A method for extracting iron, niobium, and titanium from complex associated ores in a low-carbon and green manner

Abstract

The present invention relates to the technical field of mineral processing, and specifically to a method for low-carbon and green extraction of iron, niobium, and titanium from complex associated ores, including: heating the raw ore to a preset reduction temperature and then introducing a hydrogen-rich gas for selective reduction, obtaining a reduction product after a preset reduction time; grinding the reduction product and performing magnetic separation to remove iron under a preset magnetic field intensity to obtain a niobium-rich residue; leaching the niobium-rich residue in an acid solution, and filtering the leached pulp to obtain a leaching solution and a leaching residue. The method mentioned in this application uses hydrogen metallurgy technology to regulate the complex primary ore phase, realizes the efficient reduction of iron minerals, regulates the occurrence states of valuable metals such as niobium and titanium, changes the thermodynamic stability of the primary ore phase, and creates favorable ore phase conditions for the leaching of niobium.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral processing, and particularly relates to a method for low-carbon and green extraction of iron, niobium, and titanium from complex associated ores. Background Art

[0002] Niobium is considered an important critical strategic metal element and has attracted much attention due to its excellent superconducting properties, high melting point, and excellent high-temperature resistance and corrosion resistance. In addition, the addition of trace amounts of niobium can significantly improve the properties of materials, making it widely used in high-end technical fields such as iron and steel metallurgy, aerospace, medical equipment, superconducting materials, energy, and nuclear industry.

[0003] The Bayan Obo ore is located in the northern part of Baotou City, Inner Mongolia Autonomous Region, China. It is a world-renowned polymetallic associated deposit rich in important elements such as iron, rare earths, and niobium. The niobium resource reserves in this ore reach 6.6 million tons, accounting for more than 60% of the proven niobium reserves in China and more than 80% of the industrial reserves. The main niobium-containing minerals in the Bayan Obo ore include columbite (FeNb2O6), pyrochlore ((Ce,Th)(Ti,Nb)2O6), columbite rutile ((Ti,Nb,Fe)O2), and pyrochlore ((Ca,Na)2(Nb,Ti)2O6F). However, since niobium mainly occurs as complex oxides associated with elements such as rare earths, titanium, calcium, silicon, and iron, its chemical composition and mineral phase composition are complex, and the niobium grade in the ore is low, the dissemination size is fine, and the intergrowth characteristics between minerals are significant, resulting in extremely low utilization rate of niobium resources. These characteristics not only limit the separation and extraction of niobium minerals but also cause a large number of valuable components to be discarded in the tailings pond, becoming potential secondary resources.

[0004] In previous studies on pyrometallurgical selective reduction, carbonaceous materials were often used as reducing agents, and carbothermal reduction easily led to the formation of niobium carbide. Since carbides are insoluble in acid, it is not conducive to the subsequent leaching of niobium. And the commonly used wet niobium extraction technology is prone to equipment corrosion, and a large amount of hazardous waste gas and fluorine-containing waste residue will be generated during the mineral decomposition process, which is extremely harmful to the environment. Summary of the Invention

[0005] (I) Technical Problems to be Solved

[0006] In view of the prior art, how to overcome the technical problems in the separation and extraction of niobium minerals, such as complex ore dressing process, long process flow, high energy consumption, and poor economic benefits.

[0007] (II) Technical Solutions

[0008] To this end, the present invention mentions a method for low-carbon and green extraction of iron, niobium, and titanium from complex associated ores, including:

[0009] Step 1: Heat the raw ore to a preset reduction temperature, then introduce a hydrogen-rich gas for selective reduction. After a preset reduction time, a reduced product is obtained.

[0010] Step 2: Grind the reduced product and perform magnetic separation to remove iron under a preset magnetic field intensity to obtain a niobium-rich residue.

[0011] Step 3: Leach the niobium-rich residue in an acid solution. After filtration of the leached pulp, a leachate and a leached residue are obtained. The acid solution is at least one of a tartaric acid solution, a citric acid solution, an ascorbic acid solution, or an acetic acid solution.

[0012] Further, in Step 1, based on the sum of mass percentages being 100%, the composition of the raw ore includes: T.Fe: 0 - 55%, Nb2O5: 0.5 - 15%, TiO2: 1 - 30%, REO: 1 - 20%, SiO2: 5 - 40%, CaO: 2 - 15%, F: 2 - 10%, and the balance is inevitable impurities.

[0013] Further, in Step 1, the amount of the raw ore ground to a particle size less than or equal to 200 mesh accounts for 80 - 90 wt% of the total ore amount.

[0014] Further, the hydrogen-rich gas includes one or more of hydrogen, coke oven gas, pyrolyzed natural gas, and coal gas reformate.

[0015] Further, in Step 1, the reduction temperature is 800 - 1500 °C, the reduction time is 10 - 180 min, and the flow rate of the hydrogen-rich gas is 300 - 1500 mL / min.

[0016] Further, in Step 1, place the raw ore in a high-temperature furnace for heating. The high-temperature furnace includes at least one of a plasma smelting furnace, a high-temperature tubular dropping furnace, a hydrogen-based shaft furnace, a blast furnace, a rotary kiln, and a fluidized bed.

[0017] Further, in Step 2, the amount of the reduced product ground to a particle size less than 200 mesh accounts for 40 - 85 wt% of the total ore amount, and the magnetic field intensity is 50 - 250 mT.

[0018] Further, in Step 3, the concentration of the acid solution is 0.5 - 8 mol / L, the leaching time is 1 - 10 h, and the leaching temperature is 70 - 150 °C.

[0019] Further, in Step 3, the liquid-solid ratio of the acid solution to the niobium-rich residue is 5 - 50 mL / g.

[0020] (III) Beneficial effects

[0021] The beneficial effects of the present invention are as follows: The present invention mentions a method for low-carbon and green extraction of iron, niobium, and titanium from complex associated ores, including: heating the raw ore to a preset reduction temperature and then introducing a hydrogen-rich gas for selective reduction, obtaining a reduction product after a preset reduction time; grinding the reduction product and performing magnetic separation to remove iron under a preset magnetic field intensity to obtain a niobium-rich residue; leaching the niobium-rich residue in an acid solution, and filtering the leached pulp to obtain a leachate and a leached residue, where the acid solution is at least one of a tartaric acid solution, a citric acid solution, an ascorbic acid solution, or an acetic acid solution.

[0022] The method mentioned in this application uses hydrogen metallurgy technology to regulate the complex primary ore phase. It not only realizes the efficient reduction of iron minerals but also regulates the occurrence states of valuable metals such as niobium and titanium, changes the thermodynamic stability of the primary ore phase, and creates favorable ore phase conditions for the leaching of niobium. In addition, iron recovery is achieved through magnetic separation. This application combines pyrometallurgy and hydrometallurgy, realizes the ore phase regulation of Bayan Obo ore and the efficient leaching of valuable components, meets the process development requirements of low-carbon and green, and opens up a new path for the efficient enrichment, separation, and extraction of valuable components. Description of the Drawings

[0023] Figure 1 It is a process flow diagram of a method for low-carbon and green extraction of iron, niobium, and titanium from complex associated ores mentioned in this application;

[0024] Figure 2 It is another process flow diagram of a method for low-carbon and green extraction of iron, niobium, and titanium from complex associated ores mentioned in this application. Detailed Embodiments

[0025] In order to better explain the present invention for easy understanding, the present invention will be described in detail below with reference to the drawings through specific embodiments.

[0026] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper limit preferred values and lower limit preferred values, it should be understood that all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value are specifically disclosed, regardless of whether the range is separately disclosed. For example, when the range "1 - 5" is disclosed, the described range should be interpreted as including ranges "1 - 4", "1 - 3", "1 - 2", "1 - 2 and 4 - 5", "1 - 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0027] In these embodiments, unless otherwise specified, the parts and percentages are by mass. "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 3.527 g, etc. If we say that the mass of component A is a parts by mass and the mass of component B is b parts by mass, it means the mass ratio of component A to component B is a:b. Or it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of parts by mass, the sum of the parts by mass of all components is not limited to 100 parts. "And / or" is used to indicate that one or both of the described situations occur. For example, A and / or B includes (A and B) and (A or B).

[0028] Reference Figure 1 and Figure 2 , a method for extracting iron, niobium, and titanium from complex associated ores with low carbon and green, mentioned in this application, includes: Step 1: Heating the raw ore to a preset reduction temperature and then introducing a hydrogen-rich gas for selective reduction.

[0029] It should be noted that selective reduction can specifically reduce iron, preparing for subsequent magnetic separation of iron. Using hydrogen-rich gases such as hydrogen and coke oven gas, on the one hand, the strong reducing ability of hydrogen can be utilized to achieve efficient reduction at relatively low temperatures; on the other hand, using hydrogen-rich gas as a reducing agent effectively avoids the formation of carbides and significantly reduces carbon dioxide emissions, meeting the development direction of green processes and having great environmental benefits. At the same time, the present invention regulates the complex primary ore phase through hydrogen metallurgy technology, realizes the reduction of iron minerals in Bayan Obo ore, and regulates the occurrence states of valuable metal elements such as niobium and titanium, creating more favorable ore phase conditions for the leaching of niobium.

[0030] Controlling the reduction temperature at 800 - 1500 °C, the reduction time at 10 - 180 min, and the hydrogen-rich gas flow rate at 300 - 1500 mL / min can ensure the full progress of the reduction reaction, improve the reduction efficiency and product quality.

[0031] Placing the raw ore in various high-temperature furnaces for heating, such as plasma melting furnaces and high-temperature tubular dropping furnaces, the appropriate equipment can be selected according to the actual situation to improve the flexibility and adaptability of production.

[0032] The above reduction time can ensure the complete progress of the iron reduction reaction, improve the reduction efficiency and product quality. If the reduction time is less than 10 min, it will lead to insufficient iron reduction, affecting the subsequent magnetic separation effect and element extraction. While a reduction time greater than 180 min will increase production costs and energy consumption.

[0033] Step 2: Grind the reduced product and then perform magnetic separation to remove iron. Grind the reduced product to a specific particle size such that the amount of ore less than 200 mesh accounts for 40 - 85 wt% of the total ore, which can significantly increase the specific surface area of the mineral. The increase in specific surface area means that more mineral surfaces are exposed to the magnetic field, thereby improving the magnetic separation effect. Furthermore, more iron particles can be adsorbed by the magnetic field, enhancing the iron separation efficiency.

[0034] Perform magnetic separation at a magnetic field intensity of 50 - 250 mT to effectively separate iron and obtain niobium-rich residue. By controlling the magnetic field intensity at 50 - 250 mT, while ensuring the iron separation effect, it is possible to avoid the loss of other useful elements caused by over-magnetic separation, obtain niobium-rich residue, and provide convenience for the subsequent extraction of elements such as niobium and titanium.

[0035] Step 3: Leach the niobium-rich residue in an acid solution. After leaching, the pulp is filtered to obtain the leachate and the leached residue. The acid solution is at least one of tartaric acid solution, citric acid solution, ascorbic acid solution, or acetic acid solution.

[0036] It should be noted that by controlling the acid solution concentration at 0.5 - 8 mol / L, the leaching time at 1 - 10 h, and the leaching temperature at 70 - 150 °C, it is possible to ensure that elements such as niobium and titanium in the niobium-rich residue are fully dissolved into the acid solution, improving the leaching efficiency.

[0037] It should be noted that the liquid-solid ratio of the acid solution to the niobium-rich residue is 5 - 50 mL / g, which can ensure sufficient contact between the acid solution and the niobium-rich residue during the leaching process, improving the leaching effect. After leaching, the pulp is filtered to obtain the leachate and the leached residue, facilitating the subsequent further extraction and separation of elements such as niobium and titanium in the leachate.

[0038] The method mentioned in this application uses hydrogen metallurgy technology to regulate complex primary ore phases. It not only realizes the efficient reduction of iron minerals but also regulates the occurrence states of valuable metals such as niobium and titanium, changes the thermodynamic stability of the primary ore phase, and creates favorable ore phase conditions for the leaching of niobium. In addition, iron recovery is achieved through magnetic separation. This application combines pyrometallurgy and hydrometallurgy, realizes the ore phase regulation of Bayan Obo ore and the efficient leaching of valuable components, meets the process development requirements of low-carbon and green, and opens up a new path for the efficient enrichment, separation, and extraction of valuable components.

[0039] To better understand the technical solution, the exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to be able to convey the scope of the present invention completely to those skilled in the art.

[0040] Example 1

[0041] Step 1: Place the raw ore in a fluidized bed, heat it to 1000 °C, then introduce hydrogen for selective reduction. After 30 minutes of reduction, a reduced product is obtained.

[0042] Step 2: Grind the reduced product obtained in Step 1 until the ore with a particle size of 200 mesh accounts for 70% of the total ore, and perform magnetic separation to remove iron under a magnetic field intensity of 75 mT to obtain a niobium-rich residue.

[0043] Step 3: Leach the niobium-rich residue obtained in Step 2 at an oxalic acid concentration of 2 mol / L, a leaching time of 7 h, a liquid-solid ratio of 25 mL / g, and a leaching temperature of 95 °C. After leaching, the pulp is filtered to obtain a leachate and a leaching residue.

[0044] After analysis, through the above steps, the leaching rate of niobium can reach 97.3%, the leaching rate of titanium is 98.4%, and the recovery rate of iron is 65.7%.

[0045] Example 2

[0046] Step 1: Place the raw ore in a hydrogen-based shaft furnace, heat it to 900 °C, then introduce coke oven gas for selective reduction. After 60 minutes of reduction, a reduced product is obtained.

[0047] Step 2: Grind the reduced product obtained in Step 1 until the ore with a particle size of 200 mesh accounts for 80% of the total ore, and perform magnetic separation to remove iron under a magnetic field intensity of 95 mT to obtain a niobium-rich residue.

[0048] Step 3: Leach the niobium-rich residue obtained in Step 2 at a citric acid concentration of 1 mol / L, a leaching time of 9 h, a liquid-solid ratio of 15 mL / g, and a leaching temperature of 110 °C. After leaching, the pulp is filtered to obtain a leachate and a leaching residue.

[0049] After analysis, through the above steps, the leaching rate of niobium can reach 96.8%, the leaching rate of titanium is 97.6%, and the recovery rate of iron is 68.5%.

[0050] Example 3

[0051] Step 1: Place the raw ore in a fluidized bed, heat it to 1100 °C, then introduce pyrolytic natural gas for selective reduction. After 90 minutes of reduction, a reduced product is obtained.

[0052] Step 2: Grind the reduced product obtained in Step 1 until the ore with a particle size of 200 mesh accounts for 85% of the total ore, and perform magnetic separation to remove iron under a magnetic field intensity of 120 mT to obtain a niobium-rich residue.

[0053] Step 3: Leach the niobium-rich residue obtained in Step 2 at a tartaric acid concentration of 5 mol / L, a leaching time of 3 h, a liquid-solid ratio of 30 mL / g, and a leaching temperature of 95 °C. After leaching, the pulp is filtered to obtain a leaching solution and a leaching residue.

[0054] After analysis, the leaching rate of niobium can reach 95.5%, the leaching rate of titanium is 96.1%, and the recovery rate of iron is 70.8% through the above steps.

[0055] The above describes the basic principles, main features, and advantages of the present invention. However, the above are only specific embodiments of the present invention, and the technical features of the present invention are not limited thereto. Any other embodiments obtained by those skilled in the art without departing from the technical solution of the present invention should be covered within the patent scope of the present invention.

[0056] In the description of the present invention, each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0057] In the description of the present invention, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. In the description of the present invention, the meaning of "a plurality of" is two or more, unless otherwise specifically defined. Moreover, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device including a series of elements includes not only those elements but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, article, or device including the said element.

[0058] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below", and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0059] In the description of this specification, the descriptions of terms such as "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0060] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A low-carbon green method for extracting iron, niobium and titanium from complex co-existing ores, characterized in that: include: Step 1: After heating the raw ore to a preset reduction temperature, hydrogen-rich gas is introduced for selective reduction, and a reduction product is obtained after a preset reduction time; Step 2: Grinding the reduction product, and performing magnetic separation to remove iron under a preset magnetic field strength to obtain niobium-rich residue; Step 3: leaching the niobium-rich residue in an acid solution, filtering the leached pulp to obtain a leachate and a leached residue, wherein the acid solution is at least one of a tartaric acid solution, a citric acid solution, an ascorbic acid solution or an acetic acid solution; In step 1, based on the sum of the mass percentages being 100%, the components of the raw ore include: T.Fe: 0-55%, Nb2O5: 0.5-15%, TiO2: 1-30%, REO: 1-20%, SiO2: 5-40%, CaO: 2-15%, F: 2-10%, and the remainder being unavoidable impurities.

2. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 1, characterized in that: In step 1, the raw ore is ground to a particle size of less than or equal to 200 mesh, and the amount of the ore accounts for 80-90wt% of the total ore.

3. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 1, characterized in that: The hydrogen-rich gas includes one or more of hydrogen, coke oven gas, cracked natural gas, and coal gas reforming gas.

4. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 3, characterized in that: In step 1, the reduction temperature is 800-1500° C., the reduction time is 10-180 min, and the flow rate of the hydrogen-rich gas is 300-1500 mL / min.

5. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 1, characterized in that: In step 1, the raw ore is placed in a high-temperature furnace for heating. The high-temperature furnace includes at least one of a plasma melting furnace, a high-temperature tubular dripping furnace, a hydrogen-based vertical furnace, a blast furnace, a rotary kiln, and a fluidized bed.

6. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 1, characterized in that: In step 2, the reduction product is ground to a particle size less than 200 mesh, and the amount of the ore accounts for 40-85wt% of the total ore, and the magnetic field strength is 50-250mT.

7. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 1, characterized in that: In step 3, the concentration of the acid solution is 0.5-8 mol / L, the leaching time is 1-10 h, and the leaching temperature is 70-150°C.

8. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 1, characterized in that: In step 3, the liquid-to-solid ratio of the acid solution to the niobium-rich residue is 5-50 mL / g.

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