A method for leaching lithium from waste glass powder

Abstract

The application belongs to the field of solid waste recycling, and particularly relates to a method for water leaching lithium from waste glass powder, wherein lithium-containing waste glass powder and an additive are mixed and subjected to ball milling modification, and then are subjected to thermal modification at a temperature of 300-900 DEG C to obtain a thermal modification material; the thermal modification material is subjected to water leaching treatment to obtain a lithium-rich water leaching solution; Na2CO3 is added to the lithium-rich water leaching solution to obtain Li2CO3 through evaporation crystallization. Through the modification of the additive, the ball milling modification and the thermal treatment, the method can reduce the thermal treatment temperature, reduce the introduction of impurities, efficiently recover lithium components in the glass powder and prepare high-purity lithium carbonate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of solid waste recycling, and particularly relates to a method for recovering lithium from waste glass powder. BACKGROUND

[0002] With the transformation of global energy structure and the rapid development of new energy vehicles, the demand for lithium resources is increasing. As a light metal, lithium has become particularly important due to its key application in battery technology.

[0003] Waste glass materials, especially glass products containing lithium, have become potential lithium resources due to their wide use in production and use. It is estimated that the amount of waste glass produced globally each year is in the millions of tons, some of which contains a certain amount of lithium. However, most of these waste glasses are currently landfilled or recycled for reuse, and the lithium resources in them have not been effectively recovered. Existing waste glass treatment methods mainly focus on physical recycling, i.e., crushing the glass for road construction, building materials, etc. These methods do not fully utilize the valuable elements in the glass, especially lithium.

[0004] To recover lithium resources from waste glass powder, existing technologies generally use acid leaching. For example, Chinese Patent Publication No. CN 116445735 A discloses a method for extracting lithium from waste glass, which grinds lithium-containing waste glass into glass powder, processes the glass powder with a grinding agent, and calcines it in a high-temperature furnace. The processed glass powder is mixed with an acid solution, and the glass powder is contacted with hydrofluoric acid and perchloric acid for first heating treatment. After cooling, water is added to the cooled product for second heating treatment, and a glass dissolution solution is obtained. The prepared glass dissolution solution is washed and filtered, and finally lithium carbonate is extracted.

[0005] Chinese Patent Publication No. CN118813959A discloses a method for recovering valuable elements from lithium-containing glass waste, specifically describing an acid leaching scheme for lithium-containing glass waste. Chinese Patent Publication No. CN118497499A discloses a method for comprehensively recovering valuable components from lithium-containing glass powder, also describing an acid leaching scheme for lithium-containing glass powder. In addition, Chinese Patent Publication No. CN118207428A discloses a method for extracting lithium from lithium-containing silicon-aluminum glass, specifically describing a scheme of mixing lithium-containing silicon-aluminum glass, soluble M salt, and sulfuric acid solution, pressure leaching, separating to obtain filtrate and filter residue, and the filter residue containing aluminum alumina precipitate containing M, Al, and sulfate.

[0006] In summary, in the prior art, when lithium is extracted from waste glass, a large amount of acid is usually used to leach out the lithium, resulting in an increase in use cost, and in addition, acid leaching also easily leaches out impurity elements in the glass powder, resulting in an increase in the difficulty of subsequent impurity separation and a decrease in the purity of lithium carbonate. Therefore, it is of great significance to develop a method for water leaching lithium from waste glass powder, which is efficient, low in cost, friendly to the environment and reduces the leaching of impurity elements. SUMMARY

[0007] In view of the problems existing in the recycling of waste glass powder, the present application aims to provide a method for recycling lithium from waste glass powder, which aims to provide a method for efficiently recycling lithium in an acid-free system with inexpensive reaction raw materials and a short reaction process, and finally produce lithium carbonate.

[0008] Li in glass and components such as silicon and Al are highly fused at high temperature to form a dense fused phase, which is significantly more difficult to leach out than conventional minerals, and it is difficult to simply adapt the leaching process of conventional lithium ore to glass lithium extraction. In view of the difficulty of lithium extraction from glass, the main means of the existing technology is to perform acid leaching treatment after calcination, which will introduce more impurities into the glass, increasing the difficulty of subsequent lithium separation and purity. In view of this problem, the present application attempts to use a water leaching process to extract lithium, but research shows that there are few existing technologies that can effectively adapt to the pretreatment method of the super-dense and hydrophobic characteristics of glass, making it difficult to achieve the expected water leaching rate of lithium components. In view of this problem, the present application provides the following improved scheme after in-depth research:

[0009] A method for recycling lithium from waste glass powder, waste glass powder containing lithium and an additive are mixed for ball milling modification, and then heat modification is performed at a temperature of 300-900 DEG C to obtain a heat modified material;

[0010] The heat modified material is subjected to water leaching treatment to obtain a lithium-rich water leaching solution;

[0011] The additive comprises MCln, wherein M is at least one of Ca, Fe, Mg and NH4, and n is the valence of M.

[0012] The additive is used in situ to participate in the ball milling modification and heat modification of the waste glass powder, and based on the combination of the additive, ball milling modification and mechanical modification, the internal structure of the glass can be effectively broken down, the surface physicochemical properties can be optimized, and the water leaching rate of lithium can be effectively improved. In addition, it also helps to significantly reduce the leaching of impurities in the glass, thereby effectively reducing the difficulty of lithium separation and purification, and facilitating the obtaining of high-quality lithium products.

[0013] In the application, the lithium-containing waste glass powder contains 20-30 wt.% of Al, 40-50 wt.% of Si, 1.0-10 wt.% of Li, 1-3 wt.% of Mg, 0.5-2 wt.% of Ca, 0-2 wt.% of Na, and less than 0.5 wt.% of other trace elements such as Fe, Ni, Mn, Cr, Pb, Ti, etc., and the particle size is greater than or equal to 100 mesh.

[0014] In the application, the MCln preferably contains NH4Cl, and further preferably contains CaCl2 and NH4Cl in a weight ratio of 0.5-2:1. Research shows that the preferred MCln can achieve synergy unexpectedly, and can obtain better glass water lithium extraction efficiency and effect at a lower treatment temperature.

[0015] In the application, the auxiliary agent further includes an auxiliary auxiliary agent, and the auxiliary auxiliary agent includes at least one of calcium carbonate, calcium oxide, and magnesium carbonate. Research shows that the combination of the preferred MCln and the auxiliary auxiliary agent can further improve the ball milling-thermal double modification effect of the glass, and help to further improve the lithium extraction efficiency and purity.

[0016] In the application, the content of the MCln in the auxiliary agent is more than 50 wt.%, and can be 50-70 wt.%.

[0017] In the application, the weight ratio of the lithium-containing waste glass powder to the auxiliary agent is 1:0.5-2, and can be 1:1-1.5.

[0018] In the application, the ball milling speed in the ball milling modification stage is 150-400 r / min, and can be 300-350 r / min.

[0019] Preferably, the ball milling modification time is 0.5-5 h, and can be 1-3 h.

[0020] In the application, the atmosphere in the thermal modification is at least one of air, argon, and nitrogen.

[0021] In the application, the heat treatment temperature is 700-900℃, and under the preferred auxiliary agent, the heat treatment temperature can be reduced to 300-600℃, and can be 350-450℃. Research shows that under the preferred auxiliary agent of the application, it helps to further optimize the ball milling-thermal modification effect, and can further optimize the efficiency and effect of the glass water lithium extraction, and in addition, helps to improve the purity of the prepared lithium product.

[0022] In the application, the holding time at the heat treatment temperature is 0.5-4 h, and can be 1-3 h.

[0023] In the present application, the liquid-solid ratio of the water immersion stage is 10-50:1 (ml / g), and further can be 15-25 (ml / g).

[0024] Preferably, the water immersion time is 0.5-3h, and further can be 1-2h.

[0025] In the present application, the lithium-rich water immersion liquid is subjected to carbonization precipitation treatment to obtain lithium carbonate.

[0026] Beneficial effects

[0027] In the present application, part of the lithium oxide in the waste glass powder can be wrapped inside by silicon dioxide and aluminum oxide, and is highly fused, with greater surface hydrophobicity, and is also difficult to be efficiently water immersed after heat treatment. In view of this problem, the present application innovatively uses an additive to participate in in-situ ball milling modification and thermal modification, and the additive can be mixed and ball milled with the glass powder to activate the additive, so that the additive can better adhere to and contact the glass powder, and even penetrate into the surface cracks of the glass powder, which is beneficial to the subsequent thermal modification step. Based on the combination of additive-ball milling modification and thermal modification, the fused structure of the glass is effectively destroyed, and in addition, the surface hydrophilicity of the glass is improved, thereby effectively improving the subsequent water immersion effect of the glass, reducing the accompanying leaching of impurities in the glass, and facilitating the efficient and high-purity production of lithium products. At the same time, when ammonium chloride is used as an additive or mixed with other additives for heat treatment, the heat treatment temperature can be reduced, and further, the impurity separation step before the subsequent water immersion step can be greatly reduced or even avoided, the reaction process is shortened, and the auxiliary additive can be further recycled and used. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The process flow chart of Example 1 is shown in Figure 1.

[0029] Figure 2 The XRD of the regenerated Li2CO3 sample of Example 1 is shown in Figure 2. DETAILED DESCRIPTION

[0030] The present application will be further described in conjunction with specific examples, but the present application is not limited to the following examples.

[0031] In the following cases, the lithium-containing glass powder is recycled from glass cooking surfaces, automobile windshields, and fireplace panels, etc. For example, as an optional scheme, the content of the main components is respectively: Al content 20-25wt.%, Si content 40-45wt.%, Li content 1.1-5.0wt.%, Mg content 1.3-1.5wt.%, Ca content 1-1.2wt.%, Na content 0.3-0.5wt.%, and the content of other trace elements such as Fe, Ni, Mn, Cr, Pb, Ti, etc. is less than 0.5wt.%, and the particle size is ≥100 mesh.

[0032] Example 1:

[0033] Step (1): The waste lithium-containing glass powder was crushed and then sieved through a 100-mesh screen. The sieved sample was collected to obtain powder A. The lithium content in powder A was 2.7% by testing.

[0034] Step (2): The auxiliary agent (containing CaCl2 and auxiliary auxiliary agent CaCO3 at a weight ratio of 1:1) was mixed with powder A at a mass ratio of 2:2 and placed in a ball mill tank. Then, the mixture was put into a high-energy planetary ball mill, and ball milling was performed at a speed of 300 r / min for 2 h to obtain mixed ball mill B.

[0035] Step (3): The mixed ball mill B was placed in a high-temperature furnace in an air atmosphere, and the calcination temperature was set to 850 ℃. The calcination time was 2 h to obtain clinker C.

[0036] Step (4): The clinker C was subjected to water immersion treatment at a liquid-solid ratio of 30:1 (ml / g). After stirring at room temperature for 1 h, solid-liquid separation was performed to obtain lithium-containing leaching solution D. The lithium leaching rate was 98.7%.

[0037] Step (5): The precipitant sodium carbonate was added to the lithium-containing leaching solution D. After adjusting the solution pH to 9-10, the Ca impurities were removed by filtration. The filter residue was calcium carbonate, which could be further recovered and used as an auxiliary auxiliary agent. Then, the filtrate was evaporated and concentrated to solution E with a lithium concentration of 14.3 g / L. Sodium carbonate was added to solution E for evaporation and crystallization. After filtration and washing, a lithium carbonate sample with a purity of 99.5% was obtained.

[0038] Example 2

[0039] Compared with Example 1, the only difference is that the type of auxiliary agent in Step 2 and the calcination temperature and time in Step 3 are changed. Other parameters such as the amount of auxiliary agent are the same as in Example 1. The experimental groups are as follows:

[0040] Group A: The auxiliary agent is FeCl3 and CaCO3 at a weight ratio of 1:1, and the temperature is 800 ℃. The lithium leaching rate is 97.3%, and the purity of lithium carbonate is 99.2%.

[0041] Group B: The auxiliary agent is MgCl2 and CaCO3 at a weight ratio of 1:1, and the temperature is 850 ℃ for 1.5 h. The lithium leaching rate is 98.4%, and the purity of lithium carbonate is 99.3%.

[0042] Group C: The auxiliary agent is NH4Cl and CaCO3 at a weight ratio of 1:1, and the temperature is 350 ℃. The lithium leaching rate is 96.8%, and the purity of lithium carbonate is 99.9%.

[0043] Group D: the auxiliary agent is CaCl2, NH4Cl and CaCO3 with a weight ratio of 0.5:0.5:1, the temperature is 450℃, and the liquid-solid ratio of water immersion is 20ml / g. The lithium leaching rate is 99.3%, and the purity of lithium carbonate is 99.8%.

[0044] Group E: no auxiliary agent, the auxiliary agent is only CaCl2, the temperature is 850℃, and the lithium leaching rate is 87.3%, and the purity of lithium carbonate is 98.1%.

[0045] From Examples 1 and 2, it can be seen that the glass is modified by ball milling-heat double modification using an auxiliary agent containing MCln, which can improve the lithium extraction efficiency and effect of the glass. In addition, on this basis, the auxiliary agent MCln- auxiliary agent is used as an auxiliary agent, especially CaCl2-NH4Cl- auxiliary agent is used as an auxiliary agent, which can further improve the modification effect of the glass, and is helpful to further improve the lithium extraction rate and extraction purity of the glass.

[0046] Example 3

[0047] Compared with Example 1, the only difference is that in step 2, the weight ratio of the auxiliary agent and the powder A is 1.5:1, the ball milling speed is set to 350 r / min, and the ball milling time is set to 2.5h: the lithium leaching rate is 99.4%, and the purity of lithium carbonate is 99.6%.

[0048] Example 4

[0049] Compared with Example 1, the only difference is that step 3 is calcined under an argon atmosphere: the lithium leaching rate is 99.2%, and the purity of lithium carbonate is 99.7%.

[0050] Example 5

[0051] Compared with Example 1, the only difference is that the auxiliary agent in step 2 is replaced by CaO, and the calcination temperature is set to 900℃: the lithium leaching rate is 98.4%, and the purity of lithium carbonate is 99.4%.

[0052] Comparative Example 1:

[0053] Compared with Example 1, the only difference is that acid immersion is used instead of water immersion, specifically in step 4, the calcined product is treated with 0.5M H2SO4 with a liquid-solid ratio of 30:1 (ml / g), and after stirring at room temperature for 1h, the solid-liquid is separated to obtain a lithium-containing leaching solution D, the lithium leaching rate is 98.8%, and the purity of the finally obtained lithium carbonate is 90.3%.

[0054] Comparative Example 2:

[0055] Compared with Example 1, the only difference is that in step 2, no auxiliary agent is added, and the other operation conditions are the same as in Example 1, and the result is that the lithium leaching rate is 5.8%.

[0056] Comparative Example 3:

[0057] Compared with Example 1, the difference is only that in Step 2, CaCl2 is not added in the auxiliary agent, only auxiliary auxiliary agent is contained, and the total auxiliary agent dosage and other operation conditions are the same as those in Example 1. As a result, the lithium leaching rate is 33.1%.

[0058] Comparative Example 4:

[0059] Compared with Example 1, the difference is only that in the auxiliary agent, NaCl is used to replace CaCl2 in the auxiliary agent by weight, the total auxiliary agent dosage and other operation conditions are the same as those in Example 1. As a result, the lithium leaching rate is 75.8%, and the purity of lithium carbonate is 96.3%.

[0060] Comparative Example 5:

[0061] Compared with Example 1, the difference is only that the auxiliary agent in Step 2 is added in Step 3, and other operations and parameters are the same as those in Example 1. As a result, the lithium leaching rate is 72.2%, and the purity of lithium carbonate is 97.9%.

[0062] From Examples 1 and 2, it can be seen that by using the auxiliary agent of the application, especially the combined auxiliary agent containing MCln n and auxiliary auxiliary agent, excellent glass water leaching lithium effect can be obtained. In addition, from the comparison of Examples 1 and Comparative Examples 1-5, it can be seen that by using the in-situ parameter glass ball milling and thermal modification of MCln of the application, a synergistic effect can be unexpectedly achieved, and the glass water leaching lithium effect can be improved.

Claims

1. A method of recovering lithium from waste glass powder, characterized by, The lithium-containing waste glass powder and an additive are mixed and modified by ball milling, and then the modified material is heat-modified at a temperature of 300-600 DEG C to obtain a heat-modified material; The heat-modified material is treated by water immersion to obtain a lithium-rich water immersion liquid; The additive comprises MCln and an auxiliary additive, wherein the MCln is CaCl2 and NH4Cl in a weight ratio of 0.5-2:1; and the auxiliary additive is calcium carbonate. The content of the MCln in the additive is more than 50wt.%. The weight ratio of the lithium-containing waste glass powder to the additive is 1:0.5-2. The ball milling speed in the ball milling modification stage is 150-400 r / min, and the ball milling modification time is 0.5-5 h. The lithium-containing waste glass powder contains 20-30wt.% of Al, 40-50wt.% of Si, 1.0-10wt.% of Li, 1-3wt.% of Mg, 0.5-2wt.% of Ca, and 0-2wt.% of Na, and contains less than 0.5wt.% of other trace elements Fe, Ni, Mn, Cr, Pb, and Ti, and has a particle size of greater than or equal to 100 mesh.

2. The method of claim 1, wherein, The content of the MCln is 50-70wt.%.

3. The method of claim 1, wherein, The weight ratio of the lithium-containing waste glass powder to the additive is 1:1-1.

5.

4. The method of claim 1, wherein, The ball milling speed in the ball milling modification stage is 300-350 r / min, and the ball milling modification time is 1-3 h.

5. The method of claim 1, wherein, The heat modification atmosphere is at least one of air, argon, and nitrogen.

6. The method of claim 1, wherein, The heat treatment temperature is 350-450 DEG C.

7. The method of claim 1, wherein, The heat treatment temperature is 350-450 DEG C.

8. The method of claim 1, wherein, The heat treatment temperature is 350-450 DEG C. The liquid-solid ratio in the water immersion stage is 10-50:1 mL / g.

9. The method of claim 1, wherein, The water immersion time is 0.5-3 h. The lithium-rich water immersion liquid is treated by carbonization and precipitation to obtain lithium carbonate.

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