Comprehensive utilization method of by-product aluminum and sodium-containing material slag in process of extracting lithium from aluminum electrolyte

Abstract

The invention relates to a comprehensive utilization method of by-product aluminum-sodium-containing material slag in an aluminum electrolyte lithium extraction process, which comprises the following steps: mixing the by-product aluminum-sodium-containing material slag with acid liquid for reaction, and after the reaction is finished, carrying out solid-liquid separation to obtain filter residue A and filtrate A; washing and calcining the filter residue A to obtain aluminum fluoride; and mixing the filtrate A with a sodium solution to obtain sodium fluoride. By adopting the method to treat the slag after lithium extraction, the final product can be converted into high-quality sodium fluoride and aluminum fluoride; therefore, not only can the resource utilization be maximized effectively, but also economic benefits can be made for the process for extracting lithium from the aluminum electrolyte.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of aluminum resources, and specifically relates to a method for comprehensive utilization of aluminum-sodium-containing slag as a by-product of an aluminum electrolyte lithium extraction process. Background Art

[0002] In recent years, my country's electrolytic aluminum industry has developed rapidly, and its electrolytic aluminum production capacity and output have ranked first in the world for many years. However, the grade of bauxite in my country is relatively low, and it is accompanied by a small amount of alkali metal elements such as lithium and potassium. In addition, the market demand for high-priced lithium elements has gradually increased, and the lithium extraction process of lithium-aluminum electrolytes has been continuously studied. After the lithium element is extracted and converted into lithium carbonate, a large amount of aluminum-sodium compounds will be produced as by-products. For example, patents CN 114438329B and CN 114438329A both mention that the product after lithium extraction is sub-cryolite, which is mainly a mixture of fluorine, aluminum, and sodium. How to convert such substances into high-quality aluminum-containing and sodium-containing products with greater value, fully create the recycling of elements in industrialization, and at the same time create greater economic benefits for the lithium extraction process has become the focus of subsequent research.

[0003] Based on this, this application was developed. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a comprehensive utilization method for the by-product of the aluminum electrolyte lithium extraction process containing sodium aluminum slag. The method of the present invention is used to treat the slag after lithium extraction, so that the final product can be converted into high-quality sodium fluoride and aluminum fluoride; this can not only effectively maximize the utilization of resources, but also create economic benefits for the aluminum electrolyte lithium extraction process.

[0005] To achieve the above object, the present invention adopts the following technical solution: A method for comprehensively utilizing by-product sodium aluminum-containing slag in an aluminum electrolyte lithium extraction process, comprising the steps of firstly mixing the by-product sodium aluminum-containing slag with an acidic liquid for reaction, and performing solid-liquid separation after the reaction to obtain filter residue A and filtrate A; washing the filter residue A with water and calcining it to obtain aluminum fluoride; and mixing the filtrate A with a sodium liquid to obtain sodium fluoride.

[0006] As a preferred embodiment, a method for comprehensive utilization of the aluminum-sodium-containing slag as a by-product of the aluminum electrolyte lithium extraction process comprises the following steps: 1) Mix the by-product sodium aluminum-containing slag with an acidic liquid, and react at 40°C to 70°C for 2 to 4 hours (to obtain aluminum fluoride with crystal water). After the reaction, separate the solid and liquid to obtain filter residue A and filtrate A. Wash the filter residue A with water to obtain filter residue A' and filtrate A'. Calcinate the filter residue A' to obtain solid high-quality aluminum fluoride; 2) Filtrate A and filtrate A' are mixed to form liquid A''; liquid A'' is mixed and stirred with sodium liquid at room temperature, and filtrate B and filter residue B are obtained after solid-liquid separation. The filter residue B is dried to obtain large-particle sodium fluoride.

[0007] Specifically, the acidic liquid is a fluorine-containing acidic liquid, and the acidic liquid may include one or more of hydrochloric acid, sulfuric acid, and nitric acid, and the fluorine content in the acidic liquid is 5% to 15%, and the hydrogen ion concentration is 3 mol / L to 5 mol / L.

[0008] Furthermore, the mass ratio of the by-product sodium aluminum-containing slag to the acidic liquid can be 1:5~8.

[0009] Specifically, the calcination temperature is 100°C to 550°C, and the calcination time is 1-3 hours. Calcination can remove crystal water and a small amount of gray impurities, so that the final aluminum fluoride is white.

[0010] Furthermore, the sodium liquid can be one or more of sodium hydroxide, sodium carbonate and sodium bicarbonate.

[0011] As a preferred embodiment, when filtrate A is mixed with sodium solution, part of the sodium solution is used as the base, and a certain amount of sodium fluoride seed crystals are added at the same time. The filtrate A and the remaining sodium solution are added at the same time, and the addition speed of the sodium solution is faster than the addition speed of the filtrate A. The end point pH is controlled at 10-12 (that is, the pH is controlled within the required range by the addition amount of the sodium solution). In step 2), the mixing speed is controlled at 50-150rpm.

[0012] In the method of the present invention, the by-product aluminum sodium slag is recombined in a fluorine-containing acid solution, and the generated solid ointment is aluminum fluoride with crystal water. The crystal water and gray impurities can be removed by calcination. The separated liquid contains sodium, fluorine and dissolved impurities, and sodium fluoride is obtained by mixing with sodium liquid. The mixing method determines the particle size of sodium fluoride. The present invention can obtain large particles of sodium fluoride by mixing with water as the base. Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The technical solution of the present invention can comprehensively utilize the aluminum-sodium slag by-product after the aluminum electrolyte lithium extraction process, and the final product is high-quality aluminum fluoride (the yield is more than 97.5%, and the quality meets GB / T4292-2027 AF-1 after testing) and large-particle sodium fluoride (the purity is more than 99.5%).

[0013] 2) The present invention is used to modify the by-product of aluminum-sodium slag, which has a simple process and can not only turn waste slag into treasure, but also effectively maximize resource utilization to obtain high-purity aluminum fluoride and large-particle sodium fluoride, and can also create economic benefits for the aluminum-containing electrolyte lithium extraction process when the lithium carbonate market is depressed. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is further described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited thereto.

[0015] In the following examples, the raw materials used are all commercially available products or can be prepared by conventional methods in the art. Among them, the aluminum electrolyte lithium extraction process by-product containing aluminum sodium slag comes from the aluminum electrolyte lithium extraction process by-product containing aluminum sodium slag of Duofuduo Company, the main elements are fluorine, aluminum, and sodium, and the proportion of each element is shown in the following table, and the impurity content is not listed.

[0016] Room temperature refers to 25±5°C.

[0017] Example 1 A method for comprehensive utilization of aluminum-sodium-containing slag as a by-product of an aluminum electrolyte lithium extraction process, which specifically comprises the following steps: 1) Prepare 600g of fluorine-containing hydrochloric acid solution with a hydrogen ion concentration of 4mol / L and a fluorine content of 10%.

[0018] 2) Then, 100g of the by-product of the lithium extraction process, the aluminum-sodium-containing slag 1#, was slowly added to the above acid solution for reaction for 3h at a reaction temperature of 60°C. After the reaction was completed and the solid-liquid was separated, an ointment and a filtrate A were obtained. The ointment was washed with 200g of water to obtain 123.4g of a paste. The washing liquid and the filtrate A were combined to obtain a liquid A''.

[0019] 3) The paste was calcined, and the calcination procedure was: heating to 100°C and keeping the temperature for 1 hour, and then heating to 550°C and keeping the temperature for 1 hour, to obtain 56.5 g of high-quality aluminum fluoride with a yield of 97.5%. The quality of the aluminum fluoride met GB / T4292-2027 AF-1 after testing.

[0020] 4) 100g of sodium liquid (20% sodium carbonate solution) was used as the base, and 10g of seed crystals were added at the same time. The liquid A'' obtained in step 2) and the remaining sodium carbonate solution with a mass concentration of 20% were added at the same time at room temperature (the mixing speed was controlled at 100rpm), wherein the sodium liquid addition rate was twice that of the liquid A'', and the end point pH was 12. After solid-liquid separation, the ointment was obtained, and then dried to obtain 137g of sodium fluoride, with D50 of 175μm and a purity of 99.7%.

[0021] Example 2 A method for comprehensive utilization of aluminum-sodium-containing slag as a by-product of an aluminum electrolyte lithium extraction process, which specifically comprises the following steps: 1) Prepare 800 g of fluorine-containing sulfuric acid solution with a hydrogen ion concentration of 5 mol / L and a fluorine content of 8%.

[0022] 2) Then, 100 g of the by-product of the lithium extraction process, the aluminum-sodium-containing slag 2#, was slowly added to the above acid solution for reaction for 3 hours at a reaction temperature of 70°C. After the reaction was completed and the solid-liquid was separated, an ointment and a filtrate A were obtained. The ointment was washed with 300 g of water to obtain 115.9 g of a paste. The washing liquid and the filtrate A were combined to obtain a liquid A''.

[0023] 3) The paste was calcined at 150°C for 1 hour, and then at 550°C for 1 hour to obtain 55.6 g of high-quality aluminum fluoride with a yield of 98.7%. The quality of the aluminum fluoride was tested to meet GB / T4292-2027 AF-1.

[0024] 4) 150g of sodium liquid (20% sodium carbonate solution) was used as the base, and 15g of seed crystals were added at the same time. The liquid A'' obtained in step 2) and the remaining mass concentration of 20% sodium bicarbonate solution were added at the same time at room temperature (the mixing speed was controlled at 100rpm), wherein the sodium liquid addition rate was 1.5 times that of liquid A'', and the endpoint pH was 10. After solid-liquid separation, the ointment was dried to obtain 146g of sodium fluoride, with D50 of 184μm and a purity of 99.5%.

[0025] Example 3 A method for comprehensive utilization of aluminum-sodium-containing slag as a by-product of an aluminum electrolyte lithium extraction process, which specifically comprises the following steps: 1) Prepare 600g of fluorine-containing nitric acid solution with a hydrogen ion concentration of 4.5mol / L and a fluorine content of 12%.

[0026] 2) Then, 100 g of the by-product of the lithium extraction process, the aluminum-sodium-containing slag 1#, was slowly added to the above acid solution for reaction for 3 hours at a reaction temperature of 70°C. After the reaction was completed and the solid-liquid separation was performed, an ointment and a filtrate A were obtained. The ointment was washed with 300 g of water to obtain a paste g. The washing liquid and the filtrate A were combined to obtain a liquid A''.

[0027] 3) The paste was calcined at 150°C for 1 hour, and then at 550°C for 1 hour to obtain 57.1 g of high-quality aluminum fluoride with a yield of 98.7%. The quality of the aluminum fluoride was tested to meet GB / T4292-2027 AF-1.

[0028] 4) 100g of aqueous sodium solution (15% sodium hydroxide solution) was used as the base, and 15g of seed crystals were added at the same time. Liquid A'' obtained in step 2) and a residual sodium hydroxide solution with a mass concentration of 15% were added at the same time at room temperature (the mixing speed was controlled at 100rpm), wherein the sodium solution addition rate was twice that of liquid A'', and the end point pH was 11. After solid-liquid separation, the ointment was obtained and dried to obtain 150g of sodium fluoride, with a D50 of 181μm and a purity of 99.6%.

Claims

1. A method for comprehensive utilization of aluminum-sodium-containing slag as a by-product of aluminum electrolyte lithium extraction process, characterized in that: The by-product sodium aluminum-containing slag is mixed with an acidic liquid for reaction, and after the reaction is completed, the solid and liquid are separated to obtain filter residue A and filtrate A; the filter residue A is washed with water and calcined to obtain aluminum fluoride; the filtrate A is mixed with sodium liquid to obtain sodium fluoride.

2. The method for comprehensive utilization of the by-product of the aluminum electrolyte lithium extraction process containing aluminum sodium slag as claimed in claim 1, characterized in that: The steps include: 1) Mix the by-product sodium aluminum-containing slag with an acidic liquid, react at 40°C to 70°C for 2 to 4 hours, separate the solid and liquid after the reaction to obtain filter residue A and filtrate A, wash the filter residue A with water to obtain filter residue A' and filtrate A', and calcine the filter residue A' to obtain aluminum fluoride; 2) Filtrate A and filtrate A' are mixed to form liquid A''; liquid A'' is mixed and stirred with sodium liquid at room temperature, and filtrate B and filter residue B are obtained after solid-liquid separation. The filter residue B is dried to obtain sodium fluoride.

3. The method for comprehensive utilization of the by-product of aluminum-sodium slag from the aluminum electrolyte lithium extraction process as claimed in claim 1, characterized in that: The acidic liquid is a fluorine-containing acidic liquid, and the acidic liquid includes one or more of hydrochloric acid, sulfuric acid and nitric acid, and the fluorine content in the acidic liquid is 5% to 15%, and the hydrogen ion concentration is 3 mol / L to 5 mol / L.

4. The method for comprehensive utilization of the by-product of the aluminum electrolyte lithium extraction process containing sodium aluminum slag as claimed in claim 1, characterized in that: The mass ratio of by-product aluminum-sodium slag to acidic liquid is 1:5~8.

5. The method for comprehensive utilization of the by-product of aluminum-sodium slag from the aluminum electrolyte lithium extraction process as claimed in claim 1, characterized in that: The calcination temperature is 100°C~550°C, and the calcination time is 1-3h.

6. The method for comprehensive utilization of the by-product of aluminum-sodium slag from the aluminum electrolyte lithium extraction process as claimed in claim 1, characterized in that: The sodium liquid is one or more of sodium hydroxide, sodium carbonate and sodium bicarbonate.

7. The method for comprehensive utilization of the by-product of aluminum-sodium slag from the aluminum electrolyte lithium extraction process as claimed in claim 1, characterized in that: When filtrate A is mixed with sodium solution, part of the sodium solution is used as the base, and a certain amount of sodium fluoride seed is added at the same time. Filtrate A and the remaining sodium solution are added at the same time. The addition speed of sodium solution should be faster than that of filtrate A, and the end point pH is controlled at 10-12.

8. The method for comprehensive utilization of the by-product of aluminum-sodium slag from the aluminum electrolyte lithium extraction process as claimed in claim 2, characterized in that: The mixing speed is controlled at 50~150rpm.

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