A system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue

Abstract

The present application relates to waste residue recycling, and provides a system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue, which comprises a ball milling system, a slurry preparation system, an alkali leaching system, an acid leaching system, a fluoride salt directional conversion system, a impurity removal system and a post-treatment system connected in sequence; the alkali leaching system is connected with the fluoride salt directional conversion system. The system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue can efficiently extract valuable lithium elements in the water treatment residue, and significantly improves the economic benefits of harmless disposal and comprehensive utilization of aluminum electrolysis overhaul residue and carbon residue.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste residue recycling, in particular to a system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue. BACKGROUND

[0002] The overhaul residue is waste residue generated by repairing and replacing the cathode lining of the electrolytic cell in the process of electrolytic aluminum production. According to the actual aluminum electrolysis production, the overhaul residue is further divided into three categories: waste cathode, waste refractory material and mixed material.

[0003] The carbon residue is a substance generated by the uneven combustion and selective oxidation of carbon anodes, and the main components of aluminum electrolysis carbon residue are carbon and electrolyte, generally containing 20-30% of carbon and 60-70% of electrolyte.

[0004] For the disposal and comprehensive utilization of aluminum electrolysis overhaul residue and carbon residue, a large number of researches have been conducted by domestic college scholars. At present, the harmless disposal and comprehensive utilization of aluminum electrolysis hazardous waste residue can be divided into two categories: wet treatment and pyrometallurgical treatment. The wet treatment process mainly includes water immersion method, alkali leaching method, acid leaching method and acid-alkali combined leaching method. The pyrometallurgical treatment process mainly adopts high-temperature oxygen-enriched combustion for harmless treatment, or uses the waste cathode as carbonaceous material with available heat value, or recovers electrolyte at high temperature.

[0005] In the process of collaborative treatment and resource utilization of aluminum electrolysis overhaul residue and carbon residue, the alkali leaching liquid and the acid leaching liquid are prepared into cryolite and aluminum fluoride + aluminum oxide products through the neutralization and precipitation process. In order to ensure the safe and efficient operation of the nanofiltration system, the liquid after neutralization and precipitation needs to be treated to remove residues before entering the nanofiltration system. However, in the process of removing residues, the valuable Li elements in the liquid after neutralization and precipitation will enter the water treatment residue, resulting in a large loss of valuable Li elements. In order to improve the utilization rate of valuable Li elements in the process of collaborative treatment and resource utilization of aluminum electrolysis overhaul residue and carbon residue, it is necessary to study the technology for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue. SUMMARY

[0006] The present application aims to provide a system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue, which can efficiently extract valuable lithium elements from the water treatment residue thereof, and significantly improve the economic benefits of the harmless disposal and comprehensive utilization of aluminum electrolysis overhaul residue and carbon residue.

[0007] The embodiment of the present application is implemented by the following technical scheme: the system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue, which comprises a ball milling system, a slurry preparation system, an alkali leaching system, an acid leaching system, a fluoride salt directional conversion system, a impurity removal system and a post-treatment system connected in sequence, and the alkali leaching system is connected with the fluoride salt directional conversion system.

[0008] Further, the post-treatment system comprises an evaporation concentration system, a cooling crystallization system, and a washing and drying system.

[0009] Further, the impurity removal system comprises a mixing tank, filter cloth attached to the inner side wall and the inner bottom wall of the mixing tank, and an air inlet device arranged below the inside of the mixing tank; the filter cloth has a cylindrical structure with a closed lower end.

[0010] Further, the air inlet device comprises an air inlet hole formed in the bottom wall of the mixing tank, an air inlet pipe arranged at the air inlet hole, and a gas supply device connected to the air inlet pipe.

[0011] Further, the air inlet device further comprises a baffle arranged at the air inlet hole, and a spring arranged in the air inlet pipe to support the baffle.

[0012] Further, the air inlet device further comprises a partition plate arranged in the air inlet pipe, and a plurality of air holes formed in the partition plate; the spring is arranged between the partition plate and the baffle.

[0013] Further, the diameter of the upper end surface of the baffle is greater than the diameter of the lower end surface.

[0014] Further, the impurity removal system further comprises a compression ring arranged at the bottom edge of the filter cloth.

[0015] Further, the upper side of the compression ring is provided with a plurality of pull rods, the upper end of each pull rod is provided with a hook, and the hook is hung on the upper side wall of the mixing tank.

[0016] The technical scheme of the embodiment of the present application has at least the following advantages and beneficial effects: the system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue of the present application uses a ball milling system to crush and grind the overhaul residue, carbon residue and the like into powder, then sends the powder into a slurry preparation system to prepare slurry, sends the slurry into an alkali leaching system, uses alkali solution to leach the slurry, after filtration, sends the solid into an acid leaching system, uses acid solution to leach the solid, then sends the alkali leaching solution and the acid leaching solution into a fluoride salt directional conversion system, after solid-liquid separation, sends the neutralized and precipitated liquid into an impurity removal system, in the impurity removal system, air is introduced into the precipitated liquid and a flocculating agent is added to remove Fe, Si, F, AI, Ca, Mg and other impurities, and Li is also precipitated into the filter residue, in the post-treatment system, the filter residue is dissolved in a solution, Fe, Si, F, AI, Ca, Mg and other impurities are removed, and a filtrate containing high Li is obtained. The filtrate is concentrated to obtain a high-concentration Li-containing solution. Through the system, the valuable lithium elements in the water treatment residue can be efficiently extracted, and the economic benefits of harmless disposal and comprehensive utilization of aluminum electrolysis overhaul residue and carbon residue are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0018] Figure 1 The structural schematic diagram of the system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residues provided by the embodiments of the present application is shown in the figure.

[0019] Figure 2 The structural schematic diagram of the impurity removal system provided by the embodiments of the present application is shown in the figure.

[0020] Figure 3 The structural schematic diagram of the inside of the mixing tank provided by the embodiments of the present application is shown in the figure.

[0021] Figure 4 The structural schematic diagram of the filter cloth part provided by the embodiments of the present application is shown in the figure.

[0022] Figure 5 The structural schematic diagram of the pressure ring part provided by the embodiments of the present application is shown in the figure.

[0023] Figure 6 The structural schematic diagram of the pressure ring part provided by the embodiments of the present application is shown in the figure. Figure 3 The enlarged view of part A in the figure.

[0024] Figure legend: 10-ball milling system, 20-slurry system, 30-alkali leaching system, 40-acid leaching system, 50-fluoride salt directional conversion system, 60-impurity removal system, 61-mixing tank, 62-air inlet hole, 63-air inlet pipe, 64-baffle, 65-spring, 66-baffle, 67-air hole, 68-air supply device, 69-filter cloth, 610-pressure ring, 611-pull rod, 612-hook, 70-post-treatment system. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] The following detailed description of embodiments of the application in the drawings provided merely by way of exemplification is not intended to limit the scope of the application as claimed. Based upon a reading and understanding of the application in the drawings, all other embodiments obtained by persons of ordinary skill in the art are intended to be within the scope of the application.

[0027] It should be noted that like reference numerals and letters refer to like items in the drawings, and once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0028] In the description of the application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship in which the product of the application is usually placed, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0029] In the description of the application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "provided", "mounted", "connected", "linked" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, can be electrically connected; can be directly connected, can be indirectly connected through an intermediate medium, or can be connected internally between two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0030] Embodiments

[0031] The following is further illustrated in conjunction with specific embodiments, such as the accompanying drawings Figure 1 - the accompanying drawings Figure 6As shown, the system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residue in the embodiment includes a ball milling system 10, a slurry preparation system 20, an alkali leaching system 30, an acid leaching system 40, a fluoride salt directional conversion system 50, an impurity removal system 60, and a post-treatment system 70 connected in sequence. The alkali leaching system 30 is connected with the fluoride salt directional conversion system 50. Specifically, the ball milling system 10 is used to crush and grind the overhaul residue, carbon residue and the like into powder, which is then sent to the slurry preparation system 20 to be prepared into slurry. The slurry is sent to the alkali leaching system 30, and the slurry is leached with alkali solution. After filtration, the solid is sent to the acid leaching system 40, and the solid is leached with acid solution. Then, the alkali leaching solution and the acid leaching solution are sent to the fluoride salt directional conversion system 50 (i.e. neutralization and precipitation system, in which neutralization and precipitation reactions occur). After solid-liquid separation, the neutralized and precipitated solution is sent to the impurity removal system 60. In the impurity removal system 60, air is introduced into the precipitated solution and a flocculating agent is added to remove Fe, Si, F, Al, Ca, Mg and other impurities, and Li is also precipitated into the filter residue. In the post-treatment system 70, the filter residue is dissolved in solution, and Fe, Si, F, Al, Ca, Mg and other impurities are removed to obtain a filtrate containing a high content of Li. The filtrate is concentrated to obtain a high-concentration Li-containing solution. Through the system, the valuable lithium elements in the water treatment residue can be efficiently extracted, and the economic benefits of harmless disposal and comprehensive utilization of aluminum electrolysis overhaul residue and carbon residue can be significantly improved.

[0032] The post-treatment system 70 in the embodiment includes an evaporation and concentration system, a cooling and crystallization system, and a washing and drying system. Specifically, the high-concentration Li-containing solution can be further evaporated and concentrated and crystallized by the evaporation and concentration system and the cooling and crystallization system to obtain a high-concentration lithium sulfate solution. The lithium sulfate solution is mixed with a sodium carbonate solution to prepare lithium carbonate. After washing and drying by the washing and drying system, industrial-grade lithium carbonate is obtained.

[0033] The impurity removal system 60 in the embodiment includes a mixing tank 61, filter cloth 69 attached to the inner side wall and inner bottom wall of the mixing tank 61, and an air inlet device arranged at the lower part inside the mixing tank 61. The filter cloth 69 has a closed-end cylindrical structure. Specifically, the air inlet device can continuously introduce air into the mixing tank 61 to accelerate the precipitation of the solution. Moreover, since the filter cloth 69 is provided, the gas discharged from the air inlet device will automatically disperse when passing through the filter cloth 69, thereby being better dispersed in the solution. Not only can the solution be better agitated, but also can be better contacted with the solution. After the precipitation is completed, the filter cloth 69 is directly lifted to filter the solution.

[0034] The air intake device in this embodiment includes an air intake hole 62 formed in the bottom wall of the mixing tank 61, an air intake pipe 63 disposed at the air intake hole 62, and an air supply device 68 connected to the air intake pipe 63. The air intake device also includes a baffle 64 disposed at the air intake hole 62, and a spring 65 disposed in the air intake pipe 63 to support the baffle 64. Specifically, when air supply is required, the air supply device 68 delivers high-pressure air into the air intake pipe 63. The high-pressure gas pushes open the baffle 64 and enters the mixing tank 61 through the gap between the baffle 64 and the air intake hole 62. When air intake is not required, the air supply device 68 is closed, and the baffle 64 blocks the air intake hole 62 under the tension of the spring 65, preventing liquid in the mixing tank 61 from entering the air intake pipe 63. Furthermore, since the baffle 64 is pressed down by the filter cloth 69, even if the liquid in the mixing tank 61 is stirred by the stirring device, the flow of the liquid will not affect the baffle 64 and will not cause the baffle 64 to shift.

[0035] The air intake device in this embodiment also includes a baffle 66 disposed inside the air intake pipe 63, and a plurality of vent holes 67 formed on the baffle 66; a spring 65 is disposed between the baffle 66 and the baffle 64. Specifically, the baffle 66 is used to block liquid entering the air intake pipe 63, wherein the vent holes 67 are small enough to prevent liquid from easily passing through the baffle 66.

[0036] In this embodiment, the diameter of the upper end face of the baffle 64 is larger than the diameter of the lower end face. Specifically, see attached... Figure 6 As shown, this allows the baffle 64 to fit better onto the upper part of the vent 67.

[0037] The impurity removal system 60 in this embodiment also includes a pressure ring 610 disposed at the bottom edge of the filter cloth 69. Specifically, the pressure ring 610 is used to press down the filter cloth 69 to prevent it from shaking.

[0038] In this embodiment, the pressure ring 610 is provided with a plurality of pull rods 611 on its upper side, and the upper end of the pull rod 611 is provided with a hook 612, which is hung on the upper side wall of the mixing tank 61. Specifically, the hook 612 and the pull rod 611 can fix the position of the pressure ring 610, and the pull rod 611 can also abut against the side wall of the filter cloth 69.

[0039] To sum up, the system for extracting valuable lithium elements from aluminum electrolysis solid waste water treatment residues in the embodiment uses the ball milling system 10 to crush and grind the overhaul residues, carbon residues and the like into powder, and then sends the powder into the slurry preparation system 20 to prepare the slurry, sends the slurry into the alkali leaching system 30, uses the alkali solution to leach the slurry, after filtration, sends the solid into the acid leaching system 40, uses the acid solution to leach the solid, then sends the alkali leaching solution and the acid leaching solution into the fluoride salt directional conversion system 50, after solid-liquid separation, sends the neutralized and precipitated solution into the impurity removal system 60, in the impurity removal system 60, air is introduced into the precipitated solution and a flocculating agent is added to remove Fe, Si, F, Al, Ca, Mg and the like, and L i is precipitated into the filter residue together, in the post-treatment system 70, the filter residue is dissolved in the solution, Fe, Si, F, Al, Ca, Mg and the like are removed, and the filtrate containing high Li is obtained. The filtrate is concentrated to obtain a high-concentration Li-containing solution. Through the system, the valuable lithium elements in the water treatment residues can be efficiently extracted, and the economic benefits of the harmless disposal and comprehensive utilization of aluminum electrolysis overhaul residues and carbon residues are significantly improved.

[0040] The above merely describes the preferred embodiments of the present application, but should not be used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement and the like within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A system for extracting valuable lithium from the solid wastewater treatment residue of aluminum electrolysis, characterized in that: It includes a ball milling system (10), a slurry preparation system (20), an alkaline leaching system (30), an acid leaching system (40), a fluoride salt directional conversion system (50), a purification system (60), and a post-treatment system (70) connected in sequence. The alkaline leaching system (30) is connected to the fluoride salt directional conversion system (50); in the impurity removal system (60), air is introduced into the precipitated liquid and flocculant is added to remove Fe, Si, F, Al, Ca, and Mg impurities, and Li is precipitated into the filter residue. In the post-treatment system (70), the filter residue is dissolved in the solution to remove Fe, Si, F, Al, Ca, and Mg impurities, thereby obtaining a filtrate with a high Li content. The post-processing system (70) includes an evaporation and concentration system, a cooling and crystallization system, and a washing and drying system; the impurity removal system (60) includes a mixing tank (61), a filter cloth (69) attached to the inner side wall and the inner bottom wall of the mixing tank (61), and an air inlet device located at the bottom of the mixing tank (61); the filter cloth (69) has a cylindrical structure with the lower end closed; the air inlet device includes an air inlet hole (62) opened on the bottom wall of the mixing tank (61), and an air inlet pipe (63) located at the air inlet hole (62). The air intake device includes a baffle (64) located at the air intake hole (62) and a spring (65) located in the air intake pipe (63) to support the baffle (64). The air intake device also includes a partition (66) located in the air intake pipe (63) and a plurality of vent holes (67) opened on the partition (66). The spring (65) is located between the partition (66) and the baffle (64).

2. The system for extracting valuable lithium from aluminum electrolysis solid wastewater treatment residue according to claim 1, characterized in that: The diameter of the upper end face of the baffle (64) is larger than the diameter of the lower end face.

3. The system for extracting valuable lithium from aluminum electrolysis solid wastewater treatment residue according to claim 1, characterized in that: The impurity removal system (60) also includes a pressure ring (610) disposed at the bottom edge of the filter cloth (69).

4. The system for extracting valuable lithium from aluminum electrolysis solid wastewater treatment residue according to claim 3, characterized in that: The pressure ring (610) is provided with a plurality of pull rods (611) on its upper side, and the upper end of the pull rod (611) is provided with a hook (612), which is hung on the upper side wall of the mixing tank (61).

Images