Method for resource utilization of lithium extraction residue

Abstract

This invention discloses a resource utilization method for lithium extraction slag that is high in purity, low in cost, and simple in process, comprising the following steps: S100, sequentially subjecting the lithium extraction slag to roasting, water leaching, and solid-liquid separation to obtain a first filter residue and a first filtrate; S200, sequentially subjecting the first filter residue to acidification, water leaching, and solid-liquid separation to obtain a second filtrate and a second filter residue; S300, sequentially subjecting the first filtrate to carbon removal and solid-liquid separation to obtain a third filtrate and a third filter residue; S400, sequentially subjecting the second and third filtrates to heat treatment and solid-liquid separation to obtain a fourth filtrate and a fourth filter residue; S500, a silica recovery process; and S600, a potassium, rubidium, and cesium resource recovery process.

Description

Technical Field

[0001] This invention relates to the technical field of lithium extraction slag resource recovery, and more specifically, to a method for utilizing lithium extraction slag resources. Background Technology

[0002] Lithium-ion batteries, with their unparalleled advantages such as high operating voltage, long cycle life, and environmental friendliness, have experienced rapid development in recent years, leading to a surge in demand for lithium carbonate, a key raw material. As a major raw material for lithium carbonate production, lepidolite mines, with their advantages of resource self-sufficiency, considerable reserves, and value-added byproducts, have become a crucial pillar of China's lithium battery industry. However, the currently common salt-based lithium extraction process generates approximately 40 tons of lithium extraction slag for every ton of lithium carbonate produced. Even using the acid-based lithium extraction process disclosed in the series of patent applications filed by the applicant on May 30, 2024 (such as CN118598168A), approximately 16 tons of lithium extraction slag are generated for every ton of finished lithium carbonate produced. Traditional stockpiling and disposal methods lead to resource waste, soil alkalization, and heavy metal pollution. Therefore, the reduction, resource recovery, and harmless treatment of lithium extraction slag have become an inevitable trend.

[0003] Chinese invention patent application CN117985741A discloses a comprehensive recycling method for lithium extraction slag from lepidolite. This method involves leaching the slag with an alkaline solution, which disrupts the unstable structure of the slag and releases lithium ions, potassium ions, aluminate ions, and silicate ions, thus efficiently recovering elements such as lithium, potassium, and aluminum. However, the silicon-containing material in the slag used in this patent has a simple structure, which differs from the complex structures found in actual lithium extraction slag, such as leucite (KAlSi2O6) and feldspar (K(Na)AlSi3O8). Literature review shows that the silicon-aluminum bonds and silicon-oxygen bonds in leucolite slag are extremely stable and only melt and decompose at high temperatures; therefore, its applicability is limited.

[0004] Chinese invention patent CN115948655B discloses a method for the comprehensive recovery of lithium, rubidium, and cesium from lithium mica slag. The method involves converting lithium in the slag into soluble lithium through high-temperature roasting, followed by the recovery of each element. Products include lithium carbonate, cement raw materials, and rare metals such as rubidium and cesium. This patent primarily focuses on lithium recovery from the slag, while the high-content silica is only used for cement raw material sales. Furthermore, potassium and aluminum are not separated and utilized, resulting in low solid waste resource utilization.

[0005] It is evident that existing methods for utilizing lithium extraction slag still suffer from technical problems such as incomplete resource utilization, low process feasibility, high environmental pollution, and high costs. To address these issues, the applicant of this application filed a Chinese invention patent application with publication number CN121244663A entitled "Method for Utilizing Lithium Extraction Slag," which achieves near-complete processing of lithium extraction slag through fluxing agents and a simple, easily controllable step-by-step treatment. Furthermore, practical experience has revealed that existing technologies for obtaining high-purity products such as silica, cesium sulfate, and potassium sulfate still present complex and costly technical challenges. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a resource utilization method for lithium extraction slag with high purity, low cost, and simple process, as well as a silicon resource utilization system, a potassium rubidium and cesium resource utilization system, and a full-scale resource utilization system. The technical solution is as follows: The resource utilization method of lithium extraction slag includes the following steps: S100, after sequentially roasting, water immersion and solid-liquid separation of lithium extraction residue, the first filter residue and the first filtrate are obtained; S200, the first filter residue is subjected to acidification treatment, water immersion treatment and solid-liquid separation treatment in sequence to obtain the second filtrate and the second filter residue; S300, after sequentially performing carbon fractionation and solid-liquid separation on the first filtrate, a third filtrate and a third filter residue are obtained; S400, after heat treatment and solid-liquid separation treatment of the second and third filtrates in sequence, a fourth filtrate and a fourth filter residue are obtained; S500, the silica recycling process includes the following steps: S510, after sequentially performing water immersion treatment and solid-liquid separation treatment on the second filter residue, filter residue one and filtrate one are obtained; S520, after sequentially performing acid leaching and solid-liquid separation treatment on the third filter residue, filter residue two and filtrate two are obtained; S530 is used to calcine filter residue one and filter residue two to obtain silica. S600, the potassium-rubidium-cesium resource recovery process, includes the following steps: S610, after sequentially performing evaporation and concentration treatment, cooling and crystallization treatment and solid-liquid separation treatment on the fourth filtrate, sodium sulfate and mother liquor 1 are obtained; S620, after sequentially performing evaporation and concentration treatment, cooling and crystallization treatment and solid-liquid separation treatment on mother liquor one, potassium sulfate and mother liquor two are obtained; S630, the mother liquor II is extracted to obtain organic phase I and aqueous phase I; organic phase I is back-extracted to obtain organic phase II and aqueous phase II; aqueous phase II is evaporated and crystallized and then separated into solid and liquid phases to obtain cesium sulfate; S640 is used to extract aqueous phase one to obtain organic phase three and aqueous phase three; organic phase three is back-extracted to obtain organic phase four and aqueous phase four; aqueous phase four is then subjected to evaporation crystallization and solid-liquid separation to obtain rubidium sulfate.

[0007] A silicon resource utilization system for lithium extraction slag includes: The first roasting furnace is used to roast the lithium extraction slag and output roasted clinker. The first separation unit is used to perform water immersion treatment and solid-liquid separation treatment on the roasted clinker and output the first filter residue and the first filtrate. The second separation unit is used to perform acidification, water immersion and solid-liquid separation on the first filter residue and output the second filter residue and the second filtrate. The third separation unit is used to perform carbon fractionation and solid-liquid separation on the first filtrate and output the third filter residue and the third filtrate. A silica recycling unit, the silica recycling unit comprising: A water immersion reaction tank is used to leach the second filter residue and output a solid-liquid mixture. Filter 1 is used to filter the solid-liquid mixture output from the water immersion reaction tank and output filter residue 1 and filtrate 1. The acid leaching reaction tank is used to leach the third filter residue and output a solid-liquid mixture. Filter 2 is used to filter the solid-liquid mixture output from the acid leaching reaction tank and output filter residue 2 and filtrate 2. The second roasting furnace is used to roast filter residue one and filter residue two and output precipitated silica.

[0008] A potassium, rubidium, and cesium resource utilization system for lithium extraction slag includes: The first roasting furnace is used to roast the lithium extraction slag and output roasted clinker. The first separation unit is used to perform water immersion treatment and solid-liquid separation treatment on the roasted clinker and output the first filter residue and the first filtrate. The second separation unit is used to perform acidification, water immersion and solid-liquid separation on the first filter residue and output the second filter residue and the second filtrate. The third separation unit is used to perform carbon fractionation and solid-liquid separation on the first filtrate and output the third filter residue and the third filtrate. The fourth separation unit is used to perform heat treatment and solid-liquid separation on the second and third filtrates and output the fourth filter residue and the fourth filtrate. A potassium-rubidium-cesium resource recovery unit, comprising: The sodium sulfate separation assembly includes a primary reaction tank and a primary filter; the primary reaction tank is used to evaporate and concentrate the fourth filtrate, cool and crystallize it, and output a solid-liquid mixture; the primary filter is used to filter the solid-liquid mixture output from the primary reaction tank and output sodium sulfate and mother liquor. A potassium sulfate separation assembly includes a secondary reaction tank and a secondary filter; the secondary reaction tank is used to evaporate and concentrate mother liquor one, cool and crystallize it, and output a solid-liquid mixture; the secondary filter is used to filter the solid-liquid mixture output from the secondary reaction tank and output potassium sulfate and mother liquor two. A cesium sulfate separation assembly includes a primary extraction device, a primary back-extraction device, a tertiary reaction tank, and a tertiary filter. The primary extraction device is used to extract mother liquor II and output organic phase I and aqueous phase I. The primary back-extraction device is used to back-extract organic phase I and output organic phase II and aqueous phase II. The tertiary reaction tank is used to evaporate and crystallize aqueous phase II and output a solid-liquid mixture. The tertiary filter is used to filter the solid-liquid mixture output from the tertiary reaction tank and output cesium sulfate. A rubidium sulfate separation assembly includes a two-stage extraction device, a two-stage back-extraction device, a four-stage reaction tank, and a four-stage filter. The two-stage extraction device is used to extract the aqueous phase I and output organic phase III and aqueous phase III. The two-stage back-extraction device is used to back-extract organic phase III and output organic phase IV and aqueous phase IV. The four-stage reaction tank is used to evaporate and crystallize the aqueous phase IV and output a solid-liquid mixture. The four-stage filter is used to filter the solid-liquid mixture output from the four-stage reaction tank and output rubidium sulfate.

[0009] A comprehensive resource utilization system for lithium extraction slag, including the aforementioned silicon resource utilization system and / or potassium, rubidium, and cesium resource utilization system.

[0010] The advantages of the method and system of the present invention are: (1) Simple process / system: First, the silicon element in the lithium extraction slag is converted from silicate in the liquid phase to white carbon black and then obtained from the solid phase after acidification to destroy the structure. This not only obtains high-value-added silicon products, but also fundamentally eliminates the hidden dangers of "silicification" and "emulsification" in the subsequent potassium, rubidium and cesium resource recovery process; then, sodium sulfate and potassium sulfate products are obtained by stepwise crystallization, and high-value cesium sulfate and rubidium sulfate products are obtained by stepwise extraction. The required equipment is simple, the operation steps are few, it is easy to control, and the production cost is low. (2) High resource utilization rate: On the one hand, more than 60% of the silicon in the lithium extraction slag is converted into soluble silicon and dissolved in water leaching solution and obtained as white carbon black product through carbon fractionation. On the other hand, nearly 40% of the silicon is converted into nepheline group compounds and obtained as white carbon black product through acid leaching. The total silicon conversion rate of the two steps is greater than 99%. The recovery rates of potassium, rubidium and cesium in the lithium extraction slag can all reach more than 95%. (3) High product purity: The silica content in the obtained silica product (calcined product) is greater than 99.5%, the potassium sulfate purity is greater than 95.5%, and the cesium sulfate and rubidium sulfate purity is greater than 99.5%, all of which have high economic benefits. (4) Economic and environmentally friendly: Very little waste residue is discharged, and the generated filtrate can be returned to the system or used in subsequent processes for the extraction of other elements. A closed-loop circulation system with acid-base internal balance is constructed, which not only greatly reduces the generation of wastewater and significantly reduces the consumption of fresh acid and base reagents, but also allows trace amounts of rubidium and cesium ions that have not been completely extracted or crystallized to continuously accumulate in the system, realizing the deep recovery of rare metals.

[0011] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to aid in understanding the invention. The content provided in the drawings and their related descriptions can be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the silicon resource utilization system for lithium extraction slag in this embodiment.

[0013] Figure 2 This is a schematic diagram of the potassium rubidium and cesium resource utilization system for lithium extraction slag in this embodiment.

[0014] The relevant markings in the above figures are: 100 - First calcining furnace, 111 - First reaction tank, 112 - First filter, 121 - Second reaction tank, 122 - Second filter, 131 - Third reaction tank, 132 - Third filter, 141 - Fourth reaction tank, 142 - Fourth filter, 210 - Water immersion reaction tank, 220 - Filter 1, 230 - Acid leaching reaction tank, 240 - Filter 2, 250 - Second calcining furnace, 260 - Storage tank 1, 270 - Storage tank 2, 280 - Dryer, 310 - Primary reaction tank, 32 0- Primary filter, 410- Secondary reaction tank, 420- Secondary filter, 510- Primary evaporator, 520- Primary tubular mixer, 530- Primary extraction equipment, 540- Primary back-extraction equipment, 550- Tertiary reaction tank, 560- Tertiary filter, 610- Secondary evaporator, 620- Secondary tubular mixer, 630- Secondary extraction equipment, 640- Secondary back-extraction equipment, 650- Quaternary reaction tank, 660- Quaternary filter, 710- Fifth-stage reaction tank, 720- Storage tank. Detailed Implementation

[0015] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that: The technical solutions and features provided in the various parts of this invention, including the following description, can be combined with each other without conflict.

[0016] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0017] Regarding the terminology and units used in this invention: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this invention are intended to cover non-exclusive inclusion.

[0018] Example 1

[0019] Figure 1 This is a schematic diagram of the silicon resource utilization system for lithium extraction slag in this embodiment.

[0020] Figure 1 The lithium extraction slag silicon resource utilization system shown includes a first roasting furnace 100, a first separation unit, a second separation unit, a third separation unit, and a silica recovery unit. The first roasting furnace 100 is used to roast the lithium extraction slag and output roasted clinker.

[0021] The first separation unit is used to perform water immersion treatment and solid-liquid separation treatment on the roasted clinker and output a first filter residue and a first filtrate. The first separation unit includes a first reaction tank 111 and a first filter 112. The first reaction tank 111 is used to perform water immersion treatment on the roasted clinker and output a solid-liquid mixture. The first filter 112 is used to perform solid-liquid separation treatment on the solid-liquid mixture output from the first reaction tank 111 and output a first filter residue and a first filtrate.

[0022] The second separation unit is used to perform acidification, water immersion, and solid-liquid separation treatment on the first filter residue and output a second filter residue and a second filtrate. The second separation unit includes a second reaction tank 121 and a second filter 122. The second reaction tank 121 is used to perform acidification and water immersion treatment on the first filter residue and output a solid-liquid mixture. The second filter 122 is used to perform solid-liquid separation treatment on the solid-liquid mixture output from the second reaction tank 121 and output a second filter residue and a second filtrate. The third separation unit is used to perform carbon separation and solid-liquid separation on the first filtrate and output a third filter residue and a third filtrate. The third separation unit includes a third reaction tank 131 and a third filter 132. The third reaction tank 131 is used to perform carbon separation on the first filtrate and output a solid-liquid mixture. The third filter 132 is used to perform solid-liquid separation on the solid-liquid mixture output from the third reaction tank 131 and output a third filter residue and a third filtrate.

[0023] The silica recovery unit includes a water leaching reaction tank 210, a first filter 220, an acid leaching reaction tank 230, a second filter 240, a first storage tank 260, a second storage tank 270, a dryer 280, and a second calcining furnace 250. The water leaching reaction tank 210 is used to leach the second filter residue and output a solid-liquid mixture. The first filter 220 is used to filter the solid-liquid mixture output from the water leaching reaction tank 210 and output filter residue one and filtrate one. The first storage tank 260 is used to store filtrate one; its inlet is connected to the outlet of the first filter 220, and its outlet is connected to the inlet of the first reaction tank 111, thus filtrate one can be reused for water leaching treatment of the calcined clinker. The acid leaching reaction tank 230 is used to leach the third filter residue and output a solid-liquid mixture. The second filter 240 is used to filter the solid-liquid mixture output from the acid leaching reaction tank 230 and output filter residue two and filtrate two. The storage tank 270 is used to store the second filtrate. Its inlet is connected to the outlet of the second filter 240, and its outlet is connected to the inlet of the second reaction tank 121. Thus, the second filtrate can be reused for water immersion treatment of the first filter residue. The dryer 280 is used to dry filter residue one and filter residue two. Its inlet is connected to the discharge ports of both filter one 220 and filter two 240, and its discharge port is connected to the inlet of the second calcining furnace 250. The dryer 280 is a rotary flash dryer, and its air inlet is connected to the flue gas outlet of the second calcining furnace 250. Therefore, the calcining flue gas can quickly break up and dry the filter cake into powder before it enters the second calcining furnace 250, significantly saving energy. Since a relatively dilute sulfuric acid (0.01–1.0 wt%) is used to leach the third filter residue (neutralization reaction and washing), the resulting filter residue two does not need to be washed again before drying and can be combined with filter residue one for further processing. The second calcining furnace 250 is used to calcinate filter residue one and filter residue two and output precipitated silica.

[0024] Example 2

[0025] Figure 2 This is a schematic diagram of the potassium rubidium and cesium resource utilization system for lithium extraction slag in this embodiment.

[0026] like Figure 2 The illustrated potassium, rubidium, and cesium resource utilization system for lithium extraction slag includes a first roasting furnace 100, a first separation unit, a second separation unit, a third separation unit, a fourth separation unit, and a potassium, rubidium, and cesium resource recovery unit. The first roasting furnace 100 is used to roast the lithium extraction slag and output roasted clinker. The potassium, rubidium, and cesium resource recovery unit includes a sodium sulfate separation component, a potassium sulfate separation component, a cesium sulfate separation component, and a rubidium sulfate separation component.

[0027] The first separation unit is used to perform water immersion treatment and solid-liquid separation treatment on the roasted clinker and output a first filter residue and a first filtrate. The first separation unit includes a first reaction tank 111 and a first filter 112. The first reaction tank 111 is used to perform water immersion treatment on the roasted clinker and output a solid-liquid mixture. The first filter 112 is used to perform solid-liquid separation treatment on the solid-liquid mixture output from the first reaction tank 111 and output a first filter residue and a first filtrate.

[0028] The second separation unit is used to perform acidification, water immersion, and solid-liquid separation treatment on the first filter residue and output a second filter residue and a second filtrate. The second separation unit includes a second reaction tank 121 and a second filter 122. The second reaction tank 121 is used to perform acidification and water immersion treatment on the first filter residue and output a solid-liquid mixture. The second filter 122 is used to perform solid-liquid separation treatment on the solid-liquid mixture output from the second reaction tank 121 and output a second filter residue and a second filtrate. The third separation unit is used to perform carbon separation and solid-liquid separation on the first filtrate and output a third filter residue and a third filtrate. The third separation unit includes a third reaction tank 131 and a third filter 132. The third reaction tank 131 is used to perform carbon separation on the first filtrate and output a solid-liquid mixture. The third filter 132 is used to perform solid-liquid separation on the solid-liquid mixture output from the third reaction tank 131 and output a third filter residue and a third filtrate.

[0029] The fourth separation unit is used to perform heat treatment and solid-liquid separation on the second and third filtrates, and output a fourth filter residue and a fourth filtrate. The fourth separation unit includes a fourth reaction tank 141 and a fourth filter 142. The fourth reaction tank 141 is used to heat treat the second and third filtrates and output a fourth solid-liquid mixture. The fourth filter 142 is used to perform solid-liquid separation on the solid-liquid mixture output from the fourth reaction tank 141 and output a fourth filter residue and a fourth filtrate.

[0030] The sodium sulfate separation assembly includes a primary reaction tank 310 and a primary filter 320; the primary reaction tank 310 is used to evaporate and concentrate the fourth filtrate, cool and crystallize it, and output a solid-liquid mixture; the primary filter 320 is used to filter the solid-liquid mixture output from the primary reaction tank 310 and output sodium sulfate and mother liquor.

[0031] The potassium sulfate separation assembly includes a secondary reaction tank 410 and a secondary filter 420; the secondary reaction tank 410 is used to evaporate and concentrate the mother liquor, cool and crystallize it, and output a solid-liquid mixture; the secondary filter 420 is used to filter the solid-liquid mixture output from the secondary reaction tank 410 and output potassium sulfate and mother liquor II.

[0032] The cesium sulfate separation assembly includes a primary evaporator 510, a primary tubular mixer 520, a primary extraction device 530, a primary back-extraction device 540, a primary back-extraction agent preparation tank, a tertiary reaction tank 550, and a tertiary filter 560. The inlet of the primary tubular mixer 520 is connected to the outlet of the primary evaporator 510, the primary alkali addition pipeline, and the primary extractant inlet pipeline. The outlet of the primary tubular mixer 520 is connected to the inlet of the primary extraction device 530. The primary evaporator 510 is used to evaporate and concentrate the mother liquor, and its inlet is connected to the outlet of the secondary filter 420 and the outlet of the primary extraction device 530. The primary extraction device 530 is used to extract the mother liquor and output organic phase one (containing cesium) and aqueous phase one (containing rubidium). The primary stripping unit 540 is used to strip organic phase one and output organic phase two and aqueous phase two (containing cesium). It is connected to the primary stripping agent mixing tank through a primary stripping agent delivery pipe. The tertiary reaction tank 550 is used to evaporate and crystallize aqueous phase two and output a solid-liquid mixture. The tertiary filter 560 is used to filter the solid-liquid mixture output from the tertiary reaction tank 550 and output cesium sulfate.

[0033] The rubidium sulfate separation assembly includes a secondary evaporator 610, a secondary tubular mixer 620, a secondary extraction device 630, a secondary back-extraction device 640, a secondary back-extraction agent preparation tank, a fourth-stage reaction tank 650, and a fourth-stage filter 660. The inlet of the secondary tubular mixer 620 is connected to the outlet of the secondary evaporator 610, the secondary alkali addition pipeline, and the secondary extractant inlet pipeline. The outlet of the secondary tubular mixer 620 is connected to the inlet of the secondary extraction device 630. The secondary evaporator 610 is used for evaporating and concentrating the aqueous phase I. Its inlet is connected to the aqueous phase outlet of the primary extraction device 530, and its outlet is connected to the inlet of the secondary extraction device 630. The secondary extraction device 630 is used for extracting the aqueous phase I and outputs an organic phase III (containing rubidium) and an aqueous phase III (which can be reused for water leaching of roasted clinker or for water leaching of the first filter residue; preferably, it undergoes oil removal treatment before reuse). The secondary stripping unit 640 is used to strip organic phase three and output organic phase four and aqueous phase four (containing rubidium). It is connected to the secondary stripping agent mixing tank through a secondary stripping agent delivery pipe. The quaternary reaction tank 650 is used to evaporate and crystallize aqueous phase four and output a solid-liquid mixture. The quaternary filter 660 is used to filter the solid-liquid mixture output from the quaternary reaction tank 650 and output rubidium sulfate.

[0034] The primary tubular mixer 520 and the secondary tubular mixer 620 can be selected as static tubular mixers, which can significantly improve the mixing effect and thus improve the extraction and separation effect. To improve oil-water separation, coalescence separators are preferably installed at the outlets of the primary extraction unit 530, the primary back-extraction unit 540, the secondary extraction unit 630, and the secondary back-extraction unit 640. To improve the purity of cesium sulfate and rubidium sulfate, adsorption towers are preferably installed at the inlet of the tertiary reaction tank 550 and the quaternary reaction tank 650. These adsorption towers are filled with a layer of granular activated carbon to further adsorb impurities.

[0035] In addition, the potassium, rubidium, and cesium resource recovery unit also includes a storage tank 720 and a five-stage reaction tank 710. The inlet of the storage tank 720 is connected to the outlets of the three-stage filter 560 and the four-stage filter 660, and the outlet is connected to the inlet of the second reaction tank 121. The five-stage reaction tank 710 is used to regenerate organic phase two and organic phase four. Its inlet is connected to the organic phase outlet of the first-stage back-extraction device 540, the organic phase outlet of the second-stage back-extraction device 640, and the tertiary alkali addition pipeline, respectively. Its outlet is connected to the inlet of the first-stage extraction device 530 and the inlet of the second-stage extraction device 630 through the first-stage extractant inlet pipe and the second-stage extractant inlet pipe, respectively.

[0036] Example 3

[0037] The lithium extraction slag full-scale resource utilization system of this embodiment includes a first roasting furnace, a first separation unit, a second separation unit, a third separation unit, and a fourth separation unit. Figure 1 The white carbon black recovery unit shown and Figure 2 The illustrated potassium, rubidium, and cesium resource recovery unit preferably also includes an aluminum resource recovery unit, comprising a fifth reaction tank, a fifth filter, a sixth reaction tank, and a sixth filter. The fifth reaction tank is used to react the fourth filter residue with a sodium hydroxide solution and output a solid-liquid mixture. The fifth filter is used to perform solid-liquid separation treatment on the solid-liquid mixture output from the fifth reaction tank and output filter residue three and filtrate three. The sixth reaction tank is used to perform carbon separation treatment on filter residue three and output a solid-liquid mixture. The sixth filter is used to perform solid-liquid separation treatment on the solid-liquid mixture output from the sixth reaction tank and output aluminum hydroxide and filtrate four. Filtrate four is stored in storage tank one and can be reused for water leaching treatment of roasted clinker.

[0038] In the above embodiments, each reaction tank is equipped with a stirrer, a pH sensor, a temperature sensor, and a heater.

[0039] An embodiment of the resource utilization method for lithium extraction slag of the present invention includes the following steps: S100, after sequentially roasting, water immersion and solid-liquid separation of lithium extraction residue, the first filter residue and the first filtrate are obtained; The process parameters for the roasting treatment are as follows: using sodium carbonate as a flux, the lithium extraction slag is mixed with the flux at a mass ratio of 1:1, and then roasted at 850°C for 60 minutes. The process parameters for the water immersion treatment are as follows: the liquid-to-solid ratio of water to calcined clinker is 3:1 (mass ratio, the same below), the water immersion temperature is 50℃, and the water immersion time is 30 minutes.

[0040] S200, the first filter residue is subjected to acidification treatment, water immersion treatment and solid-liquid separation treatment in sequence to obtain the second filtrate and the second filter residue; The process parameters for the acidification treatment are as follows: the first filter residue with a mass ratio of 1:0.8 and sulfuric acid solution (mass fraction of 95%) are mixed and then aged for 20 minutes at a temperature of 50°C to obtain aged material.

[0041] The process parameters for the water immersion treatment are as follows: the liquid-to-solid ratio of water to the first filter residue in the aged material is 3:1, the water immersion temperature is 50℃, and the water immersion time is 30 minutes.

[0042] S300, after sequentially performing carbon fractionation and solid-liquid separation on the first filtrate, a third filtrate and a third filter residue are obtained; The process parameters for carbon fractionation are as follows: first, anhydrous ethanol is added as a dispersant to the first filtrate, with a volume ratio of anhydrous ethanol to the first filtrate of 0.1:1. The reaction temperature is controlled at 60°C. Then, carbon dioxide is continuously introduced until the pH of the solid-liquid mixture reaches 9, at which point the reaction ends.

[0043] S400, after heat treatment and solid-liquid separation treatment of the second and third filtrates in sequence, a fourth filtrate and a fourth filter residue are obtained; The process parameters for the heat treatment are as follows: the reaction temperature is controlled at 50°C, and the third filtrate (mainly sodium carbonate / sodium bicarbonate) is continuously added dropwise to the second filtrate under stirring until the pH of the fourth solid-liquid mixture is 5, at which point the reaction ends. During this process, impurities such as Al and Fe precipitate in the fourth filter residue in the form of hydroxides, while K, Rb, Cs, and Na remain in the fourth filtrate.

[0044] S500, the silica recycling process includes the following steps: S510, the second filter residue is subjected to water immersion treatment and solid-liquid separation treatment in sequence to obtain filter residue one and filtrate one; wherein, the liquid-solid ratio is 3:1, the temperature is 50℃, and the duration is 30 minutes; filtrate one is reused for water immersion treatment in S100.

[0045] S520, after sequentially acid leaching and solid-liquid separation of the third filter residue, filter residue two and filtrate two are obtained; wherein, 0.5wt% dilute sulfuric acid is used, the liquid-to-solid ratio is 3:1, the temperature is 60℃, and the duration is 30 minutes; filtrate two is reused for acidification treatment in S200.

[0046] S530, filter residue one and filter residue two are calcined to obtain silica; wherein the calcination temperature is 400℃ and the calcination time is 50 minutes.

[0047] S600, the potassium-rubidium-cesium resource recovery process, includes the following steps: S610, the fourth filtrate is subjected to evaporation and concentration treatment, cooling and crystallization treatment and solid-liquid separation treatment in sequence to obtain sodium sulfate and mother liquor 1; wherein, it is first evaporated and concentrated at 70℃, then cooled to 0-10℃, and sodium sulfate seed crystals are added to promote the crystallization of sodium sulfate.

[0048] S620, after sequentially performing evaporation and concentration treatment, cooling and crystallization treatment and solid-liquid separation treatment on mother liquor one, potassium sulfate and mother liquor two are obtained; wherein, firstly, the mother liquor is evaporated and concentrated at 80℃, then cooled to 20-30℃, and potassium sulfate seed crystals are added to promote the crystallization and precipitation of potassium sulfate.

[0049] S630, the mother liquor II is extracted to obtain organic phase I and aqueous phase I; organic phase I is back-extracted to obtain organic phase II and aqueous phase II; aqueous phase II is subjected to evaporation crystallization and solid-liquid separation to obtain cesium sulfate; wherein, The extraction process parameters are as follows: after evaporating and concentrating the mother liquor, the pH is adjusted to 13 and the temperature to 50℃. The extractant is added at an O / A ratio of 1:4, the shaking time is 25 minutes, and the standing time is 50 minutes. The extractant is a mixture of t-BAMBP (4-tert-butyl-2(α-methylbenzyl)phenol) and sulfonated kerosene, with the sulfonated kerosene having a volume percentage of 20 vol% and the remainder being t-BAMBP. The mixing time of the two is 8 minutes.

[0050] The process parameters for back-extraction are as follows: temperature is set at 55℃, the first back-extraction agent is added at a ratio of O / A of 5:1, shaking time is 20 minutes, and standing time is 50 minutes. The first back-extraction agent is a mixture of sulfuric acid and citric acid, with a sulfuric acid concentration of 2 mol / L and a citric acid concentration of 0.08 mol / L. Citric acid, as an auxiliary agent, not only optimizes the pH buffering capacity of the back-extraction environment and inhibits the co-extraction of impurity ions, but also allows the carboxyl groups of citric acid to form water-soluble complexes with metal ions in an acidic environment, thus blocking their hydrolysis.

[0051] S640, aqueous phase one is extracted to obtain organic phase three and aqueous phase three; organic phase three is back-extracted to obtain organic phase four and aqueous phase four; aqueous phase four is subjected to evaporation crystallization and solid-liquid separation to obtain rubidium sulfate, wherein, The extraction process parameters are as follows: after evaporating and concentrating the aqueous phase, adjust the pH to 10-11 and the temperature to 30℃, add the extractant at an O / A ratio of 1:2, shake for 25 minutes, and let stand for 50 minutes; the extractant is the same as above.

[0052] The process parameters for back-extraction are as follows: temperature is adjusted to 50℃, a second back-extraction agent is added at a ratio of O / A of 4:1, shaking time is 50 minutes, and standing time is 50 minutes. The second back-extraction agent is a mixture of sulfuric acid and glycerol, with a sulfuric acid concentration of 1.2 mol / L and a glycerol volume percentage of 6 vol%. The addition of glycerol not only adjusts the polarity and viscosity of the back-extraction system and improves the interfacial tension, but also allows the polyhydroxy structure of glycerol to adsorb onto the surface of Rb3H(SO4)2 crystal nuclei, inhibiting the growth of complex salt crystals through steric hindrance. Preferably, citric acid (concentration of 0.08 mol / L) can be added to the second back-extraction agent. This effectively inhibits the formation of Rb3H(SO4)2 crystals through the compound system, significantly improving the back-extraction kinetics and phase separation effect, achieving stable storage of the sulfuric acid back-extraction solution without precipitation, and ultimately obtaining rubidium sulfate with high purity.

[0053] In step 600, to improve the purity of cesium sulfate and rubidium sulfate, the aqueous phases II and IV are further purified by adding 8 wt% activated carbon, mixing for 25 minutes, and then filtering. To reuse the extractant, organic phases II and IV are combined and then regenerated: a 3 wt% sodium hydroxide solution is added at an O / A ratio of 5:1, shaken for 50 minutes, allowed to stand for 50 minutes, and then separated into layers to obtain the regenerated extractant. To conserve water resources, the filtrate from the solid-liquid separation processes in S630 and S640 is reused for water leaching in S200.

[0054] S700, aluminum resource recycling process, includes the following steps: S710, after sequentially performing alkalization and solid-liquid separation treatment on the fourth filter residue, filter residue three and filtrate three are obtained; wherein, the process parameters for alkalization treatment are: using a sodium hydroxide solution with a mass fraction of 3wt%, a temperature of 70℃, a reaction termination pH of 13.0, and a duration of 50 minutes; filter residue three is mainly composed of iron hydroxide, which can be further recycled.

[0055] S720, after sequentially treating the filtrate with carbonation and solid-liquid separation, aluminum hydroxide is obtained. The resulting filtrate is recycled for water leaching treatment in S100. The process parameters for carbonation treatment are: controlling the reaction temperature at 40°C, and continuously introducing carbon dioxide until the pH of the solid-liquid mixture reaches 9, at which point the reaction ends.

[0056] Sampling and testing revealed that the final precipitated silica (calcined product) contained 99.95% silica, 96.1% potassium sulfate, 99.7% cesium sulfate, 99.6% rubidium sulfate, and 98.6% aluminum hydroxide. The total silicon conversion rate in the lithium extraction slag reached 99.4%, and the total recovery rates of potassium, rubidium, cesium, and aluminum reached 96.4%, 97.1%, 96.8%, and 97.3%, respectively, achieving near-full-scale high-value utilization of the lithium extraction slag.

[0057] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A method for utilizing lithium extraction slag, including the following steps: S100, after sequentially roasting, water immersion and solid-liquid separation of lithium extraction residue, the first filter residue and the first filtrate are obtained; S200, the first filter residue is subjected to acidification, water immersion and solid-liquid separation treatment in sequence to obtain the second filtrate and the second filter residue; S300, after sequentially performing carbon fractionation and solid-liquid separation on the first filtrate, a third filtrate and a third filter residue are obtained; S400, after heat treatment and solid-liquid separation treatment of the second and third filtrates in sequence, a fourth filtrate and a fourth filter residue are obtained; Its features are: It also includes the following steps: S500, the silica recycling process includes the following steps: S510, after sequentially performing water immersion treatment and solid-liquid separation treatment on the second filter residue, filter residue one and filtrate one are obtained; S520, after sequentially performing acid leaching and solid-liquid separation treatment on the third filter residue, filter residue two and filtrate two are obtained; S530 is used to calcine filter residue one and filter residue two to obtain silica. S600, the potassium-rubidium-cesium resource recovery process, includes the following steps: S610, after sequentially performing evaporation and concentration treatment, cooling and crystallization treatment and solid-liquid separation treatment on the fourth filtrate, sodium sulfate and mother liquor 1 are obtained; S620, after sequentially performing evaporation and concentration treatment, cooling and crystallization treatment and solid-liquid separation treatment on mother liquor one, potassium sulfate and mother liquor two are obtained; S630, the mother liquor II is extracted to obtain organic phase I and aqueous phase I; organic phase I is back-extracted to obtain organic phase II and aqueous phase II; aqueous phase II is evaporated and crystallized and then separated into solid and liquid phases to obtain cesium sulfate; S640 is used to extract aqueous phase one to obtain organic phase three and aqueous phase three; organic phase three is back-extracted to obtain organic phase four and aqueous phase four; aqueous phase four is then subjected to evaporation crystallization and solid-liquid separation to obtain rubidium sulfate.

2. The resource utilization method of lithium extraction slag as described in claim 1, characterized in that: The process parameters for water immersion treatment in S510 are: liquid-to-solid ratio of (0.5-4):1, temperature of 20-90℃, and duration of 10-90 minutes; the filtrate is reused for water immersion treatment in S100.

3. The resource utilization method of lithium extraction slag as described in claim 1, characterized in that: The process parameters for acid leaching in S520 are as follows: use dilute sulfuric acid with a mass fraction of 0.01 to 1.0 wt%, liquid-to-solid ratio of (0.5 to 4):1, temperature of 30 to 90°C, and duration of 10 to 90 minutes; the filtrate is reused for acidification treatment in S200.

4. The resource utilization method of lithium extraction slag as described in claim 1, characterized in that: The process parameters for calcination in S530 are: temperature 200–800℃, duration 10–60 minutes.

5. The resource utilization method of lithium extraction slag as described in claim 1, characterized in that: The process parameters for extraction in S630 are as follows: After evaporating and concentrating the mother liquor, adjust the pH to 12-14 and the temperature to 40-60℃. Add the extractant at an O / A ratio of 1:(3-5), shake for 15-30 minutes, and let stand for 30-60 minutes. The extractant is a mixture of t-BAMBP and sulfonated kerosene, with the sulfonated kerosene having a volume percentage of 10-30 vol% and the remainder being t-BAMBP.

6. The resource utilization method of lithium extraction slag as described in claim 1, characterized in that: The process parameters for back-extraction in S630 are as follows: the temperature is adjusted to 50-60℃, the first back-extraction agent is added at a ratio of O / A of (4-6):1, the shaking time is 15-30 minutes, and the standing time is 30-60 minutes; the first back-extraction agent is a mixture of sulfuric acid and citric acid, with the concentration of sulfuric acid being 1-3 mol / L and the concentration of citric acid being 0.05-0.1 mol / L.

7. The method for resource utilization of lithium extraction slag as described in claim 1, characterized in that: The process parameters for extraction in S640 are as follows: after evaporating and concentrating the aqueous phase, the pH is adjusted to 10-11 and the temperature to 25-35℃. The extractant is added at an O / A ratio of 1:(1-3), the shaking time is 15-30 minutes, and the standing time is 30-60 minutes. The extractant is a mixture of t-BAMBP and sulfonated kerosene, with the volume percentage of sulfonated kerosene being 10-30 vol%, and the remainder being t-BAMBP.

8. The resource utilization method of lithium extraction slag as described in claim 1, characterized in that: The process parameters for back-extraction in S640 are as follows: the temperature is adjusted to 40-60℃, the second back-extraction agent is added at a ratio of O / A of (3-5):1, the shaking time is 30-60 minutes, and the standing time is 30-60 minutes; the second back-extraction agent is a mixture of sulfuric acid and glycerol, the concentration of sulfuric acid is 1-1.5 mol / L, and the volume percentage of glycerol is 3-8 vol.

9. The resource utilization method of lithium extraction slag as described in claim 1, characterized in that: The S600 also includes: After combining organic phase II and organic phase IV, a regeneration treatment was performed: a sodium hydroxide solution with a concentration of 2-5 wt% was added at a ratio of O / A of 10:(1-3), the mixture was shaken for 30-60 minutes, allowed to stand for 30-60 minutes, and then separated into layers to obtain the regenerated extractant. The filtrate from the solid-liquid separation process in S630 and S640 is reused for water immersion treatment in S200.

10. The method for resource utilization of lithium extraction slag as described in claim 1, characterized in that: It also includes the following steps: S700, aluminum resource recycling process, includes the following steps: S710, after sequentially performing alkalization and solid-liquid separation treatment on the fourth filter residue, filter residue three and filtrate three are obtained; S720, after sequentially treating the filtrate with carbonation and solid-liquid separation, yields aluminum hydroxide.

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