Preparation method of precipitated magnesium oxide for metallurgical cobalt precipitation

Abstract

The application discloses a preparation method of precipitated magnesium oxide for metallurgical cobalt precipitation, and belongs to the field of magnesium oxide preparation, and aims to solve the technical problem that the specific surface area, pore size of the magnesium oxide for metallurgical cobalt precipitation in the prior art and the cobalt removal rate in a complex coexisting ion system need to be further improved, and specifically comprises the following steps: adding an organic modified magnesium precursor into a crucible placed in a muffle furnace, heating to 550-650 DEG C at a rate of 3-5 DEG C / min, keeping the temperature for 2-4 h, grinding after cooling to pass a 200-mesh screen, and obtaining the precipitated magnesium oxide. The organic modified precursor is prepared by mixing magnesium chloride and phosphonic acid-based polyacrylate and star phosphorus-nitrogen prepolymer, dropwise adding ammonia water for co-precipitation, washing and drying, and constant temperature calcination, so that the precipitated magnesium oxide with a three-dimensional mesoporous network and a high specific surface area is finally prepared, and the cobalt removal rate of the magnesium oxide in a complex metallurgical solution is improved.

Description

Technical Field

[0001] This invention relates to the field of magnesium oxide preparation technology, and specifically to a method for preparing precipitated magnesium oxide for metallurgical cobalt deposition. Background Technology

[0002] Magnesium oxide, due to its moderate alkalinity, wide availability, controllable cost, and precipitation reaction and surface mineralization coupling with cobalt ions, has gradually evolved from a traditional neutralizing agent into a magnesium-based material with precipitation, adsorption, and synergistic removal functions. As hydrometallurgy continues to demand higher cobalt recovery efficiency, impurity tolerance, and process stability, the performance development direction of magnesium oxide materials has shifted from simply increasing magnesium oxide content to controlling multi-dimensional structural parameters such as particle size, surface active sites, and lattice defects to improve its reaction rate, effective utilization rate, and selective cobalt precipitation ability in complex systems.

[0003] Currently, commonly used materials in the metallurgical cobalt precipitation process mainly include lime slurry, sodium hydroxide, carbonates, sulfiding agents, and magnesium-based precipitants. Among them, magnesium oxide has attracted attention due to its mild reaction and relatively low entrainment. To improve the activity of magnesium oxide, existing technologies have adopted methods such as mechanical crushing activation, inorganic salt doping, surfactant pore-forming, acid and alkali etching, template method pore expansion, hydrothermal crystallization, and loading composite to improve its dispersibility and reactivity. However, the above methods often have problems such as complicated preparation processes, insufficient pore structure stability, insufficient utilization of active sites, or relatively simple modification effects. In metallurgical baths with high salt content and multiple metal impurities, it is still difficult to achieve the desired cobalt precipitation rate.

[0004] Meanwhile, when magnesium oxide is used for cobalt precipitation in metallurgy, its particles tend to agglomerate, resulting in high utilization of the outer surface while the internal active regions are difficult to participate in the reaction. Due to insufficient pore connectivity, the mass transfer of cobalt ions at the liquid-solid interface is limited, leading to uneven precipitation nucleation and growth processes. Furthermore, the limited number of defects and high-energy sites on the magnesium oxide surface results in insufficient directional effect on cobalt ions and insufficient driving force for continuous mineralization. Under the interference of coexisting ions such as copper and nickel, the surface reaction of the material is easily affected by competitive site occupation, which in turn leads to a decrease in cobalt precipitation efficiency and process stability.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] This invention addresses the technical problem that the specific surface area and pore size of magnesium oxide used in metallurgical cobalt deposition, as well as the cobalt removal rate in complex coexisting ion systems, need to be further improved in the existing technology.

[0007] The objective of this invention can be achieved through the following technical solution: a method for preparing precipitated-grade magnesium oxide for cobalt deposition in metallurgy, comprising the following steps: S1. Place magnesium chloride hexahydrate and deionized water in a reactor and stir. Add star-shaped phosphorus nitrogen prepolymer and phosphonic acid polyacrylate. Stir at room temperature for 20-30 min. Heat the reactor to 45-55℃ and add ammonia water to make the pH 10±0.1. Keep the reaction at this temperature for 4-6 h. Post-treatment yields organic modified magnesium precursor. S2. Add the organic modified magnesium precursor to a crucible placed in a muffle furnace, heat it to 550-650℃ at 3-5℃ / min, hold it at the temperature for 2-4 hours, cool it and grind it through a 200-mesh sieve to obtain precipitated magnesium oxide.

[0008] Further, in step S1, the ratio of magnesium chloride hexahydrate, deionized water, star-shaped phosphorus nitrogen prepolymer, and phosphonic acid-based polyacrylate is 9-11g:80-100mL:0.2-0.4g:0.1-0.2g, and the concentration of ammonia is 15-25wt%. The post-treatment steps include: after the reaction is completed, the reaction vessel is cooled to room temperature, filtered, the filter cake is washed 1-3 times with deionized water and ethanol, transferred to an oven at 60-70℃, and dried to constant weight to obtain the organic modified magnesium precursor.

[0009] Furthermore, the star-shaped phosphorus-nitrogen prepolymer is prepared by the following steps: A1. Place hexachlorocyclotriphosphazene and tetrahydrofuran in a reaction vessel and stir. Cool the reaction vessel to 0-5℃ and slowly introduce ammonia gas for 11-13 hours. After post-treatment, obtain all-aminophosphazene. A2. Place all-aminophosphazene and N,N-dimethylformamide in a nitrogen-protected reactor and stir. Cool the reactor to 0-5℃, add pyromellitic dianhydride solution, and restore the reactor to room temperature. React at room temperature for 6-8 hours. Post-treatment yields star-shaped phosphorus-nitrogen prepolymer.

[0010] Further, in step A1, the ratio of hexachlorocyclotriphosphazene to tetrahydrofuran is 8-10g:140-160mL, the ammonia gas introduction rate is 0.12-0.15L / min, and the post-treatment steps include: after the reaction is completed, filtering, transferring the filtrate to a rotary evaporator at a temperature of 70-80℃, distilling under reduced pressure until no liquid is collected, adding n-hexane to the concentrated liquid for recrystallization, filtering, washing the filter cake with n-hexane 1-3 times, transferring it to a vacuum drying oven at a temperature of 50-60℃, and drying under vacuum to constant weight to obtain all-aminophosphazene.

[0011] Further, in step A2, the ratio of the amount of the allaminophosphazene, N,N-dimethylformamide, and pyromellitic dianhydride solution is 5-7g:40-60mL:80-100mL, and the pyromellitic dianhydride solution is composed of pyromellitic dianhydride and N,N-dimethylformamide in a ratio of 1.5g:10mL. The post-treatment step includes: after the reaction is completed, adding the reaction solution to three times the volume of diethyl ether to precipitate, filtering, washing the filter cake with ethanol 1-3 times, transferring it to an oven at a temperature of 35-45℃, and drying for 6-8 hours to obtain the star-shaped phosphorus nitrogen prepolymer.

[0012] Furthermore, the phosphonic acid-based polyacrylate is prepared by the following steps: B1. 4-Cyano-4-(thiobenzoyl)valerate, methanol and deionized water were placed in a reaction vessel and stirred. 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added and stirred at room temperature for 1-2 h. Alendronate sodium trihydrate was added, and ammonia was added to adjust the pH to 8.0±0.1. The mixture was stirred at room temperature for 20-24 h. The bisphosphonate chain transfer agent was obtained after post-treatment. B2. Bisphosphonic acid chain transfer agent, diethylaminoethyl methacrylate, azobisisobutyronitrile and 1,4-dioxane were placed in a reaction vessel under nitrogen atmosphere and stirred. The reaction vessel was heated to 65-75℃ and kept at this temperature for 14-16 hours. The phosphonic acid polyacrylate was obtained after post-treatment.

[0013] Further, in step B1, the ratio of 4-cyano-4-(thiobenzoyl)valerate, methanol, deionized water, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and sodium alendronate trihydrate is 1-3g:40-60mL:40-60mL:1-3g:0.5-1.5g:2-4g, and the concentration of ammonia is 0.5-1.0mol / L. The post-processing step includes: after the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 500Da, dialyzed in deionized water for 2 days, and the deionized water is replaced every 6 hours. The dialyzed product is transferred to a freeze dryer at a temperature of -60℃ and freeze-dried for 8-10 hours to obtain the bisphosphonate chain transfer agent.

[0014] Further, in step B2, the ratio of the bisphosphonic acid chain transfer agent, diethylaminoethyl methacrylate, azobisisobutyronitrile, and 1,4-dioxane is 0.4-0.6g:17-19g:0.01-0.02g:15-25mL. The post-treatment step includes: after the reaction is completed, wait for the reaction to cool to room temperature, add half the volume of tetrahydrofuran to the reaction solution for dilution, add five times the volume of n-hexane to precipitate, filter, wash the filter cake with n-hexane 2-4 times, transfer it to an oven at 50-60℃, and dry it for 4-6 hours to obtain phosphonic acid-based polyacrylate.

[0015] The present invention has the following beneficial effects: This invention utilizes the confined pore-forming mechanism of macromolecular polymers to construct a three-dimensional mesoporous network with a high specific surface area. In this network, phosphonic acid-based polyacrylate and star-shaped prepolymer are co-precipitated and pyrolyzed in situ, which avoids the collapse of high-temperature pores and opens up deep mass transfer channels. This mesoporous structure and high porosity greatly reduce the mass transfer resistance at the liquid-solid interface, providing a very high density of active adsorption sites for cobalt ions and significantly improving the cobalt removal rate of precipitated magnesium oxide.

[0016] This invention also achieves deep coupling between trace heteroatom doping and lattice defects through in-situ pyrolysis. The star-shaped phosphorus-nitrogen prepolymer induces lattice distortion in magnesium oxide during isothermal calcination, generating abundant oxygen vacancies. This not only activates the heterogeneous nucleation activity on the surface but also strengthens the specific chemical bonding force to cobalt ions by regulating the local electron cloud density. This allows precipitated magnesium oxide to maintain a good cobalt removal rate in complex metallurgical solutions containing competing copper and nickel ions. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1

[0019] This embodiment provides a method for preparing phosphonic acid-based polyacrylate, specifically including the following steps: Step I: Preparation of bisphosphonic acid chain transfer agent Weigh 10g of 4-cyano-4-(thiobenzoyl)valerate, 400mL of methanol, and 400mL of deionized water and place them in a reaction vessel and stir. Add 10g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 5g of N-hydroxysuccinimide. Stir at room temperature for 1h. Add 20g of alendronate sodium trihydrate and adjust the pH to 7.9 with 0.5mol / L ammonia. Stir at room temperature for 20h. After the reaction is complete, put the reaction solution into a dialysis bag with a molecular weight cutoff of 500Da and dialyze it in deionized water for 2 days, changing the deionized water every 6h. Transfer the dialyzed product to a freeze dryer at -60℃ and freeze dry for 8h to obtain the bisphosphonate chain transfer agent.

[0020] Step II: Preparation of phosphonic acid-based polyacrylate Weigh out 4g of bisphosphonic acid chain transfer agent, 170g of diethylaminoethyl methacrylate, 0.1g of azobisisobutyronitrile, and 150mL of 1,4-dioxane and place them in a reaction vessel under nitrogen atmosphere and stir. Heat the reaction vessel to 65℃ and maintain the temperature for 14h. After the reaction is complete, wait for the reaction to cool to room temperature, add half the volume of tetrahydrofuran to the reaction solution for dilution, add five times the volume of n-hexane to precipitate, filter, wash the filter cake twice with n-hexane, transfer it to an oven at 50℃ and dry for 4h to obtain phosphonic acid polyacrylate.

[0021] The free carboxyl group of 4-cyano-4-(thiobenzoyl)valeric acid was activated by a coupling reaction of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride / N-hydroxysuccinimide to generate an active NHS ester intermediate. Subsequently, under weakly alkaline conditions, an amidation reaction was carried out with the primary amino group of sodium alendronate to prepare a chain transfer agent with a bisphosphonic acid anchoring group at one end. Further, using this bisphosphonic acid chain transfer agent as a control agent and azobisisobutyronitrile as a thermal initiator, a reversible addition-fragmentation chain transfer living radical polymerization of diethylaminoethyl methacrylate monomer was initiated. The reversible addition-fragmentation chain transfer mechanism suppressed the bimolecular termination side reaction, achieving controllable chain growth of the monomer, and finally synthesizing a phosphonic acid-terminated polyacrylate macromolecule.

[0022] By introducing bisphosphonic acid end groups, specific anchoring sites with strong polydentate coordination effects on magnesium ions and primary phase crystal nuclei were constructed, achieving directional confinement of the inorganic precursor crystallization interface and control of crystal face growth. Furthermore, a flexible macromolecular framework of polyacrylate was constructed by reversible addition-fragmentation chain transfer active radical polymerization. In the coprecipitation system, the disordered agglomeration of primary grains was effectively suppressed by the uniform steric hindrance effect. It also served as an in-situ pore-forming template for macromolecules, inducing lattice rearrangement of magnesium oxide and constructing a rich mesoporous network during subsequent high-temperature calcination and pyrolysis. This significantly improved the specific surface area and surface defect density of precipitated magnesium oxide, providing dense and efficient ion exchange and nucleation sites for the cobalt metallurgical precipitation process.

[0023] Example 2

[0024] This embodiment provides a method for preparing phosphonic acid-based polyacrylate, specifically including the following steps: Step I: Preparation of bisphosphonic acid chain transfer agent Weigh 20g of 4-cyano-4-(thiobenzoyl)valerate, 500mL of methanol, and 500mL of deionized water and place them in a reaction vessel and stir. Add 20g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 10g of N-hydroxysuccinimide. Stir at room temperature for 1.5h. Add 30g of alendronate sodium trihydrate and adjust the pH to 8.0 with 0.75mol / L ammonia. Stir at room temperature for 22h. After the reaction is complete, put the reaction solution into a dialysis bag with a molecular weight cutoff of 500Da and dialyze it in deionized water for 2 days, changing the deionized water every 6h. Transfer the dialyzed product to a freeze dryer at -60℃ and freeze dry for 9h to obtain the bisphosphonate chain transfer agent.

[0025] Step II: Preparation of phosphonic acid-based polyacrylate Weigh out 5g of bisphosphonic acid chain transfer agent, 180g of diethylaminoethyl methacrylate, 0.15g of azobisisobutyronitrile, and 200mL of 1,4-dioxane and place them in a nitrogen-protected reactor. Stir the reactor and heat it to 70℃. Keep the reactor at this temperature for 15h. After the reaction is complete, let the reaction cool to room temperature. Add half the volume of tetrahydrofuran to the reaction solution to dilute it. Add five times the volume of n-hexane to precipitate the precipitate. Filter the precipitate and wash the filter cake three times with n-hexane. Transfer the precipitate to an oven at 55℃ and dry it for 5h to obtain phosphonic acid polyacrylate.

[0026] Example 3

[0027] This embodiment provides a method for preparing phosphonic acid-based polyacrylate, specifically including the following steps: Step I: Preparation of bisphosphonic acid chain transfer agent Weigh out 30g of 4-cyano-4-(thiobenzoyl)valerate, 600mL of methanol and 600mL of deionized water and place them in a reaction vessel and stir. Add 30g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 15g of N-hydroxysuccinimide and stir at room temperature for 2h. Add 40g of alendronate sodium trihydrate and adjust the pH to 8.1 with 1.0mol / L ammonia water. Stir at room temperature for 24h. After the reaction is complete, put the reaction solution into a dialysis bag with a molecular weight cutoff of 500Da and dialyze it in deionized water for 2 days, changing the deionized water every 6h. Transfer the dialyzed product to a freeze dryer at -60℃ and freeze dry for 10h to obtain the bisphosphonate chain transfer agent.

[0028] Step II: Preparation of phosphonic acid-based polyacrylate Weigh out 6g of bisphosphonic acid chain transfer agent, 190g of diethylaminoethyl methacrylate, 0.2g of azobisisobutyronitrile, and 250mL of 1,4-dioxane and place them in a reaction vessel under nitrogen atmosphere. Stir the mixture and heat it to 75℃. Keep the temperature for 16h. After the reaction is complete, let the reaction cool to room temperature. Add half the volume of tetrahydrofuran to the reaction solution to dilute it. Add five times the volume of n-hexane to precipitate the precipitate. Filter the precipitate and wash it four times with n-hexane. Transfer the precipitate to an oven at 60℃ and dry it for 6h to obtain phosphonic acid polyacrylate.

[0029] Example 4

[0030] This embodiment provides a method for preparing a star-shaped phosphorus-nitrogen prepolymer, specifically including the following steps: Step (1): Preparation of all-aminophosphazene Weigh 80g of hexachlorocyclotriphosphazene and 1400mL of tetrahydrofuran and place them in a reaction vessel and stir. Cool the reaction vessel to 0℃ and slowly introduce ammonia gas at a rate of 0.12L / min for 11h. After the reaction is complete, filter the solution and transfer the filtrate to a rotary evaporator at 70℃. Distill under reduced pressure until no liquid is collected. Add n-hexane to the concentrated solution for recrystallization, filter, wash the filter cake once with n-hexane, and transfer it to a vacuum drying oven at 50℃. Dry under vacuum to constant weight to obtain all-aminophosphazene.

[0031] Step 2: Preparation of star-shaped phosphorus-nitrogen prepolymer Pyromellitic dianhydride and N,N-dimethylformamide were mixed evenly at a ratio of 15g:100mL to obtain a pyromellitic dianhydride solution for later use. Weigh 50g of peraminophosphazene and 400mL of N,N-dimethylformamide and place them in a nitrogen-protected reactor and stir. Cool the reactor to 0℃ and add 800mL of pyromellitic dianhydride solution. Return the reactor to room temperature and react at room temperature for 6h. After the reaction is complete, add the reaction solution to three times the volume of diethyl ether to precipitate. Filter the solution and wash the filter cake once with ethanol. Transfer the filter cake to an oven at 35℃ and dry for 6h to obtain star-shaped phosphorus nitrogen prepolymer.

[0032] A complete nucleophilic substitution reaction of hexachlorocyclotriphosphazene with ammonia is used to convert the six active chlorine atoms on the phosphazene ring into amino groups, generating a multifunctional all-amino phosphazene intermediate with a rigid inorganic heterocyclic skeleton. Further, using this all-amino phosphazene molecule as the multi-arm center, the primary amino group on its surface undergoes a nucleophilic addition ring-opening acylation reaction with the anhydride group in the pyromellitic dianhydride molecule. Polyamic acid segments are constructed by breaking the anhydride bonds, thus preparing a star-shaped phosphorus nitrogen topological prepolymer with a phosphazene ring as the core and a large number of free carboxyl groups in the outer side chains.

[0033] The rigid phosphorus-nitrogen heterocyclic core provides a highly symmetrical topological steric node for the inorganic coprecipitation system, and enables in-situ trace lattice doping of phosphorus and nitrogen atoms in the subsequent high-temperature pyrolysis stage. This increases the oxygen vacancy and surface active defect density of the magnesium oxide lattice. The dense free carboxyl clusters, relying on the multi-tooth bridge connection, generate strong chemical adsorption and crystal plane confinement effects on magnesium ions and primary phase grain boundaries, strictly blocking the disordered aggregation of primary nanocrystals. During the calcination removal process, this star-shaped topological network acts as a sacrificial template for macromolecules and undergoes in-situ pyrolysis, inducing the rearrangement of the inorganic framework and constructing a multi-level mesoporous channel with high porosity. This synergistically endows the final product with a high specific surface area and excellent solid-liquid interface ion exchange capacity, significantly optimizing the nucleation and mass transfer capabilities of the metallurgical cobalt precipitation process.

[0034] Example 5

[0035] This embodiment provides a method for preparing a star-shaped phosphorus-nitrogen prepolymer, specifically including the following steps: Step (1): Preparation of all-aminophosphazene Weigh 90g of hexachlorocyclotriphosphazene and 1500mL of tetrahydrofuran and place them in a reaction vessel and stir. Cool the reaction vessel to 3℃ and slowly introduce ammonia gas at a rate of 0.13L / min for 12h. After the reaction is complete, filter the solution and transfer the filtrate to a rotary evaporator at 75℃. Distill under reduced pressure until no liquid is collected. Add n-hexane to the concentrated solution for recrystallization, filter, wash the filter cake twice with n-hexane, and transfer it to a vacuum drying oven at 55℃. Dry under vacuum to constant weight to obtain all-aminophosphazene.

[0036] Step 2: Preparation of star-shaped phosphorus-nitrogen prepolymer Pyromellitic dianhydride and N,N-dimethylformamide were mixed evenly at a ratio of 15g:100mL to obtain a pyromellitic dianhydride solution for later use. Weigh 60g of peraminophosphazene and 500mL of N,N-dimethylformamide and place them in a reaction vessel under a nitrogen atmosphere and stir. Cool the reaction vessel to 3℃ and add 900mL of pyromellitic dianhydride solution. Return the reaction vessel to room temperature and react at room temperature for 7h. After the reaction is complete, add the reaction solution to three times the volume of diethyl ether to precipitate. Filter the solution and wash the filter cake twice with ethanol. Transfer the filter cake to an oven at 40℃ and dry for 7h to obtain star-shaped phosphorus nitrogen prepolymer.

[0037] Example 6

[0038] This embodiment provides a method for preparing a star-shaped phosphorus-nitrogen prepolymer, specifically including the following steps: Step (1): Preparation of all-aminophosphazene Weigh 100g of hexachlorocyclotriphosphazene and 1600mL of tetrahydrofuran and place them in a reaction vessel and stir. Cool the reaction vessel to 5℃ and slowly introduce ammonia gas at a rate of 0.15L / min for 13h. After the reaction is complete, filter the solution and transfer the filtrate to a rotary evaporator at 80℃. Distill under reduced pressure until no liquid is collected. Add n-hexane to the concentrated solution for recrystallization, filter, wash the filter cake three times with n-hexane, and transfer it to a vacuum drying oven at 60℃. Dry under vacuum to constant weight to obtain all-aminophosphazene.

[0039] Step 2: Preparation of star-shaped phosphorus-nitrogen prepolymer Pyromellitic dianhydride and N,N-dimethylformamide were mixed evenly at a ratio of 15g:100mL to obtain a pyromellitic dianhydride solution for later use. Weigh 70g of peraminophosphazene and 600mL of N,N-dimethylformamide and place them in a reaction vessel under a nitrogen atmosphere and stir. Cool the reaction vessel to 5℃ and add 1000mL of pyromellitic dianhydride solution. Return the reaction vessel to room temperature and react at room temperature for 8h. After the reaction is complete, add the reaction solution to three times the volume of diethyl ether to precipitate. Filter the solution and wash the filter cake three times with ethanol. Transfer the filter cake to an oven at 45℃ and dry for 8h to obtain star-shaped phosphorus nitrogen prepolymer.

[0040] Example 7

[0041] This embodiment provides a method for preparing precipitated magnesium oxide for metallurgical cobalt precipitation, specifically including the following steps: Step ①: Preparation of organically modified magnesium precursor Weigh out 90g of magnesium chloride hexahydrate and 800mL of deionized water and place them in a reaction vessel and stir. Add 2g of the star-shaped phosphorus nitrogen prepolymer prepared in Example 1 and 1g of phosphonic acid polyacrylate prepared in Example 4. Stir at room temperature for 20min. Heat the reaction vessel to 45℃ and add 15wt% ammonia water to make the pH 9.9. Keep the reaction at this temperature for 4h. After the reaction is complete, wait for the reaction vessel to cool to room temperature, filter, wash the filter cake once with deionized water and ethanol, transfer it to an oven at 60℃ and dry it to constant weight to obtain the organic modified magnesium precursor.

[0042] Step ②: Preparation of precipitated magnesium oxide The organic modified magnesium precursor was added to a crucible placed in a muffle furnace, heated to 550°C at 3°C / min, held at that temperature for 2 hours, cooled, and then ground through a 200-mesh sieve to obtain precipitated magnesium oxide.

[0043] In an alkaline ammonia system, magnesium ions are hydrolyzed and crystallized to form a primary phase of magnesium hydroxide. The bisphosphonic acid groups introduced into the system, together with the star-shaped polycarboxyl groups, are anchored to the surface of the primary inorganic core through multidentate coordination and interfacial chemisorption. The topological steric hindrance of the organic macromolecules restricts the disordered aggregation and growth of the crystals, constructing an organic-inorganic hybrid precursor with macromolecular confined co-assembly. Heating is then used to induce the dehydration phase transition of magnesium hydroxide to form magnesium oxide, and simultaneously, the organic polymer skeleton interspersed in the precursor undergoes pyrolysis and volatilization. Through the in-situ pore-forming effect of the macromolecular sacrificial template and the inorganic lattice rearrangement induced by trace element doping, precipitated magnesium oxide with a specific mesoporous network and defect structure is finally obtained.

[0044] The multidentate synergistic coordination and topological steric hindrance effect of bisphosphonic acid and star-shaped polycarboxyl groups enable interfacial confinement control of the primary phase of magnesium hydroxide in the early stage of crystal growth, suppressing the disordered aggregation of primary nanocrystals and constructing a uniform organic-inorganic hybrid precursor network. Then, with the help of high-temperature phase transformation dehydration and in-situ pyrolysis of organic macromolecular framework, inorganic lattice rearrangement is triggered to construct a three-dimensional interconnected mesoporous network. At the same time, the accompanying trace element doping generates high-density surface lattice defects and oxygen vacancies, thereby synergistically constructing an active solid-liquid interface with high specific surface area. This provides dense chemical adsorption sites and low-resistance channels for isomorphic substitution, ion exchange mass transfer and heterogeneous nucleation of cobalt phase in the metallurgical cobalt deposition system.

[0045] Example 8

[0046] This embodiment provides a method for preparing precipitated magnesium oxide for metallurgical cobalt precipitation, specifically including the following steps: Step ①: Preparation of organically modified magnesium precursor Weigh 100g of magnesium chloride hexahydrate and 900mL of deionized water and place them in a reaction vessel and stir. Add 3g of star-shaped phosphorus nitrogen prepolymer prepared in Example 5 and 1.5g of phosphonic acid-based polyacrylate prepared in Example 2. Stir at room temperature for 25min. Heat the reaction vessel to 50℃ and add 22wt% ammonia water to make the pH 10. Keep the reaction vessel at this temperature for 5h. After the reaction is complete, let the reaction vessel cool to room temperature, filter, wash the filter cake twice with deionized water and ethanol, transfer it to an oven at 65℃ and dry it to constant weight to obtain the organic modified magnesium precursor.

[0047] Step ②: Preparation of precipitated magnesium oxide The organic modified magnesium precursor was added to a crucible placed in a muffle furnace, heated to 600℃ at 4℃ / min, held for 3 hours, cooled, and then ground through a 200-mesh sieve to obtain precipitated magnesium oxide.

[0048] Example 9

[0049] This embodiment provides a method for preparing precipitated magnesium oxide for metallurgical cobalt precipitation, specifically including the following steps: Step ①: Preparation of organically modified magnesium precursor Weigh 110g of magnesium chloride hexahydrate and 1000mL of deionized water and place them in a reaction vessel and stir. Add 4g of the star-shaped phosphorus nitrogen prepolymer prepared in Example 6 and 2g of the phosphonic acid-based polyacrylate prepared in Example 3. Stir at room temperature for 30min. Heat the reaction vessel to 55℃ and add 25wt% ammonia water to make the pH 10.1. Keep the reaction at this temperature for 6h. After the reaction is complete, wait for the reaction vessel to cool to room temperature, filter, wash the filter cake three times with deionized water and ethanol, transfer it to an oven at 70℃ and dry it to constant weight to obtain the organic modified magnesium precursor.

[0050] Step ②: Preparation of precipitated magnesium oxide The organic modified magnesium precursor was added to a crucible placed in a muffle furnace, heated to 650°C at 5°C / min, held at that temperature for 4 hours, cooled, and then ground through a 200-mesh sieve to obtain precipitated magnesium oxide.

[0051] Comparative Example 1 The difference between this comparative example and Example 9 is that the star-shaped phosphorus-nitrogen prepolymer was omitted in step ① when preparing the organic modified magnesium precursor.

[0052] Comparative Example 2 The difference between this comparative example and Example 9 is that phosphonic acid-based polyacrylate was omitted in step ① when preparing the organic modified magnesium precursor.

[0053] Performance testing: The specific surface area of ​​precipitated magnesium oxide prepared in Examples 7-9 and Comparative Examples 1-2 was determined according to the standard GB / T 19587-2017 "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET Method". The average pore size of precipitated magnesium oxide prepared in Examples 7-9 and Comparative Examples 1-2 was determined according to the standard GB / T 45528-2025 "Nanotechnology - Test of Pore Size and Pore Size Distribution of Nanoporous Materials - Fluorescent Probe Method". The mass fraction of precipitated magnesium oxide prepared in Examples 7-9 and Comparative Examples 1-2 was determined according to the standard GB / T 19587-2017 "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET Method". Weigh out cobalt chloride hexahydrate, copper chloride and nickel chloride impurity salts, dissolve and make up to volume. Add dilute ammonia dropwise to adjust the pH of the solution to stabilize at 8.5, and prepare a simulated metallurgical solution with an initial cobalt ion concentration of 150 mg / L, a copper ion concentration of 10 mg / L and a nickel ion concentration of 10 mg / L. Accurately measure 100 mL of simulated cobalt-containing metallurgical solution and place it in a stoppered container. Add 0.50 g of precipitated magnesium oxide prepared in Examples 7-9 and Comparative Examples 1-2 at a solid-liquid ratio of 1:200 (g / mL). Place the mixture in a 45℃ constant temperature water bath shaker and stir until adsorption and isomorphous displacement precipitation reach equilibrium. After the reaction, the mixture is centrifuged at high speed and filtered through a 0.22 μm polyethersulfone microporous membrane to achieve solid-liquid separation. Collect the filtrate and acidify it with a small amount of nitric acid. Use inductively coupled plasma atomic emission spectrometry to accurately determine the concentration of residual cobalt ions in the supernatant. Based on the difference in cobalt ion concentration before and after the reaction, calculate the cobalt removal rate of the precipitated magnesium oxide on the simulated metallurgical solution. Detailed data are shown in Table 1 below.

[0054] Table 1 - Performance Test Data of Samples

[0055] Comparative analysis of the data in Table 1 above shows that the specific surface area of ​​the precipitated magnesium oxide prepared by this invention is 221.5 m². 2 The sample exhibited a cobalt removal rate of 99.7% in simulated metallurgical slurry, with an average pore size of 13.8 nm and a mass fraction of 98.8%, all of which were superior to the comparative sample.

[0056] This invention involves mixing magnesium chloride with phosphonic acid-based polyacrylate and star-shaped phosphorus nitrogen prepolymer, then adding ammonia water for co-precipitation to obtain an organic modified precursor. After washing and drying, the precursor is calcined at a constant temperature to finally obtain precipitated magnesium oxide with a three-dimensional mesoporous network and high specific surface area, thereby improving the cobalt removal rate of magnesium oxide in complex metallurgical solutions.

[0057] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing precipitated-grade magnesium oxide for metallurgical cobalt precipitation, characterized in that, Includes the following steps: S1. Place magnesium chloride hexahydrate and deionized water in a reactor and stir. Add star-shaped phosphorus nitrogen prepolymer and phosphonic acid polyacrylate. Stir at room temperature for 20-30 min. Heat the reactor to 45-55℃ and add ammonia water to make the pH 10±0.

1. Keep the reaction at this temperature for 4-6 h. Post-treatment yields organic modified magnesium precursor. S2. Add the organic modified magnesium precursor to a crucible placed in a muffle furnace, heat it to 550-650℃ at 3-5℃ / min, hold it at the temperature for 2-4 hours, cool it and grind it through a 200-mesh sieve to obtain precipitated magnesium oxide.

2. The method for preparing precipitated-grade magnesium oxide for metallurgical cobalt deposition according to claim 1, characterized in that, In step S1, the ratio of magnesium chloride hexahydrate, deionized water, star-shaped phosphorus nitrogen prepolymer and phosphonic acid polyacrylate is 9-11g:80-100mL:0.2-0.4g:0.1-0.2g, and the concentration of ammonia is 15-25wt%.

3. The method for preparing precipitated-grade magnesium oxide for metallurgical cobalt deposition according to claim 1, characterized in that, The star-shaped phosphorus-nitrogen prepolymer was prepared by the following steps: A1. Place hexachlorocyclotriphosphazene and tetrahydrofuran in a reaction vessel and stir. Cool the reaction vessel to 0-5℃ and slowly introduce ammonia gas for 11-13 hours. After post-treatment, obtain all-aminophosphazene. A2. Place all-aminophosphazene and N,N-dimethylformamide in a nitrogen-protected reactor and stir. Cool the reactor to 0-5℃, add pyromellitic dianhydride solution, and restore the reactor to room temperature. React at room temperature for 6-8 hours. Post-treatment yields star-shaped phosphorus-nitrogen prepolymer.

4. The method for preparing precipitated-grade magnesium oxide for metallurgical cobalt precipitation according to claim 3, characterized in that, In step A1, the ratio of hexachlorocyclotriphosphazene to tetrahydrofuran is 8-10g:140-160mL, and the ammonia gas introduction rate is 0.12-0.15L / min.

5. The method for preparing precipitated-grade magnesium oxide for metallurgical cobalt precipitation according to claim 3, characterized in that, In step A2, the ratio of the amount of the allaminophosphazene, N,N-dimethylformamide and pyromellitic dianhydride solution is 5-7g:40-60mL:80-100mL, and the pyromellitic dianhydride solution is composed of pyromellitic dianhydride and N,N-dimethylformamide in a ratio of 1.5g:10mL.

6. The method for preparing precipitated-grade magnesium oxide for metallurgical cobalt deposition according to claim 1, characterized in that, The phosphonic acid-based polyacrylate is prepared by the following steps: B1. 4-Cyano-4-(thiobenzoyl)valerate, methanol and deionized water were placed in a reaction vessel and stirred. 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added and stirred at room temperature for 1-2 h. Alendronate sodium trihydrate was added, and ammonia was added to adjust the pH to 8.0±0.

1. The mixture was stirred at room temperature for 20-24 h. The bisphosphonate chain transfer agent was obtained after post-treatment. B2. Bisphosphonic acid chain transfer agent, diethylaminoethyl methacrylate, azobisisobutyronitrile and 1,4-dioxane were placed in a reaction vessel under nitrogen atmosphere and stirred. The reaction vessel was heated to 65-75℃ and kept at this temperature for 14-16 hours. The phosphonic acid polyacrylate was obtained after post-treatment.

7. The method for preparing precipitated-grade magnesium oxide for metallurgical cobalt deposition according to claim 6, characterized in that, In step B1, the ratio of 4-cyano-4-(thiobenzoyl)valerate, methanol, deionized water, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and sodium alendronate trihydrate is 1-3g:40-60mL:40-60mL:1-3g:0.5-1.5g:2-4g, and the concentration of ammonia is 0.5-1.0mol / L.

8. The method for preparing precipitated-grade magnesium oxide for metallurgical cobalt precipitation according to claim 6, characterized in that, In step B2, the ratio of the bisphosphonic acid chain transfer agent, diethylaminoethyl methacrylate, azobisisobutyronitrile, and 1,4-dioxane is 0.4-0.6g:17-19g:0.01-0.02g:15-25mL.

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