71.80%) is lower than that of the super iron concentrate after concentration by flotation (72.15%), but both meet the requirements of the market super iron concentrate index (iron grade > 71.5%, SiO2 content < 0.25%).

[0056] Effect Example 2

[0057] Determine that in the super iron concentrate prepared in Example 1, trace amounts of RE and Nb elements are contained. The mass percentage of each element is determined by SEM (see Figure 2) and EDS detection, and the results are shown in Table 2 (1-5 in the table are the elemental detections of micro-area point scanning by SEM).

[0058] Table 2

[0059]

[0060] As can be seen from Table 2, the super iron concentrate prepared by the present invention contains trace amounts of RE and Nb elements compared with the commercial super iron concentrate. Individual micro-area scanning points show pure iron oxide (Group 1), but other micro-area scanning points show small amounts of RE and Nb elements (Groups 2-5). Therefore, RE and Nb elements are contained as a whole.

[0061] Effect Example 3

[0062] Using the RE and Nb-containing super iron concentrate prepared in Example 1 as raw materials, strontium ferrite was prepared, and its magnetic properties (magnetization intensity and coercive force) were measured. The magnetic properties of strontium ferrite prepared from pure Fe2O3 powder and commercial super iron powder were compared, and the results are shown in Table 3.

[0063] Commercial super iron powder is usually prepared by the "grinding-magnetic separation" process. Its main components are Fe3O4 (TFe content 71.5%, SiO2 content 0.25%), and it does not contain elements such as RE and Nb. SrCO3 is added to commercial super iron powder (Fe3O4), and after mixing evenly according to the stoichiometric ratio, solid-phase sintering is carried out at 1200 °C to obtain strontium ferrite.

[0064] Table 3

[0065] Raw materials for preparing strontium ferrite Sintering temperature / °C Heat preservation time / h <![CDATA[M S / (emu / g)]]> <![CDATA[M r / (emu / g)]]> <![CDATA[H C / (Oe)]]> <![CDATA[Pure Fe2O3 powder]]> 1200 3 73.25 36.17 3487.2 Commercial super iron concentrate 1200 3 61.89 40.21 3079.0 Super iron concentrate of the present invention 1200 3 71.89 36.32 3826.7

[0066] As can be seen from Table 3, under the same sintering conditions (sintering temperature 1200 °C, holding time / 3 h), the coercive force (3826.7 Oe) of the strontium ferrite prepared with the super iron concentrate prepared by the present invention is higher than that of the strontium ferrite prepared with pure Fe2O3 powder and commercial super iron powder (3487.2 Oe and 3079.0 Oe, respectively).

[0067] Effect Example 4

[0068] Only by using the Dongmain Mine of Bayan Obo (the original ore contains 2-5% of RE and 0.1-0.5% of Nb) can a high-purity (99.6%) super iron concentrate containing trace amounts of RE and Nb (the contents of RE and Nb are less than those of the original ore, see Effect Example 2) be prepared through the combined process of "grinding-magnetic separation-flotation" (simultaneously using the flotation composite activator of the present invention). The innovation of the present invention is that no super iron concentrate containing RE and Nb with such high purity has been prepared by the method of Example 1 at present, and it is a high-quality raw material for the subsequent development of new functional materials (such as magnetic materials).

[0069] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the spirit of the design of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing super iron concentrate containing RE and Nb, characterized in that, It includes the following steps: Using the Bayan Obo ore as raw material, magnetite concentrate is obtained through magnetic separation. Then, the magnetite concentrate is rougher-selected by reverse flotation to obtain a rougher-concentrated pulp, and the rougher-concentrated pulp is further finer-selected by reverse flotation to obtain the super iron concentrate containing RE and Nb; The reverse flotation rougher-selection specifically includes: preparing a magnetite concentrate pulp after slurrying the magnetite concentrate, adding a rougher-selection activator to activate it in the magnetite concentrate pulp and then adjusting the pH value to 8, and then adding a rougher-selection collector for collection to obtain a rougher-concentrated pulp; the mass fraction of magnetite concentrate in the magnetite concentrate pulp is 30-60%; the rougher-selection activator includes ferric chloride and calcium chloride; The dosage of the rougher-selection activator is 0.02-0.06% of the pulp mass; the dosage of the rougher-selection collector is 0.01-0.03% of the pulp mass; The reverse flotation finer-selection specifically includes: adding a finer-selection activator to activate it in the rougher-concentrated pulp and then adjusting the pH value to 8, and then adding a finer-selection collector for collection to obtain the super iron concentrate containing RE and Nb; the finer-selection activator is a composite activator composed of ferric chloride and calcium chloride in a certain proportion; The dosage of the finer-selection activator is 0.03% of the rougher-concentrated pulp mass; the dosage of the finer-selection collector is 0.015% of the rougher-concentrated pulp mass; The molar ratio of ferric chloride to calcium chloride in the rougher-selection activator and the finer-selection activator is 1:1-10:1; the rougher-selection collector and the finer-selection collector include any one of sodium dodecyl sulfonate or dodecylamine.

2. The method for preparing a super iron concentrate containing RE and Nb according to claim 1, characterized in that, The iron grade in the Bayan Obo ore is 30-68%, the mass percentage of Nb element is 0.1-0.5%, the mass percentage of rare earth elements is 2-5%, and the content of SiO2 is 7.0-20.0%; the iron grade in the magnetite concentrate is 69-70.00%, the mass percentage of Nb element is 0.02-0.05%, the mass percentage of rare earth elements is 0.1-0.5%, and the content of SiO2 is 0.30-0.90%.

3. The method for preparing a super iron concentrate containing RE and Nb according to claim 1, characterized in that, The Bayan Obo ore is the original ore of the Bayan Obo Main East Mine or the Bayan Obo mixed magnetite concentrate.

4. The method for preparing a super iron concentrate containing RE and Nb according to claim 1, characterized in that, The magnetic separation specifically includes: grinding the Bayan Obo ore into original ore particles, with at least 90% of the original ore particles having a particle size ≤ 0.030 mm, and then performing magnetic separation on the original ore particles under a magnetic field intensity of 1900-3500 Oe.

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