WO2024037305A1

WO2024037305A1 - Method for recovering waste lithium-aluminum-silicon glass ceramic

Info

Publication number: WO2024037305A1
Application number: PCT/CN2023/109572
Authority: WO
Inventors: 郑宇�; 刘勇奇; 陈乾坤; 李成刚; 巩勤学; 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: 2023-07-27
Filing date: 2023-07-27
Publication date: 2024-02-22
Also published as: CN117222767A

Abstract

A method for recovering a waste lithium-aluminum-silicon glass ceramic, which method comprises the following steps: subjecting the waste lithium-aluminum-silicon glass ceramic to ball milling, so as to obtain a glass powder; formulating a hydrofluoric acid solution with a preset concentration as a leaching agent, adding the glass powder to the leaching agent according to a preset liquid-solid ratio, performing leaching according to a preset leaching temperature and preset leaching time, and filtering same to obtain an extract; adding a calcium chloride solution to the extract to dissolve the extract, and filtering same to obtain a conversion solution; extracting the conversion solution, mixing the water phases obtained by two-stage extraction to obtain an extracted conversion solution, mixing oil phases obtained by two-stage extraction to obtain an extraction solution, subjecting the extraction solution to reverse extraction in a sulfuric acid solution, and filtering same to obtain zirconium sulfate; and adjusting the pH of the obtained extracted conversion solution, and filtering same to obtain an aluminum hydroxide precipitate and a lithium-containing solution.

Description

A method for recycling waste lithium-aluminum-silicon-based glass-ceramics

Technical field

The present disclosure relates to the field of waste resource recycling, and in particular, to a method for recycling waste lithium-aluminum-silicon-based glass-ceramics.

Background technique

As a material that has been used for thousands of years, glass is closely related to industrial development and people's lives. Traditional glass mainly includes flat glass and daily glass, which basically covers all types of glass products in life and production. With the increasing consumer demand for glass products, especially glass packaging and decorative glass, the amount of waste glass is also increasing year by year. Waste glass mainly comes from leftovers in the production process and normal disposal of products. According to the relevant United Nations Statistics show that waste glass accounts for 7% of solid waste. Among the municipal solid waste, waste glass in developed countries in Europe and the United States accounts for 4% to 8%. The situation in China is not optimistic either. About 10.4 million tons of waste glass are produced every year, accounting for about 5% of the total solid waste, and it is rising year by year.

However, discarded traditional glass is a low-value waste that is huge in quantity and difficult to process. If recycled, the efficiency is not high. If recycling is abandoned and treated directly as primary waste, it not only harms the environment but also wastes resources; although some In order to meet different usage needs, traditional glass adds metal oxides (such as Li ₂ O, Al ₂ O ₃ , ZrO _2, etc.), which increases the value of traditional glass waste, but its recycling benefits are still limited.

With the advancement of science and technology, the production process of glass has gradually developed, and new types of glass produced using new processes have appeared on the market, including optical glass, energy glass, etc. Among them, lithium aluminum silicate glass (also known as lithium aluminum silicate glass-ceramics) ) is a new type of high-performance glass, which is crystallized glass based on Li ₂ O-Al ₂ O ₃ -SiO _2. It is classified from the perspective of main crystals and includes quartz with high light transmittance and zero expansion performance. Solid solution glass-ceramics, spodumene solid solution glass-ceramics, and transparent aluminum-lithium-silicon glass-ceramics; compared with ordinary glass, lithium-aluminum-silicate glass has the advantages of good chemical stability, high temperature resistance, high hardness, and high mechanical strength. , widely used in the field of electronic products; compared with traditional glass waste, lithium aluminum silicon-based glass-ceramics has a higher recycling value because it contains relatively more Li, Al, and Zr. However, there are currently no relevant reports on the recycling of waste lithium-aluminum-silicon-based glass-ceramics.

Contents of the invention

Based on this, the purpose of the present disclosure is to provide a method for recycling waste lithium aluminum silicon-based glass-ceramics, which realizes the recovery and resource utilization of Li, Al, Zr, and Si in the waste lithium-aluminum silicon-based glass-ceramics. The recovered Li, Al, Zr, and Si are prepared into lithium carbonate, cryolite and zirconium silicate, which has the advantages of high recovery rate, environmentally friendly process, and high economic value.

A method for recycling waste lithium-aluminum-silicon-based glass-ceramics, including the following steps:

Ball-mill the waste lithium aluminum silicon-based glass-ceramics to obtain glass powder;

Prepare a hydrofluoric acid solution with a preset concentration as a leaching agent, and add the glass powder to the leaching agent according to the preset liquid-to-solid ratio. In the extracting agent, leaching is carried out according to the preset leaching temperature and preset leaching time, and the leachate is obtained by filtration;

Add calcium chloride solution to the leachate to dissolve the leachate, and filter to obtain a transformation liquid;

Extract the conversion liquid, mix the extracted water phase to obtain a post-extraction conversion liquid, mix the extracted oil phase to obtain an extraction liquid, back-extract the extraction liquid in a sulfuric acid solution, and filter to obtain sulfuric acid. zirconium;

Adjust the pH of the obtained post-extraction conversion liquid, and filter to obtain aluminum hydroxide precipitate and lithium-containing solution.

The method for recycling waste lithium-aluminum-silicon-based glass-ceramics disclosed in the present disclosure realizes the recovery of Li, Al, and Zr in the waste lithium-aluminum-silicon-based glass-ceramics, and has the advantages of high recovery rate and high economic value.

In one embodiment, the method further includes the following step: adding citric acid and oxalic acid according to a preset molar ratio during the ball milling process. Citric acid and oxalic acid can reduce the energy required to destroy the Si/Al-O bond on the surface of waste glass, that is, reduce the activation energy required for the reaction and increase the decomposition rate of transition state complexes; and the surface complexes formed will change Si /The geometry of the Al-OH bond makes it easier for waste glass to dissolve.

In one embodiment, the ball milling method is: adding a preset stainless steel ball group to the ball mill, adding the waste lithium aluminum silicon-ceramic glass into the ball mill according to the preset ball-to-material ratio, and grinding according to the preset ball-to-material ratio. ball milling according to the rotation speed and preset ball milling time.

In one embodiment, in the leaching step, the preset concentration is 39-41%, the preset liquid-to-solid ratio is (6:1)-(10:1), and the preset leaching temperature The temperature is 80°C to 100°C, and the preset leaching time is 240min to 360min. The preset concentration is greater than 41%, resulting in excessive material consumption and high production costs. The preset concentration is less than 39%, and the Li leaching rate is low; the preset liquid-to-solid ratio is less than 6:1, which is prone to incomplete leaching. The preset concentration If the liquid-to-solid ratio is greater than 10:1, it will lead to waste of leaching liquid; the preset leaching temperature is lower than 80°C, the leaching reaction is incomplete, and the production efficiency is low; the preset temperature is higher than 100°C, which consumes too much energy and improves the leaching effect. Limited; if the preset leaching time is too short, the leaching will be incomplete; if the preset leaching time is too long, the pace of recycling will be slowed down and the cost of recycling will be increased.

In one embodiment, a preset extraction agent compounded of trioctylamine, tributyl phosphate and sulfonated kerosene is used to extract the conversion liquid with a preset oil-to-water ratio, a preset extraction temperature and a preset extraction time.

In one embodiment, the volume ratio of the trioctylamine, the tributyl phosphate and the sulfonated kerosene is 1:1:4. This volume ratio is cost-effective. On this basis, if the proportion of trioctylamine or tributyl phosphate is increased, the extraction effect will be improved to a certain extent, but the cost increase will be greater. On this basis, the proportion of trioctylamine or tributyl phosphate can be reduced. The proportion of tributyl phosphate will reduce the extraction effect and affect normal production.

In one embodiment, the preset oil-to-water ratio is (2:1) to (3:1), the preset extraction temperature is 25°C to 30°C, and the preset extraction time is 5min to 8min. If the preset oil-water ratio is less than 2:1, incomplete extraction will occur. If the preset oil-water ratio is greater than 3:1, on the one hand, the extraction agent often has excess extraction capacity, and on the other hand, due to the increase in the extraction agent, the extraction process will be difficult. The time spent will also increase, affecting production efficiency; if the extraction temperature is lower than 25°C, the extraction efficiency will be low, and if the extraction temperature is higher than At 30°C, it takes more energy and time to heat, which consumes high energy and affects production efficiency; the extraction time is too short, which results in the extraction ending before complete extraction, affecting the yield; the extraction time is too long, which affects the extraction efficiency.

In one embodiment, the preset molar ratio is (1:2)-(1:1). If the molar ratio is less than 1:2, the activation effect will be poor. If the molar ratio is greater than 1:1, the cost will increase and the economic benefits will be affected.

In one embodiment, the preset stainless steel ball group includes a stainless steel ball with a radius of 5 mm and a stainless steel ball with a radius of 3 mm. The mass ratio of the stainless steel ball with a radius of 5 mm and the stainless steel ball with a radius of 3 mm is (1: 2～1:1); the preset ball-to-material ratio is (2:1)～(4:1); the preset ball milling speed is 400r/min～600r/min; the preset ball milling time is 180min ~240min. If the ball-to-material ratio is less than 2:1, the amount of added material is too much, which exceeds the ball milling capacity, resulting in the failure to achieve the expected ball milling effect; if the ball-to-material ratio is greater than 4:1, it will easily lead to a waste of ball milling resources; if the ball milling speed is less than 400r/min, then If the ball milling speed is slow, uneven grinding may even occur. If the ball milling speed is greater than 600r/min, it will easily cause the device to lose its crushing effect. If the ball milling time is shorter than 180min, the material will not be completely ground. If the ball milling time is longer than 240min, the ball milling time will be too long, which will affect production efficiency.

In one embodiment, the particle size of the glass powder is 0.2 mm to 0.8 mm. If the particle size is less than 0.2mm, the grinding will be too fine and the production efficiency will be low. If the particle size is greater than 0.8mm, the reaction will be insufficient.

In one embodiment, the aluminum hydroxide is precipitated with soda ash and hydrofluoric acid to synthesize cryolite. The recovered aluminum hydroxide is further prepared into a high-purity cryolite product. Cryolite has a wide range of industrial uses and can be used in the electrolytic aluminum industry, glass enamel industry, and pesticide manufacturing. Therefore, the aluminum hydroxide is further prepared into cryolite. Can increase the value of recycled materials.

In one embodiment, the zirconium sulfate and silica are reacted to form zirconium silicate. By further preparing zirconium sulfate, which easily brings environmental risks, into zirconium silicate, on the one hand, it can avoid possible environmental hazards caused by recycled materials. On the other hand, zirconium silicate is a high-quality opacifying agent that can be used in various building ceramics, In the production of handicrafts, ceramics, etc., preparing zirconium sulfate into zirconium silicate can increase the value of the recycled materials.

In one embodiment, the lithium-containing solution is reacted with soda ash to obtain lithium carbonate. The lithium-containing solution is further prepared into lithium carbonate. Lithium carbonate is widely used in the new energy industry. The crude lithium carbonate can be sold externally for customers to prepare battery-grade lithium carbonate. Similarly, battery-grade carbonic acid can also be prepared by themselves. Lithium is then sold externally. To prepare battery-grade lithium carbonate, you only need to extract and remove impurities from the lithium-containing solution and then prepare lithium carbonate. Therefore, preparing the lithium-containing solution into lithium carbonate can increase the value of the recycled product.

In one embodiment, the silicon tetrafluoride produced in the leaching step is collected, the silicon tetrafluoride is reacted with a sodium carbonate solution to generate hydrofluoric acid, and the hydrogen fluoride derived from the silicon tetrafluoride is Acids are used to synthesize the cryolite. Collecting the colorless toxic gas silicon tetrafluoride during the leaching process and converting it into hydrofluoric acid used to prepare cryolite can avoid pollution and make it resourceful.

In one embodiment, the silicon tetrafluoride produced in the leaching step is collected, and the silicon tetrafluoride is reacted with the sodium carbonate solution. Orthosilicic acid should be produced, which is heated to obtain silica, and the silica derived from the silicon tetrafluoride is used to synthesize the zirconium silicate. Collecting the colorless toxic gas silicon tetrafluoride during the leaching process and converting it into silica used to prepare zirconium silicate can avoid pollution and make it resourceful.

In one embodiment, the calcium chloride solution is a hydrochloric acid solution of calcium chloride. An acidic environment can avoid the formation of aluminum hydroxide.

The beneficial effects of this disclosure are:

1. Achieved the recovery of Li, Al, Zr, and Si in waste lithium aluminum silicon-based glass-ceramics;

2. Realize the resource utilization of Li, Al, Zr, and Si recovered from waste lithium aluminum silicon-based glass-ceramics. Specifically, the recovered Li, Al, Zr, and Si are prepared into lithium carbonate, cryolite, and silicic acid. Zirconium; among them, lithium carbonate is widely used in the new energy industry. Crude lithium carbonate can be sold externally, while refined lithium carbonate is more valuable. Cryolite has a wide range of industrial uses and can be used in the electrolytic aluminum industry, glass Enamel industry, pesticide manufacturing; zirconium silicate is a high-quality opacifying agent that can be used in the production of various building ceramics, handicraft ceramics, etc.;

3. By ball milling the waste lithium-aluminum-silicon-based glass-ceramics, the Si-O bonds in the waste lithium-aluminum-silicon-based glass-ceramics are destroyed through physical effects such as particle collisions, increasing its surface defects and specific surface area, and improving its reaction. ability. Specifically, after the waste lithium-aluminum-silicon-based glass-ceramics is ball-milled using a planetary ball mill, the waste lithium-aluminum-silicon-based glass-ceramics will undergo processes such as microstructure collapse, lattice distortion, and chemical bond breakage, which will increase the reaction activity. After mechanical activation, the structural integrity and order of the silicate in the waste lithium aluminum silicon-based glass-ceramics are effectively reduced, making the raw material highly reactive;

4. By adding citric acid and oxalic acid during the ball milling process, the energy required to destroy the Si/Al-O bond on the surface of the waste glass is reduced, that is, the activation energy required for the reaction is reduced, and the decomposition rate of the transition state complex is increased; and The surface complexes formed will change the geometry of the Si/Al-OH bond, making the waste glass more easily dissolved;

5. Through the joint action of ball milling and organic acids, the microstructure of the waste lithium aluminum silicon-based glass-ceramics collapses, the crystal lattice is distorted, the chemical bonds are broken, and the reaction activity is increased, which is beneficial to subsequent recycling.

6. By collecting silicon tetrafluoride produced during hydrofluoric acid leaching, and allowing it to undergo an incomplete hydrolysis reaction with sodium carbonate solution to produce hydrofluoric acid and orthosilicic acid, where hydrofluoric acid is used to participate in the preparation of cryolite, and Orthosilicic acid is decomposed to prepare silica, and the obtained silica is used to participate in the preparation of zirconium silicate; the present disclosure realizes the harmlessness and resource utilization of silicon tetrafluoride through the aforementioned method, and converts harmful substances into green and efficient materials. into valuable products;

7. By using a preset extraction agent composed of trioctylamine, tributyl phosphate and sulfonated kerosene for extraction, the Zr in the conversion solution is separated, and zirconium sulfate is obtained through three extractions;

8. The disclosed method for recycling waste lithium-aluminum-silicon-based glass-ceramics has a high recovery rate, an environmentally friendly process, and has great economic value and environmental protection effects.

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

Description of drawings

Figure 1 shows the XRD detection results of the waste lithium aluminum silicon-based glass-ceramics of Type 1 and Type 2 selected in this disclosure;

Figure 2 is a flow chart of a recycling method for waste lithium aluminum silicon-based glass-ceramics described in Embodiment 1;

Figure 3 is an SEM image of the waste lithium aluminum silicon-based glass-ceramics before activation according to Example 1;

Figure 4 is an SEM image of the waste lithium aluminum silicon-based glass-ceramics after activation according to Example 1;

Figure 5 shows the XRD detection results of the high-purity cryolite prepared in Examples 1 to 3.

Detailed ways

The disclosed method for recycling waste lithium aluminum silicon-based glass-ceramics is suitable for common waste lithium-aluminum silicon-based glass-ceramics containing SiO ₂ , Al ₂ O ₃ , Li ₂ O and ZrO ₂ . In the following examples, the present disclosure exemplifies two common types of waste lithium aluminum silicon-based glass-ceramics (model 1 and model 2). This application implements the disclosure of waste lithium-aluminum silicon-based glass-ceramics for model 1. Recycling methods. The component content (wt%) of Model 1 and Model 2 is shown in Table 1 below. The XRD detection results of Model 1 and Model 2 are shown in Figure 1. The diffraction peaks of the crystallized glass of Model 1 and Model 2 are consistent, and the object composition is the same. .

Table 1 Component contents of model 1 and model 2

Example 1

This embodiment provides a method for recycling waste lithium aluminum silicon-based glass-ceramics, as shown in Figure 2, including the following steps:

Add a certain amount of waste lithium aluminum silicon-based glass-ceramics to the planetary ball mill, and add a stainless steel ball group with a ball-to-material ratio of 2:1. The stainless steel ball group consists of stainless steel balls with a radius of 5mm and stainless steel balls with a radius of 3mm. The mass ratio of a stainless steel ball with a radius of 5mm and a stainless steel ball with a radius of 3mm is 1:2. The ball milling speed is 400r/min for 180min. During the ball milling process, the molar ratio of citric acid and oxalic acid added to the planetary ball mill is 1. :2. A mixed solution with a concentration of 1 mol/L; after ball milling, a glass powder with a particle size of 0.2 mm to 0.8 mm is obtained; the aforementioned step is the process of activating waste lithium aluminum silicon-based glass-ceramics. Before activation and The SEM images after activation can be seen in Figures 3 and 4. It is not difficult to see that the structure is more loose after activation. During the activation process, on the one hand, the waste lithium aluminum silicon-based glass-ceramics is destroyed through physical effects such as collisions between particles. Si-O bonds, increase its surface defects and specific surface area, and improve its reactivity; on the other hand, citric acid and oxalic acid can reduce the energy required to destroy the Si/Al-O bonds on the surface of waste glass, that is, reduce the reaction required The activation energy increases the decomposition rate of the transition state complex; and the surface complex formed will change the geometry of the Si/Al-OH bond, making the waste glass easier to dissolve; through the joint action of ball milling and organic acids, the waste glass The microstructure collapse and crystal lattice of lithium aluminum silicon-based glass-ceramics Distortion, chemical bond breakage, and increased reactivity are beneficial to subsequent recycling.

Then prepare a 40% hydrofluoric acid solution as the leaching agent, add the glass powder to the leaching agent according to the liquid-to-solid ratio of 6:1, leaching at 80°C for 240 minutes, and collect the gas generated during the leaching process (mainly tetrafluoride Silicon gas), and react the gas with a sodium carbonate solution to obtain hydrofluoric acid and orthosilicic acid. The hydrofluoric acid is collected and temporarily stored, and the orthosilicic acid is further prepared into silica through thermal decomposition, etc., and the silica is Collect and store temporarily; after leaching is completed, filter to obtain the leachate. During the leaching process, the reactions that occur include: LiAlSi ₂ O ₆ +12HF==AlF ₃ (s) + LiF (s) + 2SiF ₄ (g) + 6H ₂ O; in addition, in the waste lithium aluminum silicon glass-ceramics Sodium oxide, zirconium oxide, etc. will also react with hydrofluoric acid. Therefore, during the leaching process, Al, Li, and Zr in the lithium aluminum silicon-based glass-ceramics are converted into AlF ₃ precipitation, LiF precipitation, and ZrF ₄ precipitation (i.e. The aforementioned leachate), Na in the lithium aluminum silicon-based glass-ceramics is converted into NaF and dissolved in hydrofluoric acid, while Si in the lithium-aluminum silicon-based glass-ceramics is converted into colorless and toxic SiF ₄ gas, therefore, Through this leaching step combined with filtration, the mixture of Al, Li, Zr, Na and Si can be initially separated.

Then, a hydrochloric acid solution of calcium chloride is added to the leachate to dissolve it, and the transformation liquid is obtained by filtration; in this step, the reactions involved in the dissolution process include: 2LiF+CaCl ₂ =2LiCl+CaF ₂ (s); 2AlF ₃ + 3CaCl ₂ =2AlCl ₃ +3CaF ₂ (s); ZrF ₄ +2CaCl ₂ =ZrCl ₄ +2CaF ₂ (s); therefore, the components of the aforementioned conversion solution include LiCl, AlCl ₃ and ZrCl ₄ , and the main valuable metals in the conversion solution are The component contents are shown in Table 2 below.

Table 2 Contents of main valuable metals in the conversion solution of Example 1

Then, an extraction agent compounded of trioctylamine, tributyl phosphate and sulfonated kerosene in a volume ratio of 1:1:4 was used to perform secondary extraction on the aforementioned transformation liquid with an oil-to-water ratio of 2:1. The extraction time was 5 minutes. , the extraction temperature is 25°C. Mix the water phase obtained by the two-stage extraction to obtain a post-extraction conversion liquid. The composition of the post-extraction conversion liquid includes LiCl and AlCl ₃ ; mix the oil phase obtained from the two-stage extraction to obtain an extraction liquid. The extraction liquid The ingredients include ZrCl ₄ , in which the extraction rate of zirconium after secondary extraction is 99.2%. The extract is then back-extracted in a sulfuric acid solution, where the back-extraction rate of zirconium is 96.23%. Zirconium sulfate is obtained by filtration; because zirconium sulfate is easy to Brings environmental risks, so zirconium sulfate is further prepared into zirconium silicate. On the one hand, it can avoid possible environmental hazards caused by recycled materials. On the other hand, zirconium silicate is a high-quality opacifying agent that can be used in various applications. In the production of architectural ceramics, handicraft ceramics, etc., preparing zirconium sulfate into zirconium silicate can increase the value of the recycled materials; the method of preparing zirconium silicate is to react zirconium sulfate with silicon dioxide. In the process of preparing zirconium silicate, The silica prepared from silicon tetrafluoride gas in the leaching step can be used to realize the resource utilization of the recycled material obtained in the leaching step; the zirconium silicate prepared in this embodiment can meet the requirements of "JC/T1094-2009 Zirconium silicate for ceramics" 》Standard requirements, the dry basis test results are shown in Table 3 below.

Table 3 Dry basis test results of zirconium silicate prepared in Example 1

Use soda ash to adjust the pH of the post-extraction conversion liquid until no precipitation precipitates, and then filter to obtain aluminum hydroxide precipitate and lithium-containing solution. The filtered aluminum hydroxide precipitate is reacted with soda ash and HF to synthesize a high-purity cryolite (Na ₃ AlF ₆ ) product. The XRD detection results of the high-purity cryolite prepared in this example are shown in Figure 5, and its crystal form is good. , no obvious impurity peaks, the preparation principle is: 12HF+3Na ₂ CO ₃ +2Al(OH) ₃ =2Na ₃ AlF ₆ +3CO ₂ +9H ₂ O. Cryolite has a wide range of industrial uses and can be used in the electrolytic aluminum industry. , glass enamel industry, and pesticide manufacturing, therefore further preparing aluminum hydroxide into cryolite can increase the value of the recycled materials; in the process of preparing cryolite, HF prepared from silicon tetrafluoride gas in the leaching step can be used to achieve Recycling of recycled materials from the leaching step.

Add soda ash to the lithium-containing solution to prepare crude lithium carbonate. Lithium carbonate is widely used in the new energy industry. The crude lithium carbonate can be sold externally for customers to prepare battery-grade lithium carbonate. The same can be done Prepare battery-grade lithium carbonate yourself and then sell it externally. To prepare battery-grade lithium carbonate, you only need to extract and remove impurities from the lithium-containing solution and then prepare lithium carbonate. Therefore, preparing the lithium-containing solution into lithium carbonate can increase the value of the recycled materials. The reaction principle is: 2LiCl+Na ₂ CO ₃ =2NaCl+Li ₂ CO ₃ (s). After washing, the crude lithium carbonate prepared by using the lithium-containing solution of the present disclosure can meet the GBT11075-2013 "Lithium Carbonate" indicators. Requirements, the dry basis detection results of the crude lithium carbonate of this embodiment are shown in Table 4 below.

Table 4 Dry basis test results of crude lithium carbonate prepared in Example 1

Example 2

This embodiment provides a method for recycling waste lithium aluminum silicon-based glass-ceramics, which includes the following steps:

Add a certain amount of waste lithium aluminum silicon-based glass-ceramics to the planetary ball mill, and add a stainless steel ball group with a ball-to-material ratio of 4:1. The stainless steel ball group consists of stainless steel balls with a radius of 5mm and stainless steel balls with a radius of 3mm. The mass ratio of a stainless steel ball with a radius of 5mm and a stainless steel ball with a radius of 3mm is 1:1. The ball milling speed is 600r/min for 240 minutes. During the ball milling process, the molar ratio of citric acid and oxalic acid added to the planetary ball mill is 1. : 1. A mixed solution with a concentration of 1 mol/L; after ball milling, a glass powder with a particle size of 0.2 mm to 0.8 mm is obtained; the aforementioned steps are the process of activating waste lithium aluminum silicon-based glass-ceramics. It is not difficult to see that after activation Its structure is more loose; during the activation process, on the one hand, the Si-O bonds in the waste lithium aluminum silicon-based glass-ceramics are destroyed through physical effects such as collisions between particles, increasing its surface defects and specific surface area, and improving its reactivity. ; On the other hand, citric acid and oxalic acid can reduce the energy required to destroy the Si/Al-O bond on the surface of waste glass, that is, reduce the activation energy required for the reaction and increase the decomposition rate of the transition state complex; and the surface formed The complex will change The geometric shape of the Si/Al-OH bond makes the waste glass easier to dissolve; through the joint action of ball milling and organic acids, the microstructure of the waste lithium aluminum silicon-based glass-ceramics collapses, the crystal lattice is distorted, the chemical bonds are broken, and the reactivity is increased. Large, conducive to subsequent recycling.

Then prepare a 40% hydrofluoric acid solution as the leaching agent, add the glass powder to the leaching agent according to the liquid-to-solid ratio of 6:1, leaching at 70°C for 180 minutes, and collect the gas generated during the leaching process (mainly tetrafluoride Silicon gas), and react the gas with a sodium carbonate solution to obtain hydrofluoric acid and orthosilicic acid. The hydrofluoric acid is collected and temporarily stored, and the orthosilicic acid is further prepared into silica through thermal decomposition, etc., and the silica is Collect and store temporarily; after leaching is completed, filter to obtain the leachate. During the leaching process, the reactions that occur include: LiAlSi ₂ O ₆ +12HF==AlF ₃ (s) + LiF (s) + 2SiF ₄ (g) + 6H ₂ O; in addition, in the waste lithium aluminum silicon glass-ceramics Sodium oxide, zirconium oxide, etc. will also react with hydrofluoric acid. Therefore, during the leaching process, Al, Li, and Zr in the lithium aluminum silicon-based glass-ceramics are converted into AlF ₃ precipitation, LiF precipitation, and ZrF ₄ precipitation (i.e. The aforementioned leachate), Na in the lithium aluminum silicon-based glass-ceramics is converted into NaF and dissolved in hydrofluoric acid, while Si in the lithium-aluminum silicon-based glass-ceramics is converted into colorless and toxic SiF ₄ gas, therefore, Through this leaching step combined with filtration, the mixture of Al, Li, Zr, Na and Si can be initially separated.

Then, a hydrochloric acid solution of calcium chloride is added to the leachate to dissolve it, and the transformation liquid is obtained by filtration; in this step, the reactions involved in the dissolution process include: 2LiF+CaCl ₂ =2LiCl+CaF ₂ (s); 2AlF ₃ + 3CaCl ₂ =2AlCl ₃ +3CaF ₂ (s); ZrF ₄ +2CaCl ₂ =ZrCl ₄ +2CaF ₂ (s); therefore, the components of the aforementioned conversion solution include LiCl, AlCl ₃ and ZrCl ₄ , and the main valuable metals in the conversion solution are The component contents are shown in Table 5 below.

Table 5 Main valuable metal contents in the conversion solution of Example 2

Then, an extraction agent compounded of trioctylamine, tributyl phosphate and sulfonated kerosene in a volume ratio of 1:1:4 was used to perform secondary extraction on the aforementioned transformation liquid with an oil-to-water ratio of 2:1. The extraction time was 8 minutes. , the extraction temperature is 30°C. Mix the water phase obtained by the two-stage extraction to obtain a post-extraction conversion liquid. The composition of the post-extraction conversion liquid includes LiCl and AlCl ₃ ; mix the oil phase obtained from the two-stage extraction to obtain an extraction liquid. The extraction liquid The ingredients include ZrCl ₄ , in which the extraction rate of zirconium after secondary extraction is 99.8%. The extract is then back-extracted in a sulfuric acid solution, and the stripping rate of zirconium is 99.23%. Zirconium sulfate is obtained by filtration; because zirconium sulfate is easy to Brings environmental risks, so zirconium sulfate is further prepared into zirconium silicate. On the one hand, it can avoid possible environmental hazards caused by recycled materials. On the other hand, zirconium silicate is a high-quality opacifying agent that can be used in various applications. In the production of architectural ceramics, handicraft ceramics, etc., preparing zirconium sulfate into zirconium silicate can increase the value of the recycled materials; the method of preparing zirconium silicate is to react zirconium sulfate with silicon dioxide. In the process of preparing zirconium silicate, The silica prepared from silicon tetrafluoride gas in the leaching step can be used to realize the resource utilization of the recycled material obtained in the leaching step; the zirconium silicate prepared in this embodiment can meet the requirements According to the requirements of the "JC/T1094-2009 Zirconium Silicate for Ceramics" standard, the dry basis test results are shown in Table 6 below.

Table 6 Dry basis test results of zirconium silicate prepared in Example 2

Add soda ash to the lithium-containing solution to prepare crude lithium carbonate. Lithium carbonate is widely used in the new energy industry. The crude lithium carbonate can be sold externally and used by customers to prepare battery-grade lithium carbonate. The same can be done in the same way. To prepare battery-grade lithium carbonate yourself and then sell it externally, to prepare battery-grade lithium carbonate, you only need to extract and remove impurities from the lithium-containing solution and then prepare lithium carbonate. Therefore, preparing the lithium-containing solution into lithium carbonate can increase the value of the recycled materials. The reaction principle is: 2LiCl+Na ₂ CO ₃ =2NaCl+Li ₂ CO ₃ (s). After washing, the crude lithium carbonate prepared by using the lithium-containing solution of the present disclosure can meet the GBT11075-2013 "Lithium Carbonate" indicators. Requirements, the dry basis detection results of the crude lithium carbonate of this embodiment are shown in Table 7 below.

Table 7 Dry basis test results of crude lithium carbonate prepared in Example 2

Example 3

Add a certain amount of waste lithium aluminum silicon-based glass-ceramics to the planetary ball mill, and add a stainless steel ball group with a ball-to-material ratio of 4:1. The stainless steel ball group consists of stainless steel balls with a radius of 5mm and stainless steel balls with a radius of 3mm. The mass ratio of a stainless steel ball with a radius of 5mm and a stainless steel ball with a radius of 3mm is 1:1. The ball milling speed is 600r/min for 240 minutes. During the ball milling process, the molar ratio of citric acid and oxalic acid added to the planetary ball mill is 1. : 1. A mixed solution with a concentration of 1 mol/L; after ball milling, a glass powder with a particle size of 0.2 mm to 0.8 mm is obtained; the aforementioned steps are the process of activating waste lithium aluminum silicon-based glass-ceramics. It is not difficult to see that after activation Its structure is more loose; during the activation process, on the one hand, the Si-O bonds in the waste lithium aluminum silicon-based glass-ceramics are destroyed through physical effects such as collisions between particles, increasing its surface defects and specific surface area, and improving Its reactivity; on the other hand, citric acid and oxalic acid can reduce the energy required to destroy the Si/Al-O bond on the surface of waste glass, that is, reduce the activation energy required for the reaction and increase the decomposition rate of the transition state complex; and the The surface complex formed will change the geometry of the Si/Al-OH bond, making the waste glass more easily dissolved; through the combined action of ball milling and organic acids, the microstructure of the waste lithium aluminum silicon-based glass-ceramics will collapse and the crystal lattice will be distorted. , chemical bonds are broken, and the reaction activity increases, which is beneficial to subsequent recycling.

Then, a hydrochloric acid solution of calcium chloride is added to the leachate to dissolve it, and the transformation liquid is obtained by filtration; in this step, the reactions involved in the dissolution process include: 2LiF+CaCl ₂ =2LiCl+CaF ₂ (s); 2AlF ₃ + 3CaCl ₂ =2AlCl ₃ +3CaF ₂ (s); ZrF ₄ +2CaCl ₂ =ZrCl ₄ +2CaF ₂ (s); therefore, the components of the aforementioned conversion solution include LiCl, AlCl ₃ and ZrCl ₄ , and the main valuable metals in the conversion solution are The component contents are shown in Table 8 below.

Table 8 Main valuable metal contents in the conversion solution of Example 3

Then, an extraction agent compounded of trioctylamine, tributyl phosphate and sulfonated kerosene in a volume ratio of 1:1:4 was used to perform secondary extraction on the aforementioned transformation liquid with an oil-to-water ratio of 2:1. The extraction time was 8 minutes. , the extraction temperature is 30°C. Mix the water phase obtained by the two-stage extraction to obtain a post-extraction conversion liquid. The composition of the post-extraction conversion liquid includes LiCl and AlCl ₃ ; mix the oil phase obtained from the two-stage extraction to obtain an extraction liquid. The extraction liquid The ingredients include ZrCl ₄ , in which the extraction rate of zirconium after secondary extraction is 99.8%. The extract is then back-extracted in a sulfuric acid solution, and the stripping rate of zirconium is 99.23%. Zirconium sulfate is obtained by filtration; because zirconium sulfate is easy to Brings environmental risks, so zirconium sulfate is further prepared into zirconium silicate. On the one hand, it can avoid possible environmental hazards caused by recycled materials. On the other hand, zirconium silicate is a high-quality opacifying agent that can be used in various applications. In the production of architectural ceramics, handicraft ceramics, etc., preparing zirconium sulfate into zirconium silicate can increase the value of the recycled materials; the method for preparing zirconium silicate is to make sulfuric acid Zirconium reacts with silica. In the process of preparing zirconium silicate, the silica prepared from silicon tetrafluoride gas in the leaching step can be used to realize the resource utilization of the recycled material obtained in the leaching step; Zirconium silicate can meet the requirements of the "JC/T1094-2009 Zirconium silicate for ceramics" standard. The dry basis test results are shown in Table 9 below.

Table 9 Dry basis test results of zirconium silicate prepared in Example 3

Add soda ash to the lithium-containing solution to prepare crude lithium carbonate. Lithium carbonate is widely used in the new energy industry. The crude lithium carbonate can be sold externally and used by customers to prepare battery-grade lithium carbonate. The same can be done in the same way. To prepare battery-grade lithium carbonate yourself and then sell it externally, to prepare battery-grade lithium carbonate, you only need to extract and remove impurities from the lithium-containing solution and then prepare lithium carbonate. Therefore, preparing the lithium-containing solution into lithium carbonate can increase the value of the recycled materials. The reaction principle is: 2LiCl+Na ₂ CO ₃ =2NaCl+Li ₂ CO ₃ (s). After washing, the crude lithium carbonate prepared by using the lithium-containing solution of the present disclosure can meet the GBT11075-2013 "Lithium Carbonate" indicators. Requirements, the dry basis test results of the crude lithium carbonate of this embodiment are shown in Table 10 below.

Table 10 Dry basis test results of crude lithium carbonate prepared in Example 3

The beneficial effects of this disclosure are:

Claims

A method for recycling waste lithium-aluminum-silicon-based glass-ceramics, which is characterized by including the following steps:

Ball-mill the waste lithium aluminum silicon-based glass-ceramics to obtain glass powder;

Prepare a hydrofluoric acid solution with a preset concentration as a leaching agent, add the glass powder to the leaching agent according to the preset liquid-to-solid ratio, perform leaching according to the preset leaching temperature and preset leaching time, and filter to obtain the leachate;

Add calcium chloride solution to the leachate to dissolve the leachate, and filter to obtain a transformation liquid;

Extract the conversion liquid, mix the extracted water phase to obtain a post-extraction conversion liquid, mix the extracted oil phase to obtain an extraction liquid, back-extract the extraction liquid in a sulfuric acid solution, and filter to obtain sulfuric acid. zirconium;

Adjust the pH of the obtained post-extraction conversion liquid, and filter to obtain aluminum hydroxide precipitate and lithium-containing solution.
A method for recycling waste lithium-aluminum-silicon-based glass-ceramics according to claim 1, further comprising the following steps: adding citric acid and oxalic acid according to a preset molar ratio during the ball milling process.
A method for recycling waste lithium-aluminum-silicon-based glass-ceramics according to claim 1, characterized in that the ball milling method is: adding a preset stainless steel ball group to the ball mill, and grinding all the balls according to the preset ball-to-material ratio. The waste lithium-aluminum-silicon-based glass-ceramics is added to the ball mill and ball-milled according to the preset ball milling speed and preset ball milling time.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 1, characterized in that in the leaching step, the preset concentration is 39wt% to 41wt%, and the preset liquid-solid The ratio is (6:1) to (10:1), the preset leaching temperature is 80°C to 100°C, and the preset leaching time is 240min to 360min.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 1, characterized in that a preset extraction agent compounded from trioctylamine, tributyl phosphate and sulfonated kerosene is used to preset The conversion liquid is extracted according to the oil-water ratio, preset extraction temperature and preset extraction time.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 5, characterized in that the volume ratio of the trioctylamine, the tributyl phosphate and the sulfonated kerosene is 1:1 :4.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 5, characterized in that the preset oil-to-water ratio is (2:1) to (3:1), and the preset extraction temperature The temperature is 25°C to 30°C, and the preset extraction time is 5min to 8min.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 2, wherein the preset molar ratio is (1:2) to (1:1).
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 3, characterized in that the preset stainless steel ball group includes a stainless steel ball with a radius of 5 mm and a stainless steel ball with a radius of 3 mm, and the radius The mass ratio of a stainless steel ball with a radius of 5mm and a stainless steel ball with a radius of 3mm is (1:2) ~ (1:1); the preset ball-to-material ratio is (2:1) ~ (4:1); The preset ball milling speed is 400r/min～600r/min; the preset ball milling time is 180min～240min.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 1, characterized in that the particle size of the glass powder is 0.2 mm to 0.8 mm.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 1, characterized in that the aluminum hydroxide precipitation is combined with soda ash and hydrofluoric acid to synthesize cryolite.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 1, characterized in that the zirconium sulfate and silicon dioxide are reacted to generate zirconium silicate.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 1, characterized in that the lithium-containing solution is reacted with soda ash to obtain lithium carbonate.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 11, characterized in that the silicon tetrafluoride produced in the leaching step is collected, and the silicon tetrafluoride is reacted with a sodium carbonate solution Hydrofluoric acid is generated, and the hydrofluoric acid derived from the silicon tetrafluoride is used to synthesize the cryolite.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 12, characterized in that the silicon tetrafluoride produced in the leaching step is collected, and the silicon tetrafluoride is reacted with a sodium carbonate solution Orthosilicic acid is generated, and the orthosilicic acid is heated to obtain silica. The silica derived from the silicon tetrafluoride is used to synthesize the zirconium silicate.
A method for recycling waste lithium aluminum silicon-based glass-ceramics according to claim 1, characterized in that the calcium chloride solution is a hydrochloric acid solution of calcium chloride.