Method for extracting iron element from red mud

Abstract

The invention discloses a method for extracting an iron element from red mud, and belongs to the field of industrial waste reutilization and environmental protection. The method comprises the following steps: sequentially carrying out pretreatment and acid leaching on a red mud raw material to obtain a leaching solution, carrying out stirring reaction on an extracting agent, ethanol and the leaching solution to obtain a mixed extracting solution, sequentially carrying out water washing and acid pickling on resin to obtain pretreated resin, carrying out oscillation reaction on the pretreated resin and the mixed extracting solution, and filtering to obtain saturated resin and a mixed solution, and the saturated resin and the hydrochloric acid solution are subjected to oscillatory reaction to prepare the iron material. The method provided by the invention can effectively recover the iron element in the red mud and improve the utilization rate of resources; compared with traditional methods such as pyrometallurgy, the method provided by the invention is relatively low in energy consumption. After the extracting agent provided by the invention is subjected to a specific acid treatment process, the original extraction efficiency of the extracting agent can be recovered, so that the extracting agent can be repeatedly used for multiple times.

Description

Technical Field

[0001] The invention relates to the field of industrial waste recycling and environmental protection, and in particular to a method for extracting iron from red mud. Background Art

[0002] Red mud is an industrial solid waste generated during the production of alumina using bauxite as raw material. China is a major producer of alumina, but currently lacks mature comprehensive red mud utilization technology, and mainly relies on stockpiling. Therefore, there is an urgent need to develop clean and efficient red mud utilization technology. Due to the high iron content in red mud, recovering iron from red mud is currently an important way to utilize red mud. The coal-based direct reduction process is a common process for effectively recovering iron from red mud. The process mainly involves mixing red mud, additives (mainly fluxing agents such as calcium carbonate and sodium carbonate) and reducing agents (mainly carbon-containing substances such as coal and coke), and performing direct reduction in a high-temperature process. The iron oxides in the red mud are reduced by the reducing agent carbon, and then recovered by grinding and magnetic separation.

[0003] In addition to ferric oxide, red mud also contains aluminum oxide, silicon dioxide and calcium oxide. In a high-temperature reducing atmosphere, FeO is easy to react with these aluminum and silicon compounds to generate some complex compounds during the red mud reduction roasting process, thereby reducing the reduction activity of FeO and affecting the reduction roasting effect. By adding alkali metal compounds, aluminum and silicon compounds can react with additives first, thereby hindering the combination of aluminum, silicon and FeO, so that iron minerals are fully combined with reducing agents, and the reduction activity of FeO is correspondingly increased, thereby improving the reduction roasting effect. For example, the patent application with publication number CN115784642A discloses a method for extracting iron from high-iron red mud and direct cement raw materials. High-iron red mud is used as the main raw material, and reducing agents and auxiliary materials such as anthracite and lime are added. Iron is extracted by high-temperature reduction and cement clinker is produced. Although red mud can be used as a resource and cement costs can be reduced, it is limited by the iron recovery rate and requires a large amount of raw material processing to obtain sufficient iron resources. In addition, high-temperature reduction may produce waste gas, which requires additional environmental protection treatment.

[0004] Therefore, providing a green, environmentally friendly and sustainable method for extracting iron from red mud is an important issue that needs to be solved urgently in this field. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for extracting iron from red mud. Specifically, the technical solution of the present invention includes the following contents:

[0006] A method for extracting iron from red mud, the method comprising the following steps:

[0007] The red mud raw material is sequentially pretreated and acid-leached to obtain a leachate, the extractant, ethanol and the leachate are stirred to react to obtain a mixed extract, the resin is sequentially washed with water and acid-washed to obtain a pretreated resin, the pretreated resin and the mixed extract are subjected to an oscillation reaction and then filtered to obtain a saturated resin and a mixed solution, the saturated resin and a hydrochloric acid solution are subjected to an oscillation reaction to obtain a preliminary extract, the preliminary extract and deionized water are stirred to react to obtain a solid, the solid is calcined, mixed with graphite and subjected to heat preservation to obtain the iron material.

[0008] Furthermore, the preparation method of the extractant comprises the following steps:

[0009] The potassium pineol is reacted with pine alcohol and potassium hydroxide to obtain potassium pineol, the potassium pineol and 5-chlorosalicylaldehyde are reacted with each other to obtain an intermediate product, and the intermediate product and 3-amino-3-phenylpropionic acid are reacted with each other to obtain the extractant.

[0010] Furthermore, the weight ratio of pineol to potassium hydroxide is 1-2:0.4-1.

[0011] Furthermore, the mixed reaction of terpineol and potassium hydroxide includes a reaction temperature of 55 to 58° C. and a reaction time of 2 to 3 hours.

[0012] Furthermore, the weight ratio of potassium terpineol to 5-chlorosalicylaldehyde is 1-1.5:0.9-1.2.

[0013] Furthermore, the mixed reaction of potassium terpineol and 5-chlorosalicylaldehyde includes a reaction temperature of 110 to 120° C. and a reaction time of 3 to 5 hours.

[0014] Furthermore, the weight ratio of the intermediate product to 3-amino-3-phenylpropionic acid is 0.8-1.2:0.5-0.9.

[0015] Furthermore, the mixed reaction of the intermediate product and 3-amino-3-phenylpropionic acid includes a reaction temperature of 75 to 80° C. and a reaction time of 5 to 8 hours.

[0016] Furthermore, the weight ratio of the extractant, ethanol and leachate is 0.3-0.8:50-100:100.

[0017] Furthermore, the stirring reaction of the extractant, anhydrous ethanol and the leaching solution includes a reaction temperature of 60 to 80° C. and a reaction time of 0.5 to 1.5 h.

[0018] Furthermore, the resin is D001 type resin.

[0019] Furthermore, the weight ratio of the pretreatment resin to the mixed extract is 1:3-4.

[0020] Furthermore, the oscillation reaction of the pretreated resin and the mixed extract includes a reaction temperature of 35 to 55° C., a reaction time of 0.5 to 1.5 h, and an oscillation rate of 150 r / min.

[0021] Furthermore, the weight ratio of the saturated resin to the hydrochloric acid solution is 1:3-5.

[0022] Furthermore, the concentration of the hydrochloric acid solution is 2 to 5% by mass.

[0023] Furthermore, the oscillation reaction of the saturated resin and the hydrochloric acid solution includes a reaction temperature of 23 to 25° C., a reaction time of 0.5 to 1 h, and an oscillation rate of 150 r / min.

[0024] Furthermore, the stirring reaction of the preliminary extract and deionized water includes a reaction temperature of 80 to 90° C. and a reaction time of 0.5 to 1 h.

[0025] Furthermore, the calcination temperature is 600-80° C. and the calcination time is 2-3 hours.

[0026] Furthermore, the weight ratio of the solid to graphite is 60-80:9-10.

[0027] Furthermore, the heat preservation includes a reaction temperature of 1000-1200° C. and a reaction time of 2-4 hours.

[0028] Furthermore, after the mixed solution is mixed with 1 mol / L hydrochloric acid solution, the mixture is stirred and reacted at 40-50° C. for 40-60 minutes, and an acid treatment is performed to restore the adsorption and chelating capabilities of the active groups of the extractant.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) In the present invention, 5-chlorosalicylaldehyde is hydrophobically modified by pine alcohol, and then reacted with 3-amino-3-phenylpropionic acid to obtain an extractant, which contains multiple coordination sites of amino, carboxyl and hydroxyl groups and can chelate iron ions and aluminum ions in the leachate. The extractant is then treated with resin and hydrochloric acid in sequence to obtain an iron material.

[0031] (2) The method provided by the present invention can effectively recover the iron element in red mud and improve the utilization rate of resources; compared with traditional methods such as pyrometallurgy, the method provided by the present invention has lower energy consumption.

[0032] (3) The extractant provided by the present invention can restore its original extraction efficiency after undergoing a specific acid treatment process, thereby achieving multiple reuses, which not only significantly reduces production costs, but also improves resource utilization efficiency and reduces waste generation, which is of great significance to environmental protection and sustainable development. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below through the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0034] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0035] Preparation Example 1:

[0036] The preparation method of the extractant comprises the following steps:

[0037] 1 part by weight of terpineol and 0.4 part by weight of potassium hydroxide are dispersed in 50 parts by weight of a mixed solvent (V 丙酮 :V 去离子水 =5:1), mixed and reacted at 55°C for 2h, and after the reaction was completed, potassium terpineol was obtained by standing and filtering; 1 weight part of potassium terpineol and 0.9 weight part of 5-chlorosalicylaldehyde were dispersed in 100 weight parts of ethylene glycol, mixed and reacted at 110°C for 3h, cooled to 23°C after the reaction was completed, 500 weight parts of deionized water were added, and then filtered and recrystallized to obtain an intermediate product; 0.8 weight part of the intermediate product and 0.5 weight part of 3-amino-3-phenylpropionic acid were dispersed in 100 weight parts of anhydrous ethanol, mixed and reacted at 75°C in a nitrogen protection environment for 5h, and after the reaction was completed, the extractant was obtained by filtering and recrystallizing.

[0038] Preparation Example 2:

[0039] The preparation method of the extractant comprises the following steps:

[0040] 1.3 parts by weight of terpineol and 0.6 parts by weight of potassium hydroxide are dispersed in 60 parts by weight of a mixed solvent (V 丙酮 :V 去离子水 =5:1), mixed and reacted at 56°C for 2.3h, and after the reaction was completed, potassium terpineol was obtained by standing and filtering; 1.1 parts by weight of potassium terpineol and 1 part by weight of 5-chlorosalicylaldehyde were dispersed in 100 parts by weight of ethylene glycol, mixed and reacted at 112°C for 3.5h, cooled to 24°C after the reaction was completed, 500 parts by weight of deionized water were added, and then filtered and recrystallized to obtain an intermediate product; 0.9 parts by weight of the intermediate product and 0.7 parts by weight of 3-amino-3-phenylpropionic acid were dispersed in 100 parts by weight of anhydrous ethanol, mixed and reacted at 76°C in a nitrogen protection environment for 6h, and after the reaction was completed, the extractant was obtained by filtering and recrystallizing.

[0041] Preparation Example 3:

[0042] The preparation method of the extractant comprises the following steps:

[0043] 1.6 parts by weight of terpineol and 0.8 parts by weight of potassium hydroxide are dispersed in 70 parts by weight of a mixed solvent (V 丙酮 :V 去离子水 =5:1), mixed and reacted at 57°C for 2.7h, and after the reaction was completed, potassium pineol was obtained by standing and filtering; 1.3 parts by weight of potassium pineol and 1.1 parts by weight of 5-chlorosalicylaldehyde were dispersed in 100 parts by weight of ethylene glycol, mixed and reacted at 115°C for 4h, cooled to 24°C after the reaction was completed, 500 parts by weight of deionized water were added, and then filtered and recrystallized to obtain an intermediate product; 1 part by weight of the intermediate product and 0.8 part by weight of 3-amino-3-phenylpropionic acid were dispersed in 100 parts by weight of anhydrous ethanol, mixed and reacted at 78°C in a nitrogen protection environment for 7h, and after the reaction was completed, the extractant was obtained by filtering and recrystallizing.

[0044] Preparation Example 4:

[0045] The preparation method of the extractant comprises the following steps:

[0046] 2 parts by weight of terpineol and 1 part by weight of potassium hydroxide are dispersed in 80 parts by weight of a mixed solvent (V 丙酮 :V 去离子水 =5:1), mixed and reacted at 58°C for 3h, and after the reaction was completed, potassium terpineol was obtained by standing and filtering; 1.5 parts by weight of potassium terpineol and 1.2 parts by weight of 5-chlorosalicylaldehyde were dispersed in 100 parts by weight of ethylene glycol, mixed and reacted at 120°C for 5h, cooled to 25°C after the reaction was completed, 500 parts by weight of deionized water were added, and then filtered and recrystallized to obtain an intermediate product; 1.2 parts by weight of the intermediate product and 0.9 parts by weight of 3-amino-3-phenylpropionic acid were dispersed in 100 parts by weight of anhydrous ethanol, mixed and reacted at 80°C in a nitrogen protection environment for 8h, and after the reaction was completed, the extractant was obtained by filtering and recrystallizing.

[0047] Preparation Example 5:

[0048] The preparation method of the extractant comprises the following steps:

[0049] 1.2 parts by weight of salicylaldehyde and 0.9 parts by weight of 3-amino-3-phenylpropionic acid are dispersed in 100 parts by weight of anhydrous ethanol, mixed and reacted at 80° C. for 8 hours in a nitrogen atmosphere, and after the reaction, filtered and recrystallized to obtain an extractant.

[0050] Embodiment 1:

[0051] A method for extracting iron from red mud comprises the following steps:

[0052] The red mud raw material was dried at 100°C for 5h, and then a small amount of large-particle stones were removed by preliminary screening, and then the red mud was fully ground in a crusher to a particle size of 70μm to obtain pretreated red mud powder; 20 parts by weight of pretreated red mud powder were dispersed in 100 parts by weight of 3% hydrochloric acid solution, stirred at 70°C for 1.5h, and centrifuged to obtain a leachate after the reaction; 0.3 parts by weight of the extractant prepared in Preparation Example 1, 50 parts by weight of ethanol and 100 parts by weight of the leachate were stirred at 60°C for 0.5h, and after the reaction, the ethanol phase was collected and washed twice with deionized water to obtain a mixed extract; D001 resin was washed with deionized water 4 times to make the washing liquid colorless and transparent, and then washed twice with a 1% hydrochloric acid solution for acid washing, and after filtering out the washing liquid, it was washed 4 times with deionized water to obtain a pretreated resin; 100 parts by weight The pretreated resin and 300 parts by weight of the mixed extract are oscillated at 35°C at an oscillation rate of 150 r / min for 0.5 h, and then filtered to obtain a saturated resin and a mixed solution; 100 parts by weight of the saturated resin and 300 parts by weight of a 2% hydrochloric acid solution are oscillated at 23°C at an oscillation rate of 150 r / min for 0.5 h, and then solid-liquid separation is performed, and a preliminary extract is obtained by evaporation concentration, cooling crystallization and drying in sequence; the preliminary extract obtained above is dispersed in 200 parts by weight of deionized water, adjusted to pH 3, and stirred for reaction at 80°C for 0.5 h. After the reaction is completed, it is washed, precipitated and dried in sequence to obtain a solid; 60 parts by weight of the solid are calcined at 600°C for 2 h, 9 parts by weight of graphite are added, ground and mixed for 5 min, and then kept warm at 1000°C for 2 h in a nitrogen protection environment. After the insulation is completed, it is cooled to 23°C in a nitrogen protection environment to obtain an iron material.

[0053] Embodiment 2:

[0054] A method for extracting iron from red mud comprises the following steps:

[0055] The red mud raw material was dried at 101°C for 5.2h, and then a small amount of large-particle stones were removed by preliminary screening, and then fully ground in a crusher to a particle size of 70μm to obtain pretreated red mud powder; 20 parts by weight of pretreated red mud powder were dispersed in 120 parts by weight of 4% hydrochloric acid solution, stirred at 75°C for 1.8h, and centrifuged to obtain a leachate after the reaction; 0.35 parts by weight of the extractant prepared in Preparation Example 2, 70 parts by weight of ethanol and 100 parts by weight of the leachate were stirred at 65°C for 0.8h, and after the reaction, the ethanol phase was collected and washed twice with deionized water to obtain a mixed extract; D001 resin was washed with deionized water 4 times to make the washing liquid colorless and transparent, and then washed twice with a 1% hydrochloric acid solution for acid washing, and after filtering out the washing liquid, it was washed 4 times with deionized water to obtain a pretreated resin; 100 parts by weight of pre The treated resin and 320 parts by weight of the mixed extract were oscillated at 40°C at an oscillation rate of 150 r / min for 0.8 h, and then filtered to obtain a saturated resin and a mixed solution; 100 parts by weight of the saturated resin and 350 parts by weight of a 3% hydrochloric acid solution were oscillated at 24°C at an oscillation rate of 150 r / min for 0.8 h, and then solid-liquid separation was performed, and a preliminary extract was obtained by evaporation concentration, cooling crystallization and drying in sequence; the preliminary extract obtained above was dispersed in 200 parts by weight of deionized water, adjusted to pH 3.5, and stirred for reaction at 83°C for 0.6 h. After the reaction was completed, solids were washed, precipitated and dried in sequence to obtain a solid; 65 parts by weight of the solid were calcined at 650°C for 2.2 h, 9.3 parts by weight of graphite were added, ground and mixed for 7 min, and then kept warm at 1100°C for 3 h in a nitrogen protection environment. After the insulation was completed, the iron material was cooled to 24°C in a nitrogen protection environment to obtain the iron material.

[0056] Embodiment 3:

[0057] A method for extracting iron from red mud comprises the following steps:

[0058] The red mud raw material was dried at 103 ° C for 5.6 hours, and then a small amount of large-particle stones were removed by preliminary screening, and then fully ground in a crusher to a particle size of 70 μm to obtain pretreated red mud powder; 20 parts by weight of pretreated red mud powder were dispersed in 160 parts by weight of 4% hydrochloric acid solution, stirred at 80 ° C for 2.1 hours, and centrifuged to obtain a leachate after the reaction; 0.45 parts by weight of the extractant prepared in Preparation Example 3, 90 parts by weight of ethanol and 100 parts by weight of the leachate were stirred at 70 ° C for 1.2 hours, and after the reaction, the ethanol phase was collected and washed with deionized water 3 times to obtain a mixed extract; D001 resin was washed with deionized water 5 times to make the washing liquid colorless and transparent, and then washed with a hydrochloric acid solution of 1% by mass for acid washing 3 times, and the washing liquid was filtered out and washed with deionized water 5 times to obtain a pretreated resin; 100 parts by weight of pretreated The saturated resin and 350 parts by weight of the mixed extract were oscillated at 50°C at an oscillation rate of 150 r / min for 1.2 hours, and then filtered to obtain a saturated resin and a mixed solution; 100 parts by weight of the saturated resin and 400 parts by weight of a 4% hydrochloric acid solution were oscillated at 24°C at an oscillation rate of 150 r / min for 0.8 hours, and then solid-liquid separation was performed, and the preliminary extract was obtained by evaporation concentration, cooling crystallization and drying in sequence; the preliminary extract obtained above was dispersed in 200 parts by weight of deionized water, adjusted to pH 3.5, and stirred at 86°C for 0.8 hours. After the reaction, it was washed, precipitated and dried in sequence to obtain a solid; 70 parts by weight of the solid was calcined at 700°C for 2.8 hours, 9.6 parts by weight of graphite was added, ground and mixed for 8 minutes, and then kept warm at 1150°C for 3.5 hours in a nitrogen protection environment. After the insulation, it was cooled to 24°C in a nitrogen protection environment to obtain an iron material.

[0059] Embodiment 4:

[0060] A method for extracting iron from red mud comprises the following steps:

[0061] The red mud raw material was dried at 105°C for 6h, and then a small amount of large-particle stones were removed by preliminary screening, and then fully ground in a crusher to a particle size of 70μm to obtain pretreated red mud powder; 20 parts by weight of pretreated red mud powder were dispersed in 200 parts by weight of 5% hydrochloric acid solution, stirred at 90°C for 2.5h, and centrifuged to obtain a leachate after the reaction; 0.5 parts by weight of the extractant prepared in Preparation Example 4, 100 parts by weight of ethanol and 100 parts by weight of the leachate were stirred at 80°C for 1.5h, and after the reaction, the ethanol phase was collected and washed with deionized water 3 times to obtain a mixed extract; D001 resin was washed with deionized water 5 times to make its washing liquid colorless and transparent, and then washed with 1% hydrochloric acid solution 3 times for acid washing, and after filtering out the washing liquid, it was washed with deionized water 5 times to obtain a pretreated resin; 100 parts by weight of the extractant prepared in Preparation Example 4, 100 parts by weight of ethanol and 100 parts by weight of the leachate were stirred at 80°C for 1.5h, and after the reaction, the ethanol phase was collected and washed with deionized water 3 times to obtain a mixed extract; D001 resin was washed with deionized water 5 times to make its washing liquid colorless and transparent, and then washed with 1% hydrochloric acid solution 3 times for acid washing, and after filtering out the washing liquid, it was washed with deionized water 5 times to obtain a pretreated resin; The invention discloses a method for preparing a saturated resin and a mixed solution. The method comprises the following steps: a) 100 parts of saturated resin and 500 parts of a 5% hydrochloric acid solution are oscillated at 25°C at a rate of 150 r / min for 1 hour, and then the saturated resin and the mixed solution are filtered. b) 100 parts of saturated resin and 500 parts of a 5% hydrochloric acid solution are oscillated at 25°C at a rate of 150 r / min for 1 hour, and then the solid-liquid separation is carried out. The evaporation concentration, cooling crystallization and drying are carried out in sequence to obtain a preliminary extract. The preliminary extract obtained above is dispersed in 200 parts of deionized water, and after adjusting the pH to 4, the mixture is stirred at 90°C for 1 hour. After the reaction is completed, the mixture is washed, precipitated and dried in sequence to obtain a solid. c) 80 parts of the solid are calcined at 800°C for 3 hours, 10 parts of graphite are added, and the mixture is ground and mixed for 10 minutes. The mixture is then kept at 1200°C for 4 hours in a nitrogen protection environment. After the heat preservation is completed, the mixture is cooled to 25°C in a nitrogen protection environment to obtain an iron material.

[0062] Comparative Example 1:

[0063] A method for extracting iron from red mud comprises the following steps:

[0064] The red mud raw material was dried at 105°C for 6 hours, and then a small amount of large-particle stones were removed by preliminary screening, and then fully ground in a crusher to a particle size of 70 μm to obtain pretreated red mud powder; 20 parts by weight of pretreated red mud powder were dispersed in 200 parts by weight of 5% hydrochloric acid solution, stirred at 90°C for 2.5 hours, and centrifuged to obtain an extract after the reaction; 0.5 parts by weight of the extractant prepared in Preparation Example 5, 100 parts by weight of ethanol and 100 parts by weight of the extract were stirred at 80°C for 1.5 hours, and after the reaction, they were centrifuged and washed in sequence to obtain a mixed extract; D001 resin was washed with deionized water 5 times to make its washing liquid colorless and transparent, and then washed with a hydrochloric acid solution of 1% by mass for acid washing 3 times, and after filtering out the washing liquid, it was washed with deionized water 5 times to obtain a pretreated resin; 100 parts by weight of pretreated resin and 400 parts by weight of mixed extract, oscillated at 55°C at an oscillation rate of 150 r / min for 1.5 hours, and then filtered to obtain a saturated resin and a mixed solution; 100 parts by weight of saturated resin and 500 parts by weight of 5% hydrochloric acid solution were oscillated at 25°C at an oscillation rate of 150 r / min for 1 hour, and then solid-liquid separation was performed, and a preliminary extract was obtained by evaporation concentration, cooling crystallization and drying in sequence; the preliminary extract obtained above was dispersed in 200 parts by weight of deionized water, adjusted to pH 4, and stirred at 90°C for 1 hour. After the reaction, it was washed, precipitated and dried in sequence to obtain a solid; 80 parts by weight of the solid was calcined at 800°C for 3 hours, 10 parts by weight of graphite was added, ground and mixed for 10 minutes, and then kept warm at 1200°C for 4 hours in a nitrogen protection environment. After the insulation, it was cooled to 25°C in a nitrogen protection environment to obtain an iron material.

[0065] Comparative Example 2:

[0066] A method for extracting iron from red mud comprises the following steps:

[0067] The red mud raw material was dried at 105°C for 6 hours, and then a small amount of large-particle stones were removed by preliminary screening, and then the red mud was fully ground in a crusher to a particle size of 70 μm to obtain pretreated red mud powder; 20 parts by weight of the pretreated red mud powder were dispersed in 200 parts by weight of a 5% hydrochloric acid solution, stirred and reacted at 90°C for 2.5 hours, and centrifuged to obtain a leachate after the reaction; 0.5 parts by weight of sodium ethylenediaminetetraacetate, 100 parts by weight of ethanol and 100 parts by weight of the leachate were stirred and reacted at 80°C for 1.5 hours, and after the reaction, they were centrifuged and washed in sequence to obtain a mixed extract; D001 resin was washed with deionized water for 5 times to make the washing liquid colorless and transparent, and then washed with a 1% hydrochloric acid solution for 3 times for acid washing, and after filtering out the washing liquid, it was washed with deionized water for 5 times to obtain a pretreated resin; 100 parts by weight of the pretreated resin and 400 parts by weight of the mixed extract are subjected to an oscillation reaction at 55°C at an oscillation rate of 150 r / min for 1.5 hours, and then filtered to obtain a saturated resin and a mixed solution; 100 parts by weight of the saturated resin and 500 parts by weight of a 5% hydrochloric acid solution are subjected to an oscillation reaction at 25°C at an oscillation rate of 150 r / min for 1 hour, and then solid-liquid separation is performed, and a preliminary extract is obtained by evaporation concentration, cooling crystallization and drying in sequence; the preliminary extract obtained above is dispersed in 200 parts by weight of deionized water, adjusted to pH 4, and stirred for reaction at 90°C for 1 hour, and after the reaction is completed, the solid is washed, precipitated and dried in sequence to obtain a solid; 80 parts by weight of the solid are calcined at 800°C for 3 hours, 10 parts by weight of graphite are added, ground and mixed for 10 minutes, and then kept warm at 1200°C for 4 hours in a nitrogen protection environment. After the insulation is completed, the iron material is obtained by cooling to 25°C in a nitrogen protection environment.

[0068] Comparative Example 3:

[0069] A method for extracting iron from red mud comprises the following steps:

[0070] The red mud raw material was dried at 105°C for 6 hours, and then a small amount of large-particle stones were removed by preliminary screening, and then the red mud was fully ground in a crusher to a particle size of 70 μm to obtain pretreated red mud powder; 20 parts by weight of the pretreated red mud powder were dispersed in 200 parts by weight of a 5% hydrochloric acid solution, stirred and reacted at 90°C for 2.5 hours, and centrifuged to obtain a leachate after the reaction; 0.5 parts by weight of N, N "-di (2-hydroxybenzyl) ethylenediamine-N, N "-diacetic acid monohydrochloride hydrate, 100 parts by weight of ethanol and 100 parts by weight of the leachate were stirred and reacted at 80°C for 1.5 hours, and after the reaction, the mixed extract was obtained by centrifugation and washing in sequence; D001 resin was washed with deionized water for 5 times to make the washing liquid colorless and transparent, and then washed with a 1% hydrochloric acid solution for 3 times for acid washing, and after filtering out the washing liquid, it was washed with deionized water for 5 times to obtain the pretreated resin 100 parts by weight of pretreated resin and 400 parts by weight of mixed extract were oscillated at 55°C at an oscillation rate of 150 r / min for 1.5 hours, and then filtered to obtain saturated resin and mixed solution; 100 parts by weight of saturated resin and 500 parts by weight of 5% hydrochloric acid solution were oscillated at 25°C at an oscillation rate of 150 r / min for 1 hour, and then solid-liquid separation was performed, and the preliminary extract was obtained by evaporation concentration, cooling crystallization and drying in sequence; the preliminary extract obtained above was dispersed in 200 parts by weight of deionized water, adjusted to pH 4, and stirred at 90°C for 1 hour. After the reaction, it was washed, precipitated and dried in sequence to obtain a solid; 80 parts by weight of the solid was calcined at 800°C for 3 hours, 10 parts by weight of graphite was added, ground and mixed for 10 minutes, and then kept warm at 1200°C for 4 hours in a nitrogen protection environment. After the insulation, it was cooled to 25°C in a nitrogen protection environment to obtain an iron material.

[0071] Performance testing:

[0072] Test Example 1:

[0073] The iron recovery rate and iron grade of the iron materials obtained in Examples 1 to 4 of the present invention and Comparative Examples 1 to 3 were tested, and the test results are shown in Table 1.

[0074] Table 1. Iron recovery and iron grade

[0075]

[0076] It can be seen from the experimental results in Table 1 that the methods of Examples 1 to 4 of the present invention have good iron recovery rates and iron grades, while the methods of Comparative Examples 1 to 3 are not conducive to iron recovery.

[0077] Test Example 2:

[0078] 1 mol / L hydrochloric acid solution was added to the mixed solution in Examples 1 to 3 of the present invention and Comparative Examples 1 to 3, respectively, and the mixture was stirred at 40 to 50° C. for 40 to 60 min. The adsorption and chelating abilities of the active groups of the extractant were restored by acid treatment, and the extractant obtained after the acid treatment was recycled to Examples 1 to 4 of the present invention and Comparative Examples 1 to 3. The iron recovery rate and iron grade of the iron materials prepared by the methods of Examples 1 to 4 of the present invention and Comparative Examples 1 to 3 after the fourth cycle regeneration of the extractant were detected. The detection results are shown in Table 2.

[0079] Table 2. Iron recovery and iron grade after the fifth cycle

[0080]

[0081] It can be observed from the experimental results in Table 2 that the extractant provided by the present invention can be reused multiple times, which not only significantly reduces the production cost, but also improves the utilization efficiency of resources and reduces the generation of waste, which is of great significance to environmental protection and sustainable development.

[0082] The above-described embodiments provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected.

Claims

1. A method for extracting iron from red mud, characterized in that: The method comprises the following steps: The red mud raw material is sequentially pretreated and acid-leached to obtain a leachate, the extractant, ethanol and the leachate are stirred to react to obtain a mixed extract, the resin is sequentially washed with water and acid-washed to obtain a pretreated resin, the pretreated resin and the mixed extract are subjected to an oscillation reaction and then filtered to obtain a saturated resin and a mixed solution, the saturated resin and a hydrochloric acid solution are subjected to an oscillation reaction to obtain a preliminary extract, the preliminary extract and deionized water are stirred to react to obtain a solid, the solid is calcined, mixed with graphite and subjected to heat preservation to obtain the iron material.

2. A method for extracting iron from red mud as claimed in claim 1, characterized in that: The preparation method of the extractant comprises the following steps: The potassium pineol is reacted with pine alcohol and potassium hydroxide to obtain potassium pineol, the potassium pineol and 5-chlorosalicylaldehyde are reacted with each other to obtain an intermediate product, and the intermediate product and 3-amino-3-phenylpropionic acid are reacted with each other to obtain the extractant.

3. A method for extracting iron from red mud as claimed in claim 2, characterized in that: The weight ratio of the pineol to potassium hydroxide is 1-2:0.4-1.

4. A method for extracting iron from red mud as claimed in claim 2, characterized in that: The weight ratio of the intermediate product to 3-amino-3-phenylpropionic acid is 0.8-1.2:0.5-0.

9.

5. A method for extracting iron from red mud as claimed in claim 1, characterized in that: The weight ratio of the extractant, ethanol and leaching solution is 0.3-0.8:50-100:

100.

6. A method for extracting iron from red mud as claimed in claim 1, characterized in that: The resin is D001 type resin.

7. A method for extracting iron from red mud as claimed in claim 1, characterized in that: The weight ratio of the pretreatment resin to the mixed extract is 1:3-4.

8. A method for extracting iron from red mud as claimed in claim 1, characterized in that: The weight ratio of the saturated resin to the hydrochloric acid solution is 1:3-5.

9. A method for extracting iron from red mud as claimed in claim 1, characterized in that: The concentration of the hydrochloric acid solution is 2-5% by mass.

10. A method for extracting iron from red mud as claimed in claim 1, characterized in that: The weight ratio of the solid to the graphite is 60-80:9-10.

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