CN117604272A

CN117604272A - Process for extracting lithium from low-grade spodumene raw ore

Info

Publication number: CN117604272A
Application number: CN202311544293.5A
Authority: CN
Inventors: 闻广学; 佘勇; 付海; 李玉静; 曹宗林; 关云浩; 杨兵; 张军; 李强; 张亮
Original assignee: Tangshan Xinfeng Lithium Industry Co ltd
Current assignee: Tangshan Xinfeng Lithium Industry Co ltd
Priority date: 2023-11-18
Filing date: 2023-11-18
Publication date: 2024-02-27
Anticipated expiration: 2043-11-18
Also published as: CN117604272B

Abstract

The application relates to the field of spodumene extraction of lithium, and particularly discloses a process for extracting lithium from low-grade spodumene raw ores, which comprises the following steps: grinding spodumene and alkali liquor under ultrasonic conditions to obtain slurry, wherein the spodumene is ground to a particle size of below 100 mu m; reacting the slurry with sodium metaaluminate solution at 240-310 ℃ for 2-5h, adding water for leaching for multiple times to obtain leaching liquid and leaching residue; adding ethanol and ammonia water into the leaching residue for heating reflux reaction, evaporating the ethanol, and filtering to obtain a reaction solution; mixing the leaching solution and the reaction solution, evaporating and concentrating to obtain a purified solution, introducing carbon dioxide gas into the purified solution, and heating to separate out lithium carbonate precipitate. The process for extracting lithium from spodumene not only can effectively reduce the pollution to the environment, but also has high additional value of byproducts and obviously reduced industrial energy consumption, and can also improve the leaching rate of lithium and the purity of products at the same time, thereby having good economic benefit.

Description

Process for extracting lithium from low-grade spodumene raw ore

Technical Field

The application relates to the field of spodumene extraction, in particular to a process for extracting lithium from low-grade spodumene raw ores.

Background

Lithium is a very versatile metallic material and is also a very important strategic resource. The method has important application in the traditional industrial fields of metallurgy, medicine, chemical industry and the like, and also in the fields of aviation, new energy, military industry and the like. In recent years, with the continuous expansion of the industrial scale of new energy, the demand of lithium batteries is continuously increased, the consumption of lithium is in explosive growth worldwide, the development of lithium mineral resources is rapidly developed, spodumene is one of important mineral resources for extracting lithium, and a great amount of research work is carried out on the spodumene lithium extraction process.

At present, most of large-scale production enterprises adopt a sulfuric acid method for extracting lithium, and the route for extracting lithium by a sulfuric acid method process is as follows: the method comprises the steps of firstly roasting alpha-spodumene at high temperature to convert the alpha-spodumene into beta-spodumene with higher activity, then carrying out mixed reaction on the beta-spodumene and concentrated sulfuric acid, roasting at about 300 ℃, leaching water to obtain a lithium sulfate solution, adding lime powder and excessive sulfuric acid to remove impurities such as iron and aluminum, evaporating and concentrating to obtain a lithium sulfate purifying solution, and adding sodium carbonate to obtain lithium carbonate precipitate, so that the effect of extracting lithium is achieved. The process consumes a large amount of sulfuric acid, the leaching rate of lithium is only about 80%, sulfur-containing waste gas, calcium sulfate waste residue and the like generated in the reaction process have great environmental pollution, and the purity of the product is poor.

Disclosure of Invention

The process for extracting lithium from the low-grade spodumene raw ore can effectively reduce environmental pollution and improve the leaching rate of lithium and the purity of products.

The process for extracting lithium from the low-grade spodumene raw ore provided by the application adopts the following technical scheme:

a process for extracting lithium from low-grade spodumene raw ores comprises the following steps:

grinding spodumene and alkali liquor under ultrasonic conditions to obtain slurry, wherein the spodumene is ground to a particle size of below 100 mu m; reacting the slurry with sodium metaaluminate solution at 240-310 ℃ for 2-5h, adding water for leaching for multiple times to obtain leaching liquid and leaching residue; adding ethanol and ammonia water into the leaching residue for heating reflux reaction, evaporating the ethanol, and filtering to obtain a reaction solution;

mixing the leaching solution and the reaction solution, evaporating and concentrating to obtain a purified solution, introducing carbon dioxide gas into the purified solution, and heating to separate out lithium carbonate precipitate.

By adopting the technical scheme, the alkali liquor is added in the spodumene grinding process and is matched with the ultrasonic action, so that spodumene plays a certain modifying role in the grinding process, the ultrasonic wave can generate mechanical effect, thermal effect, cavitation effect and chemical effect in the propagation process, and the alkali liquor is matched with the mechanical grinding to play a good modifying role on the crystal structure and apparent performance of spodumene, so that the silicon-oxygen bond of spodumene is easier to break, the silicon ion is facilitated to be dissolved out, more aluminum ions are exposed on the surface, meanwhile, the active sites on the surface of spodumene can be increased, the surface morphology of spodumene can also play a certain shaping role, the corrosion phenomenon appears, the roughness of the surface is increased, and the subsequent extraction of lithium and the removal of impurities are further facilitated.

The slurry is reacted with the sodium metaaluminate solution, so that silicon and aluminum dissolved by alkali liquor in the solution are combined to form aluminosilicate, meanwhile, replacement of lithium and sodium is promoted, the leaching rate of lithium is improved, and the leached lithium exists in the leaching solution in the form of ions. The leaching residue is further treated by adopting ammonia water and ethanol for reflux reaction, the residual unleached lithium in the leaching residue can be further leached, impurities such as calcium, magnesium and iron are further removed in a precipitation form, and the leached lithium is reduced to be adsorbed and attached on the precipitation impurities, so that the purity of a product and the leaching rate of lithium are improved, the leaching solution and the reaction solution are evaporated and concentrated to obtain a purifying solution, the purity of the product can be further improved, and the purifying solution enriched with lithium ions is reacted in a carbon dioxide introducing form.

Preferably, the lye comprises sodium hydroxide solution and/or ammonia water.

Further, the alkali solution can be sodium hydroxide solution, ammonia water solution, or a mixture of sodium hydroxide solution and ammonia water solution. Specifically, when the alkali liquor is a mixture of sodium hydroxide solution and ammonia water solution, the volume ratio of the sodium hydroxide solution to the ammonia water solution is 4:0.5-1.

By adopting the technical scheme, the sodium hydroxide solution and the ammonia water can both provide alkaline environment, the ammonia water can also be changed into gas for removal in the subsequent heating process, no new impurities are introduced, and good conditions can be created for the reaction.

Preferably, the ultrasonic conditions are: the ultrasonic power is 110-150W, and the ultrasonic frequency is 145-200kHz.

By adopting the technical scheme, the ultrasonic frequency is set to be 145-200kHz, the ultrasonic power is 110-150W, the ultrasonic energy-saving lithium ion battery pack has good penetration depth and energy, and can play a good role in modifying the crystal structure and apparent performance of spodumene by matching with alkali liquor and cooperating with mechanical grinding, thereby being beneficial to the subsequent extraction of lithium and the removal of impurities, and improving the leaching rate of lithium and the purity of products.

Preferably, the ratio of spodumene to alkali liquor is (1-2) g (5-11) mL.

By adopting the technical scheme, the dosage relation of spodumene and alkali liquor is optimized, the modification effect of the alkali liquor on spodumene by matching with the ultrasonic effect and mechanical grinding is further promoted, and the alkali liquor can also be used as a reaction raw material to participate in subsequent reactions.

Preferably, the volume ratio of the slurry to the sodium metaaluminate solution is 10 (1-3).

Further, the volume of the slurry and the sodium metaaluminate solution is 10:1, can be 10:1.8, can be 10:2.2, can also be 10:2.5 and the like.

By adopting the technical scheme, the dosage relation of the slurry and the sodium metaaluminate solution is optimized, so that the silicon dissolved out of the raw materials can be completely removed, the leaching of lithium is influenced by the existence of sodium silicate, and the purity of the product and the leaching rate of lithium are improved.

Preferably, the mass concentration of the sodium metaaluminate solution is 4-10%.

Further, the mass concentration of the sodium metaaluminate solution may be 5.3%, 5.8%, 6.5%, 7%, 8%, 8.5%, 9%, or the like.

By adopting the technical scheme, the concentration of the sodium metaaluminate solution is optimized, so that the silicon and aluminum dissolved in the solution are combined to form aluminosilicate, the replacement of lithium and sodium is facilitated, the leaching rate of lithium is improved in an auxiliary manner, the existence of impurities is reduced, and the purity of a product is improved.

Preferably, the mass concentration of the sodium hydroxide solution is 18-30%, and the mass concentration of the ammonia water is 8-12%.

By adopting the technical scheme, the mass concentration of the sodium hydroxide solution and the ammonia water is optimized, and the good alkaline environment of the reaction system is maintained, so that the structural damage of spodumene is facilitated, and the leaching of lithium is promoted.

Preferably, the heating reflux reaction is: heating to 80-95deg.C and refluxing for 1-2h.

Preferably, the volume ratio of the ethanol to the ammonia water is (1-3): 4.

Further, the mass concentration of the ethanol is 20-30%.

Further, the volume ratio of ethanol to ammonia water may be 1:4, may be 1.5:4, may be 2.2:4, may be 2.5:4, and may be 3:4.

By adopting the technical scheme, the specific conditions of the heating reflux reaction are optimized, the elution of lithium ions attached to the impurity precipitate into the reaction liquid is facilitated, ethanol is gradually evaporated at the temperature, ammonia water is used for removing impurities in a gas form, and magnesium ions, calcium ions and the like which are not removed can be further removed in a precipitate form, so that the leaching rate of lithium is further improved, and the purity of a product is improved.

Preferably, the spodumene has d90=60-73 μm after grinding.

By adopting the technical scheme, D90 is the particle size corresponding to the particle size cumulative distribution reaching 90%, and the particle size distribution of spodumene after grinding is optimized, so that the particle size of the spodumene raw material is small, the specific surface area is increased, the contact with alkali liquor is increased, and the leaching rate of lithium can be improved.

In summary, the present application has the following beneficial effects:

1. the method has the advantages that the alkali liquor is added in the spodumene grinding process and is matched with the ultrasonic action, so that spodumene plays a certain modification role in the grinding process, the ultrasonic wave can generate mechanical effect, thermal effect, cavitation effect and chemical effect in the propagation process, the alkali liquor is matched with the mechanical grinding to play a good modification role in the crystal structure and apparent performance of spodumene, silicon-oxygen bonds of spodumene can be broken more easily, silicon ion dissolution is facilitated, more aluminum ions are exposed on the surface, active sites on the surface of spodumene can be increased, the surface morphology of spodumene can also play a certain shaping role, the corrosion phenomenon of spodumene appears, the roughness of the surface is increased, and subsequent extraction of lithium and removal of impurities are further facilitated.

2. The slurry is reacted with the sodium metaaluminate solution, so that silicon and aluminum dissolved by alkali liquor in the solution are combined to form aluminosilicate, and meanwhile, the replacement of lithium and sodium is promoted, and the leaching rate of lithium and the purity of a product are improved.

3. The leaching residue is further subjected to reflux reaction treatment by adopting ammonia water and ethanol, so that the leachable lithium remained in the leaching residue can be further leached, impurities such as calcium, magnesium, iron and the like are further removed in a precipitation form, and the absorption and adhesion of the leached lithium on the precipitation impurities are reduced, thereby being beneficial to improving the purity of the product and the leaching rate of the lithium.

Drawings

Fig. 1 is a flow chart of a process for extracting lithium from low-grade spodumene raw ore of the present application.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the following examples, which are to be construed as merely illustrative and not limitative of the scope of the invention, but are not intended to limit the scope of the invention to the specific conditions set forth in the examples, either as conventional or manufacturer-suggested, nor are reagents or apparatus employed to identify manufacturers as conventional products available for commercial purchase.

Examples

Example 1

step 1, grinding spodumene and sodium hydroxide solution with mass concentration of 18% under the conditions that the ultrasonic power is 110W and the ultrasonic frequency is 200kHz to obtain slurry, wherein the particle size D90=73 mu m of spodumene; wherein the dosage ratio of spodumene to sodium hydroxide solution is 1g to 5mL;

step 2, mixing the slurry with a sodium metaaluminate solution with the mass concentration of 4% in a volume ratio of 10:1, reacting for 5 hours at the temperature of 240 ℃, and adding deionized water to repeatedly leach for 3 times to obtain leaching liquid and leaching residues;

step 3, adding 20% ethanol and 8% ammonia water into the leaching residue, refluxing for 2 hours at the temperature of 80 ℃, evaporating the ethanol, and filtering to obtain a reaction solution; the volume ratio of the ethanol to the ammonia water is 1:4;

and step 4, mixing the leaching solution and the reaction solution, evaporating and concentrating to obtain a purified solution, introducing carbon dioxide gas into the purified solution, and heating to separate out lithium carbonate precipitate.

Example 2

step 1, grinding spodumene and ammonia water with the mass concentration of 12% under the conditions that the ultrasonic power is 150W and the ultrasonic frequency is 145kHz to obtain slurry, wherein the particle size D90=60 mu m of spodumene; wherein the dosage ratio of spodumene to sodium hydroxide solution is 1g to 11mL;

step 2, mixing the slurry with a sodium metaaluminate solution with the mass concentration of 10% in a volume ratio of 10:3, reacting for 2 hours at the temperature of 310 ℃, and adding deionized water to repeatedly leach for 3 times to obtain leaching liquid and leaching residues;

step 3, adding ethanol with the mass concentration of 30% and ammonia water with the mass concentration of 12% into the leaching residue, refluxing for 2 hours at the temperature of 95 ℃, evaporating the ethanol, and filtering to obtain a reaction solution; the volume ratio of the ethanol to the ammonia water is 3:4;

Example 3

The difference from example 1 is that in step 1, the lye is a volume ratio of 4:0.5 of sodium hydroxide solution and ammonia water, the mass concentration of the sodium hydroxide solution is 20%, wherein the use amount ratio of spodumene to lye is 2g:9mL, and the rest is the same as example 1.

Example 4

The difference from example 1 is that in step 1, the lye is a sodium hydroxide solution and ammonia water in a volume ratio of 4:1, the mass concentration of the sodium hydroxide solution is 28%, wherein the use amount ratio of spodumene to lye is 1.5g:8mL, and the rest is the same as example 1.

Example 5

The difference from example 4 is that in step 1, spodumene and alkali liquor are ground under the conditions that the ultrasonic power is 140W and the ultrasonic frequency is 180kHz to obtain slurry, and the particle size d90=70 μm of spodumene; the remainder was the same as in example 4.

Example 6

The difference from example 4 is that in step 1, spodumene and sodium hydroxide solution with mass concentration of 12% are ground under the conditions that the ultrasonic power is 80W and the ultrasonic frequency is 100kHz to obtain slurry; wherein the dosage ratio of spodumene to sodium hydroxide solution is 1g to 6mL; the remainder was the same as in example 4.

Example 7

The difference with example 5 is that in step 2, the slurry and the sodium metaaluminate solution with the mass concentration of 8% are mixed according to the volume ratio of 10:2.3, and react for 3.5 hours at the temperature of 290 ℃, deionized water is added for repeated leaching for 3 times, so as to obtain leaching liquid and leaching residue; the remainder was the same as in example 5.

Example 8

The difference from example 7 is that in step 3, ethanol with mass concentration of 25% and ammonia water with mass concentration of 10% are added into the leaching residue, reflux is carried out for 1.5 hours at 90 ℃, and the reaction solution is obtained by filtering after ethanol is evaporated to dryness; the volume ratio of the ethanol to the ammonia water is 2:4; the remainder was the same as in example 7.

Example 9

The difference from example 7 is that in step 3, ethanol with the mass concentration of 40% and ammonia water with the mass concentration of 5% are added into the leaching residue, reflux is carried out for 1h at 110 ℃, and the reaction liquid is obtained after the ethanol is evaporated to dryness and filtered; the volume ratio of the ethanol to the ammonia water is 2:1; the remainder was the same as in example 7.

Comparative example

Comparative example 1

The difference from example 8 is that step 1 is omitted, spodumene is directly crushed and ground to less than 100 mu m, then mixed with 28% sodium hydroxide solution and 8% sodium metaaluminate solution, heated to 260 ℃ and reacted for 3.5 hours, and deionized water is added for repeated leaching for 3 times to obtain leaching liquid and leaching residue; the remainder was the same as in example 8.

Comparative example 2

The difference with example 8 is that in step 2, the slurry is directly heated to 200 ℃ for 3.5 hours without adding sodium metaaluminate solution, and deionized water is added for repeated leaching for 3 times to obtain leaching liquid and leaching residue; the remainder was the same as in example 8.

Comparative example 3

The difference from example 8 is that step 3 is omitted, the leaching solution is directly evaporated and concentrated to obtain a purified solution, carbon dioxide gas is introduced into the purified solution, and lithium carbonate precipitate is separated out by heating; the remainder was the same as in example 8.

Comparative example 4

The difference from example 8 is that in step 3, the aqueous ammonia solution is replaced with the aqueous sodium hydroxide solution in equal amounts, and the remainder is the same as example 8.

Performance test

The purity of the lithium carbonate product obtained in examples 1-9 and comparative examples 1-4 was tested by acid-base titration, and the results are recorded in table 1, and the lithium leaching rates of examples 1-9 and comparative examples 1-4 were calculated as% lithium leaching= (lithium content in 1-reaction slag/lithium content in spodumene) ×100%.

TABLE 1

It can be seen by combining examples 1-9 and combining Table 1 that the process of the application for extracting spodumene not only can effectively reduce environmental pollution, but also has high byproduct added value, does not need to be roasted at a high speed Wen Zhuaijing, remarkably reduces industrial energy consumption, can also improve the leaching rate of lithium and the purity of the product, has good economic benefit, can be widely applied to industrial production, and has wide application range.

It can be seen from the combination of example 8 and comparative example 1, and the combination of table 1, that spodumene is directly crushed, not in cooperation with alkali liquor and ultrasonic treatment, and spodumene cannot be modified only mechanically, even if sodium hydroxide solution and sodium metaaluminate solution are added during the reaction, the leaching rate of spodumene is significantly reduced, but the purity of the product is less affected. The method is characterized in that alkali liquor is added in the spodumene grinding process and is matched with an ultrasonic action, so that spodumene plays a certain modification role in the grinding process, mechanical effect, thermal effect, cavitation effect and chemical effect can be generated in the ultrasonic wave transmission process, the alkali liquor is matched with the mechanical grinding to play a good modification role on the crystal structure and apparent performance of spodumene, silicon-oxygen bonds of the spodumene are easier to break, silicon ions are facilitated to be dissolved out, more aluminum ions are exposed on the surface, active sites on the surface of the spodumene can be increased, certain shaping effect can be realized on the surface morphology of the spodumene, a corrosion phenomenon is generated on the spodumene, the surface roughness is increased, the subsequent extraction of lithium and the removal of impurities are further facilitated, and the leaching rate of lithium is effectively improved and the product purity is assisted.

As can be seen by combining example 8 and comparative example 2 and combining table 1, in comparative example 2, sodium metaaluminate solution is not added, the temperature is too low in the heating reaction process, lithium leaching is obviously limited, and impurities in the product are more, and the purity is obviously reduced, because sodium metaaluminate solution is added and certain reaction temperature is matched, lithium in spodumene can be more easily dissolved out, and silicon and aluminum dissolved out by alkali liquor in the solution combine to form aluminosilicate, thereby promoting substitution of lithium and sodium, and improving leaching rate of lithium and purity of the product.

It can be seen from the combination of example 8 and comparative examples 3-4 and the combination of Table 1 that step 3 was directly omitted in comparative example 3 without further treatment of the leaching residue, the extraction of spodumene was not complete enough in comparative example 3, the leaching rate of lithium was significantly reduced, and the purity of the product was also affected to some extent; in comparative example 4, sodium hydroxide solution is used to replace ammonia solution for treatment, and sodium ethoxide impurity is generated by reaction of sodium hydroxide solution and ethanol solution under heating condition, so that lithium leaching is unfavorable, product purity is further damaged, and therefore, only by adopting reflux reaction treatment of ammonia water and ethanol to leaching residues, the residual unleached lithium in the leaching residues can be further leached, and impurities such as calcium, magnesium and iron are further removed in a precipitation form, and meanwhile, the absorption and adhesion of leached lithium on the precipitation impurities are reduced, so that the purity of the product and the leaching rate of lithium are improved.

The present embodiment is merely illustrative of the present application and is not intended to be limiting, and those skilled in the art, after having read the present specification, may make modifications to the present embodiment without creative contribution as required, but is protected by patent laws within the scope of the claims of the present application.

Claims

1. A process for extracting lithium from low-grade spodumene raw ore, comprising the steps of:

grinding spodumene and alkali liquor under ultrasonic conditions to obtain slurry, wherein the spodumene is ground to a particle size of below 100 mu m;

reacting the slurry with sodium metaaluminate solution at 240-310 ℃ for 2-5h, adding water for leaching for multiple times to obtain leaching liquid and leaching residue;

adding ethanol and ammonia water into the leaching residue for heating reflux reaction, evaporating the ethanol, and filtering to obtain a reaction solution;

2. The process for extracting lithium from low-grade spodumene raw ore as claimed in claim 1, wherein: the alkali liquor comprises sodium hydroxide solution and/or ammonia water.

3. The process for extracting lithium from low-grade spodumene raw ore as claimed in claim 1, wherein: the ultrasonic conditions are as follows: the ultrasonic power is 110-150W, and the ultrasonic frequency is 145-200kHz.

4. The process for extracting lithium from low-grade spodumene raw ore as claimed in claim 2, wherein: the dosage ratio of spodumene to alkali liquor is (1-2) g (5-11) mL.

5. The process for extracting lithium from low-grade spodumene raw ore as recited in claim 4, wherein: the volume ratio of the slurry to the sodium metaaluminate solution is 10 (1-3).

6. The process for extracting lithium from low-grade spodumene raw ore according to claim 1 or 5, wherein: the mass concentration of the sodium metaaluminate solution is 4-10%.

7. The process for extracting lithium from low-grade spodumene raw ore according to claim 1 or 2, characterized in that: the mass concentration of the sodium hydroxide solution is 18-30%, and the mass concentration of the ammonia water is 8-12%.

8. The process for extracting lithium from low-grade spodumene raw ore as claimed in claim 1, wherein: the heating reflux reaction is as follows: heating to 80-95deg.C and refluxing for 1-2h.

9. The process for extracting lithium from low-grade spodumene raw ore as recited in claim 8, wherein: the volume ratio of the ethanol to the ammonia water is (1-3): 4.

10. The process for extracting lithium from low-grade spodumene raw ore as claimed in claim 1, wherein: the spodumene was milled d90=60-73 μm.