Low-carbon green method for extracting iron, niobium and titanium from complex associated ore

Abstract

The invention relates to the technical field of mineral processing, in particular to a low-carbon green method for extracting iron, niobium and titanium in complex associated ore, which comprises the following steps: heating raw ore to a preset reduction temperature, introducing hydrogen-rich gas for selective reduction, and obtaining a reduction product after preset reduction time; the reduction product is ground, magnetic separation iron removal is carried out under the preset magnetic field intensity, and niobium-rich residues are obtained; the niobium-rich residues are leached in an acid solution, and leached ore pulp is filtered to obtain leachate and leached residues. According to the method, the hydrogen metallurgy technology is used for regulating and controlling the complex primary ore phase, efficient reduction of iron minerals is achieved, the occurrence state of valuable metal such as niobium and titanium is regulated and controlled, the thermodynamic stability of the primary ore phase is changed, and beneficial ore phase conditions are created for leaching of niobium.

Description

Technical Field

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

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

[0003] The Bayan Obo Mine is located in the north of Baotou City, Inner Mongolia Autonomous Region, China. It is a world-renowned polymetallic co-existing deposit rich in important elements such as iron, rare earths, and niobium. The mine has a niobium resource reserve of 6.6 million tons, accounting for more than 60% of China's proven niobium reserves and more than 80% of industrial reserves. The main niobium-containing minerals in the Bayan Obo Mine include niobium iron ore (FeNb2O6), calcite ((Ce, Th)(Ti, Nb)2O6), niobium iron rutile ((Ti, Nb, Fe)O2) and pyrochlore ((Ca, Na)2(Nb, Ti)2O6F). However, since niobium is mainly associated with rare earths, titanium, calcium, silicon, iron and other elements in the form of complex oxides, its chemical composition and mineral phase composition are complex, and the niobium grade in the ore is low, the embedded particle size is fine, and the inter-mineral intergrowth characteristics are significant, resulting in extremely low utilization 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 abandoned in tailings ponds, becoming potential secondary resources.

[0004] In the previous pyrometallurgical selective reduction research, carbonaceous materials were often used as reducing agents. Carbon thermal reduction easily leads to the formation of niobium carbide, which is difficult to dissolve in acid and is not conducive to the subsequent leaching of niobium. The commonly used wet niobium extraction technology is prone to equipment corrosion, and the mineral decomposition process will produce a large amount of hazardous waste gas and fluorine-containing waste residue, which is extremely harmful to the environment. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the existing technology, how to overcome the technical problems of separation and extraction of niobium minerals, complex mineral processing, long process, high energy consumption and poor economic benefits.

[0006] (II) Technical solution To this end, the present invention discloses a low-carbon green method for extracting iron, niobium and titanium from complex co-existing ores, comprising: 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: Grind the reduced product and perform 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 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.

[0007] Further, 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.

[0008] Furthermore, in step 1, the raw material 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.

[0009] Furthermore, the hydrogen-rich gas includes one or more of hydrogen, coke oven gas, cracked natural gas, and coal gas reforming gas.

[0010] Furthermore, 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.

[0011] Furthermore, in step 1, the raw ore is placed in a high temperature furnace for heating, and 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.

[0012] Further, 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.

[0013] Furthermore, 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.

[0014] Furthermore, in step 3, the liquid-to-solid ratio of the acid solution to the niobium-rich residue is 5-50 mL / g.

[0015] (III) Beneficial effects The beneficial effects of the present invention are as follows: the present invention mentions a low-carbon green method for extracting iron, niobium and titanium from complex co-existing ores, comprising: heating the raw ore to a preset reduction temperature and then introducing a hydrogen-rich gas for selective reduction, to obtain a reduction product after a preset reduction time; grinding the reduction product, and performing magnetic separation to remove iron under a preset magnetic field strength to obtain a niobium-rich residue; leaching the niobium-rich residue in an acid solution, and filtering the leached slurry to obtain a leachate and a leaching 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.

[0016] The method mentioned in this application uses hydrogen metallurgy technology to regulate complex primary mineral phases, which not only achieves efficient reduction of iron minerals, but also regulates the occurrence state of valuable metals such as niobium and titanium, changes the thermodynamic stability of the primary mineral phase, and creates favorable mineral phase conditions for niobium leaching. In addition, iron recovery is achieved through magnetic separation. This application combines pyrometallurgy with hydrometallurgy to achieve mineral phase regulation and efficient leaching of valuable components in the Bayan Obo mine, which meets the needs of low-carbon and green process development, and opens up a new path for efficient enrichment and separation and extraction of valuable components. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A process flow chart of a low-carbon green method for extracting iron, niobium and titanium from complex co-existing ores mentioned in this application; Figure 2 This is another process flow chart of a low-carbon, green method for extracting iron, niobium and titanium from complex co-existing ores mentioned in this application. DETAILED DESCRIPTION

[0018] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0019] When amount, concentration or other value or parameter is represented by range, preferred range or a series of upper preferred value and lower preferred value, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1-5", described range should be interpreted as including range "1-4", "1-3", "1-2", "1-2 and 4-5", "1-3 and 5" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0020] In these embodiments, unless otherwise specified, the parts and percentages are all by mass. "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1 g, 3.527 g, etc. If we say that the mass parts of component A are a parts and the mass parts of component B are b parts, it means the ratio of the mass of component A to the mass of component B, a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts. "And / or" is used to indicate that one or both of the situations described occur, for example, A and / or B include (A and B) and (A or B).

[0021] refer to Figure 1 and Figure 2 The present application mentions a low-carbon green method for extracting iron, niobium and titanium from complex co-existing ores, comprising: Step 1: heating the raw ore to a preset reduction temperature and then introducing hydrogen-rich gas for selective reduction.

[0022] It should be noted that selective reduction can reduce iron in a targeted manner to prepare for subsequent magnetic separation and iron removal. The use of hydrogen-rich gases, such as hydrogen, coke oven gas, etc., can, on the one hand, utilize the strong reducing ability of hydrogen to achieve efficient reduction at a relatively low temperature; on the other hand, the use of hydrogen-rich gas as a reducing agent effectively avoids the formation of carbides and significantly reduces carbon dioxide emissions, which is in line with the development direction of green technology and has huge environmental benefits. At the same time, the present invention regulates and controls complex primary mineral phases through hydrogen metallurgical technology, realizes the reduction of iron minerals in the Bayan Obo mine, and regulates the occurrence state of valuable metal elements such as niobium and titanium, creating more favorable mineral phase conditions for niobium leaching.

[0023] Controlling the reduction temperature at 800-1500°C, the reduction time at 10-180min and the hydrogen-rich gas flow rate at 300-1500mL / min can ensure that the reduction reaction proceeds fully, thereby improving the reduction efficiency and product quality.

[0024] The raw ore is placed in a variety of high-temperature furnaces for heating, such as a plasma melting furnace, a high-temperature tubular dripping furnace, etc. Appropriate equipment can be selected according to actual conditions to improve production flexibility and adaptability.

[0025] The above reduction time can ensure that the iron reduction reaction is completely carried out, improve the reduction efficiency and product quality. If the reduction time is less than 10 minutes, the iron reduction will be insufficient, affecting the subsequent magnetic separation effect and element extraction. If the reduction time is greater than 180 minutes, the production cost and energy consumption will increase.

[0026] Step 2: Grind the reduction product and then perform magnetic separation to remove iron. Grind the reduction product to a specific particle size so that the amount of ore less than 200 mesh accounts for 40-85wt% of the total ore amount, 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, which in turn allows more iron particles to be adsorbed by the magnetic field and improves the iron separation efficiency.

[0027] Magnetic separation at a magnetic field strength of 50-250mT can effectively separate iron and obtain niobium-rich residue. By controlling the magnetic field strength to 50-250mT, the iron separation effect can be ensured while avoiding the loss of other useful elements caused by excessive magnetic separation, and niobium-rich residue can be obtained, which facilitates the subsequent extraction of elements such as niobium and titanium.

[0028] Step 3: Leaching the niobium-rich residue in an acid solution, filtering the leached pulp to obtain a leachate and 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.

[0029] It should be noted that controlling the acid solution concentration to 0.5-8 mol / L, the leaching time to 1-10 h and the leaching temperature to 70-150° C. can ensure that elements such as niobium and titanium in the niobium-rich residue are fully dissolved in the acid solution, thereby improving the leaching efficiency.

[0030] It should be noted that the liquid-to-solid ratio of the acid solution to the niobium-rich residue is 5-50 mL / g, which can ensure that there is enough acid solution in contact with the niobium-rich residue during the leaching process, thereby improving the leaching effect. The leached pulp is filtered to obtain the leachate and the leachate residue, which is convenient for the subsequent extraction and separation of elements such as niobium and titanium in the leachate.

[0031] The method mentioned in this application uses hydrogen metallurgy technology to regulate complex primary mineral phases, which not only achieves efficient reduction of iron minerals, but also regulates the occurrence state of valuable metals such as niobium and titanium, changes the thermodynamic stability of the primary mineral phase, and creates favorable mineral phase conditions for niobium leaching. In addition, iron recovery is achieved through magnetic separation. This application combines pyrometallurgy with hydrometallurgy to achieve mineral phase regulation and efficient leaching of valuable components in the Bayan Obo mine, which meets the needs of low-carbon and green process development, and opens up a new path for efficient enrichment and separation and extraction of valuable components.

[0032] In order to better understand the technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0033] Example 1 Step 1: Place the raw ore in a fluidized bed, heat it to 1000°C, introduce hydrogen for selective reduction, and obtain the reduced product after 30 minutes of reduction.

[0034] Step 2: Grind the reduction product obtained in step 1 to a particle size of 200 mesh, which accounts for 70% of the total ore volume, and perform magnetic separation to remove iron under a magnetic field strength of 75mT to obtain a niobium-rich residue.

[0035] 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-to-solid ratio of 25 mL / g, and a leaching temperature of 95° C. The leached pulp is filtered to obtain a leachate and a leaching residue.

[0036] According to analysis, the leaching rate of niobium, titanium and iron can be 97.3%, 98.4% and 65.7% respectively.

[0037] Example 2 Step 1: The raw ore is placed in a hydrogen-based vertical furnace and heated to 900° C., and then coke oven gas is introduced for selective reduction. After 60 minutes of reduction, a reduction product is obtained.

[0038] Step 2: Grind the reduction product obtained in step 1 to a particle size of 200 mesh, which accounts for 80% of the total ore volume, and perform magnetic separation to remove iron under a magnetic field intensity of 95mT to obtain a niobium-rich residue.

[0039] Step 3: The niobium-rich residue obtained in step 2 is leached at a citric acid concentration of 1 mol / L, a leaching time of 9 h, a liquid-to-solid ratio of 15 mL / g, and a leaching temperature of 110° C. The leached pulp is filtered to obtain a leachate and a leaching residue.

[0040] According to analysis, the leaching rate of niobium, titanium and iron can be 96.8%, 97.6% and 68.5% respectively.

[0041] Example 3 Step 1: The raw ore is placed in a fluidized bed and heated to 1100° C., cracked natural gas is introduced for selective reduction, and a reduction product is obtained after 90 minutes of reduction.

[0042] Step 2: Grind the reduction product obtained in step 1 to a particle size of 200 mesh, which accounts for 85% of the total ore volume, and perform magnetic separation to remove iron under a magnetic field intensity of 120 mT to obtain a niobium-rich residue.

[0043] Step 3: The niobium-rich residue obtained in step 2 is leached at a tartaric acid concentration of 5 mol / L, a leaching time of 3 h, a liquid-to-solid ratio of 30 mL / g, and a leaching temperature of 95° C. The leached pulp is filtered to obtain a leachate and a leaching residue.

[0044] According to analysis, the leaching rate of niobium, titanium and iron can be 95.5%, 96.1% and 70.8% respectively.

[0045] The above describes the basic principles, main features and advantages of the present invention. However, the above is only a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other implementation methods derived by any technician in the field without departing from the technical solution of the present invention should be included in the patent scope of the present invention.

[0046] In the description of the present invention, each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0047] In the description of the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically limited. Moreover, the term "includes", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the sentence "comprising one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0048] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0049] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction 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, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0050] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify 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 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.

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, 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.

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: 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.

4. 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.

5. The method for low-carbon green extraction of iron, niobium and titanium from complex co-existing ores according to claim 4, 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.

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 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.

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 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.

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 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.

9. 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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