A method for high-selectivity recovery of beryllium from lithium smelting beryllium-containing clinker
By employing a synergistic control system of limiting liquid-to-solid ratio and targeted proton dissociation in beryllium-containing lithium smelting clinker, the problems of impurity explosive dissolution and solid-liquid separation difficulties were solved, achieving highly selective beryllium recovery and efficient resource utilization, and significantly improving the beryllium grade of the product.
Patent Information
- Application Number
- CN202610760784.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-29
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies for processing beryllium-containing lithium smelting clinker suffer from problems such as impurity explosive dissolution, amorphous colloidal encapsulation, and difficulties in solid-liquid separation, resulting in low beryllium grade and low resource utilization efficiency.
A synergistic regulatory system combining low water activity inhibition under extreme liquid-solid ratio and targeted proton dissociation with alkaline-driven multinuclear phase transition was adopted. By controlling pH and temperature, concentrated acid was added dropwise at an extremely low liquid-solid ratio to carry out the reaction, followed by precipitation at appropriate pH and temperature to form a high-density potassium-sodium cryolite composite concentrate, thereby achieving highly selective recovery of beryllium.
It achieves highly selective recovery of beryllium, with a beryllium grade of over 5.5% in the product, improving the recovery rate, simplifying solid-liquid separation, reducing energy consumption and wastewater generation, and realizing efficient utilization of resources.
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Figure CN122445960A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for recovering beryllium from beryllium-containing solid waste, and particularly to a method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting, belonging to the field of resource utilization technology of beryllium-containing solid waste. Background Technology
[0002] Beryllium is gaining increasing attention as an emerging material. Due to its excellent low density, high specific strength, and high stability, it is an indispensable material in nuclear energy, aerospace, beryllium-copper alloys, and high-precision technologies. Beryllium is extremely rare in the Earth's crust and is often found as an associated element in light element deposits such as lithium and fluorite. With the explosive growth of the global lithium battery industry, large amounts of beryllium are enriched in smelting clinker and tailings during the mining, smelting, and subsequent material processing of lithium ore (such as lepidolite and spodumene). Beryllium and its compounds are extremely toxic and are classified as Category I pollutants.
[0003] However, current technologies generally treat beryllium-containing solid waste treatment as a simple beryllium removal process, often employing a crude "low-concentration acid leaching - strong alkali precipitation" process, merely to ensure that the beryllium in the solution meets emission standards. To maximize beryllium leaching, a large liquid-to-solid ratio (usually greater than 4:1) is typically used, coupled with a strongly acidic environment. Excessive acid and extremely high water activity can cause disordered and deep co-dissolution of large amounts of associated impurities in the clinker (such as large amounts of silicon, iron, and aluminum). In the subsequent alkali neutralization and precipitation stage, large amounts of iron and aluminum ions readily form massive amorphous colloidal precipitates. These colloids not only make solid-liquid separation extremely difficult but also tightly encapsulate the precipitated beryllium, resulting in a very low beryllium grade in the final beryllium-containing slag (often less than 0.1%). This leads to an extremely awkward industrial situation: companies consume large amounts of acid and alkali reagents. Summary of the Invention
[0004] To address the technical shortcomings of existing technologies in the treatment of beryllium-containing solid waste, such as "excessive dissolution of impurities, amorphous colloidal encapsulation, difficulty in solid-liquid separation, and lack of economic value of the products," the present invention aims to provide a method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting. This method transforms beryllium-containing clinker in lithium smelting into a beryllium-rich potassium-sodium cryolite composite concentrate with crystalline potassium-sodium cryolite as the main phase and a beryllium grade of over 5.5% for recovery. This method achieves high beryllium grade, high recovery rate, and obtains high-value-added potassium-sodium cryolite, truly realizing the resource utilization of beryllium-containing clinker in lithium smelting.
[0005] To achieve the above-mentioned technical objectives, this invention provides a method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting. The method involves pulverizing the beryllium-containing clinker and adjusting it into a slurry at a liquid-to-solid ratio of 1L:0.8kg to 1L:1kg. Under shearing action, concentrated acid is slowly added dropwise to the slurry to precisely control its pH within the range of 3.0 to 3.5 for reaction. After the reaction is complete, solid and liquid are separated to obtain a beryllium-containing filtrate. The beryllium-containing filtrate is then precipitated using sodium hydroxide solution to precisely control the final pH within the range of 8.5 to 9.0, resulting in a composite precipitate containing beryllium hydroxide and potassium sodium cryolite.
[0006] The method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting provided by this invention has a core mechanism that involves constructing a synergistic regulatory system of "low water activity inhibition under extreme liquid-to-solid ratio + targeted proton dissociation + alkaline-driven multinuclear phase transition". First, at extremely low liquid-to-solid ratios, the "free water" in the slurry is extremely scarce. When concentrated acid is added dropwise and strictly controlled within an appropriate pH range, high-energy protons preferentially attack the most active beryllium-oxygen coordination bonds in the solid lattice, inducing targeted beryllium dissociation. Simultaneously, due to the extremely low "water activity" and strong "common ion effect" in the slurry, the lattice disintegration of large quantities of silicon, iron, and excess aluminum is strongly suppressed, thus achieving highly selective beryllium release. This fundamentally prevents the subsequent formation of large amounts of amorphous colloids. Second, in the precipitation stage, this invention cleverly utilizes the appropriate amount of residual aluminum ions and fluoride ions (F) in the solution system. - ), potassium ions (K) + ) and sodium ions (Na + By controlling the pH and temperature within appropriate windows, not only do free beryllium ions undergo directional deprotonation and polynuclear hydroxyl-bridged polymerization to form dense particles, but more importantly, fluorine, aluminum, and alkali metal ions in the liquid phase break through the nucleation energy barrier and spontaneously undergo thermodynamic phase rearrangement, crystallizing and precipitating high-density potassium-sodium cryolite (K2NaAlF6). Beryllium hydroxide particles are stably anchored and co-precipitated in the cryolite crystal network, thus obtaining a beryllium-rich potassium-sodium cryolite composite concentrate.
[0007] As a preferred embodiment, the beryllium-containing lithium smelting clinker is a solid waste containing fluorine, aluminum, alkali metals and beryllium produced in the smelting process of spodumene or lepidolite.
[0008] As a preferred embodiment, the beryllium content in the beryllium-containing lithium smelting clinker is 0.01% to 0.15% by mass.
[0009] As a preferred embodiment, the acid solution is concentrated sulfuric acid. The concentrated sulfuric acid is 98% sulfuric acid. Concentrated sulfuric acid has a higher hydrogen proton concentration compared to other inorganic acids, which reduces the introduction of water. Furthermore, the heat generated by the reaction of concentrated sulfuric acid with water is used to regulate the temperature and promote the dissolution of beryllium.
[0010] As a preferred embodiment, the reaction conditions are: temperature of 15℃~30℃ and time of 20~40 min. Under these preferred reaction conditions, beryllium is selectively dissolved, while impurity elements such as aluminum and iron are leached at lower rates, thus avoiding the formation of a large amount of colloid during subsequent precipitation.
[0011] As a preferred embodiment, the precipitation conditions are: temperature 15℃~30℃, time 20~40 min. Under these preferred precipitation conditions, free beryllium ions in the solution are directionally transformed into high-density particulate Be(OH)2 solid precipitate through a hydroxyl-bridged polymerization network. Simultaneously, fluorine, aluminum, and alkali metal ions in the solution overcome the nucleation energy barrier and spontaneously undergo thermodynamic phase rearrangement, crystallizing to precipitate high-density potassium-sodium cryolite (K2NaAlF6). Beryllium hydroxide particles are stably anchored and co-precipitated within the cryolite crystallization network, thus obtaining a beryllium-rich potassium-sodium cryolite composite concentrate. Within the preferred precipitation temperature range, appropriately increasing the temperature is beneficial for promoting the transformation of free beryllium cations and anions into beryllium hydroxide structures.
[0012] The beryllium-containing clinker of this invention is pulverized to -40 mesh. After pulverization, the beryllium-containing clinker is preferably processed as soon as possible, as the pore structure and beryllium activity are optimal at this stage, resulting in the most complete dissolution of beryllium during processing.
[0013] The shearing rate of this invention is 200-300 rpm.
[0014] As a preferred option, beryllium-containing clinker should be processed as soon as possible after ball milling. At this stage, the pore structure and element activity of the beryllium-containing clinker are optimal, allowing for the most thorough processing.
[0015] As a preferred embodiment, the filtrate obtained from the solid-liquid separation contains reusable ions that can be recycled back into the beryllium precipitation process.
[0016] The beryllium-containing clinker involved in this invention includes, but is not limited to, beryllium-containing clinker produced during the mining, beneficiation, smelting, and material processing of beryllium ore, lithium ore, fluorite ore, etc.
[0017] The composite precipitate containing beryllium hydroxide and potassium sodium cryolite of the present invention was analyzed by X-ray diffraction (XRD) and its main crystalline phase was potassium sodium cryolite, with high-density particulate beryllium hydroxide in a deprotonated form doped in it.
[0018] This invention separates the filtrate from a composite precipitate containing beryllium hydroxide and potassium sodium cryolite into a solution rich in alkali metal ions, which is then returned to the upstream process for recycling or used for evaporation and crystallization to recover sodium salt.
[0019] Compared with the prior art, the technical solution of the present invention brings the following beneficial effects:
[0020] 1) The beryllium and valuable metals of this invention are recovered in the form of a high-value-added "beryllium-rich potassium-sodium cryolite composite concentrate". Traditional processes often produce hydrous aluminum-iron colloidal sludge with no recycling value. This invention utilizes precise thermodynamic control to ensure that the main phase of the final precipitate is well-crystallized potassium-sodium cryolite (an important chemical raw material that can be widely used in aluminum electrolysis and glass enamel). At the same time, the highly toxic and trace amounts of beryllium are enriched nearly 80 times in this mineral network (with a grade as high as 5.5%~6.0%).
[0021] 2) This invention recovers valuable metals such as beryllium in the form of beryllium-rich potassium-sodium cryolite composite concentrate. The concentrate exhibits excellent particle size and extremely low water holding capacity, avoiding the generation of amorphous colloids in traditional processes, greatly improving solid-liquid separation kinetics, and shortening the filtration time by more than 80% compared to traditional processes, thus greatly improving the operating efficiency of industrial production.
[0022] 3) This invention uses an ultra-low liquid-to-solid ratio for slurry preparation, reducing the total volume of the system to less than 20% of that of traditional processes. This not only significantly reduces the energy consumption of stirring and heating in the reactor (even relying solely on the self-heating of the reaction), but also greatly reduces the amount of heavy metal-containing wastewater generated from the source, completely reversing the cost disadvantage of tailwater treatment in smelters.
[0023] 4) This invention eliminates expensive and toxic organic extractants throughout the entire process. The core driving agents are only inexpensive concentrated sulfuric acid and sodium hydroxide, achieving a green closed-loop process in a purely inorganic system. The resulting beryllium-free tailings meet the standards for safe landfill or building material utilization, and the filtrate can be returned to the front-end closed loop, completely eliminating the ecological pollution problems caused by lithium slag solid waste. Attached Figure Description
[0024] Figure 1 The XRD analysis results of the composite precipitate containing beryllium hydroxide and potassium sodium cryolite prepared in Example 1 are shown in the figure. The results clearly show that the diffraction peaks are sharp, the crystallinity is good, and there is no obvious amorphous colloidal broadening background. Its main mineral phase is confirmed to be potassium sodium cryolite (K2NaAlF6), which confirms the extremely high economic and phase value of the product of this invention from a crystallographic perspective. Detailed Implementation
[0025] The following embodiments are intended to further illustrate the content of the present invention, but are not intended to limit the scope of protection of the claims of the present invention.
[0026] Example 1
[0027] Condition optimization experiment:
[0028] A lithium smelting company in Chenzhou, Hunan Province, produced beryllium-containing clinker. The typical elemental composition of this batch of beryllium-containing clinker (by mass) is: Be 0.074%, Al 12.5%, Fe 1.8%, and it also contains a certain amount of fluorine and alkali metals. The beryllium-containing clinker was ground to a commonly used -40 mesh (able to pass through a 40-mesh sieve) using a vibratory mill. The leaching test conditions were: liquid-to-solid ratio of 0.8:1 (L / kg), 200g of beryllium-containing clinker, 160mL of deionized water, leaching time of 30min, leaching temperature of room temperature (25℃), and the pH of the slurry solution was adjusted to 2, 3, and 4 using 98% concentrated sulfuric acid. After leaching, the beryllium-containing filtrate was obtained by filtration. The leaching results of the beryllium-containing clinker are shown in Table 1 below.
[0029] Table 1. Elemental analysis of leachate from beryllium-containing lithium smelting clinker leaching test
[0030]
[0031] It can be seen that in the clinker leaching experiment, the highest amount of beryllium was leached from the clinker when the pulp pH was 3.
[0032] In the beryllium-containing filtrate obtained by leaching the ore pulp at a pH of 3 (pH=3.26, Be 303.800 mg / L), a certain amount of 5 mol / L sodium hydroxide solution was added to adjust the pH of the ore pulp to 5, 7, and 9, respectively. The experimental results are shown in Table 2 below. The results show that the maximum amount of beryllium precipitated in the clinker leachate was obtained when the pH reached 9. Subsequent experiments were conducted under this condition.
[0033] Table 2. Beryllium residue in beryllium-containing filtrate under different pH conditions during beryllium precipitation test
[0034]
[0035] On-site pilot-scale experiment:
[0036] Take 1000g of representative clinker from the site and grind it to -40 mesh. Place it in a reactor and add 800mL of pure water at a liquid-to-solid ratio of 0.8L:1kg. Prepare a high-concentration heavy media slurry at room temperature (25℃) and a stirring speed of 300r / min. Acid adjustment and dissociation stage: Slowly add 98% concentrated sulfuric acid, and use shear and hydration micro-heating to precisely lower the pH of the slurry system to 3.24 and maintain it stably for 20min. The extremely low water activity severely inhibits the dissolution of iron and excess aluminum, while beryllium is precisely targeted and released. After filtration and volume adjustment (see Table 3), the beryllium concentration in the beryllium-containing filtrate is as high as 892.35mg / L (leaching rate as high as 96.47%). At this time, a small amount of aluminum (2.14g / L) and abundant alkali metals remain in the solution. Synergistic mineralization stage (alkali adjustment): The beryllium-containing filtrate was transferred to a reactor, and 5 mol / L sodium hydroxide solution was added at 300 r / min until the final pH reached 8.8. After aging for 30 min, no reddish-brown iron-aluminum viscous colloid appeared in the system; instead, a large number of dense white crystalline particles rapidly precipitated. The filter residue was collected by vacuum filtration and dried at low temperature. The resulting dry residue was easily peeled off, yielding 12.1 g of filter residue. XRD analysis (see [link to XRD analysis]) was performed. Figure 1 The results showed that the main mineral phase of the filter residue was well-crystallized potassium sodium cryolite (K2NaAlF6). Digestion ICP-OES analysis revealed that the beryllium grade in the potassium sodium cryolite matrix reached 5.89% (enriched nearly 80 times), with aluminum content of 8.16%, calcium content of 0.9847%, iron content of 0.5106%, magnesium content of 0.4918%, and manganese content of 0.4947% (see Table 4). The product possesses dual economic value as both cryolite and a high-purity beryllium precursor.
[0037] Table 3. Elemental analysis of beryllium-containing clinker leachate from lithium smelting
[0038]
[0039] Table 4. Effect of beryllium precipitation in leachate from beryllium-containing lithium smelting clinker.
[0040]
[0041] Example 2
[0042] 50 kg of representative beryllium-containing clinker from the same batch (beryllium mass percentage 0.074%, aluminum mass percentage 9.06%, manganese mass percentage 0.70%, iron mass percentage 2.39%, calcium mass percentage 14.0%, magnesium mass percentage 0.88%) was taken from a lithium smelting enterprise in Yichun, Jiangxi Province. 40 L of water was added and the mixture was forcibly pulped (liquid-to-solid ratio 0.8:1 L / kg). The pH was adjusted to 3.14 with concentrated sulfuric acid. After a strong shear reaction at room temperature for 0.5 hours, the mixture was filtered through a plate and frame filter press to obtain a high-concentration beryllium-containing filtrate with a beryllium concentration of 875.12 mg / L. In a multi-stage baffled reactor, the beryllium-containing filtrate was countercurrently mixed with sodium hydroxide, and the final pH was precisely adjusted to 8.6. The mixture was then matured at room temperature for 30 minutes. The beryllium-laden filter residue obtained by pressure filtration has extremely low moisture content, exhibits good crystalline state, and shows no colloid clogging of the filter cloth, demonstrating high filtration efficiency. Approximately 625g of beryllium-rich cryolite dry residue was obtained, with an analysis showing a beryllium grade as high as 5.58%, and the main phase remaining high-quality potassium-sodium cryolite. The leachate and beryllium-laden filter residue are shown in Tables 5 and 6, respectively. This fully demonstrates that this process not only solves the critical problem of difficult filtration of beryllium-containing waste residue in industry but also achieves a ton-scale leap from bulk hazardous waste to high-value dual-effect mineral materials. Furthermore, it indicates that this method has certain feasibility in different regions.
[0043] Table 5. Elemental analysis of beryllium-containing clinker leachate from lithium smelting
[0044]
[0045] Table 6. Beryllium precipitation effect of beryllium-containing clinker leachate from lithium smelting
[0046]
[0047] Comparison Example 1
[0048] 1000g of beryllium-containing clinker from a lithium smelting company in Yichun, Jiangxi Province (see Example 2) was taken and mixed with 4000mL of water according to the traditional process with a high liquid-to-solid ratio of 4:1. Acid was forcibly added to lower the pH to 1.36 in an attempt to achieve complete dissolution. Analysis showed that although the beryllium leaching rate was 85.6% in the extremely large volume of dark reddish-brown filtrate, the aluminum concentration was as high as 15.2g / L and the iron concentration was 3.5g / L (the impurities underwent non-selective explosive dissolution, completely deviating from the suitable molar ratio for cryolite synthesis). Subsequently, NaOH was added dropwise to adjust the pH to 8.5 to induce precipitation. Due to the severe excess of aluminum and iron and the lack of suitable thermodynamic driving conditions, a massive amount of reddish-brown amorphous aluminum hydroxide / iron colloidal slurry was instantaneously and explosively generated in the system. Not only did the plate and frame filter press completely fail (filtration time increased dramatically), but the free beryllium was also tightly bound. The final product was approximately 185g of waste sludge with a beryllium grade diluted to only 0.34% by the large amount of amorphous impurities. Due to the extremely chaotic composition of the sludge, which was mainly composed of amorphous colloids, it completely lost any economic value in industry as a raw material for fluorochemicals and a precursor for beryllium extraction, and became a highly toxic waste that had to be disposed of at a cost. The leachate and beryllium precipitate filter residue are shown in Tables 7 and 8, respectively.
[0049] Table 7 Elemental analysis of beryllium-containing clinker leachate from lithium smelting
[0050]
[0051] Table 8. Effect of beryllium precipitation in leachate from beryllium-containing lithium smelting clinker
[0052]
Claims
1. A method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting, characterized in that: After crushing the beryllium-containing clinker from lithium smelting, a slurry was prepared at a liquid-to-solid ratio of 1L:0.8kg to 1L:1kg. Under shearing action, concentrated acid was slowly added dropwise to the slurry to precisely control the pH of the slurry within the range of 3.0 to 3.5 for reaction. After the reaction was completed, the solid and liquid were separated to obtain a beryllium-containing filtrate. The beryllium-containing filtrate was then precipitated using sodium hydroxide solution to precisely control the final pH of the beryllium-containing filtrate within the range of 8.5 to 9.0, resulting in a composite precipitate containing beryllium hydroxide and potassium sodium cryolite.
2. The method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting according to claim 1, characterized in that: The beryllium-containing clinker from lithium smelting is a solid waste containing fluorine, aluminum, alkali metals, and beryllium produced in the smelting process of spodumene or lepidolite.
3. The method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting according to claim 2, characterized in that: The beryllium content in the beryllium-containing lithium smelting clinker is 0.01% to 0.15% by mass.
4. The method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting according to claim 1, characterized in that: The concentrated acid is concentrated sulfuric acid.
5. The method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting according to claim 1, characterized in that: The reaction conditions are: temperature 15℃~30℃, time 20~40min.
6. The method for highly selectively recovering beryllium from beryllium-containing clinker in lithium smelting according to claim 1, characterized in that: The precipitation conditions are: temperature 15℃~30℃, time 20~40min.