Method for preparing iron oxide yellow by leaching iron ore tailings through advanced oxidation technology

Abstract

The invention relates to the technical field of iron ore tailing resource utilization, in particular to a method for preparing iron oxide yellow by leaching iron ore tailings through an advanced oxidation technology, which comprises the following steps: adding a required amount of iron ore tailing powder into a persulfate solution, stirring to react, adding a reducing agent, boiling, filtering, adding alkali liquor to adjust the pH value, and filtering, thereby obtaining the iron oxide yellow. Pure liquid containing ferrous ions is obtained; taking part of the pure solution containing ferrous ions, and adding a potassium hydroxide solution to obtain an iron oxide yellow seed crystal solution; adding a pure solution containing ferrous ions into the iron oxide yellow seed crystal solution, adding an alkali solution to adjust the pH value, reacting, and separating and drying a product to obtain the iron oxide yellow. According to the method, the persulfate is adopted to leach iron from the iron ore tailings, and the iron oxide yellow is prepared from the leachate; harmless treatment of the iron ore tailings and value-added utilization of valuable resources are achieved, the raw material source of the iron oxide yellow industry is widened, and a wider prospect is provided for development of iron oxide yellow.

Description

Technical Field

[0001] The present invention relates to the technical field of utilization of iron ore tailings resources, and is a method for leaching iron ore tailings by advanced oxidation technology to prepare iron oxide yellow. Background Art

[0002] Iron ore tailings are by-products generated during the beneficiation process of iron ore, usually containing a certain amount of un-recovered iron and associated other metal elements. Simple disposal methods such as stacking and landfilling have caused serious pollution to the soil and environment, and also caused a great waste of resources. At present, the resource utilization of iron ore tailings mainly includes recovering valuable components by mining, and using iron ore tailings to make ceramsite, building materials, soil conditioners, etc. Although these methods can achieve the resource utilization of iron ore tailings to a certain extent, due to the complex chemical composition and mineralogical properties of iron ore tailings, the added value of the developed products is relatively low.

[0003] The beneficiation of iron ore tailings mainly includes two categories: physical and chemical methods. Physical beneficiation refers to using the physical property differences between minerals, without relying on the chemical property changes of minerals, to separate useful minerals from other components through physical processes. Physical beneficiation has certain requirements for the physical properties of ores. Commonly used methods include combined processes such as magnetization roasting - magnetic separation, gravity separation, gravity separation - magnetic separation, etc., which are more suitable for separating minerals with obvious physical property differences. Chemical beneficiation is to change the chemical composition or structure of minerals through chemical reactions, so that useful components can be enriched or separated from other components. Commonly used methods include flotation, leaching, precipitation, ion exchange, etc., which are more suitable for refractory oxidized ores, complex symbiotic ores, etc. For iron ore tailings with low iron grade and complex chemical composition and mineralogical properties, it is difficult to effectively separate iron by physical methods. Therefore, the chemical leaching method is used to selectively dissolve the target minerals, and the solution temperature and pH are adjusted to achieve the expected separation effect.

[0004] Strong acid leaching, as a traditional leaching method, is widely used in tailings. Strong acids are used to dissolve the useful components in the tailings, and then further chemical or electrochemical extraction is carried out to recover and utilize the beneficial components. However, strong acid leaching (such as sulfuric acid, hydrochloric acid, etc.) has poor selectivity for metals, easily causes the target metal and non-target metals to dissolve together, bringing difficulties to the subsequent separation and purification steps; the large amount of acidic wastewater generated is directly discharged, which will cause serious environmental pollution problems; and strong acids are highly corrosive to production equipment, requiring more corrosion-resistant materials to manufacture equipment, or frequent replacement and maintenance of equipment, thus increasing the capital expenditure and operating costs, resulting in a waste of resources.

[0005] Advanced oxidation technologies are widely used in water treatment. For example, Deng Yang et al. (Deng Yang, Zhao Renzun. Advanced oxidation processes (AOPs) in wastewater treatment[J]. Current Pollution Reports, 2015, 1(3): 167-176.) reviewed the basic mechanisms of free radical generation in different advanced oxidation technologies and selected landfill leachate and biologically treated municipal wastewater as model wastewaters to discuss the wastewater treatment of different advanced oxidation technologies. Advanced oxidation processes are regarded as highly competitive water treatment methods for removing organic pollutants and have great potential in treating various pollutants and improving the biodegradability of wastewater. However, they have not been widely applied in the oxidative leaching and recovery of various metal elements. For example, Ding Anting et al. (Recovering palladium and gold by peroxydisulfate-based advanced oxidation process[J]. Science Advances, 2024, 10(21): eadm9311.) proposed an advanced oxidation process (AOP) based on peroxydisulfate (PDS) for the selective recovery of Pd and Au from waste catalysts, achieving the recovery of precious metals.

[0006] As a widely used iron oxide material, yellow iron oxide has the advantages of high coloring power, strong light resistance, heat resistance, non-toxicity, and the ability to protect substances sensitive to ultraviolet light, with high product value.

[0007] Zhang Cong (Zhang Cong. Analysis of the Development of Iron Oxide Yellow Pigment from the Perspective of Patents [J]. Information Recording Materials, 2015, 16(3): 31-39) summarized a preparation method of iron oxide yellow: Mix ferrous sulfate with calcium hydroxide to obtain a suspension of ferrous hydroxide, oxidize the obtained suspension of ferrous hydroxide, and then iron oxide yellow seeds are prepared. Mix the seeds, ferrous salts, and refined iron, and then add an oxidant for oxidation to obtain iron oxide yellow. Chinese patent document with the publication number CN106219611A discloses a low-viscosity iron oxide yellow. The method adopted for this iron oxide yellow is to react ferrous sulfate and sodium hydroxide at 25-35 °C to prepare iron oxide yellow seeds, then put the prepared seeds into an autoclave, add sodium hydroxide solution, close the valve of the autoclave when the specified pH is reached, control the system pressure at about 1.2-1.7 MPa, the reaction temperature is 70 °C, and the reaction time is controlled at 12-14 h. Finally, low-viscosity iron oxide yellow is obtained through rinsing, suction filtration, drying, and pulverization. This method obtains low-viscosity iron oxide yellow pigment by changing the reaction environment without adding other substances and changing the pH value of the pigment, but the high-pressure environment is dangerous and energy-consuming. Lu Xiongxiong (Research on the Process of Preparing Nano Iron Oxide Yellow from NdFeB Secondary Waste [D]. Jiangxi University of Science and Technology, 2024.) used NdFeB secondary waste as the raw material, and under the leaching system formed by sulfuric acid and additives, wet-process recovered iron elements from the waste, and the obtained leachate was further processed through iron powder reduction, crystallization purification, etc. to obtain high-purity FeSO4·7H2O, and then nano iron oxide yellow was prepared by air oxidation method, and studied the influence of different experimental conditions on the product performance. The research on preparing nano iron oxide yellow from NdFeB secondary waste realized the recycling of solid waste secondary resources. This method uses the traditional sulfuric acid leaching method, which is easy to pollute the environment, has a long crystallization purification cycle, and although the addition of additives can improve the iron leaching rate, the cost is high. Wu Penghui et al. (Preparation of Iron Oxide Yellow from Titanium White By-Product Ferrous Sulfate [J]. The Chinese Journal of Process Engineering, 2016, 16(02): 310-316.) used titanium white by-product ferrous sulfate as the main raw material to prepare iron oxide yellow, and investigated the molar ratio of NaOH to FeSO4·7H2O, the initial Fe 2+The effects of concentration, aeration rate, and temperature on seed crystal formation, as well as the effects of seed crystal concentration, pH value, and the dosage of FeSO4·7H2O on the product, were studied, and the process parameters were optimized. However, the average particle size of the prepared product was about 860 nm, and the larger particle size would lead to poor dispersion of the product. Wang Xiaotong et al. (Research on the preparation of iron oxide yellow from super iron concentrate [J]. Liaoning Chemical Industry, 2023, 52(5): 646-650+660.) used super iron concentrate as the initial raw material, prepared ferrous sulfate by acid dissolution-filtration-reduction method, and used ammonium bicarbonate as the precipitant to prepare iron oxide yellow by oxidation precipitation method. This method uses sulfuric acid leaching, which causes serious environmental pollution, great damage to equipment, and high cost due to the high iron content of the iron concentrate used.

[0008] At present, the industrial preparation method of iron oxide yellow is to add alkaline substances to a high-purity iron-containing salt solution to form iron oxide yellow by oxidation precipitation. Although China can produce various types of iron oxide pigments, such as iron oxide red, yellow, black, etc., compared with the international advanced level, there are fewer special uses and high-performance product types in high-end fields such as transparent iron oxide pigments and heat-resistant iron oxide pigments, and there is great potential for product development. Summary of the Invention

[0009] The present invention provides a method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology, which overcomes the above-mentioned deficiencies of the prior art and can effectively solve the problems of resource waste caused by the accumulation of existing iron ore tailings and the single source of raw materials for the preparation of iron oxide yellow.

[0010] The technical solution of the present invention is achieved by the following measures: A method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology is carried out according to the following steps: In the first step, the required amount of iron ore tailings powder is added to a persulfate solution, stirred and reacted, and after solid-liquid separation, a first mixed solution is obtained; In the second step, a reducing agent is added to the first mixed solution, boiled and filtered to obtain a second mixed solution; In the third step, an alkali solution is added to the second mixed solution to adjust the pH, and after reaction, it is filtered to obtain a pure solution containing ferrous ions; In the fourth step, a part of the pure solution containing ferrous ions is taken, potassium hydroxide solution is added, and after reaction, the supernatant is decanted to obtain an iron yellow seed crystal solution; In the fifth step, a pure solution containing ferrous ions is added to the iron yellow seed crystal solution, an alkali solution is added to adjust the pH, and after reaction, the product is separated and dried to obtain iron oxide yellow.

[0011] The following is a further optimization and / or improvement of the above-mentioned invention technical solution: In the above first step, the particle size of the iron ore tailings powder is 100 mesh to 300 mesh.

[0012] In the first step above, the persulfate is one or more of potassium persulfate, sodium persulfate, and ammonium persulfate. The concentration of the persulfate solution is 0.01 mol / L to 0.30 mol / L, and 5 g to 60 g of iron ore tailings powder is added to each 1 L of the persulfate solution. Optimally, the concentration of the persulfate solution is 0.03 mol / L to 0.20 mol / L, and 10 g to 50 g of iron ore tailings powder is added to each 1 L of the persulfate solution.

[0013] In the first step above, the reaction temperature is 25°C to 90°C, and the reaction time is 1 h to 8 h. Optimally, the reaction temperature is 30°C to 80°C, and the reaction time is 2 h to 6 h.

[0014] In the second step above, the reducing agent is reduced iron powder, and the addition amount is 0.01 g / mL to 0.20 g / mL.

[0015] In the second step above, the boiling duration is 5 min to 20 min.

[0016] In the third step above, the pH is adjusted to 4 to 6.

[0017] In the third step above, the reaction time is 5 min to 50 min.

[0018] In the fourth step above, the concentration of the potassium hydroxide solution is 0.1 mol / L to 2.5 mol / L, and the molar ratio of OH - in the potassium hydroxide solution to Fe 2+ in the pure solution containing ferrous ions is 2OH - / Fe 2+ = 0.05 to 0.6. Optimally, the concentration of the potassium hydroxide solution is 0.5 mol / L to 2.0 mol / L, the content of ferrous ions in the pure solution containing ferrous ions is 0.1 mol / L to 0.8 mol / L, and the molar ratio of OH - in the potassium hydroxide solution to Fe 2+ in the pure solution containing ferrous ions is 2OH - / Fe 2+ = 0.1 to 0.5.

[0019] In the fourth step above, the reaction is carried out at room temperature, oxygen is introduced and stirred until the pH value of the system reaches between 2 and 5, and the reaction is completed. Optimally, the reaction is completed until the pH value of the system reaches between 3 and 4.

[0020] In the above-mentioned fifth step, the concentration of ferrous ions in the pure solution containing ferrous ions is 0.01 mol / L to 1.0 mol / L, and the volume ratio of the iron yellow seed solution to the pure solution containing ferrous ions is 1:1 to 1:10. Optimally, the concentration of ferrous ions in the pure solution containing ferrous ions is 0.05 mol / L to 0.85 mol / L, and the volume ratio of the iron yellow seed solution to the pure solution containing ferrous ions is 1:1 to 1:8.

[0021] In the above-mentioned fifth step, the reaction is carried out under the conditions of pH value of 2 to 4 and temperature of 60 °C to 95 °C, while passing oxygen and stirring for 1 h to 10 h. Optimally, the reaction is carried out under the conditions of pH value of 2.5 to 3.5 and temperature of 70 °C to 95 °C, while passing oxygen and stirring for 2 h to 9 h.

[0022] The above-mentioned alkali solution is 0.01 mol / L to 2 mol / L ammonia water or 0.01 mol / L to 2 mol / L aqueous sodium hydroxide solution.

[0023] The present invention provides a method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology, leaching iron from iron ore tailings using persulfate, and preparing iron oxide yellow using the leaching solution; realizing the high-value resource utilization of iron ore tailings, breaking through the bottleneck problem of traditional strong acid leaching, and broadening the raw material sources of the iron oxide yellow industry, providing a broader prospect for the development of iron oxide yellow. Description of the Drawings

[0024] Appendix Figure 1 It is the SEM diagram of the iron oxide yellow prepared in Example 14 of the present invention.

[0025] Appendix Figure 2 It is the XRD diagram of the iron oxide yellow prepared in Example 14 of the present invention.

[0026] Appendix Figure 3 It is the SEM diagram of the iron oxide yellow prepared in Example 15 of the present invention.

[0027] Appendix Figure 4 It is the XRD diagram of the iron oxide yellow prepared in Example 15 of the present invention.

[0028] Appendix Figure 5 It is the SEM diagram of the iron oxide yellow prepared in Example 16 of the present invention.

[0029] Appendix Figure 6 It is the XRD diagram of the iron oxide yellow prepared in Example 16 of the present invention. Detailed Embodiments

[0030] The present invention is not limited by the following embodiments, and specific implementation manners can be determined according to the technical solution of the present invention and actual situations. All kinds of chemical reagents and chemical supplies mentioned in the present invention are well-known and commonly used chemical reagents and chemical supplies in the prior art without special instructions; the percentages in the present invention are mass percentages without special instructions; the solutions in the present invention are aqueous solutions with water as the solvent without special instructions. For example, a hydrochloric acid solution is an aqueous solution of hydrochloric acid; normal temperature and room temperature in the present invention generally refer to a temperature range of 15°C to 25°C, and are generally defined as 25°C.

[0031] The following further describes the present invention with reference to embodiments: Example 1: The method for leaching iron ore tailings to prepare iron oxide yellow by using advanced oxidation technology is carried out according to the following steps: In the first step, add the required amount of iron ore tailings powder into a persulfate solution, stir and react, and obtain a first mixed solution after solid-liquid separation; In the second step, add a reducing agent to the first mixed solution, boil and then filter to obtain a second mixed solution; In the third step, add an alkali solution to the second mixed solution to adjust the pH, react and then filter to obtain a pure solution containing ferrous ions; In the fourth step, take a part of the pure solution containing ferrous ions, add a potassium hydroxide solution, react and then let it stand to pour off the supernatant to obtain an iron yellow seed solution; In the fifth step, add the pure solution containing ferrous ions to the iron yellow seed solution, add an alkali solution to adjust the pH, and after reaction, the product is separated and dried to obtain iron oxide yellow.

[0032] Example 2: As an optimization of the above embodiment, in the first step, the particle size of the iron ore tailings powder is 100 mesh to 300 mesh.

[0033] Example 3: As an optimization of the above embodiment, in the first step, the persulfate is one or more of potassium persulfate, sodium persulfate, and ammonium persulfate. The concentration of the persulfate solution is 0.01 mol / L to 0.30 mol / L, and 5 g to 60 g of iron ore tailings powder is added to each 1 L of the persulfate solution. Preferably, the concentration of the persulfate solution is 0.03 mol / L to 0.20 mol / L, and 10 g to 50 g of iron ore tailings powder is added to each 1 L of the persulfate solution.

[0034] Example 4: As an optimization of the above embodiment, in the first step, the reaction temperature is 25°C to 90°C, and the reaction time is 1 h to 8 h. Preferably, the reaction temperature is 30°C to 80°C, and the reaction time is 2 h to 6 h.

[0035] Example 5: As an optimization of the above embodiment, in the second step, the reducing agent is reduced iron powder, and the addition amount is 0.01 g / mL to 0.20 g / mL.

[0036] Example 6: As an optimization of the above embodiments, in the second step, the boiling duration is 5 min to 20 min.

[0037] Example 7: As an optimization of the above embodiments, in the third step, the pH is adjusted to 4 to 6.

[0038] Example 8: As an optimization of the above embodiments, in the third step, the reaction time is 5 min to 50 min.

[0039] Example 9: As an optimization of the above embodiments, in the fourth step, the concentration of the potassium hydroxide solution is 0.1 mol / L to 2.5 mol / L, and the molar ratio of OH - in the potassium hydroxide solution to Fe 2+ in the pure solution containing ferrous ions is 2OH - / Fe 2+ = 0.05 to 0.6. Optimally, the concentration of the potassium hydroxide solution is 0.5 mol / L to 2.0 mol / L, the content of ferrous ions in the pure solution containing ferrous ions is 0.1 mol / L to 0.8 mol / L, and the molar ratio of OH - in the potassium hydroxide solution to Fe 2+ in the pure solution containing ferrous ions is 2OH - / Fe 2+ = 0.1 to 0.5.

[0040] Example 10: As an optimization of the above embodiments, in the fourth step, the reaction is carried out at room temperature while passing oxygen and stirring until the pH value of the system reaches between 2 and 5, and the reaction is completed. Optimally, the reaction is completed until the pH value of the system reaches between 3 and 4.

[0041] Example 11: As an optimization of the above embodiments, in the fifth step, the concentration of ferrous ions in the pure solution containing ferrous ions is 0.01 mol / L to 1.0 mol / L, and the volume ratio of the iron yellow seed solution to the pure solution containing ferrous ions is 1:1 to 1:10. Optimally, the concentration of ferrous ions in the pure solution containing ferrous ions is 0.05 mol / L to 0.85 mol / L, and the volume ratio of the iron yellow seed solution to the pure solution containing ferrous ions is 1:1 to 1:8.

[0042] Example 12: As an optimization of the above embodiments, in the fifth step, the reaction is carried out under the conditions of pH value 2 to 4 and 60 °C to 95 °C while passing oxygen and stirring for 1 h to 10 h. Optimally, the reaction is carried out under the conditions of pH value 2.5 to 3.5 and 70 °C to 95 °C while passing oxygen and stirring for 2 h to 9 h.

[0043] Example 13: As an optimization of the above embodiments, the alkali solution is 0.01 mol / L to 2 mol / L ammonia water or 0.01 mol / L to 2 mol / L aqueous sodium hydroxide solution.

[0044] Example 14: The method for preparing iron oxide yellow from the leaching solution of iron ore tailings is carried out according to the following steps: S1, Pretreatment of iron ore tailings: Take 400 g of iron ore tailings, grind them with a ball mill at a rotation speed of 200 r / min at room temperature, and pass through a 300-mesh sieve to obtain iron ore tailings powder.

[0045] S2, Preparation of pure liquid: Take 8.11 g of potassium persulfate and 200 mL of pure water to prepare a potassium persulfate solution. Add 6 g of iron ore tailings powder to the potassium persulfate solution. Under magnetic stirring, react at 50 °C for 4 h, let it stand, and filter to obtain the first mixed solution; Take 100 mL of the first mixed solution, add 2 g of reduced iron powder to reduce ferric iron. After boiling for 10 min, filter to obtain the second mixed solution; Adjust the pH value of the second mixed solution to 4.5 with 2 mol / L ammonia water, react for 30 min, let it stand and filter to obtain a pure liquid containing ferrous ions, and measure the concentration of ferrous ions therein.

[0046] S3, Preparation of iron yellow seed solution: Take a part of the pure liquid containing ferrous ions and dilute it to obtain 100 mL of a pure liquid containing ferrous ions with a concentration of 0.3 mol / L. Under magnetic stirring, add 7.5 mL of 1 mol / L potassium hydroxide solution, and introduce oxygen until the pH of the solution drops to 3; obtain a liquid containing iron oxide yellow seeds, let it stand for 0.5 h, and pour off the supernatant to obtain an iron yellow seed solution.

[0047] S4, Oxidation: Take a part of the pure liquid containing ferrous ions and dilute it to obtain 160 mL of a pure liquid containing ferrous ions with a concentration of 0.35 mol / L. Add it to 40 mL of the iron yellow seed solution, introduce oxygen, and dropwise add 2 mol / L ammonia water under magnetic stirring to keep the pH value between 2.5 and 3.5. At 80 °C, react for 8 h to completely oxidize ferrous ions to iron yellow; centrifuge the solution, wash the obtained solid 3 times with pure water, dry it for 5 h, and grind it to obtain iron oxide yellow powder.

[0048] The main element composition of the iron ore tailings in this example is: S: 22.85%, Fe: 21.06%, Al: 9.56%, K: 5.08%, Ca: 4.91%, Mg: 2.35%, Na: 1.42%, Cu: 0.14%.

[0049] The SEM image and XRD pattern of the iron oxide yellow prepared in this example are shown in Figure 1 and Figure 2, its phase composition is α-FeOOH, the iron oxide yellow particles are in a needle-like structure, and the average particle size is between 100 nm and 200 nm; the XRF test result determines that the content of ferric oxide in the iron oxide yellow is 93.90%, meeting the Class A standard of iron oxide pigments in GB / T 1863-2008.

[0050] Example 15: The method for preparing iron oxide yellow from the leaching solution of iron ore tailings is carried out according to the following steps: S1, pretreatment of iron ore tailings: Take 400 g of iron ore tailings, use a ball mill to grind at a rotation speed of 200 r / min at room temperature, and then pass through a 300-mesh sieve to obtain iron ore tailings powder.

[0051] S2, preparation of pure liquid: Take 7.14 g of sodium persulfate and 200 mL of pure water to prepare a sodium persulfate solution. Add 7 g of iron ore tailings powder to the sodium persulfate solution. Under magnetic stirring, react at 60 °C for 5 h, let it stand, and filter to obtain the first mixed solution; Take 100 mL of the first mixed solution, add 2.5 g of reduced iron powder to reduce ferric iron. After boiling for 10 min, filter to obtain the second mixed solution; Adjust the pH value of the second mixed solution to 5.0 with 2 mol / L ammonia water, react for 25 min, let it stand and filter to obtain a pure liquid containing ferrous ions, and measure its ferrous ion concentration.

[0052] S3, preparation of iron yellow seed solution: Take a part of the pure liquid containing ferrous ions and dilute it to obtain 100 mL of a pure liquid containing ferrous ions with a concentration of 0.2 mol / L. Under magnetic stirring, add 5 mL of 1 mol / L potassium hydroxide solution, and pass in oxygen until the pH of the solution drops to 3.5; obtain a liquid containing iron oxide yellow seeds, let it stand for 1 h, and pour off the supernatant to obtain the iron yellow seed solution.

[0053] S4, oxidation: Take a part of the pure liquid containing ferrous ions and dilute it to obtain 160 mL of a pure liquid containing ferrous ions with a concentration of 0.25 mol / L. Add it to 40 mL of the iron yellow seed solution, pass in oxygen, and dropwise add 2 mol / L ammonia water under magnetic stirring to keep the pH value between 2.5 and 3.5. At 80 °C, react for 7 h to completely oxidize ferrous ions to iron yellow; centrifuge the solution, wash the obtained solid with pure water 3 times, dry for 5 h, and grind to obtain iron oxide yellow powder.

[0054] The main element composition of the iron ore tailings in this example is the same as that in Example 14.

[0055] The SEM image and XRD pattern of the iron oxide yellow prepared in this example are shown in Figure 3 andFigure 4 Its phase composition is α-FeOOH; the iron oxide yellow particles are in a needle-like structure with an average particle size ranging from 100 nm to 200 nm; the XRF test result determines that the iron(III) oxide content in the iron oxide yellow is 86.11%, meeting the Class A standard of iron oxide pigments in GB / T 1863-2008.

[0056] Example 16: The method for preparing iron oxide yellow from the leaching solution of iron ore tailings is carried out according to the following steps: S1, Pretreatment of iron ore tailings: Take 400 g of iron ore tailings, use a ball mill to grind at a rotation speed of 200 r / min at room temperature, and then pass through a 300-mesh sieve to obtain iron ore tailings powder.

[0057] S2, Preparation of pure liquid: Take 6.85 g of ammonium persulfate and 200 mL of pure water to prepare an ammonium persulfate solution. Add 8 g of iron ore tailings powder to the ammonium persulfate solution, react at 70 °C for 6 h under magnetic stirring, let it stand, and filter to obtain a first mixed solution; Take 100 mL of the first mixed solution, add 3 g of reduced iron powder to reduce ferric iron, boil for 15 min, and then filter to obtain a second mixed solution; Adjust the pH value of the second mixed solution to 5.5 with 2 mol / L ammonia water, react for 35 min, let it stand and filter to obtain a pure liquid containing ferrous ions, and measure the ferrous ion concentration therein.

[0058] S3, Preparation of iron yellow seed solution: Take a part of the pure liquid containing ferrous ions and dilute it to obtain 100 mL of a pure liquid containing ferrous ions with a concentration of 0.4 mol / L. Under magnetic stirring, add 10 mL of 1 mol / L potassium hydroxide solution, and introduce oxygen until the pH of the solution drops to 4; obtain a liquid containing iron oxide yellow seeds, let it stand for 1.5 h, and pour off the supernatant.

[0059] S4, Oxidation: Take a part of the pure liquid containing ferrous ions and dilute it to obtain 160 mL of a pure liquid containing ferrous ions with a concentration of 0.45 mol / L. Add it to 40 mL of the iron yellow seed solution, introduce oxygen, and dropwise add 2 mol / L ammonia water under magnetic stirring to maintain the pH value between 2.5 and 3.5. React at 80 °C for 6 h to completely oxidize ferrous ions to iron yellow; centrifuge the solution, wash the obtained solid 3 times with pure water, dry for 5 h, and grind to obtain iron oxide yellow powder.

[0060] The main elements of the iron ore tailings in this example are the same as those in Example 14.

[0061] The SEM image and XRD pattern of the iron oxide yellow prepared in this example are shown in Figure 5 and Figure 6Its phase composition is α-FeOOH; the iron oxide yellow particles are in a needle-like structure, and the average particle size is between 100 nm and 200 nm; the XRF test results show that the iron(III) oxide content in the iron oxide yellow is 90.75%, meeting the Class A standard of iron oxide pigments in GB / T 1863-2008.

[0062] In summary, the present invention uses persulfate oxidation leaching of iron ore tailings to break through the bottleneck problem of traditional strong acid leaching, solves the pollution problem of iron ore tailings, recovers and utilizes the iron element in the iron ore tailings, and avoids the problem of resource waste. Using this solid waste of iron ore tailings as an iron source provides a new raw material source for the synthesis of iron oxide yellow, realizing the resource-efficient utilization and waste-to-treasure transformation of iron ore tailings. The prepared iron oxide yellow can be applied to fields such as construction, coatings, and plastics, having good economic and environmental benefits. Moreover, the method for preparing iron yellow using iron ore tailings in the present invention has the advantages of simple process and energy-saving and environmental-friendly process flow, providing a guarantee for the resource utilization of iron ore tailings, obtaining high economic benefits while actively responding to the global environmental protection call, and providing a solution to the difficult problem of waste treatment faced by the beneficiation industry.

[0063] The above technical features respectively constitute the embodiments of the present invention, which have strong adaptability and implementation effects. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology, characterized in that The following steps are carried out: In the first step, add the required amount of iron ore tailings powder into the persulfate solution, stir and react, and obtain the first mixed solution after solid-liquid separation; In the second step, add a reducing agent to the first mixed solution, boil and then filter to obtain the second mixed solution; In the third step, add an alkali solution to the second mixed solution to adjust the pH, react and then filter to obtain a pure solution containing ferrous ions; In the fourth step, take a part of the pure solution containing ferrous ions, add potassium hydroxide solution, react and then let it stand and pour off the supernatant to obtain the goethite seed solution; In the fifth step, add the pure solution containing ferrous ions to the goethite seed solution, add an alkali solution to adjust the pH, react, and the product is separated and dried to obtain iron oxide yellow.

2. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to claim 1, wherein In the first step, the particle size of the iron ore tailings powder is 100 mesh to 300 mesh; Or / and, the persulfate is one or more of potassium persulfate, sodium persulfate, ammonium persulfate, the concentration of the persulfate solution is 0.01 mol / L to 0.30 mol / L, and 5 g to 60 g of iron ore tailings powder is added to every 1 L of the persulfate solution.

3. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to claim 1 or 2, characterized in that In the first step, the reaction temperature is 25°C to 90°C, and the reaction time is 1 h to 8 h.

4. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to any one of claims 1 to 3, characterized in that In the second step, the reducing agent is reduced iron powder, and the addition amount is 0.01 g / mL to 0.20 g / mL.

5. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to any one of claims 1 to 4, characterized in that In the second step, the boiling duration is 5 min to 20 min.

6. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to any one of claims 1 to 5, characterized in that In the third step, adjust the pH to 4 to 6; or / and, in the third step, the reaction time is 5 min to 50 min.

7. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to any one of claims 1 to 6, characterized in that In the fourth step, the concentration of the potassium hydroxide solution is 0.1 mol / L to 2.5 mol / L, and the molar ratio of OH - in the potassium hydroxide solution to Fe 2+ in the pure solution containing ferrous ions is 2OH - / Fe 2+ = 0.05 to 0.6; Or / and, in the fourth step, the reaction is carried out at room temperature, oxygen is introduced and stirred until the pH value of the system reaches between 2 and 5, and the reaction is completed.

8. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to any one of claims 1 to 7, characterized in that In the fifth step, the concentration of ferrous ions in the pure solution containing ferrous ions is 0.01 mol / L to 1.0 mol / L, and the volume ratio of the goethite seed solution to the pure solution containing ferrous ions is 1:1 to 1:10; Or / and, in the fifth step, the reaction is carried out under the conditions of pH 2 to 4 and 60°C to 95°C, oxygen is introduced and stirred for 1 h to 10 h.

9. The method for preparing iron oxide yellow by leaching iron ore tailings using advanced oxidation technology according to any one of claims 1 to 8, characterized in that The alkali solution is 0.01 mol / L to 2 mol / L ammonia water or 0.01 mol / L to 2 mol / L sodium hydroxide aqueous solution.

10. Iron oxide yellow prepared by a method for leaching iron ore tailings to prepare iron oxide yellow using advanced oxidation technology according to any one of claims 1 to 9.

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