Method for selectively extracting lithium from clay type lithium ore through ferric sulfate roasting and water leaching

Abstract

The invention discloses a method for selectively extracting lithium from clay type lithium ore through ferric sulfate roasting and water leaching, and belongs to the technical field of chemical engineering. The method comprises the following steps: uniformly mixing clay type lithium ore and ferric sulfate through fine grinding to obtain a mixture, and roasting the mixture to obtain roasted clinker; and adding water into the roasted clinker to carry out leaching reaction, and carrying out solid-liquid separation to obtain a lithium-containing leachate. When the method is used for leaching lithium, the leaching rate of lithium can reach 80% or above, the leaching rate of aluminum in the leachate is low, and selective leaching of lithium is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for selectively extracting lithium from clay-type lithium ore by ferric sulfate roasting and water leaching. Background Art

[0002] Clay-type lithium ore is a new type of lithium ore distributed in Yunnan, Guizhou, Guangxi and North China. The effective development and utilization of these clay-type lithium ore will effectively alleviate the current strategic problems such as high dependence on foreign lithium resources. Since the newly discovered clay-type lithium ore is different from the traditional hard rock lithium ore and brine lithium resources, and also different from the lithium-containing clay reported abroad, there is no known mature technical method to directly refer to.

[0003] With the continuous discovery of clay-type lithium mines and the increasing demand for lithium resources in the new energy industry, the extraction of clay-type lithium mines has also received widespread attention. Some technologies have proposed the use of roasted lithium mines and then the use of various inorganic acids and organic acids to leach lithium. Since the aluminum in the lithium mine after roasting is not as good as lithium, the purpose of lithium leaching rate being higher than that of aluminum and other elements can be achieved to a certain extent. However, this type of technology has the disadvantages of large acid dosage, a large amount of acid remaining in the leaching residue, high acidity of the leaching solution, high cost of subsequent impurity removal and complex process. In order to improve the leaching rate of lithium, some technical methods have proposed adding different reagents for synergistic acid leaching, such as using chlorination roasting-acid leaching to extract lithium. However, this method has a high roasting temperature, introduces chloride ions in addition to sulfate ions, and does not achieve selective leaching of lithium (Experimental study on chlorination roasting-acid leaching of lithium from clay-type lithium ore, Nonferrous Metals (Ore Dressing Part), Zhong Zhenyu, etc.); using sulfuric acid and ferric chloride to synergistically extract lithium will also introduce two anions at the same time, which is not conducive to the subsequent separation and purification of lithium (Separation and Purification Technology 354 (2025) 129439).

[0004] The technology of reducing or not using acid in the process of lithium extraction has certain advantages, mainly the sulfidation roasting-water leaching technology solution. In addition to the low acidity of the leached residue, the water leaching also has the advantage that the leaching solution can be recycled to leach the roasted clinker. The patent with application number 202410857843.7 proposes steps such as ammonium sulfate mixed roasting to extract lithium from clay lithium ore, but the use of ammonium salts will produce ammonia during the roasting process, which is environmentally unfriendly. Similar sulfidation roasting processes also include the use of sodium sulfate or a variety of mixed sulfates (Minerals Engineering218(2024)109004; application number 202410857823.X) for sulfidation, but this method has problems such as high roasting temperature (800°C), introduction of impurity elements such as sodium, and large amount of added sulfate. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned existing sulfidation roasting technology, the present invention proposes a method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching. The method has simple process, low cost, high extraction rate, and environmental friendliness, and has practical application value.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for selectively extracting lithium from a clay-type lithium ore by a ferric sulfate roasting and water leaching method comprises the following steps: finely grinding the clay-type lithium ore and ferric sulfate to obtain a mixture, roasting the mixture to obtain a roasted clinker; adding water to the roasted clinker to carry out a leaching reaction, and performing solid-liquid separation to obtain a lithium-containing leachate.

[0008] The present invention proposes a method for selectively extracting lithium from clay-type lithium ore by roasting and leaching with iron sulfate. Iron sulfate is a kind of environmentally friendly salt with wide sources and low cost. Soluble lithium sulfate can be produced during the roasting process, while iron and aluminum are hydrolyzed and precipitated during the heating and leaching process and do not enter the leaching solution. The hydrolyzed and precipitated iron and aluminum are easy to be recycled and utilized later.

[0009] Furthermore, the mass ratio of the clay-type lithium ore to iron sulfate is 1:(0.6-1).

[0010] Furthermore, the fine grinding refers to fine grinding until the powder is smaller than 200 mesh.

[0011] Furthermore, the calcination treatment is carried out at a temperature of 550-650° C. and for a time of 1 hour.

[0012] Furthermore, the usage ratio of the roasted clinker to water is 1 g:10 mL.

[0013] Furthermore, the leaching reaction temperature is 95° C. and the time is 1-3 hours.

[0014] Compared with the prior art, the present invention has the following advantages and technical effects:

[0015] As a low-cost and environmentally friendly reagent, ferric sulfate can avoid the use of various acids during the roasting process, and also avoid the use of sodium sulfate, chloride, etc. to introduce sodium ions or chloride ions. Compared with ammonium sulfate sulfidation roasting, it avoids the production of ammonia that is not environmentally friendly. The main process involves material mixing, roasting, hot water leaching, etc. Therefore, the present invention uses ferric sulfate for sulfidation roasting to achieve the selective extraction of lithium from clay-type lithium ore. Compared with the existing roasting-acid leaching technical solution, it belongs to the acid-free system for leaching lithium; compared with the existing sulfidation roasting-water leaching technical solution, it has the advantages of environmental friendliness and simple operation.

[0016] When lithium is leached using the method of the present invention, the leaching rate of lithium is close to that of acid leaching, which can reach more than 80%. The leaching rate of aluminum in the leaching solution is low, thereby achieving selective leaching of lithium. DETAILED DESCRIPTION

[0017] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0018] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described 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.

[0019] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0020] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0021] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0022] A method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching, comprising the following steps:

[0023] (1) Mixing: Mixing clay-type lithium ore and iron sulfate in a certain mass ratio and mixing by fine grinding;

[0024] (2) calcining: calcining the mixture obtained in step (1) at a set temperature for 1 hour to obtain a calcined clinker;

[0025] (3) water leaching: leaching the roasted clinker obtained in step (2) with water, the water leaching process being carried out under temperature control;

[0026] (4) Filtration and separation: After the reaction in step (3) is completed, solid-liquid separation is performed to obtain a lithium-containing leaching solution.

[0027] In some embodiments of the present invention, the mass ratio of the clay-type lithium ore to the iron sulfate in step (1) is 1:(0.6-1). Exemplarily, in the following preferred embodiments of the present invention, the mass ratio of the clay-type lithium ore to the iron sulfate is 1:0.6, 1:0.8, 1:1 or any range between the aforementioned ratios.

[0028] In some embodiments of the present invention, the fine grinding in step (1) refers to fine grinding until the powder is smaller than 200 mesh, i.e., passing through a 200 mesh sieve.

[0029] In some embodiments of the present invention, the temperature of the calcination treatment in step (2) is 550-650°C. Exemplarily, in the following preferred embodiments of the present invention, the temperature of the calcination treatment is 550°C, 600°C, 650°C or any value between the aforementioned ranges; the calcination treatment time is 1 hour.

[0030] In some embodiments of the present invention, the ratio of the roasted clinker to water in step (3) is 1 g: 10 mL.

[0031] In some embodiments of the present invention, the temperature of the leaching reaction in step (3) is 95° C., and the leaching reaction time is 1-3 hours. Exemplarily, in the following preferred embodiments of the present invention, the leaching reaction time is 1 hour, 3 hours or any value between the aforementioned ranges.

[0032] When lithium is leached using the method of the present invention, the leaching rate of lithium is above 70%, while the leaching rate of aluminum is below 25%.

[0033] The "parts" described in the present invention, unless otherwise specified, refer to parts by mass.

[0034] The raw materials used in the present invention are all purchased from the market.

[0035] The technical solution of the present invention is further illustrated by the following embodiments.

[0036] In the following examples of the present invention, the main chemical composition of the clay-type lithium ore used includes (wt%): Al2O3 is 16%, SiO2 is 44%, CaO is 12%, Fe2O3 is 4.4%, K2O is 1.3%, TiO2 is 0.7%, the ore sample loss on ignition is 16%, and lithium (Li) is 0.239%.

[0037] Example 1

[0038] Weigh 10 parts of clay-type lithium ore and 6 parts of ferric sulfate (i.e., the mass ratio is 1:0.6) and mix them, and grind the mixture to 200 mesh to mix them. The obtained mixture is roasted at a roasting temperature of 550°C for 1 hour. The roasted clinker is leached with water, and the roasted clinker and water are mixed at a solid-liquid ratio of 1g:10mL. The water leaching process is reacted at a temperature of 95°C for 1 hour, accompanied by oscillation to ensure sufficient leaching reaction. After the reaction is completed, solid-liquid separation is carried out to obtain a lithium-containing leaching solution.

[0039] After testing, the pH value of the lithium-containing leaching solution was 3.88, the lithium leaching rate was 70.43%, the iron-lithium concentration ratio was 2.55, and the aluminum leaching rate was 7.26%.

[0040] Example 2

[0041] Weigh 10 parts of clay-type lithium ore and 8 parts of ferric sulfate (i.e., the mass ratio is 1:0.8) and mix them, and grind the mixture to 200 mesh to mix them. The obtained mixture is roasted at a roasting temperature of 550°C for 1 hour. The roasted clinker is leached with water, and the roasted clinker and water are mixed at a solid-liquid ratio of 1g:10mL. The water leaching process is reacted at a temperature of 95°C for 1 hour, accompanied by oscillation to ensure sufficient leaching reaction. After the reaction is completed, solid-liquid separation is carried out to obtain a lithium-containing leaching solution.

[0042] After testing, the pH value of the lithium-containing leaching solution was 2.52, the lithium leaching rate was 80.89%, the iron-lithium concentration ratio was 13.43, and the aluminum leaching rate was 15.37%.

[0043] Example 3

[0044] Weigh 10 parts of clay-type lithium ore and 10 parts of ferric sulfate (i.e., the mass ratio is 1:1) and mix them, and grind the mixture to 200 mesh to mix them. The obtained mixture is roasted at a roasting temperature of 550°C for 1 hour. The roasted clinker is leached with water, and the roasted clinker and water are mixed at a solid-liquid ratio of 1g:10mL. The water leaching process is reacted at a temperature of 95°C for 1 hour, accompanied by oscillation to ensure sufficient leaching reaction. After the reaction is completed, solid-liquid separation is carried out to obtain a lithium-containing leaching solution.

[0045] After testing, the pH value of the lithium-containing leaching solution was 2.50, the lithium leaching rate was 81.24%, the iron-lithium concentration ratio was 29.86, and the aluminum leaching rate was 20.17%.

[0046] It can be seen from Examples 1-3 that the leaching rate of lithium increases with the increase in the amount of iron sulfate. If the amount of iron sulfate corresponding to 1 part of clay-type lithium ore is less than 0.6 parts, it can be predicted that the leaching rate of lithium is less than 70.43%, and the leaching rate is too low to meet the extraction and utilization of lithium resources. Similarly, it can be seen from Examples 1-3 that the iron-lithium concentration ratio and the leaching rate of aluminum in the leachate increase significantly with the increase in the amount of iron sulfate. If the amount of iron sulfate corresponding to 1 part of clay-type lithium ore is greater than 1.0 parts, the concentrations of iron and aluminum in the leachate are too high, which is not conducive to the subsequent separation of lithium, and the technical advantage of lithium selective leaching is lost.

[0047] Example 4

[0048] Weigh 10 parts of clay-type lithium ore and 8 parts of ferric sulfate (i.e., the mass ratio is 1:0.8) and mix them, and grind the mixture to 200 mesh to mix them. The obtained mixture is roasted at a roasting temperature of 600°C for 1 hour. The roasted clinker is leached with water, and the roasted clinker and water are mixed at a solid-liquid ratio of 1g:10mL. The water leaching process is reacted at a temperature of 95°C for 1 hour, accompanied by oscillation to ensure sufficient leaching reaction. After the reaction is completed, solid-liquid separation is carried out to obtain a lithium-containing leaching solution.

[0049] After testing, the pH value of the lithium-containing leaching solution was 2.95, the lithium leaching rate was 81.59%, the iron-lithium concentration ratio was 3.45, and the aluminum leaching rate was 18.16%.

[0050] Example 5

[0051] Weigh 10 parts of clay-type lithium ore and 8 parts of ferric sulfate (i.e., the mass ratio is 1:0.8) and mix them, and grind the mixture to 200 mesh to mix them. The obtained mixture is roasted at a roasting temperature of 600°C for 1 hour. The roasted clinker is leached with water, and the roasted clinker and water are mixed at a solid-liquid ratio of 1g:10mL. The water leaching process is reacted at a temperature of 95°C for 3 hours, accompanied by shaking to ensure that the leaching reaction is sufficient. After the reaction is completed, solid-liquid separation is carried out to obtain a lithium-containing leaching solution.

[0052] After testing, the pH value of the lithium-containing leaching solution was 3.31, the lithium leaching rate was 78.80%, the iron-lithium concentration ratio was 2.60, and the aluminum leaching rate was 16.54%.

[0053] Example 6

[0054] Weigh 10 parts of clay-type lithium ore and 10 parts of ferric sulfate (i.e., the mass ratio is 1:1) and mix them, and grind the mixture to 200 mesh to mix them. The obtained mixture is roasted at a roasting temperature of 600°C for 1 hour. The roasted clinker is leached with water, and the roasted clinker and water are mixed at a solid-liquid ratio of 1g:10mL. The water leaching process is reacted at a temperature of 95°C for 1 hour, accompanied by shaking to ensure sufficient leaching reaction. After the reaction is completed, solid-liquid separation is carried out to obtain a lithium-containing leaching solution.

[0055] After testing, the pH value of the lithium-containing leaching solution was 2.31, the lithium leaching rate was 81.59%, the iron-lithium concentration ratio was 13.08, and the aluminum leaching rate was 23.32%.

[0056] Example 7

[0057] Weigh 10 parts of clay-type lithium ore and 10 parts of ferric sulfate (i.e., the mass ratio is 1:1) and mix them, and grind the mixture to 200 mesh to mix them. The obtained mixture is roasted at a roasting temperature of 650°C for 1 hour. The roasted clinker is leached with water, and the roasted clinker and water are mixed at a solid-liquid ratio of 1g:10mL. The water leaching process is reacted at a temperature of 95°C for 1 hour, accompanied by oscillation to ensure sufficient leaching reaction. After the reaction is completed, solid-liquid separation is carried out to obtain a lithium-containing leaching solution.

[0058] After testing, the pH value of the lithium-containing leaching solution was 3.25, the lithium leaching rate was 80.89%, the iron-lithium concentration ratio was 1.08, and the aluminum leaching rate was 22.71%.

[0059] Comparative Example 1

[0060] The same as Example 1, except that the water leaching process is carried out at a temperature of 25° C. for 1 hour to obtain a lithium-containing leaching solution.

[0061] After testing, the pH of the lithium-containing leachate was 2.52, the leaching rate of lithium was 75.52%, the leaching rate of aluminum was 6.36%, a large amount of iron precipitation appeared in the leachate, and the iron-lithium concentration ratio reached 113.28, while the iron-lithium concentration ratio in Example 1 was 2.55. It can be seen that the pH of the leachate in Comparative Example 1 is lower, and the leaching rates of lithium and aluminum do not change much, but the low immersion temperature causes a large amount of iron to not be hydrolyzed and remain in the solution, losing the technical advantage of lithium selective leaching.

[0062] Comparative Example 2

[0063] The same as Example 4, except that an equal volume of water in the water leaching process is replaced by dilute hydrochloric acid with a concentration of 0.25 mol / L to obtain a lithium-containing leaching solution.

[0064] After testing, the pH value of the lithium-containing leaching solution was 1.93, the lithium leaching rate was 81.94%, the iron-lithium concentration ratio was 8.92, and the aluminum leaching rate was 34.55%.

[0065] Compared with Example 4, dilute hydrochloric acid is selected as the leaching solution, and the pH of the lithium-containing leaching solution obtained is lower, the lithium leaching rate does not change much, while the aluminum leaching rate is significantly high, and the technical advantage of selective extraction of lithium is lost.

[0066] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching, characterized in that: The following steps are involved: The clay-type lithium ore and ferric sulfate are finely ground and mixed to obtain a mixture, and the mixture is roasted to obtain a roasted clinker; Water is added to the roasted clinker to carry out leaching reaction, and solid-liquid separation is performed to obtain a lithium-containing leaching solution.

2. The method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching according to claim 1, characterized in that: The mass ratio of the clay-type lithium ore to ferric sulfate is 1:(0.6-1).

3. The method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching according to claim 1, characterized in that: The mass ratio of the clay-type lithium ore to iron sulfate is 1:

1.

4. The method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching according to claim 1, characterized in that: The fine grinding refers to fine grinding until the powder is smaller than 200 mesh.

5. The method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching according to claim 1, characterized in that: The calcination temperature is 550-650° C. and the calcination time is 1 hour.

6. The method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching according to claim 1, characterized in that: The calcination process was carried out at a temperature of 600° C. and for a period of 1 hour.

7. The method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching according to claim 1, characterized in that: The usage ratio of the roasted clinker to water is 1g:10mL.

8. The method for selectively extracting lithium from clay-type lithium ore by iron sulfate roasting and water leaching according to claim 1, characterized in that: The leaching reaction temperature is 95° C. and the time is 1-3 hours.