WO2024179048A1

WO2024179048A1 - Method for preparing phosphorus removal agent by mixing iron-aluminum slag recycled from waste batteries and pyrolusite

Info

Publication number: WO2024179048A1
Application number: PCT/CN2023/132364
Authority: WO
Inventors: 郑宇�; 刘勇奇; 巩勤学; 陈乾坤; 李成刚; 李长东
Original assignee: 广东邦普循环科技有限公司; 湖南邦普循环科技有限公司
Priority date: 2023-11-17
Filing date: 2023-11-17
Publication date: 2024-09-06
Also published as: CN117813156A

Abstract

A method for preparing a phosphorus removal agent by mixing iron-aluminum slag recycled from waste batteries and pyrolusite, which method comprises the following steps: grinding and crushing iron-aluminum slag obtained from a recycling process of waste batteries to obtain fine iron-aluminum slag; activating and modifying the fine iron-aluminum slag to obtain modified iron-aluminum slag; subjecting pyrolusite to crushing and acid leaching, and filtering same to obtain an MnO2 solid; adding a chelating agent, a KMnO4 solution, a dilute sulfuric acid solution and hydrazine hydrate to the MnO2 solid, and filtering the mixture to obtain a modified MnO2 solid; and mixing the modified iron-aluminum slag and the modified MnO2 solid to obtain an iron-aluminum slag manganese dioxide mixture, then preparing a blank, and sintering the blank to obtain a phosphorus removal adsorbent. In the method, by modifying the iron-aluminum slag obtained by recycling waste batteries, modifying natural pyrolusite, and mixing the two to prepare the phosphorus removal agent, high-value utilization of Fe and Al from waste batteries is achieved, and the low-quality pyrolusite is also fully utilized, thereby increasing the resource utilization efficiency.

Description

A method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite

Technical Field

The present invention relates to a method for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite.

Background Art

With the improvement and maturity of my country's new energy vehicle technology, the sales of ternary lithium-ion battery-powered vehicles in my country continue to rise. As time goes by, the amount of scrapped batteries each year is also very huge.

The average life of lithium batteries is 500-1000 cycles, and the service life is about 3 years. Therefore, the recycling and treatment of waste lithium-ion batteries has received widespread attention. As the market demand for power batteries continues to rise, the number of power batteries that will be scrapped in the future will also be extremely large due to the limited service life of power batteries.

At present, the process of recycling waste batteries generally adopts wet process for recycling and impurity removal; the process will produce nickel, cobalt, manganese and lithium metal sulfate solution, which contains a certain amount of iron and aluminum ions. Therefore, removing iron and aluminum from the solution is a very important process in the recycling of lithium batteries. At present, Fe and Al are generally converted into FeOOH, Fe(OH) ₃ , AlOOH, Al(OH) ₃ in the wet process, while FeOOH, Fe(OH) ₃ , AlOOH, Al(OH) ₃ have low utilization value and are difficult to use alone.

Summary of the invention

Based on this, the purpose of the present invention is to provide a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite, so as to achieve high-value utilization of Fe and Al in waste batteries, while also making full use of low-quality pyrolusite to enhance resource utilization efficiency.

The method disclosed in the present invention for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite comprises the following steps:

Grind and crush the iron-aluminum slag obtained in the process of recycling used batteries to obtain fine iron-aluminum slag;

Activating and modifying the fine iron-aluminum slag to obtain modified iron-aluminum slag;

Crushing acid-leached manganese ore and filtering to obtain _MnO2 solid;

Adding a chelating agent, a _KMnO4 solution, a dilute sulfuric acid solution, and hydrazine hydrate to the _MnO2 solid, and filtering to obtain a modified _MnO2 solid;

The modified iron-aluminum slag and modified _MnO2 solid are mixed to obtain an iron-aluminum slag manganese dioxide mixture, which is then molded and sintered to obtain a dephosphorization adsorbent.

The main component of pyrolusite is manganese dioxide, which is a common manganese mineral. It has the advantages of large quantity, low price, no pollution and strong stability. At the same time, pyrolusite has good surface adsorption effect, redox effect and pore effect. In addition, pyrolusite also contains transition metal elements such as Ni, Ti, Co, etc., which have catalytic oxidation effect, but unmodified pyrolusite cannot adsorb phosphorus.

The present invention realizes high-value utilization of Fe and Al in waste batteries by modifying the iron-aluminum slag recovered from waste batteries, modifying the natural pyrolusite, and mixing and sintering the two to obtain a dephosphorization adsorbent with a loose porous structure, while also making full use of low-quality pyrolusite to enhance resource utilization efficiency.

The phosphorus removal adsorbent prepared by the present invention has uniform particle size, high strength, multi-microporous surface, crisscross internal network, strong adsorption capacity, less affected by water pH, and long service life. The process is simple, the cost is low, and it can achieve efficient phosphorus removal without the generation of secondary pollutants. It is easy to apply industrially and has good application prospects. The material can not only be used as an adsorbent for phosphorus-containing wastewater, but also can be used for phosphorus removal in natural water bodies and controlling the release of phosphorus in sediments. At the same time, it also makes full use of low-quality pyrolusite to enhance resource utilization efficiency.

As a preferred embodiment, the method for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite described in the present disclosure is characterized in that it also includes the following steps:

The crushed acid-leached manganese ore is filtered to obtain a solution containing Fe and Al;

Adding iron powder to the Fe and Al-containing solution to obtain a Fe(II) and Al-containing solution;

When the modified iron-aluminum slag and modified _MnO2 solid are mixed, a solution containing Fe(II) and Al is added, and after mixing, a NaOH solution is added to adjust the pH, and air is introduced at the same time. After filtering, a filter residue is obtained, and then a blank is made.

The Fe and Al ions in the acid leaching pyrolusite leaching solution are fully utilized to make them adhere to the surface of ferroaluminum slag and pyrolusite, further improving the adsorption performance.

As a preferred solution, the blank making disclosed in the present invention requires the addition of charcoal powder, the filter residue and the charcoal powder are mixed into a slurry at a mass ratio of 2 to 3:1, and the slurry is added into a mold to obtain a molding material for subsequent sintering.

As a preferred embodiment, the pH adjustment range of the present invention is 3.8-4.5, so that Fe and Al ions are converted into aluminum oxyhydroxide (AlOOH) and iron oxyhydroxide (FeOOH); on the one hand, Al ³⁺ and Fe ³⁺ react with PO ₄ ^3- , and on the other hand, Al ³⁺ is hydrolyzed into mononuclear complexes such as AlOOH and FeOOH, and further condensed into a series of multinuclear complexes Al _n (OH) _m ^(3n-m)+ (n>1, m≤3n) through collision. These aluminum multinuclear complexes often have higher positive charge and specific surface area, can quickly adsorb negatively charged impurities in water, neutralize colloid charge, reduce colloid potential, condense and precipitate, thereby showing a good phosphorus removal effect.

As a preferred embodiment, the charcoal powder disclosed in the present invention includes activated carbon. The activated carbon can play a role in making the material porous during the reaction process; in the subsequent sintering process, the activated carbon that reacts can create an access path to expand the reaction area; the activated carbon that does not react can play an adsorption role.

As a preferred solution, the present invention uses acid to activate the fine iron-aluminum slag and uses an aluminate coupling agent to modify the fine iron-aluminum slag. The acid activation treatment can remove impurities such as organic matter in the iron-aluminum slag, dredge the pores, and improve the specific surface area and surface activity of the iron-aluminum slag; the aluminate coupling agent modification treatment gives the iron-aluminum slag more active sites and stronger heavy metal binding.

As a preferred embodiment, the chelating agent disclosed in the present invention is one or more of citric acid, oxalic acid, salicylic acid, and tartaric acid, with a concentration of 0.5 to 1 mol/L; the concentration of the KMnO ₄ solution is 0.1 to 0.3 mol/L; the concentration of the dilute sulfuric acid solution is 60 to 80 g/L; and the concentration of the hydrazine hydrate is 10 to 20 g/L. The chelating agent can form a complex with Mn ²⁺ , and strongly adsorb on the surface of inorganic metal oxides such as MnO _2. The complexing effect of the chelating agent is combined with the dissolving effect of sulfuric acid to act on the MnO ₂ solid, so that its surface dissolves, and then combined with the oxidizing property of KMnO ₄ to improve the surface properties of the MnO ₂ solid, so as to improve its surface adsorption capacity. At the same time, through the leaching effect of dilute sulfuric acid and the reduction and dissolution effect of a small amount of hydrazine hydrate, the impurity components in the pores of the MnO ₂ solid are further dissolved, so that the surface layer with complete crystallization is renewed to form a new ecological surface layer, thereby improving the adsorption capacity of the MnO ₂ solid interface.

As a preferred solution, the acid leaching solution disclosed in the present invention is a 100-300 g/L sulfuric acid solution; the _MnO2 solid obtained after the filtration needs to be dried at 60-80°C for 120-240 min. Sulfuric acid can dissolve Fe and Al ions in pyrolusite and preliminarily dredge the pores of pyrolusite.

As a preferred solution, the grinding and crushing disclosed in the present invention uses a sand mill, the speed of the sand mill during grinding and crushing is 200-300 r/min, the sand milling time is 30-60 min, the volume ratio of grinding balls to raw materials is 3-5:1; the particle size of the fine iron-aluminum slag is 60-80 meshes. The particle size of the iron-aluminum slag can be reduced by crushing and grinding, which is convenient for subsequent activation and modification.

As a preferred solution, the sintering process disclosed in the present invention is carried out under the protection of an inert atmosphere, the sintering temperature is 100°C to 200°C, and the sintering time is 1 to 3 hours. The inert atmosphere can prevent oxidation during the sintering process; the dephosphorization adsorbent obtained by sintering has higher mechanical strength.

As a preferred solution, after the blank making and before the sintering, the present disclosure further includes air drying, wherein the air drying is natural air drying in an environment for 8-12 hours. Natural air drying facilitates subsequent transfer and collection and reduces energy consumption.

As a preferred solution, the air-drying and sintering step of the present invention further includes drying, which is carried out in an oven at a temperature of 100-110° C. for 30-60 minutes. The temperature is mainly to evaporate the free water therein.

For better understanding and implementation, the present disclosure is described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a method for preparing a dephosphorizing agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite.

DETAILED DESCRIPTION

As shown in FIG1 , a method for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite comprises the following steps:

The iron-aluminum slag obtained in the waste battery recycling process is crushed and ground to obtain fine iron-aluminum slag;

The natural pyrolusite is crushed, acid-leached and filtered to obtain _MnO2 solid and Fe and Al-containing solution;

Add chelating agent, _KMnO4 solution, dilute sulfuric acid solution and hydrazine hydrate to the _MnO2 solid, and obtain modified _MnO2 solid;

Adding iron powder to the Fe and Al-containing solution so that the iron ions in the solution are all in the form of divalent iron to obtain a Fe(II) and Al-containing solution;

The modified iron-aluminum slag and the modified _MnO2 solid are added to the Fe(II) and Al-containing solution, and after mixing, a NaOH solution is added to adjust the pH, and air is introduced at the same time to precipitate the iron and aluminum ions in the solution to obtain an iron-aluminum slag manganese dioxide mixture;

The iron-aluminum slag manganese dioxide mixture is mixed with charcoal powder to form slurry, the slurry is added into a mold to form a blank, and then air-dried, dried and sintered to obtain a dephosphorization adsorbent.

Example 1

The present invention provides a method for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite, comprising the following steps:

1. In the lithium-ion battery recycling process, the iron-aluminum slag obtained in the wet leaching liquid precipitation process is crushed and ground after drying. The speed of the sand mill in the crushing and grinding process is 200r/min, the sand grinding time is 30min, and the volume ratio of the grinding ball to the raw material is 3:1; the fine iron-aluminum slag product is screened to 60 mesh.

2. Use aluminate coupling agent to modify the ferroaluminum slag, giving the ferroaluminum slag structure more active sites and stronger heavy metal binding effect. At the same time, acid activation is used before the ferroaluminum slag is modified by the aluminate coupling agent to remove organic matter and other impurities in the ferroaluminum slag, dredge the pores, and improve the specific surface area and surface activity of the ferroaluminum slag.

3. Pyrolusite is usually associated with oxides such as Al and Fe ₂ O _3. Pyrolusite can be initially treated with sulfation, using 100 g/L sulfuric acid solution to dissolve Fe and Al.

4. The solution of pyrolusite treated with H ₂ SO ₄ was subjected to solid-liquid separation and dried at 60°C for 120 min to obtain relatively pure dry MnO ₂ solid.

5. Citric acid is a highly efficient chelating agent that can form a complex and strongly adsorb on the surface of _MnO2. Adding 0.5 mol/L citric acid solution dissolves its surface, and then combining it with the oxidizing property of 0.1 mol/L _KMnO4 to improve the surface properties and enhance its surface adsorption capacity.

6. The leaching effect of 60g/L dilute sulfuric acid and the reduction and dissolution effect of 10g/L hydrazine hydrate are added to cooperate with each other, so that the impurities "fixed" in the pores of natural manganese ore in the natural state are dissolved, and the crystalline surface layer is renewed to form a new ecological surface layer, thereby improving the interface adsorption capacity of natural manganese.

7. The iron-aluminum solution is mixed with iron-aluminum slag and manganese dioxide. After mixing, a dilute NaOH solution is used to adjust the pH to 3.8 to further precipitate iron and aluminum ions to generate FeOOH and AlOOH, which are attached to the surface of the iron-aluminum slag and pyrolusite to obtain an iron-aluminum slag manganese dioxide mixture.

8. Mix the iron-aluminum slag manganese dioxide mixture with charcoal powder in a mass ratio of 2:1 into a slurry and add it into the mold. Forming into columnar material.

9. After the blank is made, the material is naturally air-dried. The columnar material is placed in the environment to air-dry naturally. The natural air-drying time is 8 hours. After natural air-drying, it is easy to transfer and collect.

10. Place the air-dried columnar material in an oven and dry it at 100°C for 30 minutes; the temperature of 100°C is mainly to evaporate free water.

11. Sintering: After drying, put it into a tubular furnace and calcine it at 100°C for 1 hour under _N2 protection; high temperature calcination gives it good mechanical strength, which is conducive to regeneration and reuse.

Example 2

1. In the lithium-ion battery recycling process, the iron-aluminum slag obtained in the wet leaching liquid precipitation process is crushed and ground after drying. The speed of the sand mill during the crushing and grinding process is 250r/min, the sand grinding time is 45min, and the volume ratio of the grinding ball to the raw material is 4:1; the fine iron-aluminum slag product is screened to 70 mesh.

3. Pyrolusite is usually associated with oxides such as Al and Fe ₂ O _3. Pyrolusite can be initially treated with sulfation, using 200 g/L sulfuric acid solution to dissolve Fe and Al.

4. The solution of pyrolusite treated with H ₂ SO ₄ was subjected to solid-liquid separation and dried at 70°C for 180 min to obtain relatively pure dry MnO ₂ solid.

5. Oxalic acid is a highly efficient chelating agent that can form a complex and strongly adsorb on the surface of _MnO2 . Adding 0.7 mol/L oxalic acid solution dissolves its surface, and then combining it with the oxidizing property of 0.2 mol/L _KMnO4 to improve the surface properties and enhance its surface adsorption capacity.

6. The leaching effect of 70g/L dilute sulfuric acid and the reduction and dissolution effect of 15g/L hydrazine hydrate are added to cooperate with each other, so that the impurities "fixed" in the pores of natural manganese ore in the natural state are dissolved, and the crystalline surface layer with integrity is renewed to form a new ecological surface layer, thereby improving the interface adsorption capacity of natural manganese.

7. The iron-aluminum solution is mixed with iron-aluminum slag and manganese dioxide. After mixing, a dilute NaOH solution is used to adjust the pH to 4.0 to further precipitate iron and aluminum ions to generate FeOOH and AlOOH, which are attached to the surface of the iron-aluminum slag and pyrolusite to obtain an iron-aluminum slag manganese dioxide mixture.

8. Mix the iron-aluminum slag manganese dioxide mixture and charcoal powder in a mass ratio of 2.5:1 to form a slurry, add it into a mold for blanking, and shape it into a columnar material.

9. After the blank is made, the material is naturally air-dried. The columnar material is placed in the environment to air-dry naturally. The natural air-drying time is 10 hours. After natural air-drying, it is easy to transfer and collect.

10. Place the air-dried columnar material in an oven and dry it at 105°C for 45 minutes; the temperature of 105°C is mainly to evaporate free water.

11. Sintering: After drying, put it into a tubular furnace and calcine it at 150℃ for 2h under _N2 protection; high temperature calcination gives it good mechanical strength, which is conducive to regeneration and reuse.

Example 3

1. In the lithium-ion battery recycling process, the iron-aluminum slag obtained in the wet leaching liquid precipitation process is crushed and ground after drying. The speed of the sand mill in the crushing and grinding process is 300r/min, the sand grinding time is 60min, and the volume ratio of the grinding ball to the raw material is 5:1; the fine iron-aluminum slag product is screened to 60-80 mesh.

3. Pyrolusite is usually associated with oxides such as Al and Fe ₂ O _3. Pyrolusite can be initially treated with sulfation, using 300 g/L sulfuric acid solution to dissolve Fe and Al.

4. The solution of pyrolusite treated with H ₂ SO ₄ was subjected to solid-liquid separation and dried at 80°C for 240 min to obtain relatively pure dry MnO ₂ solid.

5. Salicylic acid is a highly efficient chelating agent that can form a complex and strongly adsorb on the surface of _MnO2. Adding 1 mol/L salicylic acid solution dissolves its surface, and then combining it with the oxidizing property of 0.3 mol/L _KMnO4 to improve the surface properties and enhance its surface adsorption capacity.

6. The leaching effect of 80g/L dilute sulfuric acid and the reduction and dissolution effect of 20g/L hydrazine hydrate are added to cooperate with each other, so that the impurities "fixed" in the pores of natural manganese ore in the natural state are dissolved, and the crystalline surface layer with integrity is renewed to form a new ecological surface layer, thereby improving the adsorption capacity of natural manganese interface.

7. The iron-aluminum solution is mixed with iron-aluminum slag and manganese dioxide. After mixing, a dilute NaOH solution is used to adjust the pH to 4.5 to further precipitate iron and aluminum ions to generate FeOOH and AlOOH, which are attached to the surface of the iron-aluminum slag and pyrolusite to obtain an iron-aluminum slag manganese dioxide mixture.

8. Mix the iron-aluminum slag manganese dioxide mixture and charcoal powder in a mass ratio of 3:1 to form a slurry, add it into a mold for blanking, and shape it into a columnar material.

9. After blanking, the material is naturally air-dried. The columnar material is placed in the environment to dry naturally. The natural drying time is 12 hours. After natural air drying, it is easy to transfer and collect.

10. Place the air-dried columnar material into an oven and dry it at 110°C for 60 minutes. The temperature of 110°C is mainly to evaporate free water.

11. Sintering: After drying, put it into a tubular furnace and calcine it at 200℃ for 3h under _N2 protection; high temperature calcination gives it good mechanical strength, which is conducive to regeneration and reuse.

Example 4

1. In the lithium-ion battery recycling process, the iron-aluminum slag obtained in the wet leaching liquid precipitation process is crushed and ground after drying. The speed of the sand mill during the crushing and grinding process is 200r/min, the sand grinding time is 30min, and the volume ratio of the grinding ball to the raw material is 3:1; the fine iron-aluminum slag product is screened to 60-80 mesh.

5. Citric acid and tartaric acid are highly efficient chelating agents, which can form complexes and strongly adsorb on the surface of _MnO2 . Adding a 1 mol/L mixed solution of citric acid and tartaric acid dissolves its surface, and then combining it with the oxidizing property of 0.1 mol/L _KMnO4 to improve the surface properties and enhance its surface adsorption capacity.

7. The iron-aluminum solution is mixed with iron-aluminum slag and manganese dioxide. After mixing, a dilute NaOH solution is used to adjust the pH to 3.8-4.2 to further precipitate iron and aluminum ions to generate FeOOH and AlOOH, which are attached to the surface of the iron-aluminum slag and pyrolusite to obtain an iron-aluminum slag manganese dioxide mixture.

8. Mix the iron-aluminum slag manganese dioxide mixture and charcoal powder in a mass ratio of 2:1 to form a slurry, add it into a mold for blanking, and shape it into a columnar material.

Claims

A method for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite, comprising the following steps:

Grind and crush the iron-aluminum slag obtained in the process of recycling used batteries to obtain fine iron-aluminum slag;

Activating and modifying the fine iron-aluminum slag to obtain modified iron-aluminum slag;

Crushing acid-leached manganese ore and filtering to obtain MnO2 solid;

Adding a chelating agent, a KMnO4 solution, a dilute sulfuric acid solution, and hydrazine hydrate to the MnO2 solid, and filtering to obtain a modified MnO2 solid;

The modified iron-aluminum slag and modified MnO2 solid are mixed to obtain an iron-aluminum slag manganese dioxide mixture, which is then molded and sintered to obtain a dephosphorization adsorbent.
The method for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite according to claim 1, characterized in that it also includes the following steps:

The crushed acid-leached manganese ore is filtered to obtain a solution containing Fe and Al;

Adding iron powder to the Fe and Al-containing solution to obtain a Fe(II) and Al-containing solution;

When the modified iron-aluminum slag and modified MnO2 solid are mixed, a solution containing Fe(II) and Al is added, and after mixing, a NaOH solution is added to adjust the pH, and air is introduced at the same time. After filtering, a filter residue is obtained, and then a blank is made.
According to claim 2, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite is characterized in that charcoal powder needs to be added during the blank making, the filter residue and the charcoal powder are mixed into a slurry in a mass ratio of 2 to 3:1, and the slurry is added to a mold to obtain a molding material.
According to claim 2, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recovered from waste batteries with pyrolusite is characterized in that the pH adjustment range is 3.8-4.5.
According to claim 3, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite is characterized in that the charcoal powder includes activated carbon.
According to claim 1, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite is characterized in that the fine iron-aluminum slag is activated with an acid and the fine iron-aluminum slag is modified with an aluminate coupling agent.
According to claim 1, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite, characterized in that the chelating agent is one or more of citric acid, oxalic acid, salicylic acid, and tartaric acid, with a concentration of 0.5 to 1 mol/L; the concentration of the KMnO4 solution is 0.1 to 0.3 mol/L; the concentration of the dilute sulfuric acid solution is 60 to 80 g/L; and the concentration of the hydrazine hydrate is 10 to 20 g/L.
According to claim 1, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite, wherein The characteristics are that the acid leaching solution is a 100-300 g/L sulfuric acid solution; the MnO2 solid obtained after the filtration needs to be dried at 60-80°C for 120-240 min.
According to claim 1, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite is characterized in that a sand mill is used for grinding and crushing, the speed of the sand mill during grinding and crushing is 200-300 r/min, the sand milling time is 30-60 min, and the volume ratio of grinding balls to raw materials is 3-5:1; the particle size of the fine iron-aluminum slag is 60-80 mesh.
According to claim 1, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite is characterized in that the sintering process is carried out under the protection of an inert atmosphere, the sintering temperature is 100°C to 200°C, and the sintering time is 1 to 3 hours.
According to claim 1, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite is characterized in that after the billet making and before sintering, it also includes air drying, and the air drying is placed in the environment for natural air drying for 8-12 hours.
According to claim 11, a method for preparing a dephosphorization agent by mixing iron-aluminum slag recycled from waste batteries with pyrolusite is characterized in that after the air-drying and before the sintering, it also includes drying, and the drying process is carried out in an oven, the drying temperature is 100-110°C, and the drying time is 30 to 60 minutes.