Method for extracting lithium and beryllium from lepidolite concentrate

Abstract

The invention provides a method for extracting lithium and beryllium from lepidolite concentrate, and relates to the technical field of lithium extraction from concentrate. The method comprises the following steps: mixing and grinding lepidolite concentrate and auxiliary materials, roasting at high temperature, leaching the roasted clinker with water, carrying out solid-liquid separation to obtain a leaching solution and leaching residues, adding a neutralizer into the leaching solution, adjusting the pH value of the leaching solution to 8, precipitating impurities such as iron, aluminum, beryllium and manganese in the leaching solution, and carrying out solid-liquid separation to obtain an impurity-removed solution and neutralized residues. By adding the auxiliary materials, the lithium and beryllium elements in the lepidolite can be selectively replaced, and the content of other impurity metal elements in the leachate is low, so that the subsequent impurity removal process is facilitated. And after neutralization and impurity removal, most beryllium in the mineral can be effectively enriched in a small amount of neutralization slag and can be used for subsequent beryllium extraction.

Description

Technical Field

[0001] The invention relates to the technical field of extracting lithium from ore concentrate, in particular to a method for extracting lithium and beryllium from lepidolite concentrate. Background Art

[0002] Lithium is the lightest metal in nature, with a relative atomic mass of 6.941. It has active chemical properties and usually exists in the form of oxides in nature. It is widely used as lithium-ion batteries to provide the necessary energy for electric vehicles, portable electronic devices, etc.

[0003] At present, the lithium ore resources commonly used for lithium extraction are divided into brine-type lithium ore and pegmatite-type lithium ore. Pegmatite-type lithium ore includes lithium-containing ores such as lepidolite, spodumene, petalite, and iron lithium mica. Among them, spodumene ore has the highest lithium grade, and lithium can be extracted by sulfuric acid method after high-temperature transformation; the lithium grade of lepidolite is relatively low. Due to the differences in the elemental composition and structure of lepidolite and spodumene, a large amount of aluminum and iron are dissolved at the same time when lithium is extracted from lepidolite by sulfuric acid method, which makes it difficult to remove impurities and has a low lithium leaching rate.

[0004] Based on such differences, the main industrial process for obtaining lithium from lepidolite is the sulfate method. The lithium extraction process of lepidolite sulfate method is very mature, and the commonly used sulfate auxiliary materials are sodium sulfate, potassium sulfate, etc. However, the mineral structure is changed during the sulfate production process, resulting in a large number of toxic elements in lithium slag, such as beryllium, thallium, arsenic, etc., being converted into active states, with high leaching toxicity, making lithium slag difficult to dispose of, resulting in waste of resources and increasing the environmental protection costs of enterprises.

[0005] The invention can not only effectively extract the lithium element in the lepidolite mineral, but also selectively extract the beryllium element therein, and enrich it in a small amount of neutralization slag through a simple neutralization process. Summary of the invention

[0006] In order to solve the problem of excessive beryllium leaching toxicity in lithium slag disposal in the prior art, the embodiment of the present invention provides a method for extracting lithium and beryllium from lepidolite concentrate. The technical solution is as follows:

[0007] S1. Calcination:

[0008] The lithium mica concentrate is fully mixed with auxiliary materials, and roasted and transformed at high temperature to transform lithium oxide and beryllium oxide in the lithium mica into lithium sulfate and beryllium sulfate;

[0009] S2. Leaching:

[0010] The clinker after roasting in step S1 is ground, leached with water, and solid-liquid separated to obtain leachate and leach residue;

[0011] S3, neutralization and impurity removal:

[0012] A neutralizing agent is added to the leachate obtained in step S2, and the pH of the leachate is adjusted to 8, and metals such as aluminum, iron, manganese, and beryllium in the leachate are precipitated. After precipitation, solid-liquid separation is performed to obtain a decontamination liquid and a neutralization slag, wherein lithium, potassium, and the like remain in the decontamination liquid, and beryllium, aluminum, iron, and manganese are enriched in the neutralization slag.

[0013] In the step S1, the mass ratio of the auxiliary material to the lepidolite concentrate is 0.5-1, and the particle size of the lepidolite concentrate is 50-80 meshes.

[0014] The auxiliary material in step S1 is at least one of potassium bisulfate and sodium bisulfate.

[0015] In step S1, the calcination temperature is 900°C to 1000°C, and the calcination time is 30 min to 90 min.

[0016] The heating rate during calcination in step S1 is 5-10°C / min, and the calcination reaction is naturally cooled to room temperature after completion.

[0017] In the step S2, the roasted clinker is ground to a particle size of 60-80 meshes.

[0018] During leaching in step S2, the liquid-to-solid ratio is 2:1, and the leaching is performed at room temperature for 1 hour.

[0019] In step S3, the neutralizing agent is one of potassium carbonate, sodium carbonate and ammonium bicarbonate.

[0020] The leached residue obtained in step S2 is washed with water and then filtered, and the process is repeated twice to obtain lithium residue.

[0021] The neutralized residue obtained in step S3 is washed with water and then filtered, and the process is repeated twice to obtain beryllium-containing waste residue.

[0022] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0023] (1) Low environmental pollution: The traditional sulfuric acid method for extracting lithium will react with fluoride ions in mica to produce hydrogen fluoride gas, which not only corrodes equipment but also causes serious pollution to the environment. The present invention does not have these concerns.

[0024] (2) High leaching rates of lithium and beryllium: With the preferred process parameters of the present invention, a lithium leaching rate of >97% and a beryllium leaching rate of >85% can be achieved.

[0025] (3) The experimental process flow is simple: The experimental process flow of the present invention is simple and similar to the currently used sulfate process flow, and can be easily applied to industrial production.

[0026] (4) Beryllium can be effectively enriched: By selecting a suitable neutralizing agent, beryllium can be enriched in a small amount of neutralization slag. Depending on the beryllium content in the lepidolite mineral, beryllium can be enriched 20 to 100 times. The beryllium content in the neutralization slag is 0.2% to 4%, which can be used for further extraction of beryllium, making the beryllium in the lepidolite mineral a resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 The present invention provides a flow chart of a method for extracting lithium and beryllium from lepidolite concentrate. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0030] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0031] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0032] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0033] The embodiment of the present invention provides a method for extracting lithium and beryllium from lepidolite concentrate. Figure 1 The method flow chart of extracting lithium and beryllium from lithium mica concentrate shown in FIG. 1 may include the following steps:

[0034] S1. Calcination:

[0035] The lithium mica concentrate is fully mixed with auxiliary materials, and roasted and transformed at high temperature to transform lithium oxide and beryllium oxide in the lithium mica into lithium sulfate and beryllium sulfate;

[0036] S2. Leaching:

[0037] The clinker after roasting in step S1 is ground, leached with water, and solid-liquid separated to obtain leachate and leach residue;

[0038] S3, neutralization and impurity removal:

[0039] A neutralizing agent is added to the leaching solution obtained in step S2 to adjust the pH value of the leaching solution to 8. After precipitation, solid-liquid separation is performed to obtain a decontaminated liquid and a neutralized slag.

[0040] The following will explain it with reference to specific embodiments.

[0041] Example 1

[0042] This embodiment provides a method for extracting lithium and beryllium from lepidolite concentrate, comprising the following steps:

[0043] Roasting and leaching: Lepidolite concentrate comes from mixed mica ore in enterprises in Yichun City, Jiangxi Province, and the composition is shown in Table 1. Weigh 20 g of lepidolite concentrate and 14 g of potassium hydrogen sulfate, grind and mix them thoroughly, and then heat them to 950 °C at a heating rate of 5 °C / min at room temperature. After roasting for 90 min, they are naturally cooled to room temperature. The transformed clinker is ground and weighed, and water is added at a liquid-solid ratio of 2:1 to leach at room temperature for 1 h. The leachate, washing solution and leach residue are obtained by filtration and washing. The dissolution of the main elements of lepidolite is as follows: lithium leaching rate is 99.5%, beryllium leaching rate is 98.7%, aluminum leaching rate is 2.9%, iron leaching rate is 4.1%, manganese leaching rate is 97.8%, and silicon is not leached. The composition of the leaching mother liquor is shown in Table 2.

[0044] Table 1 Composition of lepidolite concentrate

[0045]

[0046] Table 2 Leaching liquor composition

[0047]

[0048] Neutralization and impurity removal: The leachate is stirred and potassium carbonate solid is gradually added to adjust the pH to 8. The neutralized residue is filtered to obtain the impurity removal mother liquor. After the neutralized residue is washed twice with water, the lithium recovery rate is 99.83%, and basically no lithium loss occurs. The composition of the impurity removal liquid is shown in Table 3. The composition of the neutralized residue is shown in Table 4. It can be seen that beryllium is enriched more than 20 times compared with the lithium mica concentrate.

[0049] Table 3 Composition of neutralization and impurity removal liquid

[0050]

[0051] Table 4 Neutralized slag composition

[0052]

[0053] Example 2

[0054] This embodiment provides a method for extracting lithium and beryllium from lepidolite concentrate, comprising the following steps:

[0055] Roasting and leaching: The lithium mica concentrate comes from the mixed mica ore in the enterprise of Yichun City, Jiangxi Province, and the composition is shown in Table 1. Weigh 20 g of lithium mica concentrate and 10 g of potassium hydrogen sulfate, grind and mix them thoroughly, and then heat them to 1000 ℃ at a heating rate of 10 ℃ / min at room temperature. After roasting for 30 min, they are naturally cooled to room temperature. The transformed clinker is ground and weighed, and water is added at a liquid-solid ratio of 2:1 to leach at room temperature for 1 h. The leachate, washing liquid and leach residue are obtained by filtering and washing. The dissolution of the main elements of lithium mica is as follows: lithium leaching rate is 99.0%, beryllium leaching rate is 88.4%, aluminum leaching rate is 5.6%, iron leaching rate is 28.9%, manganese leaching rate is 99.5%, and silicon is not leached. The composition of the leaching mother liquor is shown in Table 5.

[0056] Table 5 Leaching liquor composition

[0057]

[0058] Neutralization and impurity removal: The leachate is stirred and potassium carbonate solid is gradually added to adjust the pH to 8. The neutralized residue is filtered to obtain the impurity removal mother liquor. After the neutralized residue is washed twice with water, the lithium recovery rate is 98.98%, and basically no lithium loss occurs. The composition of the impurity removal liquid is shown in Table 6. The composition of the neutralized residue is shown in Table 7. It can be seen that beryllium is enriched more than 20 times compared with the lithium mica concentrate.

[0059] Table 6 Composition of neutralization and impurity removal liquid

[0060]

[0061] Table 7 Neutralized slag composition

[0062]

[0063] Example 3

[0064] This embodiment provides a method for extracting lithium and beryllium from lepidolite concentrate, comprising the following steps:

[0065] Roasting and leaching: The lithium mica concentrate comes from the mixed mica ore in the enterprise of Yichun City, Jiangxi Province, and the composition is shown in Table 1. Weigh 20 g of lithium mica concentrate and 20 g of sodium bisulfate, grind and mix them thoroughly, and then heat them to 900 ℃ at a heating rate of 10 ℃ / min at room temperature. After roasting for 90 min, they are naturally cooled to room temperature. The transformed clinker is ground and weighed, and water is added at a liquid-solid ratio of 2:1 to leach at room temperature for 1 h. The leachate, washing solution and leach residue are obtained by filtering and washing. The dissolution of the main elements of lithium mica is as follows: lithium leaching rate is 99.1%, beryllium leaching rate is 87.6%, aluminum leaching rate is 6.7%, iron leaching rate is 36.1%, manganese leaching rate is 99.03%, and silicon is not leached. The composition of the leaching mother liquor is shown in Table 8.

[0066] Table 8 Leaching liquor composition

[0067]

[0068] Neutralization and impurity removal: The leachate is stirred and potassium carbonate solid is gradually added to adjust the pH to 8. The neutralized residue is filtered to obtain the impurity removal mother liquor. After the neutralized residue is washed twice with water, the lithium recovery rate is 99.83%, and basically no lithium loss occurs. The composition of the impurity removal liquid is shown in Table 9. The composition of the neutralized residue is shown in Table 10. It can be seen that beryllium is enriched more than 20 times compared with the lithium mica concentrate.

[0069] Table 9 Composition of neutralization and impurity removal liquid

[0070]

[0071] Table 10 Neutralized slag composition

[0072]

[0073] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for extracting lithium and beryllium from lepidolite concentrate, characterized in that: The method comprises: S1. Calcination: The lithium mica concentrate is fully mixed with auxiliary materials, and roasted and transformed at high temperature to transform lithium oxide and beryllium oxide in the lithium mica into lithium sulfate and beryllium sulfate; S2. Leaching: The clinker after roasting in step S1 is ground, leached with water, and solid-liquid separated to obtain leachate and leach residue; S3, neutralization and impurity removal: A neutralizing agent is added to the leaching solution obtained in step S2 to adjust the pH value of the leaching solution to 8. After precipitation, solid-liquid separation is performed to obtain a decontaminated liquid and a neutralized slag.

2. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: In the step S1, the mass ratio of the auxiliary material to the lepidolite concentrate is 0.5-1, and the particle size of the lepidolite concentrate is 50-80 meshes.

3. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: The auxiliary material in step S1 is at least one of potassium bisulfate and sodium bisulfate.

4. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: In step S1, the calcination temperature is 900°C to 1000°C, and the calcination time is 30 min to 90 min.

5. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: The heating rate during calcination in step S1 is 5-10°C / min, and the calcination reaction is naturally cooled to room temperature after completion.

6. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: In the step S2, the roasted clinker is ground to a particle size of 60-80 meshes.

7. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: During leaching in step S2, the liquid-to-solid ratio is 2:1, and the leaching is performed at room temperature for 1 hour.

8. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: In step S3, the neutralizing agent is one of potassium carbonate, sodium carbonate and ammonium bicarbonate.

9. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: The leached residue obtained in step S2 is washed with water and then filtered, and the process is repeated twice to obtain lithium residue.

10. The method for extracting lithium and beryllium from lepidolite concentrate according to claim 1, characterized in that: The neutralized residue obtained in step S3 is washed with water and then filtered, and the process is repeated twice to obtain beryllium-containing waste residue.

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