A method for extracting lithium from electrolytic aluminum solid waste

Abstract

The application provides a method for extracting lithium from electrolytic aluminum solid waste, which comprises the following steps: (1) mixing electrolytic aluminum solid waste with an additive and water to form a slurry; (2) adding acid to the slurry in step (1) for leaching, and then performing liquid-solid separation to obtain a leaching solution and a leaching residue; (3) adding alkali to the leaching solution in step (2) for regeneration, and then performing liquid-solid separation to obtain a lithium-containing regenerated solution and a regenerated additive, wherein the regenerated additive is used in step (1). The method adopts a wet leaching technology, the leaching additive is added in the weak acid leaching process, and the leaching rate of lithium is improved. The method is simple in operation, friendly to the environment, and the leaching additive can be regenerated and recycled, so that the amount of leaching agent acid is reduced, the cost of leaching and lithium extraction is reduced, and the method has a good industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of chemical metallurgy technology and relates to a method for extracting lithium from electrolytic aluminum solid waste. Background Technology

[0002] In the aluminum electrolysis industry, the cathode of the aluminum electrolysis cell will gradually turn into powder due to the corrosion of the electrolyte. The aluminum electrolysis cell must be overhauled, cleaned and replaced every 3-5 years. The waste residue includes cathode carbon blocks, refractory insulation materials and electrolytes.

[0003] As a huge by-product of the aluminum industry, electrolytic aluminum waste can be utilized by extracting lithium resources from it. This not only enables the resource utilization of electrolytic aluminum waste, but also allows the extracted lithium to supplement market demand for lithium resources and reduce dependence on international lithium resources.

[0004] Currently, the main processes for extracting lithium from electrolytic aluminum solid waste are direct acid leaching and sulfuric acid roasting-water leaching. CN108569711A discloses a method for extracting lithium salts from high-lithium electrolyte waste from aluminum electrolysis to prepare lithium carbonate. First, the high-lithium electrolyte and a 5-8% sulfuric acid solution are mixed at a solid-liquid ratio of 1:2-3, and then reacted at 90-95℃ for 0.5-1.5 hours. However, the lithium leaching rate is less than 75%. CN 109930174A discloses a method for delithiation, purification, and lithium recovery from aluminum electrolyte, using 2-6 mol / L nitric acid leaching to further improve the lithium leaching rate. However, the leaching process generates hydrogen fluoride, which can easily cause environmental pollution. CN 105293536 A discloses a method for extracting lithium from electrolytic aluminum waste. First, the electrolytic aluminum waste is reacted with concentrated sulfuric acid at a mass ratio of 1:1-3 at 200-400℃ for 5-12 hours, followed by water leaching to extract lithium. CN 113718107 A, CN109179457 A, etc., use a similar sulfuric acid roasting process to extract lithium. This method has a lithium leaching rate of over 95%, but sulfuric acid roasting easily produces highly corrosive hydrofluoric acid, and this process requires equipment with high corrosion resistance.

[0005] To improve the extraction rate of lithium, there are currently salt roasting method, alkali roasting method and other processes. CN 107587167A discloses a method for changing the crystal form of lithium-containing aluminum electrolyte, which mixes alkali metal oxyacid salt with aluminum electrolyte and roasts at 300-1200℃, converts lithium components into acid-soluble lithium salt, and the conversion rate is more than 95%. CN 113684369 A discloses a method for extracting lithium from waste industrial lithium-containing aluminum electrolyte by sodium hydroxide and potassium hydroxide roasting method. CN 115216645 A discloses a method for extracting lithium from electrolytic aluminum waste residue by mixed salt calcination of potassium and calcium salt. CN 115198111 A discloses a method for extracting lithium from lithium-containing waste aluminum electrolyte by adding magnesium, calcium and barium salt roasting method. CN 114314625 A discloses a method for extracting lithium from aluminum electrolyte by adding aluminum salt roasting method. The advantage of roasting method is high lithium extraction rate, but there is a problem of large amount of roasting additives. In order to reduce the amount of roasting additives, CN 105543504 A discloses a method for extracting lithium salt in aluminum electrolyte by fluorination roasting and acid leaching, but there is still the risk of concentrated acid leaching environment.

[0006] In order to improve the extraction rate of lithium, while considering reducing cost and reducing environmental pollution, CN 105349786A proposes a method for comprehensive recycling of lithium-containing aluminum electrolyte, which first mixes water with lithium-containing aluminum electrolyte at a liquid-solid ratio of 1-6:1, adds inorganic acid to adjust the pH of the system to less than 2, and then adds aluminum salt into the slurry according to the aluminum-lithium molar ratio of 1-3:3 to leach lithium, CN 11555880 A, CN 115652097 A and the like adopt similar lithium extraction process. The advantage of this method is that the amount of acid can be greatly reduced, but the amount of aluminum salt is still large, and the cost is still high. CN 110240182 A discloses a resourceful treatment method of lithium-rich aluminum electrolyte, which selects a mild aluminum salt leaching on the basis of the fluorination roasting of CN 105543504A, reduces the environmental pollution risk, but still has the problems of large amount of aluminum salt and high cost.

[0007] In summary, it is urgent to develop a new method for extracting lithium from electrolytic aluminum solid waste, which has low energy consumption, low cost, renewable leaching agent, clean and controllable process, so as to realize efficient extraction and recovery of lithium. SUMMARY

[0008] To solve the technical problems existing in the prior art, the present application provides a method for extracting lithium from electrolytic aluminum solid waste, which adopts a wet leaching technology, and improves the leaching rate of lithium by adding leaching additives in the weak acid leaching process. The method is simple to operate, environmentally friendly, and the leaching additive can be recycled, reducing the amount of leaching agent acid and the cost of leaching lithium, and has good industrial application prospect.

[0009] To achieve the above technical effects, the present application adopts the following technical solutions:

[0010] The present application provides a method for extracting lithium from electrolytic aluminum solid waste, which comprises the following steps:

[0011] (1) mixing electrolytic aluminum solid waste with additives and water to form a slurry;

[0012] (2) adding acid to the slurry of step (1) to leach, and then separating the liquid and solid to obtain leaching solution and leaching residue;

[0013] (3) adding alkali to the leaching solution of step (2) to regenerate, and then separating the liquid and solid to obtain lithium-containing regenerated solution and regenerated additives, which are returned to step (1).

[0014] As a preferred technical solution of the present application, the additive of step (1) is an alkaline earth metal compound.

[0015] As a preferred technical solution of the present application, the alkaline earth metal elements in the alkaline earth metal compound include any one or a combination of at least two of Mg, Ca, Sr or Ba, typical but non-limiting examples of which include: a combination of Ca and Ba, a combination of Mg and Ca, a combination of Mg, Sr and Ba, a combination of Mg, Ca, Sr and Ba, etc.

[0016] As a preferred technical solution of the present application, the alkaline earth metal compound includes any one or a combination of at least two of oxides, hydroxides, halides, halogen element oxoacid salts, boron element oxoacid salts, carbon element oxoacid salts, nitrogen element oxoacid salts, oxygen element oxoacid salts and transition element oxoacid salts of alkaline earth metals, typical but non-limiting examples of which include: a combination of oxides and halides, a combination of hydroxides and nitrogen element oxoacid salts, a combination of halides, halogen element oxoacid salts and oxygen element oxoacid salts, a combination of carbon element oxoacid salts, oxygen element oxoacid salts and transition element oxoacid salts, a combination of halides, halogen element oxoacid salts, carbon element oxoacid salts and transition element oxoacid salts, a combination of oxides, halides, boron element oxoacid salts, carbon element oxoacid salts and nitrogen element oxoacid salts, a combination of hydroxides, halides, carbon element oxoacid salts, nitrogen element oxoacid salts, oxygen element oxoacid salts and transition element oxoacid salts, a combination of oxides, halides, halogen element oxoacid salts, boron element oxoacid salts, carbon element oxoacid salts, nitrogen element oxoacid salts, oxygen element oxoacid salts and transition element oxoacid salts, a combination of oxides, hydroxides, halides, halogen element oxoacid salts, boron element oxoacid salts, carbon element oxoacid salts, nitrogen element oxoacid salts, oxygen element oxoacid salts and transition element oxoacid salts, etc.

[0017] As a preferred technical solution of the present application, the molar ratio of lithium element in the electrolytic aluminum solid waste to the alkaline earth metal element in the alkaline earth metal compound is 1:(0.1-20), such as 1:0.1, 1:0.11, 1:0.15, 1:0.3, 1:0.4, 1:0.5, 1:0.75, 1:1, 1:1.5, 1:2, 1:2.2, 1:2.5, 1:2.75, 1:3, 1:4, 1:5, 1:7.5, 1:10, 1:15 or 1:20, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably 1:(0.15-5), more preferably 1:(0.2-2.5).

[0018] As a preferred technical solution of the present application, the pH value of the acid leaching in step (2) is 0.1-3, such as 0.1, 0.25, 0.5, 0.75, 0.85, 0.9, 1.1, 1.2, 1.3, 1.4, 1.5, 1.75, 1.95, 2, 2.5, 2.7 or 3, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably pH=0.5-2.

[0019] As a preferred technical solution of the present application, the temperature of the acid leaching in step (2) is 20-120℃, such as 20℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃, etc.; the time is 0.5-6h, such as 0.5h, 0.75h, 1h, 1.5h, 1.75h, 2h, 3h, 4h, 5h or 6h, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0020] As a preferred technical solution of the present application, the pH value of the base regeneration in step (3) is 4-14, such as 4, 5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13 or 14, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably pH=4-12, more preferably pH=6-10.

[0021] As a preferred technical scheme of the present application, the temperature of the alkali regeneration in step (3) is 50-120℃, such as 50℃, 60℃, 65℃, 70℃, 72.5℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃ or 120℃, etc.; the time is 0.05-1h, such as 0.05h, 0.075h, 0.1h, 0.15h, 0.2h, 0.25h, 0.3h, 0.35h, 0.4h, 0.45h, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h, etc., but not limited to the listed values, other values not listed in the above ranges are also applicable, preferably 0.15-0.5h.

[0022] As a preferred technical scheme of the present application, the lithium content in the electrolytic aluminum solid waste is ≥0.3wt%, such as 0.3%, 0.399%, 0.5%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.9%, 1.0%, 1.2%, 1.5%, 1.75%, 2%, 2.25%, 2.5%, 3%, 4%, 5% and 7%, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably ≥0.5%, more preferably ≥0.7%.

[0023] Compared with the prior art, the present application has at least the following beneficial effects:

[0024] (1) The present application provides a method for extracting lithium from electrolytic aluminum solid waste, which uses an additive acid leaching process to achieve a lithium leaching rate of 95% or more, and an additive regeneration process to achieve a recovery rate of 90% or more of the additive;

[0025] (2) The present application provides a method for extracting lithium from electrolytic aluminum solid waste, which reduces the amount of leaching additive, reduces the amount of acid leaching agent, purifies the lithium solution, and has good industrial application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The flowchart of the method for extracting lithium from electrolytic aluminum solid waste is provided in the detailed description of the present application.

[0027] The present application will be further described in detail below. However, the following examples are only simple examples of the present application and do not represent or limit the scope of protection of the present application, which is defined by the claims. DETAILED DESCRIPTION

[0028] The technical scheme of the present application will be further described below through specific embodiments.

[0029] One of the purposes of the present application is to provide a method for extracting lithium from electrolytic aluminum solid waste, the method comprising the following steps:

[0030] (1) mixing electrolytic aluminum solid waste with additives and water to form a slurry;

[0031] (2) adding acid to the slurry of step (1) to leach, and then separating the liquid and solid to obtain a leaching solution and a leaching residue;

[0032] (3) adding alkali to the leaching solution of step (2) to regenerate, and then separating the liquid and solid to obtain a lithium-containing regenerated solution and a regenerated additive, wherein the regenerated additive is reused in step (1).

[0033] In the present application, electrolytic aluminum solid waste is mixed with additives, regenerated additives and water to form a slurry, and under the action of weakly acidic leaching environment and active components of the additives, lithium-containing minerals in the electrolytic aluminum solid waste are decomposed and converted into lithium salts that are easily soluble in water and acid, and then liquid-solid separation is performed to obtain a lithium-containing leaching solution and a leaching residue; the lithium-containing leaching solution is adjusted by adding alkali to control the reaction and regeneration, and then liquid-solid separation is performed to obtain a neutralized lithium-containing solution and a regenerated additive containing active components of the additives, and the regenerated additive is reused in the leaching process to realize the regeneration and recycling of the leaching additive. The method has high lithium extraction rate, mild leaching conditions, recyclable leaching additives, clean and pollution-free process, and has broad application prospects.

[0034] In one specific embodiment of the present application, the additives include regenerated additives of step (3) and supplementary additives. The molar ratio of lithium elements in the electrolytic aluminum solid waste to alkaline earth metal elements in the additives in step (1) is controlled by adding the supplementary additives.

[0035] In the present application, the supplementary additives are a supplement of the regenerated additives, and there is no specific ratio between the two. The addition of the supplementary additives ensures that the molar ratio of lithium elements in the electrolytic aluminum solid waste to alkaline earth metal elements in the additives is within the scope of the present application. However, if the amount of regenerated additives produced in continuous production itself can meet the requirements of the present application, the supplementary additives can not be added. On the contrary, if there is no regenerated additive at the beginning of production, only the supplementary additives need to be added.

[0036] In one embodiment of the present application, the additive in step (1) can contain oxides, such as magnesium oxide, calcium oxide, strontium oxide, barium oxide, calcium peroxide, barium peroxide, etc., can contain hydroxides, such as magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, etc., can contain halides, such as magnesium chloride, strontium chloride, calcium chloride, calcium fluoride, barium bromide, magnesium iodide, etc., can contain halogen element-containing oxyacid salts, such as calcium hypochlorite, barium perchlorate, magnesium bromate, calcium iodate, etc., can contain boron element-containing oxyacid salts, such as barium metaborate, calcium perborate, magnesium aluminate, calcium aluminate, magnesium gallate, etc., can contain carbon element-containing oxyacid salts, such as magnesium carbonate, calcium bicarbonate, calcium carbonate, barium silicate, magnesium silicate, calcium germanate, barium stannate, etc., can contain nitrogen element-containing oxyacid salts, such as magnesium nitrate, calcium nitrate, barium nitrate, calcium nitrite, magnesium phosphate, calcium phosphate, strontium phosphate, barium phosphate, ammonium magnesium phosphate, calcium hydrogen phosphate, calcium hypophosphite, strontium arsenate, magnesium arsenate, calcium antimonate, barium bismuthate, etc., can contain oxygen element-containing oxyacid salts, such as magnesium sulfate, calcium sulfate, strontium sulfate, barium sulfate, magnesium bisulfate, calcium bisulfate, calcium sulfite, calcium hydrosulfite, magnesium ammonium sulfate, magnesium thiosulfate, calcium selenate, magnesium selenite, strontium tellurite, etc., can contain transition element-containing oxyacid salts, such as magnesium vanadate, calcium vanadate, calcium chromate, calcium chromite, barium chromate, strontium molybdate, magnesium zirconate, calcium perrhenate, magnesium permanganate, calcium ferrite, etc. The compound containing alkaline earth metal is preferably a common acid salt containing alkaline earth metal, such as magnesium chloride, calcium chloride, strontium chloride, barium chloride, magnesium sulfate, magnesium bisulfate, calcium sulfate, strontium sulfate, barium sulfate, magnesium nitrate, calcium nitrate, strontium nitrate, calcium nitrate, magnesium phosphate, calcium phosphate, calcium hydrogen phosphate, strontium phosphate, barium phosphate, etc.

[0037] In one embodiment of the present application, the solid-liquid ratio in the slurry in step (1) is 1:(0.25-10), such as 1:0.25, 1:0.3, 1:0.5, 1:0.75, 1:1, 1:1.5, 1:2, 1:2.15, 1:2.5, 1:2.97, 1:3, 1:3.5, 1:4, 1:4.12, 1:4.5, 1:4.75, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, etc., but is not limited to the listed values, and other values not listed in the range are also applicable, preferably 1:(0.5-5), more preferably 1:(0.5-3).

[0038] In one embodiment of the present application, the slurry temperature in step (1) is 20-100℃, such as 20℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃, etc., but is not limited to the listed values, and other values not listed in the range are also applicable.

[0039] In one embodiment of the present application, the acidic substance added in step (2) can be an inorganic substance with an aqueous solution being acidic and capable of adjusting the pH required in the present application, such as aluminum sulfate, ferric nitrate, calcium chloride, and mixtures of strong acid weak base salts and strong acids such as sodium bisulfate, permanganic acid, hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, selenic acid, hydrobromic acid, hydroiodic acid, chloric acid, and other common acidic substances. Preferably, any one or a combination of at least two of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, such as a combination of hydrochloric acid and sulfuric acid, a combination of sulfuric acid and nitric acid, a combination of hydrochloric acid, sulfuric acid, and nitric acid, a combination of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and the like.

[0040] In the present application, hydrogen ions and alkaline earth metal ions with active components in the mixed slurry react with components such as LiF, NaLi2AlF6, Na2LiAlF6, Li3AlF6, and the like in lithium-containing minerals. Since the stability of lithium-containing minerals such as NaLi2AlF6, Na2LiAlF6, Li3AlF6, and the like is weaker than that of Na3AlF6 under these conditions, decomposition reactions of lithium-containing minerals to generate LiF occur preferentially. The fluorides of alkaline earth metals are more stable than LiF, so LiF further reacts with alkaline earth metal ions, lithium is dissolved into the solution by displacement, and the leaching process is strengthened.

[0041] In the present application, the supplemental additive is a compound containing alkaline earth metals, the regenerated additive is a compound containing active alkaline earth metals after regeneration, and the electrolytic aluminum solid waste also contains part of the alkaline earth metal compounds that can be used to promote leaching reactions. The leaching reaction is adjusted by adding acid and controlling the pH of the slurry formed by the electrolytic aluminum solid waste, the supplemental additive, the regenerated additive, and water within a suitable pH range. The purpose is to promote the reaction activity of the components of the supplemental additive, the regenerated additive, and part of the alkaline earth metal compounds in the electrolytic aluminum solid waste that can be used to promote leaching reactions. The components that promote leaching reactions in the present application are, in order, the regenerated additive, the supplemental additive, and part of the alkaline earth metal compounds in the electrolytic aluminum solid waste.

[0042] In the present application, the reason for adjusting and controlling the pH during the leaching process also includes the fact that the electrolytic aluminum solid waste contains acid-consuming substances and the alkaline earth metal fluorides generated by the leaching reaction need to be redissolved for recovery, and the system needs to be kept stable within a certain pH range. The leaching process involves the decomposition of lithium-containing minerals by hydrogen ions and active alkaline earth metal ions to generate lithium fluoride, which continues to react with active alkaline earth metal ions to generate soluble lithium salts and alkaline earth metal fluorides. Alkaline earth metal fluorides are continuously generated as lithium is leached, and are continuously dissolved as the pH is adjusted and controlled until the lithium dissolution is close to complete and the reaction tends to end. The leaching process in the present application is a complex process involving the dissolution, precipitation, and redissolution of multiple components.

[0043] In one embodiment of the present application, the step (3) is to adjust and control the pH of the leaching solution to the end of the regeneration reaction.

[0044] In one embodiment of the present application, the basic substance added in step (3) is a basic inorganic substance, preferably any one or a combination of at least two of lithium hydroxide, lithium carbonate, lithium bicarbonate, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, ammonia, ammonium carbonate, ammonium bicarbonate, calcium oxide, calcium hydroxide, and calcium carbonate, typical but non-limiting examples of the combination include: a combination of sodium hydroxide and potassium hydroxide, a combination of lithium carbonate, sodium carbonate, potassium bicarbonate, and calcium oxide, a combination of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, and potassium bicarbonate, a combination of lithium carbonate, lithium bicarbonate, sodium hydroxide, sodium carbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, and calcium hydroxide, a combination of lithium bicarbonate, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, ammonia, ammonium carbonate, and ammonium bicarbonate, a combination of lithium hydroxide, lithium carbonate, lithium bicarbonate, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, ammonia, ammonium carbonate, ammonium bicarbonate, calcium hydroxide, and calcium carbonate, and more preferably any one or a combination of at least two of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, and potassium bicarbonate.

[0045] In one embodiment of the present application, the basic inorganic substance refers to an inorganic substance with an alkaline aqueous solution and capable of adjusting the pH required by the present application, such as sodium sulfide, calcium bicarbonate, potassium carbonate, and other strong base weak acid salts, and a mixture of sodium hydroxide and potassium hydroxide, such as cesium hydroxide, copper hydroxide, manganese hydroxide, magnesium hydroxide, and other common basic substances.

[0046] In the present application, the regeneration additive generated by the regeneration reaction needs to be returned to step (1) for the leaching of aluminum solid waste lithium, and at the same time, the regeneration reaction also needs to reduce the loss of lithium and reduce the content of impurities such as fluorine in order to improve the subsequent lithium carbonate precipitation efficiency and product purity. Therefore, the present application regulates the regeneration reaction process through the synergistic effect of the pH of the regeneration reaction, the temperature of the regeneration reaction, and the time of the regeneration reaction. After the regulation of the regeneration reaction, the alkaline earth metal generates active hydroxide which is easy to be acid-soluble, and only a small amount exists in the form of fluoride; at the same time, the alkali metal ions introduced by the alkaline regeneration and the fluorine ions and aluminum ions dissolved in the leaching solution are controlled to re-synthesize cryolite, and not to generate aluminum hydroxide, thereby reducing the loss of lithium and reducing the content of fluorine impurities in the regeneration solution. Through the regeneration reaction, the leaching and dissolution of the cryolite is co-precipitated from the regeneration additive, and finally recovered from the leaching residue. Through the regeneration reaction, the alkaline earth metal and impurities such as fluorine and aluminum in the regeneration solution are purified, and the regeneration solution can be used to produce high-purity lithium carbonate products. The regeneration reaction of the present application occurs through synergistic effect, multiple complex reactions occur simultaneously, and multiple technical effects are unexpectedly achieved.

[0047] In one embodiment of the present application, the electrolytic aluminum solid waste in step (1) comprises one or a combination of at least two of the following: aluminum electrolyte, overhaul slag, and carbon slag. Typical, but non-limiting examples of the combination include: a combination of aluminum electrolyte and overhaul slag, a combination of overhaul slag and carbon slag, a combination of aluminum electrolyte and carbon slag, a combination of aluminum electrolyte, overhaul slag, and carbon slag, and the like.

[0048] In one embodiment of the present application, the electrolytic aluminum solid waste is crushed and ground into a fine powder before mixing and slurrying in step (1). The particle size of the electrolytic aluminum solid waste powder is not greater than 150 μm, such as 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 140 μm, or 150 μm, and the like, but is not limited to the listed values. Other values not listed within this range are also applicable.

[0049] In one embodiment of the present application, when the electrolytic aluminum solid waste contains overhaul slag and / or carbon slag raw materials, a chemical oxidizing cyanide-breaking agent is added during the regeneration reaction process in step (3). The cyanide-breaking agent is one or a combination of at least two of the following: peroxide, hypochlorous acid and its salts, perchloric acid and its salts, persulfuric acid and its salts, oxygen, ozone, and chlorine. Typical, but non-limiting examples of the combination include: a combination of peroxide and ozone, a combination of hypochlorous acid and its salts and persulfuric acid and its salts, a combination of hypochlorous acid and its salts, perchloric acid and its salts, and persulfuric acid and its salts, a combination of peroxide, perchloric acid and its salts, persulfuric acid and its salts, and chlorine, a combination of hypochlorous acid and its salts, perchloric acid and its salts, persulfuric acid and its salts, oxygen, and ozone, a combination of hypochlorous acid and its salts, perchloric acid and its salts, persulfuric acid and its salts, oxygen, ozone, and chlorine, a combination of peroxide, hypochlorous acid and its salts, perchloric acid and its salts, persulfuric acid and its salts, oxygen, ozone, and chlorine, and the like.

[0050] In the present application, when the electrolytic aluminum solid waste contains overhaul slag and / or carbon slag raw materials, the addition of a chemical oxidizing cyanide-breaking agent during the regeneration reaction process can effectively decompose cyanide in the leaching solution. The cyanide-breaking agent can be peroxide, such as sodium peroxide, potassium peroxide, calcium peroxide, and the like. The cyanide-breaking agent can be hypochlorous acid and its salts, such as hypochlorous acid, sodium hypochlorite, calcium hypochlorite, potassium hypochlorite, and the like. The cyanide-breaking agent can be perchloric acid and its salts, such as perchloric acid, sodium perchlorate, potassium perchlorate, and the like. The cyanide-breaking agent can be persulfuric acid and its salts, such as persulfuric acid, sodium persulfate, ammonium persulfate, and the like. The cyanide-breaking agent can be oxygen, ozone, and chlorine.

[0051] In one embodiment of the present application, the method for extracting lithium from electrolytic aluminum solid waste comprises the following steps:

[0052] (1) the electrolytic aluminum solid waste with a particle size of not more than 150 μm after crushing and grinding and a lithium content of 0.3% or more is mixed with an additive containing an alkaline earth metal compound and water to form a slurry, the mixing and slurrying solid-liquid mass ratio is 1: (0.25-10), the mixing and slurrying temperature is 20-100 ℃, and the electrolytic aluminum solid waste comprises one or a combination of at least two of aluminum electrolyte, overhaul slag and carbon slag;

[0053] (2) an acidic inorganic substance is added to the slurry of step (1) to adjust and control the slurry pH to 0.1-3, and leaching is carried out at 20-120 ℃ for 0.5-6 h until the leaching reaction is completed, liquid-solid separation is carried out, and a leaching solution and a leaching residue are obtained;

[0054] (3) an alkaline inorganic substance is added to the leaching solution of step (2) to adjust and control the slurry pH to 4-14, and regeneration is carried out at 50-120 ℃ for 0.05-1 h until the regeneration reaction is completed, liquid-solid separation is carried out, a regeneration solution and a regeneration additive are obtained, and the obtained regeneration additive is used in step (1).

[0055] In order to better illustrate the present application and facilitate the understanding of the technical solutions of the present application, the typical but non-limiting embodiments of the present application are as follows:

[0056] Embodiment 1:

[0057] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, and the electrolytic aluminum solid waste is aluminum electrolyte, and the main components and contents thereof are as follows: Li 2.14wt%, Al 24.08wt%, F 27.29wt%, Na 12.53wt%, K 1.62wt%, Ca 2.84wt%, Mg 0.24wt%, Si 0.16wt%, and C 0.12wt%;

[0058] The process flow chart of the method is shown in Figure 1 , and comprises the following steps:

[0059] (1) the electrolytic aluminum solid waste with a particle size of not more than 150 μm after crushing and grinding and a lithium content of 0.3% or more is mixed with an additive containing an alkaline earth metal compound and water to form a slurry, the mixing and slurrying solid-liquid mass ratio is 1: (0.25-10), the mixing and slurrying temperature is 20-100 ℃, and the electrolytic aluminum solid waste comprises one or a combination of at least two of aluminum electrolyte, overhaul slag and carbon slag;

[0060] (2) an acidic inorganic substance is added to the slurry of step (1) to adjust and control the slurry pH to 0.1-3, and leaching is carried out at 20-120 ℃ for 0.5-6 h until the leaching reaction is completed, liquid-solid separation is carried out, and a leaching solution and a leaching residue are obtained;

[0061] (3) To the leaching solution of step (2), cesium hydroxide, sodium sulfide and copper hydroxide are added to adjust and control the slurry pH = 14, and the regeneration is carried out at 120°C for 0.5h to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is recycled to step (1).

[0062] Example 2:

[0063] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, which is an aluminum electrolyte, and the main components and contents thereof are the same as those of Example 1.

[0064] The method comprises the following steps:

[0065] (1) The electrolytic aluminum solid waste control lithium element and alkali earth metal with a mole ratio of 1:20 after crushing and grinding to a particle size of not more than 108μm is mixed with magnesium sulfate, ammonium magnesium sulfate, barium nitrate, regeneration additive and water, and the slurry is formed by slurrying according to a solid-liquid mass ratio of 1:5 and a temperature of 30°C;

[0066] (2) High manganese acid, ferric nitrate and selenium acid are added to the slurry of step (1) to adjust and control the slurry pH = 2, and leaching is carried out at 20°C for 5h to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0067] (3) Cesium hydroxide, sodium sulfide and copper hydroxide are added to the leaching solution of step (2) to adjust and control the slurry pH = 14, and the regeneration is carried out at 120°C for 0.5h to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is recycled to step (1).

[0068] Example 3:

[0069] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, which is an aluminum electrolyte, and the main components and contents thereof are the same as those of Example 1.

[0070] The method comprises the following steps:

[0071] (1) The electrolytic aluminum solid waste control lithium element and alkali earth metal with a mole ratio of 1:0.5 after crushing and grinding to a particle size of not more than 74μm is mixed with calcium chloride, regeneration additive and water, and the slurry is formed by slurrying according to a solid-liquid mass ratio of 1:0.5 and a temperature of 70°C;

[0072] (2) Nitric acid is added to the slurry of step (1) to adjust and control the slurry pH = 2.5, and leaching is carried out at 95°C for 3h to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0073] (3) Add ammonia and calcium carbonate to the immersion solution in step (2) to adjust and control the pH of the slurry to 10. Regenerate at 50°C for 0.1 h until the regeneration reaction is complete. Separate the liquid and solid to obtain the regenerated liquid and the regenerated additive. The regenerated additive is reused in step (1).

[0074] Example 4:

[0075] This embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, wherein the electrolytic aluminum solid waste is overhaul slag, and its main components and contents are: Li 0.89wt%, Al 15.29wt%, F 9.82wt%, Na 11.18wt%, K 0.99wt%, Ca 4.19wt%, Mg 0.31wt%, Si 8.03wt%, and C 0.82wt%.

[0076] The method includes the following steps:

[0077] (1) The electrolytic aluminum solid waste with a particle size of no more than 74μm after crushing and grinding is mixed with magnesium sulfate, strontium nitrate, barium chloride, regeneration additives and water in a controlled lithium element and alkaline earth metal molar ratio of 1:0.2, and slurryed at a solid-liquid mass ratio of 1:0.25 and a temperature of 55℃ to form a slurry.

[0078] (2) Add hydrochloric acid to the slurry in step (1) to adjust and control the pH of the slurry to 0.1. Leach at 90℃ for 2 hours until the leaching reaction is completed. Separate the liquid and solid to obtain the leaching liquid and leaching residue.

[0079] (3) Add ammonia, calcium carbonate and hypochlorous acid to the soaking solution in step (2) to adjust and control the pH of the slurry to 4. Regenerate at 120°C for 0.15 h until the regeneration reaction is complete. Separate the liquid and solid to obtain the regenerated liquid and regeneration additive. The regeneration additive is reused in step (1).

[0080] Example 5:

[0081] This embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, wherein the electrolytic aluminum solid waste is overhaul slag, and its main components and contents are the same as those in Example 4.

[0082] The method includes the following steps:

[0083] (1) The electrolytic aluminum solid waste with a particle size of no more than 50 μm after crushing and grinding is mixed with calcium oxide, calcium peroxide, magnesium silicate, strontium phosphate, magnesium thiosulfate, strontium molybdate, barium perchlorate, strontium fluoride, calcium nitrite, calcium sulfite, calcium chromite, regeneration additives and water, and slurry is formed at a solid-liquid mass ratio of 1:1 and a temperature of 65℃.

[0084] (2) To the slurry of step (1), sulfuric acid, nitric acid, hydrochloric acid and phosphoric acid are added to adjust and control the pH of the slurry to 3, and leaching is carried out at 60°C for 4h to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0085] (3) To the leaching solution of step (2), lithium hydroxide, lithium bicarbonate, lithium carbonate, sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonia water and ozone are added to adjust and control the pH of the slurry to 12, and regeneration is carried out at 70°C for 0.2h to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is recycled to step (1).

[0086] Example 6:

[0087] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, which is a major repair residue, and the main components and contents thereof are the same as those of Example 4.

[0088] The method comprises the following steps:

[0089] (1) The electrolytic aluminum solid waste with a particle size of not more than 100μm after crushing and grinding is mixed with calcium nitrate, a regeneration additive and water, and the molar ratio of lithium element to alkaline earth metal is controlled to be 1:0.1, and then slurry is formed by slurry formation according to a solid-liquid mass ratio of 1:2 and a temperature of 35°C;

[0090] (2) To the slurry of step (1), nitric acid is added to adjust and control the pH of the slurry to 0.5, and leaching is carried out at 100°C for 0.5h to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0091] (3) To the leaching solution of step (2), sodium hydroxide and sodium peroxide, potassium perchlorate and ammonium persulfate are added to adjust and control the pH of the slurry to 8, and regeneration is carried out at 100°C for 0.05h to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is recycled to step (1).

[0092] Example 7:

[0093] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, which is a major repair residue, and the main components and contents thereof are the same as those of Example 4.

[0094] The method comprises the following steps:

[0095] (1) The electrolytic aluminum solid waste with particle size not greater than 74 μm after crushing and grinding is mixed with magnesium sulfate, regeneration additives and water, with the molar ratio of lithium element to alkali earth metal controlled at 1:0.25, and slurry is formed by slurrying at a solid-liquid mass ratio of 1:1.5 and a temperature of 60°C;

[0096] (2) Sulfuric acid is added to the slurry in step (1) to adjust and control the pH of the slurry to 1.5, and leaching is carried out at 80°C for 2 hours to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0097] (3) Ammonia water, ammonium bicarbonate and calcium peroxide are added to the leaching solution in step (2) to adjust and control the pH of the slurry to 7, and regeneration is carried out at 80°C for 1 hour to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is recycled to step (1).

[0098] Example 8:

[0099] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, which is carbon residue, and the main components and contents thereof are the same as those in Example 7.

[0100] The method comprises the following steps:

[0101] (1) The electrolytic aluminum solid waste with particle size not greater than 108 μm after crushing and grinding is mixed with calcium hydrogen phosphate, regeneration additives and water, with the molar ratio of lithium element to alkali earth metal controlled at 1:2, and slurry is formed by slurrying at a solid-liquid mass ratio of 1:2.5 and a temperature of 40°C;

[0102] (2) Phosphoric acid is added to the slurry in step (1) to adjust and control the pH of the slurry to 0.6, and leaching is carried out at 40°C for 1.5 hours to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0103] (3) Potassium bicarbonate and persulfate, potassium peroxide and oxygen are added to the leaching solution in step (2) to adjust and control the pH of the slurry to 7.5, and regeneration is carried out at 75°C for 0.6 hours to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is recycled to step (1).

[0104] Example 9:

[0105] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, which is carbon residue, and the main components and contents thereof are the same as those in Example 7.

[0106] The method comprises the following steps:

[0107] (1) The electrolytic aluminum solid waste with particle size not greater than 74 μm after crushing and grinding is mixed with calcium peroxymonosulfate, magnesium chloride, strontium sulfate, calcium peroxide, barium hydroxide, regeneration additive and water, with the molar ratio of lithium element to alkaline earth metal being 1:1.2, and slurry is formed by slurrying according to the solid-liquid mass ratio of 1:10 and at a temperature of 45℃;

[0108] (2) High perchloric acid, permanganic acid, selenic acid, hydrobromic acid and hydriodic acid are added to the slurry of step (1) to adjust and control the pH of the slurry to 1.8, and leaching is carried out at 60℃ for 3h to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0109] (3) Ammonia water, ammonium bicarbonate and sodium hypochlorite are added to the leaching solution of step (2) to adjust and control the pH of the slurry to 9, and regeneration is carried out at 95℃ for 0.5h to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is used in step (1).

[0110] Example 10:

[0111] The present embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, which is electrolyte, overhaul residue and carbon residue, and the main components and contents thereof are as follows: Li 1.35wt%, Al 18.52wt%, F 19.35wt%, Na 9.29wt%, K 1.39wt%, Ca 3.78wt%, Mg 0.19wt%, Si 5.38wt%, and C 6.43wt%.

[0112] The method comprises the following steps:

[0113] (1) The electrolytic aluminum solid waste with particle size not greater than 120 μm after crushing and grinding is mixed with strontium chloride, calcium phosphate, regeneration additive and water, with the molar ratio of lithium element to alkaline earth metal being 1:0.7, and slurry is formed by slurrying according to the solid-liquid mass ratio of 1:1 and at a temperature of 80℃;

[0114] (2) High perchloric acid, permanganic acid, selenic acid, hydrobromic acid and hydriodic acid are added to the slurry of step (1) to adjust and control the pH of the slurry to 1.6, and leaching is carried out at 85℃ for 2h to the end of the leaching reaction, and then liquid-solid separation is performed to obtain a leaching solution and a leaching residue;

[0115] (3) Calcium oxide, sodium bicarbonate and chlorine gas are added to the leaching solution of step (2) to adjust and control the pH of the slurry to 6.5, and regeneration is carried out at 60℃ for 0.3h to the end of the regeneration reaction, and then liquid-solid separation is performed to obtain a regeneration solution and a regeneration additive, which is used in step (1).

[0116] Example 11:

[0117] The embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, the electrolytic aluminum solid waste being electrolyte, overhaul slag and carbon slag, main components and contents being the same as those in embodiment 10.

[0118] The method comprises the following steps:

[0119] (1) the electrolytic aluminum solid waste with a particle size of not more than 140 mu m after crushing and grinding is mixed with magnesium carbonate, magnesium nitrate, a regenerated additive and water, the molar ratio of lithium element to alkaline earth metal is 1:0.9, and the solid-liquid mass ratio is 1:1.5, and the temperature is 50 DEG C, so that a slurry is formed by slurryizing;

[0120] (2) hydrochloric acid is added to the slurry in step (1) to adjust and control the pH of the slurry to 0.7, and the leaching reaction is carried out at 55 DEG C for 4 hours until the leaching reaction is completed, then liquid-solid separation is carried out, and a leaching solution and a leaching residue are obtained;

[0121] (3) sodium bicarbonate and calcium hypochlorite are added to the leaching solution in step (2) to adjust and control the pH of the slurry to 8.5, and the regeneration reaction is carried out at 90 DEG C for 0.15 hours until the regeneration reaction is completed, then liquid-solid separation is carried out, and a regeneration solution and a regeneration additive are obtained, and the regeneration additive is used in step (1).

[0122] Embodiment 12:

[0123] The embodiment provides a method for extracting lithium from electrolytic aluminum solid waste, the electrolytic aluminum solid waste being electrolyte, overhaul slag and carbon slag, main components and contents being the same as those in embodiment 10.

[0124] The method comprises the following steps:

[0125] (1) the electrolytic aluminum solid waste with a particle size of not more than 110 mu m after crushing and grinding is mixed with calcium nitrate, a regenerated additive and water, the molar ratio of lithium element to alkaline earth metal is 1:0.4, and the solid-liquid mass ratio is 1:2, and the temperature is 70 DEG C, so that a slurry is formed by slurryizing;

[0126] (2) hydrochloric acid is added to the slurry in step (1) to adjust and control the pH of the slurry to 0.95, and the leaching reaction is carried out at 60 DEG C for 3 hours until the leaching reaction is completed, then liquid-solid separation is carried out, and a leaching solution and a leaching residue are obtained;

[0127] (3) ammonium bicarbonate and potassium peroxide are added to the leaching solution in step (2) to adjust and control the pH of the slurry to 6, and the regeneration reaction is carried out at 100 DEG C for 0.2 hours until the regeneration reaction is completed, then liquid-solid separation is carried out, and a regeneration solution and a regeneration additive are obtained, and the regeneration additive is used in step (1).

[0128] Comparative example 1:

[0129] The comparative example provides a method for extracting lithium from electrolytic aluminum solid waste, the raw material and the method refer to embodiment 1, and the difference is that the pH of the slurry is adjusted and controlled to 3 in step (3).

[0130] The comparative example does not obtain a regeneration additive.

[0131] Comparative Example 2:

[0132] The comparative example provides a method for extracting lithium from electrolytic aluminum solid waste, the raw material and method refer to Example 1, the difference is only that the slurry alkali concentration is adjusted and controlled to 10 mol / L in step (3).

[0133] The comparative example is analyzed and detected to obtain part of the regeneration additive, but the additive has no activity, generates a large amount of fluoride, and the aluminum, fluoride and other impurities cannot regenerate cryolite, which easily reduces the purity of the subsequent lithium carbonate product.

[0134] Comparative Example 3:

[0135] The comparative example provides a method for extracting lithium from electrolytic aluminum solid waste, the raw material and method refer to Example 4, the difference is only that the regeneration temperature is 40°C in step (3).

[0136] The comparative example is analyzed and detected to obtain part of the regeneration additive, but the additive has no activity, generates a large amount of fluoride, and the aluminum, fluoride and other impurities cannot regenerate cryolite, which easily reduces the purity of the subsequent lithium carbonate product.

[0137] Comparative Example 4:

[0138] The comparative example provides a method for extracting lithium from electrolytic aluminum solid waste, the raw material and method refer to Example 4, the difference is only that the regeneration temperature is 130°C in step (3).

[0139] The comparative example is analyzed and detected to obtain part of the regeneration additive, but the additive has no activity, generates a large amount of fluoride, and the aluminum, fluoride and other impurities cannot regenerate cryolite, which easily reduces the purity of the subsequent lithium carbonate product.

[0140] Comparative Example 5:

[0141] The comparative example provides a method for extracting lithium from electrolytic aluminum solid waste, the raw material and method refer to Example 7, the difference is only that the regeneration time is 0.01 h in step (3).

[0142] The comparative example is analyzed and detected to obtain a small amount of regeneration additive, and the aluminum, fluoride and other impurities cannot regenerate cryolite, which easily reduces the purity of the subsequent lithium carbonate product.

[0143] Comparative Example 6:

[0144] The comparative example provides a method for extracting lithium from electrolytic aluminum solid waste, the raw material and method refer to Example 7, the difference is only that the regeneration time is 1.2 h in step (3).

[0145] The comparative example is analyzed and detected to obtain part of the regenerated additive, but the activity of the additive is low, and the impurities such as aluminum and fluorine in the part of the regenerated cryolite can easily reduce the purity of the subsequent lithium carbonate product.

[0146] Comparative example 7:

[0147] The comparative example provides a method for extracting lithium from electrolytic aluminum solid waste, and the raw material and method refer to example 12, and the difference is only that step (1) does not add calcium nitrate and a regeneration additive.

[0148] The comparative example is analyzed and detected to obtain part of the regenerated additive, but the activity of the additive is low, and the impurities such as aluminum and fluorine in the part of the regenerated cryolite can easily reduce the purity of the subsequent lithium carbonate product.

[0149] The lithium content and alkaline earth metal content in the lithium-containing leaching solution, leaching residue, regenerated solution and regenerated residue in examples 1-12 and comparative examples 1-7 are measured, and electron microscopy and phase analysis are performed, and the leaching rate of lithium and the regeneration recovery rate of active additive are calculated. The test results are shown in Table 1.

[0150] Table 1

[0151]

[0152]

[0153] From the above examples and comparative examples, it can be seen that the method of the present application uses acid leaching technology, and by adding alkaline earth metal-based additives, the leaching rate of lithium is improved. The leaching rate of the leaching additive is regulated by the synergistic effect of pH, temperature and time, so that the leaching rate can reach more than 95%, and the regeneration recovery rate of the additive can also reach more than 90%. The method of the present application is simple to operate, environmentally friendly, and the leaching additive can be regenerated and recycled, reducing the amount of leaching agent acid and the cost of lithium extraction. It has good industrial application prospect.

[0154] The applicant declares that the above examples illustrate the detailed structural features of the present application, but the present application is not limited to the above detailed structural features, i.e. it does not mean that the present application must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present application, equivalent replacement of the components selected by the present application, addition of auxiliary components, selection of specific methods, etc. fall within the scope of protection and disclosure of the present application.

[0155] The above detailed the preferred embodiments of the present application, but the present application is not limited to the specific details in the above embodiments, and within the technical concept of the present application, the technical solutions of the present application can be modified in many ways. These simple modifications all belong to the protection scope of the present application.

[0156] It should be further noted that each of the various technical features described in the above embodiments can be combined with any other technical features in any suitable manner, and the present application shall be deemed to disclose all possible combinations thereof, without causing unnecessary repetition.

[0157] Furthermore, any combination of the various embodiments of the present application can be made, as long as it does not deviate from the spirit of the present application, and it shall be deemed to be disclosed by the present application.

Claims

1. A method of extracting lithium from electrolytic aluminum solid waste, characterized by, The method comprises the following steps: (1) mixing and slurrying electrolytic aluminum solid waste with an additive and water to form a slurry; (2) adding acid leaching to the slurry in step (1), liquid-solid separation to obtain leaching liquid and leaching residue; (3) adding alkali to regenerate the leaching liquid in step (2), liquid-solid separation to obtain lithium-containing regenerated liquid and regenerated additive, and the regenerated additive is recycled to step (1); The additive in step (1) is an alkaline earth metal compound; The alkaline earth metal elements in the alkaline earth metal compound include any one or a combination of at least two of Mg, Ca, Sr or Ba; The alkaline earth metal compound includes any one or a combination of at least two of hydroxides, halides, halogen element-containing oxoacid salts, boron element-containing oxoacid salts, carbon element-containing oxoacid salts, nitrogen element-containing oxoacid salts, oxygen element-containing oxoacid salts and transition element-containing oxoacid salts of the alkaline earth metal; Hydrogen ions and alkaline earth metal ions with active components in the mixed slurry react with lithium-containing minerals, the lithium-containing minerals are decomposed to generate LiF, the fluoride of the alkaline earth metal has stronger stability than LiF, therefore LiF further reacts with the alkaline earth metal ions, and lithium is dissolved into the solution by displacement; The temperature of the alkali regeneration in step (3) is 50-120℃, and the time is 0.05-1h; The pH value of the alkali regeneration in step (3) is 4-14.

2. The method of extracting lithium from electrolytic aluminum solid waste according to claim 1, characterized by, The molar ratio of lithium elements in the electrolytic aluminum solid waste to the alkaline earth metal elements in the alkaline earth metal compound is 1:(0.1-20).

3. The method of extracting lithium from electrolytic aluminum solid waste according to claim 1, characterized by, The pH value of the acid leaching in step (2) is 0.1-3.

4. The method of extracting lithium from electrolytic aluminum solid waste according to claim 1, characterized by, The temperature of the acid leaching in step (2) is 20-120℃, and the time is 0.5-6h.

5. The method of extracting lithium from electrolytic aluminum solid waste according to claim 1, characterized by, The lithium content in the electrolytic aluminum solid waste is ≥0.3 wt%.

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