CN105742744B - A kind of method that lithium is extracted in the waste liquid containing lithium produced from waste and old lithium ion battery removal process - Google Patents

Abstract

The invention discloses a kind of method that lithium is extracted in waste liquid containing lithium produced from waste and old lithium ion battery removal process, comprise the following steps：(1) using sodium carbonate as precipitating reagent, sodium carbonate is added in waste liquid containing lithium and is stirred reaction, be then filtrated to get liquid and rough lithium carbonate after sinker；(2) the rough lithium carbonate for obtaining step (1) is well mixed with manganese carbonate, then carries out calcination process, obtains lithium manganate having spinel structure containing sodium.This method carries lithium rate of recovery height, and clean environment firendly, product category is rich and varied.

Description

A method for extracting lithium from lithium-containing waste liquid produced in the recycling process of waste lithium-ion batteries method

technical field

The invention relates to the technical field of lithium recovery from waste lithium-ion batteries, in particular to a method for extracting lithium from lithium-containing waste liquid generated during the recovery process of waste lithium-ion batteries.

Background technique

Since its commercialization in 1990, lithium-ion batteries have been widely used due to their high specific capacity, long cycle life, wide operating temperature range, and no memory effect. With the rapid development of the lithium battery industry, my country has become the largest battery producer in the world, with an annual output of about 4 billion lithium-ion batteries and a steady growth rate of 15% per year. In 2014, the accumulative sales volume of new energy vehicles in my country was about 60,000, a year-on-year increase of 4 times, and it is expected to rank first in the world in 2015. In 2015, the cumulative amount of scrapped power batteries in my country was about 1,000 tons. It is predicted that by 2020, the amount of scrapped batteries for various power vehicles in my country will exceed 10,000 tons. The service life of the battery is only 2-3 years, and the disposal of used lithium-ion batteries and production waste has become an urgent problem to be solved in the clean production of the battery industry.

At present, the recycling of waste lithium-ion batteries at home and abroad mainly focuses on the recovery of cobalt, nickel and other metals, while there are relatively few methods for lithium metal recovery. Lithium-containing waste liquid is obtained after cobalt and nickel are extracted from the positive electrode materials of waste lithium-ion batteries by leaching, precipitation, extraction and other methods. At present, most enterprises do not recycle lithium-containing waste liquid and treat it as waste liquid, resulting in a large amount of lithium resources. drain. Due to the low concentration of lithium ions in the lithium-containing waste liquid, if the traditional carbonate precipitation method is used for recovery, there are the following problems: (1) the recovery rate is low, the residual lithium in the solution is high, and the obtained product is single and low in purity (2) Lithium carbonate precipitate can cause product loss on the one hand in washing purification process, can cause the generation of a large amount of waste water on the other hand, economical and environmental protection not enough owing to being slightly soluble in water. Therefore, there is an urgent need to develop an economical, efficient, and clean lithium recovery method.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a method for extracting lithium from the lithium-containing waste liquid produced in the recycling process of waste lithium-ion batteries. The utilization rate of lithium resources, the lithium extraction process is more economical and environmentally friendly, and the obtained products are rich and diverse.

In order to solve the problems of the technologies described above, the technical solution proposed by the present invention is:

A method for extracting lithium from the lithium-containing waste liquid produced in the waste lithium ion battery recovery process, comprising the following steps:

(1) Using sodium carbonate as a precipitating agent, sodium carbonate is added to lithium-containing waste liquid for stirring reaction, and then filtered to obtain lithium precipitated liquid and crude lithium carbonate;

(2) Mix the crude lithium carbonate obtained in step (1) with manganese carbonate evenly, and then perform roasting treatment to obtain sodium-containing spinel lithium manganese oxide.

In the above method, preferably, the lithium precipitation liquid obtained in the step (1) is cooled and crystallized and then filtered to obtain sodium carbonate and an extraction filtrate; sodium phosphate is added to the extraction filtrate to stir the reaction, and after the reaction is completed, it is filtered to obtain filter cake, and then the filter cake is washed and dried to obtain lithium phosphate.

In the above-mentioned method, preferably, the sodium carbonate obtained by filtering after the liquid cooling and crystallization after the lithium precipitation is returned to step (1) for reuse. By reclaiming the sodium carbonate in the filtrate and returning it to step (1) for recycling, on the one hand, resources can be saved and costs can be reduced; The purity of the product), simplify the follow-up treatment process, and reduce the discharge of waste water.

In the above method, preferably, the cooling crystallization temperature is 5°C to 10°C. Combined with factors such as energy consumption and operability, the best effect can be achieved by selecting the cooling crystallization temperature in this range.

In the above method, preferably, the molar ratio of the sodium phosphate to the lithium ions in the extraction filtrate is (1˜1.1):3. The lithium ion concentration in the filtrate is measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The chemical reaction equation of this step is: Na ₃ PO ₄ +3Li ⁺ =Li ₃ PO ₄ ↓+3Na ⁺ .

In the above method, preferably, the reaction temperature of adding sodium phosphate to the extraction filtrate to stir the reaction is 25° C. to 60° C., and the reaction time is 0.5 to 2 hours. The lithium ion concentration in the filtrate obtained after sodium phosphate lithium precipitation is 5mg/L-15mg/L, the lithium recovery rate of the secondary lithium precipitation can reach more than 98%, and the lithium recovery rate of the whole process is greater than 99%.

Above-mentioned method, preferably, in described step (1), the add-on of sodium carbonate is 1～1.1 times of sodium carbonate theoretical solubility, and reaction temperature is 40 ℃～70 ℃, and the reaction times is 0.5～2 hours. Lithium carbonate is a slightly soluble substance, and its degree of precipitation is related to the concentration of CO in the solution. Therefore, a slight excess _of ^sodium carbonate should be added to the solution to achieve the highest possible recovery of lithium carbonate. The chemical reaction equation of this step is: Na ₂ CO ₃ +2Li ⁺ =Li ₂ CO ₃ ↓+2Na ⁺ . Because the solubility of sodium carbonate rises sharply and then decreases slowly with the increase of temperature, the solubility increases sharply when it is lower than 40°C, reaches the maximum value when it is around 40°C, and decreases slowly when it is higher than 40°C, and the solubility does not change. Therefore, considering factors such as lithium recovery rate, reaction efficiency and energy consumption, the best effect can be achieved by selecting the reaction temperature in this range.

The above method, preferably, in the step (1), the lithium-containing waste liquid is the lithium-containing waste liquid generated in the process of recycling the waste lithium-ion battery positive electrode material, and the concentration of lithium ions in the lithium-containing waste liquid is 4g/ L～10g/L. The lithium ion concentration in the filtrate obtained after lithium precipitation with sodium carbonate is 1.0g/L-1.8g/L, and the lithium recovery rate of one-time lithium precipitation can reach 74%-85%.

Above-mentioned method, preferably, in described step (2), the massfraction of sodium carbonate in crude lithium carbonate≤30%. When the content of sodium carbonate is controlled within 30%, sodium element will form a benign doping in the synthesis of lithium manganate, which is beneficial to the electrochemical performance of lithium manganate as a positive electrode material.

In the above method, preferably, in the step (2), the calcination temperature is 500°C-800°C, and the calcination time is 3-8 hours.

In the present invention, lithium in the lithium-containing waste liquid is recovered by two lithium-precipitating methods, and sodium carbonate is used as a precipitating agent for one lithium-precipitating process, and the obtained crude lithium carbonate can be used for the synthesis of lithium manganate cathode material without washing, thereby improving the The utilization rate of lithium resources reduces the discharge of waste water, and the lithium extraction process is more economical and environmentally friendly. The electrochemical performance of the directly synthesized sodium-containing spinel lithium manganate (mass fraction of sodium carbonate ≤ 30%) is better than that of ordinary structures. The spinel-type lithium manganese oxide material can be used as the positive electrode material of lithium-ion batteries; the obtained lithium-containing filtrate is subjected to the extraction operation of sodium carbonate, and the obtained sodium carbonate is returned to a lithium precipitation reaction for recycling, and the obtained lithium-containing filtrate is extracted The filtrate enters the secondary lithium precipitation process, which realizes the recycling of resources, reduces costs, and simplifies the subsequent treatment process. Sodium phosphate is used as the precipitant for the secondary lithium precipitation. Since the solubility product of lithium phosphate is much smaller than that of lithium carbonate, the lithium recovery rate of the secondary lithium precipitation can reach more than 98%, and the lithium recovery rate of the whole process is greater than 99%. Efficient recovery of lithium in lithium-containing waste liquid, the obtained lithium phosphate product can be used in the production of lithium iron phosphate cathode material.

Compared with the prior art, the present invention has the following advantages:

(1) The lithium salt product that the present invention obtains is more abundant, and added value is higher, and the crude lithium carbonate obtained by one-time sinking of lithium is synthesized to obtain a sodium-doped spinel type lithium manganate product, which can be used as a lithium-ion battery positive electrode material.

(2) The present invention realizes the maximum recovery and utilization of lithium resources by extracting lithium in steps (twice sinking lithium), compared with the traditional one-step carbonate precipitation method to extract lithium, and the recovery rate of lithium in the whole process is greater than 99%. .

(3) The present invention adopts the lithium precipitation method of first carbonate and then phosphate, the lithium extraction process is more economical and environmentally friendly, the precipitant can be recycled to the maximum extent, and the discharge of waste water is reduced at the same time (the phosphorus concentration in the waste water is low), The production of resources, recycling and reduction has been realized.

Description of drawings

Fig. 1 is the process flow chart of extracting lithium in the present invention.

Fig. 2 is the X-ray diffraction (XRD) figure of the crude lithium carbonate that the embodiment of the present invention 1 makes.

Fig. 3 is a comparison diagram of X-ray diffraction of pure spinel-type lithium manganate and the sodium-containing spinel-type lithium manganate prepared in Example 1 of the present invention.

Fig. 4 is a scanning electron microscope (SEM) image of the sodium-containing spinel lithium manganese oxide prepared in Example 1 of the present invention.

5 is a discharge test curve when the sodium-containing spinel lithium manganese oxide prepared in Example 1 of the present invention is used as the positive electrode material of a lithium ion battery.

Fig. 6 is an X-ray diffraction pattern of lithium phosphate prepared in Example 1 of the present invention.

detailed description

The present invention will be further described below in conjunction with specific examples, but the scope of protection claimed by the present invention is not limited to the scope described in the examples.

Example 1

The lithium-containing waste liquid produced during the recycling of waste lithium-ion battery cathode materials is an aqueous solution mainly containing Li ⁺ , Na ⁺ , H ⁺ and SO ₄ ^2- , the pH of the solution is 4-5, and the concentration of lithium ions is 7g/L .

As shown in Figure 1, a kind of method of the present invention extracts lithium from the lithium-containing waste liquid that waste lithium ion battery recovery process produces, comprises the following steps:

(1) Sodium carbonate solid with theoretical solubility (maximum solubility in 100g of water at a certain temperature) is added to 200mL, 60°C lithium-containing waste liquid to carry out sodium carbonate lithium precipitation reaction, stirred for 1 hour, and then filtered and separated to obtain Liquid (filtrate) and crude lithium carbonate after sinking lithium;

(2) Cool and crystallize the lithium-precipitated liquid (filtrate) obtained in step (1) at 5° C., filter and separate to obtain sodium carbonate crystals and extract the filtrate, and then return the sodium carbonate crystals to step (1) for recycling; (1) the crude Lithium Retard obtained detects that the sodium carbonate massfraction wherein is 15% through ICP, 0.7g crude Lithium Retard and 4.2g manganese carbonate are ground and mixed in an agate mortar and put into the crucible, and then It is placed in a muffle furnace and heated up to 600°C at a rate of 5°C/min for roasting treatment, kept for 5 hours and then cooled with the furnace to obtain a sodium-containing spinel lithium manganate product;

(3) The lithium ion concentration in the extraction filtrate obtained in step (2) was detected by ICP-OES to be 1.2g/L, and 4.2g sodium phosphate decahydrate (0.0122mol Na ₃ PO ₄ 10H ₂ O) was added to 200mL extraction The filtrate (containing 0.0346mol Li) was subjected to sodium phosphate lithium precipitation reaction, the reaction temperature was 60°C, the reaction was stirred for 1 hour, and then the filter cake was obtained by filtration and separation. After the filter cake was washed and dried, the lithium phosphate product was obtained, and the lithium extraction process was completed. .

The concentration of lithium ions in the filtrate of each step is tested by ICP-OES, wherein the lithium recovery rate of the primary sodium carbonate lithium precipitation in the step (1) is 82.8%, and the filtrate after the secondary sodium phosphate lithium precipitation in the step (3) The concentration of lithium ions in the medium is 15mg/L, the lithium recovery rate of sodium secondary phosphate lithium precipitation is 98.8%, and the lithium recovery rate of the whole process is 99.8%.

Fig. 2 is the XRD figure of the crude lithium carbonate that the present embodiment makes, as can be seen from the figure, gained product is mainly lithium carbonate, and impurity component is sodium carbonate. Fig. 3 is the XRD comparison figure of pure spinel type lithium manganate and the sodium spinel type lithium manganate prepared in the present embodiment, as can be seen from the figure, when the mass fraction of sodium carbonate is 15%, the obtained The synthetic product still maintains the spinel phase without other impurity phases, indicating that sodium doping has no effect on the lithium manganese oxide lattice. Figure 4 is an SEM image of the sodium-containing spinel lithium manganese oxide prepared in this example. It can be seen from the figure that the synthesized material mainly has an octahedral spinel structure. Fig. 5 is the discharge test curve when the sodium-containing spinel-type lithium manganese oxide prepared in this embodiment is used as the positive electrode material of the lithium ion battery. It can be seen from the figure that the discharge specific capacity is greater than 200mAh/g. Fig. 6 is the XRD pattern of the lithium phosphate prepared in this embodiment, as can be seen from the figure, the characteristic peaks are consistent with the standard PDF card of lithium phosphate, no other impurity phases are seen, the obtained product is lithium phosphate, and the product purity is higher.

Example 2

The lithium-containing waste liquid produced during the recycling of waste lithium-ion battery cathode materials is an aqueous solution mainly containing Li ⁺ , Na ⁺ , H ⁺ and SO ₄ ^2- , the pH of the solution is 4-5, and the concentration of lithium ions is 7g/L .

As shown in Figure 1, a kind of method of the present invention extracts lithium from the lithium-containing waste liquid that waste lithium ion battery recovery process produces, comprises the following steps:

(1) Add 1.1 times the theoretical solubility of sodium carbonate solid into 200mL of lithium-containing waste liquid at 40°C to carry out the sodium carbonate lithium precipitation reaction, stir the reaction for 1 hour, and then filter and separate to obtain the lithium-precipitated liquid (filtrate) and crude lithium carbonate;

(2) Cool and crystallize the lithium-precipitated liquid (filtrate) obtained in step (1) at 8° C., filter and separate to obtain sodium carbonate crystals and extract the filtrate, and then return the sodium carbonate crystals to step (1) for recycling; (1) the crude lithium carbonate obtained detects that the sodium carbonate massfraction wherein is 25% through ICP, 0.8g crude lithium carbonate and 4.4g manganese carbonate are ground and mixed in an agate mortar and put into the crucible, then It is placed in a muffle furnace and heated up to 800°C at a rate of 5°C/min for roasting treatment, kept for 5 hours and then cooled with the furnace to obtain a sodium-containing spinel lithium manganate product;

(3) The lithium ion concentration in the extraction filtrate obtained in step (2) was detected by ICP-OES to be 0.9g/L, and 3.4g sodium phosphate decahydrate (0.01mol Na ₃ PO ₄ 10H ₂ O) was added to 200mL extraction The filtrate (containing 0.026mol Li) is subjected to sodium phosphate lithium precipitation reaction, the reaction temperature is 60°C, the reaction is stirred for 1 hour, and then the filter cake is obtained by filtration and separation. After the filter cake is washed and dried, the lithium phosphate product is obtained, and the lithium extraction process is completed. .

The concentration of lithium ions in the filtrate of each step is tested by ICP-OES, wherein the lithium recovery rate of the primary sodium carbonate lithium precipitation in the step (1) is 87.1%, and the filtrate after the secondary sodium phosphate lithium precipitation in the step (3) The concentration of lithium ions in the medium is 13mg/L, the lithium recovery rate of sodium secondary phosphate lithium precipitation is 98.6%, and the lithium recovery rate of the whole process is 99.8%.

Example 3

The lithium-containing waste liquid produced during the recycling of waste lithium-ion battery cathode materials is an aqueous solution mainly containing Li ⁺ , Na ⁺ , H ⁺ and SO ₄ ^2- , the pH of the solution is 4-5, and the concentration of lithium ions is 7g/L .

As shown in Figure 1, a kind of method of the present invention extracts lithium from the lithium-containing waste liquid that waste lithium ion battery recovery process produces, comprises the following steps:

(1) Add 1.05 times the theoretical solubility of sodium carbonate solid into 200mL of lithium-containing waste liquid at 70°C to carry out sodium carbonate lithium precipitation reaction, stir the reaction for 1 hour, and then filter and separate to obtain the lithium-precipitated liquid (filtrate) and crude lithium carbonate;

(2) Cool and crystallize the lithium-precipitated liquid (filtrate) obtained in step (1) at 10° C., filter and separate to obtain sodium carbonate crystals and extract the filtrate, and then return the sodium carbonate crystals to step (1) for recycling; (1) the crude lithium carbonate obtained is 15% through testing wherein the sodium carbonate massfraction is put into the crucible after 4.3g crude lithium carbonate and 24.2g manganese carbonate are ground and mixed in an agate mortar, and then Put it in a muffle furnace and heat it up to 500°C at a rate of 5°C/min for roasting treatment, keep warm for 5 hours and then cool with the furnace to obtain a sodium-containing spinel lithium manganate product;

(3) The lithium ion concentration in the extraction filtrate obtained in step (2) was detected by ICP-OES to be 1.2g/L, and 4.6g sodium phosphate decahydrate (0.0134mol Na ₃ PO ₄ .10H ₂ O) was added to 200mL extraction The filtrate (containing 0.0346mol Li) was subjected to sodium phosphate lithium precipitation reaction, the reaction temperature was 25°C, the reaction was stirred for 1 hour, and then the filter cake was obtained by filtration and separation. After the filter cake was washed and dried, the lithium phosphate product was obtained, and the lithium extraction process was completed. .

The concentration of lithium ions in the filtrate of each step is tested by ICP-OES, wherein the lithium recovery rate of the primary sodium carbonate lithium precipitation in the step (1) is 82.8%, and the filtrate after the secondary sodium phosphate lithium precipitation in the step (3) The concentration of lithium ions in the medium is 8mg/L, the lithium recovery rate of sodium diphosphate lithium precipitation is 99.3%, and the lithium recovery rate of the whole process is 99.9%.

Claims (7)

1. extracting the method for lithium in a kind of waste liquid containing lithium produced from waste and old lithium ion battery removal process, comprise the following steps：

(1) using sodium carbonate as precipitating reagent, sodium carbonate is added in waste liquid containing lithium and is stirred reaction, sinker is then filtrated to get The mass fraction of sodium carbonate is 15%~25% in liquid and rough lithium carbonate afterwards, the rough lithium carbonate；By liquid after the sinker Filtered after crystallisation by cooling, obtain sodium carbonate and extract filtrate, gained sodium carbonate is back in sinker step and reused, to institute State in extraction filtrate and add sodium phosphate stirring reaction, filter cake is filtrated to get after the completion of reaction, then will be obtained after Washing of Filter Cake, drying Lithium phosphate；

(2) the rough lithium carbonate for obtaining step (1) is well mixed with manganese carbonate, then carries out calcination process, obtains the point containing sodium brilliant Stone-type LiMn2O4.

2. according to the method described in claim 1, it is characterised in that：The temperature of the crystallisation by cooling is 5 DEG C~10 DEG C.

3. according to the method described in claim 1, it is characterised in that：The sodium phosphate and the mol ratio for extracting lithium ion in filtrate For (1~1.1):3.

4. according to the method described in claim 1, it is characterised in that：Described extract adds the anti-of sodium phosphate stirring reaction in filtrate It is 25 DEG C~60 DEG C to answer temperature, and the reaction time is 0.5~2 hour.

5. according to method according to any one of claims 1 to 4, it is characterised in that：In the step (1), sodium carbonate plus It is 1~1.1 times of sodium carbonate theoretical dissolution degree to enter amount, and reaction temperature is 40 DEG C~70 DEG C, and the reaction time is 0.5~2 hour.

6. according to method according to any one of claims 1 to 4, it is characterised in that：In the step (1), waste liquid containing lithium is The concentration of lithium ion is in the waste liquid containing lithium produced in recovery waste lithium ion cell anode materials process, the waste liquid containing lithium 4g/L~10g/L.

7. according to method according to any one of claims 1 to 4, it is characterised in that：In the step (2), sintering temperature is 500 DEG C~800 DEG C, roasting time is 3~8 hours.