A method for separating lithium from a high magnesium-lithium ratio salt lake brine

Abstract

The application discloses a method for separating lithium from high magnesium-lithium ratio salt lake brine, comprising the following steps: S1, mixing gas and liquid in a nanobubble generator to obtain nanobubble liquid by the nanobubble generator; S2, separating lithium and magnesium; pumping the nanobubble liquid obtained in the last step into a nanobubble separator, and making the nanobubbles rise with the liquid in a cylinder; due to the quantum characteristics of the nanobubbles, chemical reactions and ion exchanges occur in the contact process, the heavier magnesium rises with the nanobubbles, and the lighter lithium remains in the liquid phase, and then the lithium ions are collected by a lithium ion collecting unit. The process flow of the application is as follows: first, nanobubble liquid is prepared by the nanobubble generator, the nanobubbles rise with the liquid in the cylinder, the heavier magnesium rises with the nanobubbles, and the lighter lithium remains in the liquid phase, and then the lithium ions are collected by the lithium ion collecting unit, so that the separation of lithium and magnesium in the salt lake brine is realized.

Description

Technical Field

[0001] This invention relates to the field of lithium separation technology using gas-liquid interface adsorption, and more specifically, to a method for separating lithium from brine in salt lakes with a high magnesium-to-lithium ratio. Background Technology

[0002] Lithium, as a vital energy metal driving global progress, is of immense significance to national economic development. It is widely used in lithium batteries, lubricants, glass, and other applications. In particular, the explosive growth of lithium-ion batteries for electric vehicles has led to a substantial increase in demand for lithium resources. Therefore, exploring new lithium resource supplies and expanding its supply channels are of paramount importance.

[0003] There are some traditional methods for separating lithium and magnesium in salt lake brine, such as precipitation. For details, please refer to the patent document publication number CN101538057A, "A Method for Separating and Extracting Lithium from Magnesium in Brine".

[0004] Solvent extraction method, the details of which can be found in patent document publication number CN102275956B, a method for extracting lithium carbonate from salt lake brine with a high magnesium-to-lithium ratio.

[0005] For details on membrane separation methods, please refer to the patent document publication number CN1281497C, which describes a method for separating magnesium and concentrated lithium from salt lake brine.

[0006] The precipitation method has the problem of solid-liquid separation difficulties. Specifically, when hydroxides are used as precipitants, the resulting Mg(OH)2 precipitate is gel-like, leading to severe lithium adsorption loss.

[0007] Solvent extraction methods suffer from problems such as long extraction and back-extraction processes, complex equipment, and high reagent consumption, resulting in relatively high operating costs.

[0008] In membrane separation methods, whether it is electrodialysis or nanofiltration, the salinity of the feed solution has a significant impact on the selectivity of the membrane. As the total salinity of the feed solution increases, its selectivity will decrease sharply.

[0009] Therefore, we propose a method for separating lithium from salt lake brines with a high magnesium-to-lithium ratio to solve the above problems. Summary of the Invention

[0010] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a method for separating lithium from brine in salt lakes with a high magnesium-to-lithium ratio. This method is based on the quantum properties of nanobubbles and the principle of surface energy changes at the gas-liquid interface in colloid and interface science, enabling the separation of lithium and magnesium. The method of the present invention has significant advantages such as simple equipment, easy process, short equilibrium time, inexpensive raw materials, low energy consumption, and no pollution, thus solving the problems mentioned in the background art.

[0011] To achieve the above objectives, the present invention provides the following technical solution: a method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake, comprising the following steps: Step S1: mixing gas and liquid in a nanobubble generator to obtain a liquid of nanobubbles. Step S2: separating lithium and magnesium; pumping the liquid of nanobubbles obtained in the previous step into a nanobubble separator, the nanobubbles rising with the liquid in a cylinder; due to the quantum properties of nanobubbles, chemical reactions and ion exchange occur during the contact process, the heavier magnesium rises with the nanobubbles, while the lighter lithium remains in the liquid phase, and is then collected by a lithium ion collection unit, thereby achieving lithium-magnesium separation.

[0012] The nanobubbles produced in this invention have a long lifespan. Based on the quantum properties of nanobubbles and the principle of surface energy change at the gas-liquid interface in colloid and interface science, this invention can achieve the separation of lithium and magnesium.

[0013] In a preferred embodiment, in step S1, the liquid contains nanobubbles, wherein the nanobubbles are air bubbles, nitrogen bubbles, oxygen bubbles, etc.

[0014] In a preferred embodiment, in step S1, the liquid is salt lake brine;

[0015] The nanobubbles or liquid contain lithium and magnesium to be separated.

[0016] In a preferred embodiment, in step S1, the substance to be separated is salt lake brine with a high magnesium-to-lithium ratio.

[0017] In a preferred embodiment, in step S1, the liquid containing nanobubbles is an air-containing brine solution from a salt lake.

[0018] In a preferred embodiment, in step S2, a liquid containing nanobubbles is prepared by a nanobubble generator. Specifically, the bubbles are first broken and dispersed to create bubbles with a size of micrometers, and then a pressure dissolution method is used to further obtain nanobubbles.

[0019] The magnesium-lithium separation coefficient S(Mg.Li) represents the degree to which lithium ions and magnesium ions are separated during the separation process, and it is calculated according to the following formula:

[0020]

[0021] The magnesium-lithium separation coefficient S(Mg.Li) refers to the ratio of the magnesium-lithium ratio at a certain stage (T) after passing through the nanobubble separator to the initial magnesium-lithium ratio (T0). When S = 1, it indicates that the nanobubble separator has no effect on magnesium-lithium separation; S < 1 indicates that the nanobubble separator has an effect on magnesium-lithium separation, and the smaller the S value, the better the separation effect of the nanobubble separator on magnesium-lithium.

[0022] In a preferred embodiment, in step S2, the nanobubble separator is a nanobubble separator unit, which includes a nanobubble generator, a cylindrical nanobubble separator, and a lithium ion feeding unit.

[0023] In a preferred embodiment, in step S2, the device is composed of multiple nanobubble separation units connected in series, and the number of nanobubble separation units increases as the product purity increases.

[0024] The technical effects and advantages of this invention are as follows:

[0025] 1. This invention provides a method for separating lithium from brine in salt lakes with a high magnesium-to-lithium ratio. The nanobubbles produced have a long lifespan. This invention is based on the quantum properties of nanobubbles and the principle of surface energy changes at the gas-liquid interface in colloid and interface science, which enables the separation of lithium and magnesium.

[0026] 2. The method for separating lithium from high magnesium-to-lithium ratio brine of this invention has significant advantages over existing technologies: precipitation methods suffer from difficult solid-liquid separation and low total lithium recovery; extraction methods involve lengthy extraction and back-extraction processes, complex equipment, and high reagent consumption, resulting in high operating costs; other lithium-magnesium separation methods also have varying degrees of drawbacks. This invention overcomes these shortcomings. Taking lithium-magnesium separation as an example, the method for separating lithium from high magnesium-to-lithium ratio brine of this invention features simple equipment, a straightforward process, operation at ambient temperature and pressure, readily available and inexpensive raw materials, low energy consumption, and no environmental pollution.

[0027] 3. The advantages of the device of this invention are: simple separation equipment; simple operation process, without the requirements of high temperature, high pressure or extremely low temperature; low energy consumption; short stabilization time and rapid production; very cheap and common raw materials required; and no wastewater or waste generated, thus having no impact on the environment. In summary, this invention has the advantages of low investment, low energy consumption, cheap raw materials, rapid production, flexible scale and no pollution. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Reference Figure 1A method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake, comprising the following steps:

[0031] Step S1: Mix gas and liquid in a nanobubble generator to obtain liquid containing nanobubbles. In step S1, the liquid containing nanobubbles includes air bubbles, nitrogen bubbles, oxygen bubbles, etc. In step S1, the liquid is brine from a salt lake. The nanobubbles or liquid contain lithium and magnesium to be separated. In step S1, the substance to be separated is brine from a salt lake with a high magnesium-to-lithium ratio. In step S1, the liquid containing nanobubbles is a brine solution from a salt lake containing air.

[0032] Step S2: Separate lithium and magnesium;

[0033] The liquid containing the nanobubbles obtained in the previous step is pumped into the nanobubble separator, and the nanobubbles rise in the cylinder along with the liquid.

[0034] Because of the quantum properties of nanobubbles, chemical reactions and ion exchanges occur during the contact process. Heavier magnesium rises with the nanobubbles, while lighter lithium remains in the liquid phase and is then collected by the lithium ion collection unit, thus achieving lithium-magnesium separation.

[0035] In step S2, a liquid containing nanobubbles is obtained by a nanobubble generator. Specifically, the bubbles are first broken and dispersed to create bubbles with a size of micrometers. Then, a pressure dissolution method is used to further obtain nanobubbles. In step S2, the nanobubble separator is a nanobubble separator unit, which includes a nanobubble generator, a cylindrical nanobubble separator, and a lithium ion feeding unit.

[0036] In step S2, the device is composed of multiple nanobubble separation units connected in series, and the number of nanobubble separation units increases as the product purity increases.

[0037] Example 1: Dongtai Jinai Salt Lake Brine

[0038] The present invention discloses a method for separating lithium from brine in salt lakes with a high magnesium-to-lithium ratio, comprising the following steps:

[0039] In this example, the raw material is brine from the Dongtaijinai Salt Lake in Qinghai Province, which initially contains Mg. 2+ Li + The concentrations were 5.6 g / L and 0.14 g / L, respectively, and the magnesium-to-lithium ratio before separation was 40:1.

[0040] Step 1: Create an aqueous solution containing air nanobubbles;

[0041] Air and brine from the Dongtai Jinai Salt Lake were mixed and an aqueous solution containing air nanobubbles was prepared using a nanobubble generator.

[0042] Step 2: Separate lithium and magnesium;

[0043] The aqueous solution containing air nanobubbles prepared in the first step is pumped into a vertical separation cylinder. Here, the magnesium and lithium to be separated are either in the air nanobubbles or in the aqueous solution. The air nanobubbles rise with the water in the cylinder and gradually fill the cylinder, forming a flocculent liquid column of white bubbles. As the air nanobubbles rise with the water, they come into contact with the water. Due to the quantum properties of the nanobubbles, chemical reactions and ion exchanges occur during the contact process. The heavier magnesium rises with the nanobubbles, while the lighter lithium remains in the liquid phase of the separation cylinder, thus achieving the separation of lithium and magnesium.

[0044] After the first stage of separation, Mg 2+ / Li + The ratio was reduced from the original 40:1 to 4:1;

[0045] After the second stage of separation, Mg 2+ / Li + The ratio was reduced to 1:2; after the third stage of separation, Mg 2 + / Li + The ratio has been reduced to 1:5;

[0046] After the fourth stage of separation, Mg 2+ / Li + The ratio has been reduced to 1:12;

[0047] After the fifth stage of separation, Mg 2+ / Li + The ratio was reduced to 1:15. The number of nanobubble separation units increased as product purity improved.

[0048] After five stages of separation, the magnesium-lithium separation coefficient can reach 1.6 × 10⁻⁶. -3 .

[0049] Example 2: Zabuye Salt Lake brine;

[0050] The present invention discloses a method for separating lithium from brine in salt lakes with a high magnesium-to-lithium ratio, comprising the following steps:

[0051] In this example, the raw material is brine from Zabuye Salt Lake in Xinjiang, which initially contains Mg. 2+ Li + The concentrations were 126 g / L and 1.26 g / L, respectively, and the magnesium-to-lithium ratio before separation was 100:1.

[0052] Step 1: Create an aqueous solution containing air nanobubbles;

[0053] Air and brine from Zabuye Salt Lake were mixed and an aqueous solution containing air nanobubbles was prepared using a nanobubble generator.

[0054] Step 2: Separate lithium and magnesium;

[0055] The aqueous solution containing air nanobubbles prepared in the first step is pumped into a vertical separation cylinder. Here, the magnesium and lithium to be separated are either in the air nanobubbles or in the aqueous solution. The air nanobubbles rise with the water in the cylinder and gradually fill the cylinder, forming a flocculent liquid column of white bubbles. As the air nanobubbles rise with the water, they come into contact with the water. Due to the quantum properties of the nanobubbles, chemical reactions and ion exchanges occur during the contact process. The heavier magnesium rises with the nanobubbles, while the lighter lithium remains in the liquid phase of the separation cylinder, thus achieving the separation of lithium and magnesium.

[0056] After the first stage of separation, Mg 2+ / Li + The ratio was reduced from the original 100:1 to 12:1;

[0057] After the second stage of separation, Mg 2+ / Li + The ratio has been reduced to 2.4:1;

[0058] After the third stage of separation, Mg 2+ / Li + The ratio has been reduced to 5:4;

[0059] After the fourth stage of separation, Mg 2+ / Li + The ratio has been reduced to 1:2;

[0060] After the fifth stage of separation, Mg 2+ / Li + The ratio has been reduced to 1:5.

[0061] The number of nanobubble separation units increases with increasing product purity. After five stages of separation, the magnesium-lithium separation coefficient can reach 2 × 10⁻⁶. -3 .

[0062] Example 3: Brine from Qarhan Salt Lake;

[0063] The present invention discloses a method for separating lithium from brine in salt lakes with a high magnesium-to-lithium ratio, comprising the following steps:

[0064] In this example, the raw material is brine from the Qarhan Salt Lake in Qinghai Province, which initially contains Mg. 2+ Li + The concentrations were 115.04 g / L and 0.08 g / L, respectively, and the magnesium-to-lithium ratio before separation was 1438:1.

[0065] Step 1: Create an aqueous solution containing air nanobubbles;

[0066] Air and brine from the Qarhan Salt Lake were mixed and an aqueous solution containing air nanobubbles was prepared using a nanobubble generator.

[0067] Step 2: Separate lithium and magnesium;

[0068] The aqueous solution containing air nanobubbles prepared in the first step is pumped into a vertical separation cylinder. Here, the magnesium and lithium to be separated are either in the air nanobubbles or in the aqueous solution. The air nanobubbles rise with the water in the cylinder and gradually fill the cylinder, forming a flocculent liquid column of white bubbles. As the air nanobubbles rise with the water, they come into contact with the water. Due to the quantum properties of the nanobubbles, chemical reactions and ion exchanges occur during the contact process. The heavier magnesium rises with the nanobubbles, while the lighter lithium remains in the liquid phase of the separation cylinder, thus achieving the separation of lithium and magnesium.

[0069] After the first stage of separation, Mg 2+ / Li + The ratio was reduced from the original 1438:1 to 154:1;

[0070] After the second stage of separation, Mg 2+ / Li + The ratio has been reduced to 52:1;

[0071] After the third stage of separation, Mg 2+ / Li + The ratio has been reduced to 14:1;

[0072] After the fourth stage of separation, Mg 2+ / Li + Reduced to 7.2:1;

[0073] After the fifth stage of separation, Mg 2+ / Li + It has been reduced to 2.8:1.

[0074] After five stages of separation, the magnesium-lithium separation coefficient can reach 1.9 × 10⁻⁶. -3 .

[0075] Table 1 shows the magnesium and lithium concentrations in the brine of three salt lakes and the magnesium-to-lithium ratio before and after separation:

[0076]

[0077]

[0078] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for separating lithium from brine in salt lakes with a high magnesium-to-lithium ratio, characterized in that; Including the following methods: Step S1: Mix gas and liquid in a nanobubble generator to obtain liquid with nanobubbles; Step S2: Separate lithium and magnesium; The liquid containing the nanobubbles obtained in the previous step is pumped into the nanobubble separator, and the nanobubbles rise in the cylinder along with the liquid. Because of the quantum properties of nanobubbles, chemical reactions and ion exchanges occur during the contact process. Heavier magnesium rises with the nanobubbles, while lighter lithium remains in the liquid phase and is then collected by the lithium ion collection unit, thus achieving lithium-magnesium separation.

2. The method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake according to claim 1, characterized in that: In step S1, the liquid contains nanobubbles, wherein the nanobubbles are air bubbles, nitrogen bubbles, or oxygen bubbles.

3. The method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake according to claim 1, characterized in that: In step S1, the liquid is brine from a salt lake; The nanobubbles or liquid contain lithium and magnesium to be separated.

4. The method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake according to claim 3, characterized in that: In step S1, the substance to be separated is salt lake brine with a high magnesium-to-lithium ratio.

5. The method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake according to claim 3, characterized in that: In step S1, the liquid containing nanobubbles is an air-containing brine solution from a salt lake.

6. The method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake according to claim 1, characterized in that: In step S2, a liquid containing nanobubbles is prepared by a nanobubble generator. Specifically, the bubbles are first broken and dispersed to create bubbles with a size of micrometers, and then a pressure dissolution method is used to further obtain nanobubbles.

7. The method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake according to claim 1, characterized in that: In step S2, the nanobubble separator is a nanobubble separator unit, which includes a nanobubble generator, a cylindrical nanobubble separator, and a lithium ion feeding unit.

8. A method for separating lithium from brine in a high magnesium-to-lithium ratio salt lake according to claim 7, characterized in that: In step S2, the nanobubble separator is composed of multiple nanobubble separation units connected in series, and the number of nanobubble separation units increases as the product purity increases.

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