CN117867292A - Method for extracting lithium from lithium ore - Google Patents

Abstract

The invention discloses a method for extracting lithium from lithium ores, and belongs to the technical field of mineral processing. The extraction method comprises the following steps: converting the alpha-spodumene to beta-spodumene by calcination; mixing the beta-spodumene with sulfuric acid and roasting; leaching the roasted product with water, filtering, and removing impurities from the filtrate to obtain a lithium-containing solution; adding carbonate into the lithium-containing solution to precipitate lithium carbonate, filtering, adding a composite extractant into the filtrate to extract lithium, separating the lithium-containing extractant, back-extracting the lithium, and continuously adding carbonate into the back-extracting solution to precipitate lithium carbonate. According to the invention, the traditional scheme of recovering lithium from lithium ore is further improved, and particularly, aiming at the situation that part of lithium still exists in the lithium precipitation mother liquor, an extractant which can coordinate with lithium ions is developed, and the extractant can be used for independently extracting lithium from the lithium precipitation mother liquor, then back-extracting and precipitating lithium to obtain lithium carbonate, so that the recovery rate of lithium is improved.

Description

A method for extracting lithium from lithium ore

Technical Field

The invention belongs to the technical field of mineral processing, and in particular relates to a method for extracting lithium from lithium ore.

Background technique

my country is a country with abundant lithium resources. Lithium resources exist in the form of solid silicate lithium ore and salt lake brine lithium ore. The lithium salt lakes containing salt lake brine lithium ore in my country are located in remote areas with high altitudes and little effective development time. In addition, the magnesium-lithium ratio of salt lake brine lithium ore in lithium salt lakes is high and difficult to separate. Therefore, solid silicate lithium ore has become the main raw material for lithium extraction in my country. How to develop and utilize these resources is of great significance to the development of my country's lithium industry.

At present, spodumene and lepidolite are mainly used for lithium extraction from ore in industry, and different lithium extraction processes have been developed for the two. The methods for extracting lithium from lepidolite include sulfate method, high-pressure alkali boiling method, sulfuric acid method, chloride method and mechanical activation method, which are less mature than the lithium extraction process of spodumene. There are two main types of lithium extraction processes using spodumene as the production raw material: one is to directly extract lithium using natural α-spodumene as the production raw material. This method has a short production process, but requires the use of a large amount of strong acid and strong alkali, with high production costs and high pollution, and also produces a large amount of reaction slag that is difficult to handle. The other type is to first convert α-spodumene into β-spodumene by high-temperature roasting (the temperature is generally between 1000 and 1200°C), and then use β-spodumene as the production raw material for lithium extraction. This method has a long production process, high energy consumption, high production cost and low efficiency of lithium extraction. How to further improve the extraction efficiency of lithium using natural α-spodumene as the raw material is a problem that needs to be solved in this field.

Summary of the invention

The object of the present invention is to provide a method for extracting lithium from lithium ore. The efficiency of extracting lithium from lithium ore is effectively improved by further extracting lithium from lithium precipitated mother liquor after conventional lithium extraction from spodumene.

To achieve the above object, the present invention provides the following technical solutions:

A method for extracting lithium from lithium ore, comprising the following steps:

α-spodumene is converted into β-spodumene by roasting; the β-spodumene is mixed with sulfuric acid and roasted; the roasted product is soaked in water, filtered, and the filtrate is impurity-removed to obtain a lithium-containing solution; carbonate is added to the lithium-containing solution to precipitate lithium carbonate, filtered, a composite extractant is added to the filtrate to extract lithium, the lithium-containing extractant is separated, lithium is stripped, and carbonate is continuously added to the stripping solution to precipitate lithium carbonate;

The composite extractant is tri(2,5-xylyl)phosphine, phosphate and diluent mixed in a volume ratio of 5-15:5-15:70-90.

Preferably, the calcination temperature of the α-spodumene is 1070-1100°C.

Preferably, the mass ratio of the β-spodumene to sulfuric acid is 5:2; and the temperature at which the β-spodumene and sulfuric acid are co-calcined is 250-300°C.

Preferably, in the water immersion step of the calcined product, the solid-liquid ratio of the calcined product to water is 1 g:2-3 mL, the immersion temperature is 80° C., and the immersion time is 30 min.

Preferably, the impurity removal step is specifically to first adjust the pH value of the filtrate to 11 using quicklime, then add 1.1 times the molar amount of sodium carbonate theoretically required for impurity removal, and filter.

Preferably, the phosphate ester is bis(2-ethylhexyl) 2-ethylhexyl phosphate and/or tributyl phosphate.

Preferably, the diluent is 260# sulfonated kerosene.

Preferably, the stripping agent used in the lithium stripping step is a 3 mol/L sulfuric acid solution.

The beneficial technical effects of the present invention are as follows:

The present invention further improves the traditional scheme of recovering lithium from lithium ore. Specifically, in view of the situation that the lithium precipitation mother liquor still contains some lithium, an extractant that can coordinate with lithium ions is developed. The extractant can extract lithium alone from the lithium precipitation mother liquor, and then perform back extraction to precipitate lithium to obtain lithium carbonate, thereby improving the recovery rate of lithium.

Detailed ways

Now, various exemplary embodiments of the present invention are described in detail, which should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the invention.

The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

Example 1

1) 300 g of Li ₂ O-containing spodumene was calcined for 2 h at a calcination temperature of 1080° C.;

2) mixing the calcined spodumene with sulfuric acid in a mass ratio of 5:2, and roasting at 280° C. for 2 h, leaching with water at a liquid-to-solid ratio of 2, at a temperature of 80° C., for a reaction time of 30 min, and filtering;

3) adding quicklime to the filtrate to adjust the pH value to 11, then adding 1.1 times the molar amount of sodium carbonate theoretically required to remove impurities such as calcium and magnesium, and filtering after precipitation;

4) adding sodium carbonate to the filtrate, filtering, and obtaining lithium carbonate and lithium precipitation mother liquor for the first time;

5) first extract the lithium-precipitated mother liquor with the prepared composite extractant, separate the lithium-rich composite extractant (organic phase), wash with water, then strip with 3 mol/L sulfuric acid solution, add sodium carbonate to the lithium-rich stripping solution, filter, wash and dry to obtain battery-grade Li ₂ CO ₃ ;

The preparation method of the composite extractant in this embodiment is as follows: the extractant is tri(2,5-xylyl)phosphine: 2-ethylhexyl bis(2-ethylhexyl) phosphate: 260# sulfonated kerosene mixed in a volume ratio of 5:15:80.

Example 2

1) 300 g of Li ₂ O-containing spodumene was calcined for 2 h at a calcination temperature of 1080° C.;

2) mixing the calcined spodumene with sulfuric acid in a mass ratio of 5:2, and roasting at 280° C. for 2 h, leaching with water at a liquid-to-solid ratio of 2, at a temperature of 80° C., for a reaction time of 30 min, and filtering;

3) adding quicklime to the filtrate to adjust the pH value to 11, then adding 1.1 times the molar amount of sodium carbonate theoretically required to remove impurities such as calcium and magnesium, and filtering after precipitation;

4) adding sodium carbonate to the filtrate, filtering to obtain lithium carbonate and lithium precipitation mother liquor for the first time;

5) first extract the lithium-precipitated mother liquor with the prepared composite extractant, separate the lithium-rich composite extractant (organic phase), wash with water, then strip with 3 mol/L sulfuric acid solution, add sodium carbonate to the lithium-rich stripping solution, filter, wash and dry to obtain battery-grade Li ₂ CO ₃ ;

The preparation method of the composite extractant in this embodiment is: tri(2,5-xylyl)phosphine: bis(2-ethylhexyl) phosphate: 260# sulfonated kerosene are uniformly mixed in a volume ratio of 10:15:75.

Example 3

1) 300 g of Li ₂ O-containing spodumene was calcined for 2 h at a calcination temperature of 1080° C.;

2) mixing the calcined spodumene with sulfuric acid in a mass ratio of 5:2, and roasting at 280° C. for 2 h, leaching with water at a liquid-to-solid ratio of 2, at a temperature of 80° C., for a reaction time of 30 min, and filtering;

3) adding quicklime to the filtrate to adjust the pH value to 11, then adding 1.1 times the molar amount of sodium carbonate theoretically required to remove impurities such as calcium and magnesium, and filtering after precipitation;

4) adding sodium carbonate to the filtrate, filtering to obtain lithium carbonate and lithium precipitation mother liquor for the first time;

5) first extract the lithium-precipitated mother liquor with the prepared composite extractant, separate the lithium-rich composite extractant (organic phase), wash with water, then strip with 3 mol/L sulfuric acid solution, add sodium carbonate to the lithium-rich stripping solution, filter, wash and dry to obtain battery-grade Li ₂ CO ₃ ;

The preparation method of the composite extractant in this embodiment is: tri(2,5-xylyl)phosphine: 2-ethylhexyl bis(2-ethylhexyl) phosphate: 260# sulfonated kerosene are uniformly mixed in a volume ratio of 10:5:85.

Example 4

1) 300 g of Li ₂ O-containing spodumene was calcined for 2 h at a calcination temperature of 1080° C.;

2) mixing the calcined spodumene with sulfuric acid in a mass ratio of 5:2, and roasting at 280° C. for 2 h, leaching with water at a liquid-to-solid ratio of 2, at a temperature of 80° C., for a reaction time of 30 min, and filtering;

3) adding quicklime to the filtrate to adjust the pH value to 11, then adding 1.1 times the molar amount of sodium carbonate theoretically required to remove impurities such as calcium and magnesium, and filtering after precipitation;

4) adding sodium carbonate to the filtrate, filtering to obtain lithium carbonate and lithium precipitation mother liquor for the first time;

5) first extract the lithium-precipitated mother liquor with the prepared composite extractant, separate the lithium-rich composite extractant (organic phase), wash with water, then strip with 3 mol/L sulfuric acid solution, add sodium carbonate to the lithium-rich stripping solution, filter, wash and dry to obtain battery-grade Li ₂ CO ₃ ;

The preparation method of the composite extractant in this embodiment is: uniformly mix tri(2,5-xylyl)phosphine: tributyl phosphate: 260# sulfonated kerosene in a volume ratio of 5:5:90.

Example 5

1) 300 g of Li ₂ O-containing spodumene was calcined for 2 h at a calcination temperature of 1080° C.;

2) mixing the calcined spodumene with sulfuric acid in a mass ratio of 5:2, and roasting at 280° C. for 2 h, leaching with water at a liquid-to-solid ratio of 2, at a temperature of 80° C., for a reaction time of 30 min, and filtering;

3) adding quicklime to the filtrate to adjust the pH value to 11, then adding 1.1 times the molar amount of sodium carbonate theoretically required to remove impurities such as calcium and magnesium, and filtering after precipitation;

4) adding sodium carbonate to the filtrate, filtering to obtain lithium carbonate and lithium precipitation mother liquor for the first time;

5) first extract the lithium-precipitated mother liquor with the prepared composite extractant, separate the lithium-rich composite extractant (organic phase), wash with water, then strip with 3 mol/L sulfuric acid solution, add sodium carbonate to the lithium-rich stripping solution, filter, wash and dry to obtain battery-grade Li ₂ CO ₃ ;

The preparation method of the composite extractant in this embodiment is: uniformly mix tri(2,5-xylyl)phosphine: tributyl phosphate: 260# sulfonated kerosene in a volume ratio of 15:15:70.

Example 6

1) 300 g of Li ₂ O-containing spodumene was calcined for 2 h at a calcination temperature of 1080° C.;

2) mixing the calcined spodumene with sulfuric acid in a mass ratio of 5:2, and roasting at 280° C. for 2 h, leaching with water at a liquid-to-solid ratio of 2, at a temperature of 80° C., for a reaction time of 30 min, and filtering;

3) adding quicklime to the filtrate to adjust the pH value to 11, then adding 1.1 times the molar amount of sodium carbonate theoretically required to remove impurities such as calcium and magnesium, and filtering after precipitation;

4) adding sodium carbonate to the filtrate, filtering to obtain lithium carbonate and lithium precipitation mother liquor for the first time;

5) first extract the lithium-precipitated mother liquor with the prepared composite extractant, separate the lithium-rich composite extractant (organic phase), wash with water, then strip with 3 mol/L sulfuric acid solution, add sodium carbonate to the lithium-rich stripping solution, filter, wash and dry to obtain battery-grade Li ₂ CO ₃ ;

The preparation method of the composite extractant in this embodiment is: tri(2,5-xylyl)phosphine: tributyl phosphate: 260# sulfonated kerosene are uniformly mixed in a volume ratio of 15:15:70.

The mass of lithium carbonate obtained in steps 4) and 5) of Example 1-6 was weighed, and the recovery rate of lithium was calculated. The calculation results are shown in Table 1.

Table 1

The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims (8)

1. A method for extracting lithium from lithium ore, characterized in that it comprises the following steps: α-spodumene is converted into β-spodumene by roasting; the β-spodumene is mixed with sulfuric acid and roasted; the roasted product is soaked in water, filtered, and the filtrate is impurity-removed to obtain a lithium-containing solution; carbonate is added to the lithium-containing solution to precipitate lithium carbonate, filtered, a composite extractant is added to the filtrate to extract lithium, the lithium-containing extractant is separated, lithium is stripped, and carbonate is continuously added to the stripping solution to precipitate lithium carbonate; The composite extractant is tri(2,5-xylyl)phosphine, phosphate and diluent mixed in a volume ratio of 5-15:5-15:70-90. 2. The method for extracting lithium from lithium ore according to claim 1, characterized in that the roasting temperature of the α-spodumene is 1070-1100°C. 3. The method for extracting lithium from lithium ore according to claim 1, characterized in that the mass ratio of the β-spodumene to sulfuric acid is 5:2; the temperature at which the β-spodumene and sulfuric acid are co-roasted is 250-300°C. 4. The method for extracting lithium from lithium ore according to claim 1, characterized in that in the water leaching step of the roasted product, the solid-liquid ratio of the roasted product to water is 1g:2-3mL, the immersion temperature is 80°C, and the time is 30min. 5. The method for extracting lithium from lithium ore according to claim 1 is characterized in that the impurity removal step specifically comprises first adjusting the pH value of the filtrate to 11 using quicklime, then adding 1.1 times the molar amount of sodium carbonate theoretically required for impurity removal, and filtering. 6. The method for extracting lithium from lithium ore according to claim 1, characterized in that the phosphate ester is 2-ethylhexyl bis(2-ethylhexyl) phosphate and/or tributyl phosphate. 7. The method for extracting lithium from lithium ore according to claim 1, characterized in that the diluent is 260# sulfonated kerosene. 8. The method for extracting lithium from lithium ore according to claim 1, characterized in that the stripping agent used in the lithium stripping step is a 3 mol/L sulfuric acid solution.