Method for separating magnesium and extracting lithium from salt lake brine with high magnesium-lithium ratio

Abstract

The invention discloses a method for separating magnesium and extracting lithium from salt lake brine with a high magnesium-lithium ratio. With adoption of the method, tributyl phosphate is taken as an extractant, number 200 solvent oil or kerosene is taken as a diluent, perchlorate is taken as a co-extraction agent, and water is taken as a stripping agent to form an extraction system; and lithium carbonate is prepared through extraction, reversed-phase extraction and deep magnesium removal by the salt lake brine. The method has the following beneficial effects: 1. the property of the co-extraction agent is stable, lithium magnesium separation can be carried out in neutral brine and the pH value of an aqueous phase needs not to be controlled; 2. the emulsification phenomenon doesn't exist and a third phase doesn't appear in the extraction process, two phases are easy to separate, the reversed-phase extraction is carried out by water and the device has little corrosion; and 3. the whole technique is simple in process, high in lithium extraction rate, good in separation effect and low in economic cost, is suitable for industrial production of the salt lake brine and is low in environmental damage degree because the co-extraction agent in water can be recycled.

Description

technical field

[0001] The invention belongs to the field of inorganic chemical industry and relates to a technology for extracting lithium from salt lake brine, in particular to a method for separating magnesium and extracting lithium from brine with a high magnesium-to-lithium ratio. Background technique

[0002] In the past two decades, lithium and its compounds have been increasingly widely used due to their excellent properties. The global demand for lithium has continued to grow. Salt lake lithium resources account for 69% of the world's industrial reserves of lithium resources, of which low-magnesium lithium is more than that of brine Ataca, Chile. The Ma-type Salt Lake was first developed. my country is a country with large salt lake resources, and the liquid lithium resources are very rich. However, most of the salt lakes in my country have the characteristics of high mass ratio of magnesium to lithium, such as Dachaidan, Yiliping, Dongtai Jinel, Xitai Jinel and Cha...

Examples

Embodiment 1

[0020] process such as figure 1 shown.

[0021] 1) Take 50mL of concentrated brine, which contains: Li + 2.21g / L, Mg 2+ 100.71g / L, Na + 3.53g / L, K + 1.85g / L, the mass ratio of magnesium to lithium is 45.6.

[0022] 2) Add the co-extraction agent sodium perchlorate in the brine, the dosage is As the standard, stir and dissolve at 25°C to obtain a pre-extraction brine solution with a pH value of 5.

[0023] 3) The organic phase TBP was added in a proportion equal to the volume of water, and a single extraction was performed at 25° C., the extraction vibration time was 10 min, and the two phases were separated.

[0024] 4) Use pure water as the stripping agent, mix the organic phase and water at a volume ratio of 1:1, carry out stripping at 25°C, strip for 10 minutes, let stand for 15 minutes, and then separate the two phases.

[0025] 5) After back-extraction, the aqueous phase is adjusted to pH ≥ 12 with caustic soda, and the magnesium is treated with Mg(OH) 2 The form...

Embodiment 2

[0028] 1) Take 50mL of concentrated brine, which consists of Li + 0.48g / L, Mg 2+ 96.21g / L, Na + 3.53g / L, K + 1.85g / L, the mass ratio of magnesium to lithium is 200.4.

[0029] 2) Add the co-extraction agent sodium perchlorate in the brine, the dosage is As the standard, stir and dissolve at 25°C to obtain a brine solution before extraction, and adjust the pH value of the solution to 7.

[0030] 3) Add the organic phase according to the volume ratio of the oil phase and the water phase as 2:1, the organic phase is composed of 80% TBP and 20% kerosene, carry out a single extraction at 25 ° C, extract vibration time for 30 min, stand still for 30 min, and then two phase separation.

[0031] 4) Use pure water as the stripping agent, mix the organic phase and water at a volume ratio of 1:1, carry out stripping at 50° C., strip for 10 minutes, let stand for 30 minutes, and then separate the two phases.

[0032] 5) After stripping, the water phase is adjusted to pH ≥ 12 with s...

Embodiment 3

[0035] 1) Take 50 mL of brine containing boron and sulfate radicals after concentration, which consists of: Li + 1.80g / L, Mg 2+ 90.51g / L, Na + 6.89g / L, K + 1.85g / L, 28.82g / L, B 2 o 3 20.89g / L, the mass ratio of magnesium to lithium is 50.3.

[0036] 2) Add the co-extraction agent sodium perchlorate in the brine, the dosage is Standard, stirred and dissolved at 25°C to obtain a pre-extraction brine solution.

[0037] 3) The organic phase TBP was added according to the volume ratio of the oil phase and the water phase at 2:1, and a single extraction was performed at 25° C., the extraction vibration time was 10 min, and the two phases were separated.

[0038] 4) Use pure water as the stripping agent, mix the organic phase and water at a volume ratio of 1:1, carry out stripping at 60° C., strip for 10 minutes, let stand for 15 minutes, and then separate the two phases.

[0039] 5) After stripping, the water phase is adjusted to pH ≥ 12 with sodium carbonate and caustic s...

technical field

[0001] The invention belongs to the field of inorganic chemical industry and relates to a technology for extracting lithium from salt lake brine, in particular to a method for separating magnesium and extracting lithium from brine with a high magnesium-to-lithium ratio. Background technique

[0002] In the past two decades, lithium and its compounds have been increasingly widely used due to their excellent properties. The global demand for lithium has continued to grow. Salt lake lithium resources account for 69% of the world's industrial reserves of lithium resources, of which low-magnesium lithium is more than that of brine Ataca, Chile. The Ma-type Salt Lake was first developed. my country is a country with large salt lake resources, and the liquid lithium resources are very rich. However, most of the salt lakes in my country have the characteristics of high mass ratio of magnesium to lithium, such as Dachaidan, Yiliping, Dongtai Jinel, Xitai Jinel and Cha...

Examples

Embodiment 1

[0020] process such as figure 1 shown.

[0021] 1) Take 50mL of concentrated brine, which contains: Li + 2.21g / L, Mg 2+ 100.71g / L, Na + 3.53g / L, K + 1.85g / L, the mass ratio of magnesium to lithium is 45.6.

[0022] 2) Add the co-extraction agent sodium perchlorate in the brine, the dosage is As the standard, stir and dissolve at 25°C to obtain a pre-extraction brine solution with a pH value of 5.

[0023] 3) The organic phase TBP was added in a proportion equal to the volume of water, and a single extraction was performed at 25° C., the extraction vibration time was 10 min, and the two phases were separated.

[0024] 4) Use pure water as the stripping agent, mix the organic phase and water at a volume ratio of 1:1, carry out stripping at 25°C, strip for 10 minutes, let stand for 15 minutes, and then separate the two phases.

[0025] 5) After back-extraction, the aqueous phase is adjusted to pH ≥ 12 with caustic soda, and the magnesium is treated with Mg(OH) 2 The form...

Embodiment 2

[0028] 1) Take 50mL of concentrated brine, which consists of Li + 0.48g / L, Mg 2+ 96.21g / L, Na + 3.53g / L, K + 1.85g / L, the mass ratio of magnesium to lithium is 200.4.

[0029] 2) Add the co-extraction agent sodium perchlorate in the brine, the dosage is As the standard, stir and dissolve at 25°C to obtain a brine solution before extraction, and adjust the pH value of the solution to 7.

[0030] 3) Add the organic phase according to the volume ratio of the oil phase and the water phase as 2:1, the organic phase is composed of 80% TBP and 20% kerosene, carry out a single extraction at 25 ° C, extract vibration time for 30 min, stand still for 30 min, and then two phase separation.

[0031] 4) Use pure water as the stripping agent, mix the organic phase and water at a volume ratio of 1:1, carry out stripping at 50° C., strip for 10 minutes, let stand for 30 minutes, and then separate the two phases.

[0032] 5) After stripping, the water phase is adjusted to pH ≥ 12 with s...

Embodiment 3

[0035] 1) Take 50 mL of brine containing boron and sulfate radicals after concentration, which consists of: Li + 1.80g / L, Mg 2+ 90.51g / L, Na + 6.89g / L, K + 1.85g / L, 28.82g / L, B 2 o 3 20.89g / L, the mass ratio of magnesium to lithium is 50.3.

[0036] 2) Add the co-extraction agent sodium perchlorate in the brine, the dosage is Standard, stirred and dissolved at 25°C to obtain a pre-extraction brine solution.

[0037] 3) The organic phase TBP was added according to the volume ratio of the oil phase and the water phase at 2:1, and a single extraction was performed at 25° C., the extraction vibration time was 10 min, and the two phases were separated.

[0038] 4) Use pure water as the stripping agent, mix the organic phase and water at a volume ratio of 1:1, carry out stripping at 60° C., strip for 10 minutes, let stand for 15 minutes, and then separate the two phases.

[0039] 5) After stripping, the water phase is adjusted to pH ≥ 12 with sodium carbonate and caustic s...

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