Beryllium element mineralizing reagent for lithium slag or beryllium-containing waste slag, curing method and application

Abstract

The invention discloses a beryllium element mineralizing reagent for lithium slag or beryllium-containing waste slag, a curing method and application, and relates to the field of slag treatment. The invention aims to solve the problems that the beryllium element in the existing lithium slag or beryllium-containing waste slag is difficult to cure, the curing structure is unstable in an acid environment, the curing mode is tedious and difficult in engineering application, the dosage of a curing agent is large, the compatibilization rate of the waste slag is high, and secondary lithium extraction and beryllium curing of the lithium slag are realized. According to the method, only the acidic phosphate needs to be added into the beryllium-containing waste residues or the lithium residues, or the phosphate needs to be added into the beryllium-containing waste residues or the lithium residues, and the staged acid environment exists, so that the using amount of the phosphate needed for curing the beryllium in the lithium residues or the beryllium-containing waste residues can be greatly reduced, a more stable mineralization effect is achieved, and the formed cured body has the beryllium adsorption capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of slag treatment, and particularly relates to a beryllium element mineralization reagent for lithium slag or beryllium-containing waste slag and a solidification method and application. BACKGROUND

[0002] Beryllium is an alkaline earth metal with a grayish white color, located in the second period of the second main group of the periodic table. Beryllium and its compounds are highly toxic. Difficultly soluble beryllium entering the human body is stored in the lungs, while soluble beryllium compounds are mainly stored in the bone, liver, kidney and lymph node, etc. These beryllium and its compounds are extremely difficult to be excreted from the body through human metabolism, and are potential carcinogens. Beryllium compounds can also react with plasma proteins to form beryllium protein complexes, causing tissue enlargement and causing granulomatous lesions of organs or tissues. On October 27, 2017, the World Health Organization's International Agency for Research on Cancer published a preliminary list of carcinogens, and beryllium and its compounds were identified as a class 1 carcinogen. At the same time, according to the standard "Hazardous Waste Identification Standard Leaching Toxicity Identification" (GB 5085.3-2007) of China, the acid leaching concentration of beryllium in solid waste exceeds 20 μg / L under the corresponding detection method, which belongs to hazardous waste.

[0003] In the natural evolution process of lithium-containing ore deposits or niobium-tantalum rare metal deposits, trace amounts of beryllium-containing minerals such as beryl and emerald will be produced. These beryllium-containing minerals are difficult to completely remove in the beneficiation process, resulting in a certain amount of beryllium elements in lithium concentrate or other rare metal concentrates. The stable structure of these beryllium-containing substances will be destroyed in the extraction process of lithium or other elements, resulting in a large amount of beryllium soluble in water or acidic solution in the tailings. These beryllium-containing waste needs to be strictly stabilized and harmlessly treated to avoid environmental impact and human harm caused by beryllium leakage.

[0004] At present, the treatment technology of beryllium-containing solid waste at home and abroad is not mature, and the main disposal methods include cement solidification, sulfide solidification, etc. However, these disposal methods can only stabilize beryllium in solid waste under alkaline conditions. When these solidified bodies are applied to building materials and serve in water environment or even acidic and corrosive environment for a long time, there is a possibility that beryllium will be dissolved again; when these solidified bodies are disposed by landfill or backfilling into mine, there is also a risk of beryllium secondary dissolution due to the destruction of alkaline environment by long-term acid rain, weathering, microbial action and other environmental factors. Therefore, the condition of satisfying the stability of beryllium elements under acidic conditions is the primary prerequisite for the backfilling, landfilling or resource utilization of beryllium-containing waste.

[0005] CN112456957B, the invention name "a stable solidification disposal method for beryllium-containing waste" discloses a disposal method:

[0006] 1) Wet grinding treatment of beryllium-containing waste slag to obtain beryllium-containing waste slag slurry;

[0007] 2) adding water-soluble metal inorganic salt into the beryllium-containing waste residue slurry, stirring and mixing to obtain mixture I; adding water-soluble phosphate into mixture I, continuously stirring and adjusting the pH value of the mixed system to 7-8.5 to complete the polycombination reaction to obtain mixture II;

[0008] 3) adding solidifying agent into mixture II and stirring uniformly, extruding and solidifying to form, and naturally placing to obtain a solidified body with a block shape.

[0009] Through the polycombination reaction, the leachable beryllium is converted into a difficultly soluble Bex-Mey-PO4 complex precipitate (wherein Me is one or more of Fe, Mg and Al), so that the beryllium is completely stabilized; the solidified body after treatment meets the requirements of the newly issued “Hazardous Waste Pollution Landfill Control Standard” (GB18598-2019) and can be directly filled into the warehouse for landfill, so that the safe disposal of the beryllium-containing waste residue is realized. Moreover, the process does not need high-temperature conditions throughout the process, and the investment of large-scale high-temperature equipment such as smelting furnace or cement kiln is completely avoided.

[0010] However, the patent needs to add “water-soluble metal inorganic salt” and phosphate to form a polycombination reaction, so as to convert the leachable beryllium into a difficultly soluble Bex-Mey-PO4 complex precipitate. Moreover, the reaction system of the phosphate is an alkaline condition, and after the formation of the Bex-Mey-PO4 complex precipitate, cement needs to be added, and the auxiliary solidifying agent is at least one of gypsum, fly ash and slag powder.

[0011] CN116966470A, the invention name “A beryllium super-stable mineralization reagent and a method for super-stable mineralization of hazardous beryllium elements in lithium slag” discloses:

[0012] The beryllium super-stable mineralization reagent includes phosphate and / or calcium compound and fluoride. The beryllium super-stable mineralization reagent can mineralize free beryllium into stable beryllium hydroxyphosphate, beryllium fluorophosphate and calcium fluoroberyllate and other minerals, realizes long-acting super-stable mineralization of free beryllium, reduces beryllium pollution in the environment, is particularly suitable for mineralization treatment of free beryllium in lithium slag, can make the leaching toxicity of beryllium in lithium slag under the natural stacking state lower than the national standard for toxicity leaching of hazardous waste, and has the advantages of low cost, non-toxicity, simple construction process, high stabilization efficiency, good long-acting stability, no secondary pollution and the like.

[0013] The solidification effect of the patent on the metal beryllium in the lithium slag is very poor by using phosphate alone. The patent also needs to add a large amount of toxic fluoride to achieve the removal of beryllium in the lithium slag. Moreover, the beryllium in the solidified lithium slag will be leached again in an acidic environment, and the amount of phosphate is large. SUMMARY

[0014] The purpose of this invention is to address the problems of difficulty in solidifying beryllium in beryllium-containing waste residues, instability of the solidified structure in acidic environments, cumbersome solidification methods that are difficult to apply in engineering, large dosage of solidification agents, and high waste residue volume expansion rate. This invention provides a beryllium mineralization reagent for lithium slag or beryllium-containing waste residues, as well as a solidification method and application. This invention discovers that under acidic conditions, the amount of phosphate required for solidifying beryllium in lithium slag or beryllium-containing waste residues can be significantly reduced, achieving a more stable mineralization effect. The formed solidified body has the ability to adsorb beryllium, thus yielding a beryllium mineralization reagent.

[0015] The present invention provides a beryllium mineralization reagent for lithium slag or beryllium-containing waste residue, wherein the beryllium mineralization reagent contains one or more of phosphoric acid and phosphates, and the solidified beryllium system containing the beryllium mineralization reagent is adjusted to acidic pH and then solidified.

[0016] Furthermore, the phosphate is one or more of a compound or mixture containing phosphate, dihydrogen phosphate, hydrogen phosphate, pyrophosphate, and metaphosphate; or the phosphate is a polyphosphate. Specifically, it can be one or more of dihydrogen phosphate, hydrogen phosphate, orthophosphate, pyrophosphate, polyphosphate, metaphosphate, and hypophosphate.

[0017] Furthermore, the pH value is between 0.01 and 6.96.

[0018] Furthermore, if the lithium slag or beryllium-containing waste slag contains sulfates, or if one or more of the following are added to the lithium slag or beryllium-containing waste slag: sulfates, acidic phosphates, hydrogen phosphates, dihydrogen phosphates, buffered phosphates, or hydrogen-releasing phosphates, or if the lithium slag or its slurry contains one or more of the following after the addition of phosphates: hydrogen phosphate, dihydrogen phosphate, buffered phosphates, or hydrogen-releasing phosphates, then the pH may or may not be adjusted to acidity.

[0019] Furthermore, the amount of beryllium mineralizing reagent added is more than 0.01% of the dry weight of lithium slag or beryllium-containing waste residue.

[0020] The present invention discloses a method for solidifying beryllium using a beryllium mineralization reagent from lithium slag or beryllium-containing waste residue. The method for solidifying beryllium is carried out in the following manner:

[0021] Add beryllium mineralization reagent to lithium slag or beryllium-containing waste residue, adjust the pH of the solidified beryllium system to acidic, and solidify beryllium under acidic conditions.

[0022] Furthermore, the addition of beryllium mineralizing reagent to lithium slag or beryllium-containing waste slag is carried out during the lithium extraction process from lithium ore, or in beryllium-containing waste slag or lithium slag or its water-immersed slurry, or in the treatment and disposal process of beryllium-containing waste slag or lithium slag, or in the preparation of materials, building materials or resource utilization processes of beryllium-containing waste slag or lithium slag.

[0023] Furthermore, lithium slag or beryllium-containing waste residue containing beryllium mineralizing reagents exhibits an acidic environment during the reaction phase. After solidifying beryllium, the pH value of the lithium slag or beryllium-containing waste residue may or may not increase.

[0024] The present invention relates to the application of a beryllium mineralization reagent in lithium slag or beryllium-containing waste residue, wherein the beryllium mineralization reagent is used to solidify beryllium and to extract lithium, potassium, rubidium or cesium from lithium slag.

[0025] The present invention relates to the application of a beryllium mineralization reagent in lithium slag or beryllium-containing waste residue, wherein the beryllium mineralization reagent is used to solidify beryllium or reduce the release of beryllium from the solidified lithium slag.

[0026] This invention has the following outstanding advantages:

[0027] 1. The method for deep solidification / stabilization of beryllium in lithium slag and beryllium-containing waste slag described in this invention reveals the important role of an acidic environment in the solidification of beryllium-containing waste by phosphate. Applying the method described in this invention only requires adding acidic phosphate to the beryllium-containing waste slag or lithium slag, or adding phosphate and a partially acidic environment. Deep solidification / stabilization of beryllium in beryllium-containing waste slag can be achieved without the addition of other chemical agents. The solidification process is simple, poses no risk of secondary pollution from foreign substances, and can be rapidly implemented in large-scale engineering applications.

[0028] 2. This invention provides a method for deep solidification / stabilization of beryllium in beryllium-containing waste residue, which greatly improves the utilization efficiency of phosphate, fundamentally reduces the actual amount of phosphate required, and achieves better beryllium mineralization, thus reducing the cost of reagents required for solidification. In comparison, in the invention patent (a beryllium ultra-stable mineralizing reagent and a method for ultra-stable mineralization of hazardous beryllium elements in lithium slag CN202310894894.2), when the sodium phosphate (alkaline phosphate) dosage is 5% of the lithium slag mass, the beryllium concentration in the leachate is 1323 μg / L, which cannot reach the national hazardous waste identification limit of below 20 μg / L. In this invention, the acidic phosphate dosage is 0.5% of the lithium slag mass, and at pH=6, the beryllium concentration in the sulfuric acid / nitric acid process lithium slag leachate is reduced to 5 μg / L.

[0029] 3. The method for deep solidification / stabilization of beryllium in beryllium-containing waste provided by this invention achieves stable beryllium solidification. The solidified waste retains a low leaching rate even in acidic environments, demonstrating good beryllium stability. The method of this invention can form beryllium-containing precipitates under acidic conditions, which will not dissolve under the same acidic conditions, nor under alkaline conditions, thus avoiding secondary release of beryllium from the solidified lithium slag. In contrast, using the invention patent (a beryllium ultra-stable mineralizing reagent and a method for ultra-stable mineralization of hazardous beryllium in lithium slag CN202310894894.2) to solidify lithium slag, and then placing the solidified lithium slag in an acidic aqueous solution with pH=6, results in a beryllium concentration as high as 1250 μg / L, which fails to meet the national hazardous waste heavy metal restriction standard of below 20 μg / L.

[0030] 4. The method for deep solidification / stabilization of beryllium in beryllium-containing waste provided by this invention has a long-lasting beryllium solidification effect. The formed solidified structure has the ability to absorb beryllium ions. Even if other forms of beryllium in the waste dissolve under the influence of the environmental medium, they can be stabilized in the adsorption structure, effectively reducing secondary pollution of beryllium-containing waste. After treatment with this invention, lithium slag has a significant absorption effect on dissolved beryllium that re-enters from the outside, which can further reduce the risk of beryllium release from lithium slag or the environment.

[0031] 5. This invention proposes the synergistic effect of sulfate and phosphate in the process of beryllium fixation in lithium slag.

[0032] 6. This invention proposes a method for extracting lithium from lithium slag by solidifying beryllium, and also has the function of extracting lithium, potassium, rubidium or cesium elements from lithium slag.

[0033] 7. This invention proposes a method for beryllium mineralization reagents to form partial hydrogen phosphate ions or dihydrogen phosphate ions under acidic conditions using phosphates, thereby further improving the mineralization effect of phosphates on beryllium in lithium slag. Attached Figure Description

[0034] Figure 1 The graph shows the difference in beryllium leaching concentration in lithium phosphate slag solids under alkaline and acidic conditions. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the spirit of the contents disclosed in the present invention will be described in detail below. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0036] The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0037] Using lithium slag or beryllium-containing waste slag provided by multiple production enterprises as examples, and referring to the "Solid Waste Leaching Toxicity Identification Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007) issued by the Ministry of Ecology and Environment, the deep stabilization effect of the present invention on beryllium in lithium slag was investigated.

[0038] Example 1-1:

[0039] The beryllium-containing waste residue is lithium slag from Plant A, and its pH is 8.06. Complete the solidification / stabilization of the beryllium-containing waste residue according to the following steps:

[0040] Step 1: Add an appropriate amount of water to the lithium slag to obtain lithium slag slurry, and stir the slurry until it is evenly mixed;

[0041] Step 2: Add sodium dihydrogen phosphate to the lithium slag slurry. The amount of sodium dihydrogen phosphate is 0.5% of the dry weight of the lithium slag. Since sodium dihydrogen phosphate is an acidic substance, there is no need to adjust the pH. The pH of the lithium slag slurry was measured to be 6.2 at this time. Continue stirring for 30 minutes.

[0042] Step 3: Separate the lithium slag slurry from the mud and water, wash away any residual phosphate in the lithium slag with water, filter to obtain solidified / stabilized lithium slag, and determine the leaching toxicity of the lithium slag according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007).

[0043] Examples 1-2:

[0044] The difference between this embodiment and Embodiment 1-1 is that the phosphorus species added in step 2 is alkaline sodium phosphate, and sulfuric acid is added at the same time to adjust the pH of the lithium slag slurry to 6.2. The rest of the process is the same as in Embodiment 1-1.

[0045] Examples 1-3:

[0046] The difference between this embodiment and Embodiment 1-1 is that the phosphorus species added in step 2 is alkaline sodium phosphate, and sulfuric acid is added at the same time to adjust the pH of the lithium slag slurry to 5.2. The rest of the process is the same as in Embodiment 1-1.

[0047] Examples 1-4:

[0048] The difference between this embodiment and Embodiment 1-1 is that the phosphorus species added in step 2 is alkaline sodium phosphate, and sulfuric acid is added at the same time to adjust the pH of the lithium slag slurry to 4.2. The rest of the process is the same as in Embodiment 1-1.

[0049] Examples 1-5:

[0050] The difference between this embodiment and Embodiment 1-1 is that the phosphorus species added in step 2 is alkaline sodium phosphate, and sulfuric acid is added at the same time to adjust the pH of the lithium slag slurry to 3.2. The rest of the process is the same as in Embodiment 1-1.

[0051] Examples 1-6:

[0052] The difference between this embodiment and Embodiment 1-1 is that the phosphorus species added in step 2 is phosphoric acid, and the pH of the lithium slag slurry is adjusted to 6.2. The rest of the process is the same as in Embodiment 1-1.

[0053] Examples 1-7:

[0054] The difference between this embodiment and Embodiment 1-1 is that the phosphorus species added in step 2 is neutral diammonium hydrogen phosphate, and sulfuric acid is added at the same time to adjust the pH of the slurry to 6.2. The rest of the process is the same as in Embodiment 1-1.

[0055] Examples 1-8:

[0056] The difference between this embodiment and Embodiment 1-1 is that the phosphorus species added in step 2 is neutral sodium pyrophosphate, and sulfuric acid is added at the same time to adjust the pH of the slurry to 6.2. The rest of the process is the same as in Embodiment 1-1.

[0057] Comparative Example 1-1:

[0058] The difference between this comparative example and Example 1-1 is that the phosphorus species added in step 2 is alkaline sodium phosphate, and the pH is not adjusted. It was found that the pH of the lithium slag slurry was 11.2 at this time. The rest of the process is the same as in Example 1-1.

[0059] Comparative Examples 1-2:

[0060] The difference between this comparative example and Example 1-1 is that the phosphorus species added in step 2 is alkaline sodium phosphate, and the pH of the lithium slag slurry is adjusted to 8.9. The rest of the process is the same as in Example 1-1.

[0061] Comparative Examples 1-3:

[0062] The difference between this comparative example and Example 1-1 is that the phosphorus species added in step 2 is alkaline sodium phosphate, which accounts for 3% of the dry weight of the lithium slag. Sodium hydroxide is also added to adjust the pH of the lithium slag slurry to 8.9. The rest of the process is the same as in Example 1-1.

[0063] Example 1 and the comparative example aim to illustrate the crucial role of the acidic environment described in this invention in the solidification of beryllium-containing waste residue. As can be seen from Table 1, the staged acidic environment has a significant impact on the reaction process between the beryllium-containing waste residue and phosphate. When alkaline disodium hydrogen phosphate is added to the beryllium-containing waste residue, and the pH of the slurry is controlled at 11.2 and 8.9, although the concentration of beryllium in the filtrate is very low, the concentration of beryllium leached by the sulfuric acid-nitric acid method is very high, and the leaching toxicity of beryllium in the waste residue is not actually changed. However, when the solidification process is acidic, the addition of small amounts of different phosphates or pyrophosphates effectively controls the leaching toxicity of beryllium in the waste residue. The concentration of beryllium in the leachate of the treated waste residue is less than 5 μg / L, meeting the beryllium limit in the wastewater discharge standard.

[0064] Table 1

[0065]

[0066] Example 2:

[0067] The beryllium-containing waste residue was lithium slag from Plant B, with a pH of 8.11. The solidification / stabilization of the beryllium-containing waste residue was carried out according to the following steps: An appropriate amount of water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; sodium phosphate was added to the lithium slag slurry at a dosage of 1.5% of the oven-dry weight of the lithium slag, adjusting the pH of the lithium slag slurry to 3.2, and stirring was continued for 30 minutes; the lithium slag slurry was separated from the water, and any residual phosphate ions in the lithium slag were washed away with water. The solidified / stabilized lithium slag was obtained by filtration. The equilibrium leaching concentration of the sample under different pH conditions was tested according to the pH-dependent leaching method proposed in CEN / TS14429 to evaluate the stability of the solidified beryllium-containing waste residue at different pH values.

[0068] Comparative Example 2-1:

[0069] The difference between this comparative example and Example 2-1 is that the pH is not adjusted in step 2, and the pH of the slurry is 11.35 at this time. The rest of the process is the same as that in Example 2-1.

[0070] Comparative Example 2-2:

[0071] The difference between this comparative example and Example 2-1 is that the lithium slag is not treated, and the equilibrium leaching concentration of the beryllium-containing waste slag under different pH conditions is tested directly according to the pH-dependent leaching method proposed in CEN / TS14429.

[0072] Example 2 compares the differences in beryllium leaching concentration in lithium phosphate slag solidified products under alkaline and acidic conditions under different acidic environments. The comparison with comparative examples aims to illustrate the stability of lithium slag or beryllium-containing waste residue solidified using the method described in this invention under different pH conditions. Under existing alkaline conditions, the leaching concentration of beryllium in beryllium-containing waste residue after phosphate solidification is significantly affected by pH. When the slurry pH decreases from 6.5 to 5.0, the leaching concentration of beryllium in Comparative Examples 2-1 and 2-2 increases sharply from 0 to approximately 600 μg / L. However, using the beryllium solidification method for phosphate under acidic conditions described in this invention, the solidified beryllium-containing waste residue maintains extremely low leaching toxicity in an acidic environment, achieving a fundamental change in the chemical form of beryllium in the waste residue.

[0073] Figure 1 The differences in beryllium leaching concentration in lithium phosphate slag solidified products under alkaline and acidic conditions were compared. The comparative examples aim to illustrate the stability of lithium slag or beryllium-containing waste solidified using the method described in this invention under different pH conditions.

[0074] Example 3:

[0075] The beryllium-containing waste residue is lithium slag from Plant C. This waste residue has a pH of 7.98 and a lithium oxide content of 0.24%. The solidification / stabilization of the beryllium-containing waste residue was completed according to the following steps: An appropriate amount of water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; sodium dihydrogen phosphate was added to the lithium slag slurry at a dosage of 0.5% of the dry weight of the lithium slag. Since sodium dihydrogen phosphate is acidic, no additional pH adjustment was required. The pH of the solution was measured to be 6.02 at this point, and stirring was continued for 30 minutes; the lithium slag slurry was separated from the water, and any residual phosphate ions in the lithium slag were washed away with water. The solidified / stabilized lithium slag was obtained by filtration. The leaching toxicity of the lithium slag was determined to be 2.3 μg / L according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007). The leaching toxicity was determined to be 2.3 μg / L according to the "Chemical Analysis Methods for Lithium Ore, Rubidium Ore, and Cesium Ore" (GB / T The residual lithium oxide content in the residue was determined to be 0.11% (17413-2010), while the concentrations of rubidium, cesium, and potassium in the lithium slag leachate increased by 51%, 49%, and 43%, respectively.

[0076] Example 3 illustrates that the solution of the present invention can promote the dissolution of lithium, rubidium, cesium and potassium in lithium slag while solidifying beryllium, thereby reducing the environmental risk of residual lithium slag during the secondary lithium extraction process.

[0077] Example 4-1:

[0078] The beryllium-containing waste residue is lithium slag from Plant A, with a pH of 8.06. The solidification / stabilization of the beryllium-containing waste residue was completed according to the following steps: An appropriate amount of water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; sodium dihydrogen phosphate was added to the lithium slag slurry at a dosage of 0.5% of the dry weight of the lithium slag. Since sodium dihydrogen phosphate is an acidic substance, no additional pH adjustment was required, and the pH of the solution was measured to be 6.2. Stirring was continued for 30 minutes; the lithium slag slurry was separated from the water, and any residual phosphate ions in the lithium slag were washed away with water. The solidified / stabilized lithium slag was obtained by filtration. The leaching toxicity of the lithium slag was determined according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007), and the pH of the leaching mixture was adjusted to 6.0 with sulfuric acid. The beryllium leaching after pH adjustment was then measured.

[0079] Comparative Example 4-1

[0080] The beryllium-containing waste residue was lithium slag from Plant A, with a pH of 8.06. The solidification / stabilization of the beryllium-containing waste residue was completed according to the following steps: Water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; 2% sodium phosphate and 1% sodium fluoride by mass were added to the slurry lithium slag, and mechanical stirring was performed for 30 minutes. Then, 2% calcium hydroxide by mass was added, and the pH of the solution was measured to be 12.62. Mechanical stirring was performed for another 30 minutes to complete the stabilization reaction. The lithium slag slurry was separated from the water, and any residual phosphate ions in the lithium slag were washed away with water. The leaching toxicity of the lithium slag was determined according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007). The pH of the leaching mixture was adjusted to 6.0 with sulfuric acid, and the beryllium leaching was measured after pH adjustment.

[0081] Comparative Example 4-2

[0082] The beryllium-containing waste residue was lithium slag from Plant A, with a pH of 8.06. The solidification / stabilization of the beryllium-containing waste residue was completed according to the following steps: Water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; 2% sodium phosphate and 1% sodium fluoride by mass were added to the slurry lithium slag, and mechanical stirring was performed for 30 minutes. The pH of the solution at this point was measured to be 12.03. Mechanical stirring was then performed for another 30 minutes to complete the stabilization reaction. The lithium slag slurry was separated from the water, and any residual phosphate ions in the lithium slag were washed away with water. The solidified / stabilized lithium slag was obtained by filtration. The leaching toxicity of the lithium slag was determined according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007). The pH of the solidified mixture after leaching was adjusted to 6.0 with sulfuric acid, and the beryllium leaching was measured after pH adjustment.

[0083] Comparative Example 4-3

[0084] The beryllium-containing waste residue was lithium slag from Plant A, with a pH of 8.06. The solidification / stabilization of the beryllium-containing waste residue was completed according to the following steps: Water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; 2% sodium phosphate was added to the slurry, and mechanical stirring was performed for 30 minutes. Then, 2% calcium hydroxide was added, and the pH of the solution was measured to be 11.9. Mechanical stirring was performed for another 30 minutes to complete the stabilization reaction. The lithium slag slurry was separated from the water, and any residual phosphate ions were washed away with water. The solidified / stabilized lithium slag was obtained by filtration. The leaching toxicity of the lithium slag was determined according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007). The pH of the leaching mixture was adjusted to 6.0 with sulfuric acid, and the beryllium leaching was measured after pH adjustment.

[0085] Example 4-1 and the comparative example were used to compare and analyze the effects of fluorides and calcium-containing compounds on phosphate-cured beryllium-containing waste. Table 2 shows that, since both sodium phosphate and calcium hydroxide are alkaline substances, their addition to the beryllium-containing waste slurry makes the slurry pH strongly alkaline. Under these conditions, the cured lithium slag still exhibits extremely high leaching toxicity in a weakly acidic environment (pH=6). However, using the method described in this invention, by simply controlling the reaction conditions to acidity and adding a small amount (0.5%) of phosphate, the leaching concentration of beryllium in a weakly acidic environment can be reduced to below 5 μ / L.

[0086] Table 2

[0087]

[0088] Example 5-1

[0089] The beryllium-containing waste residue is a high-beryllium lithium slag with a pH of 6.99 and a beryllium concentration of 163.54 mg / kg. The solidification / stabilization of the beryllium-containing waste residue is completed according to the following steps:

[0090] Step 1: Add an appropriate amount of water to the lithium slag to obtain lithium slag slurry, and stir the slurry until it is evenly mixed;

[0091] Step 2: Add sodium dihydrogen phosphate to the lithium slag slurry. The amount of sodium dihydrogen phosphate is 0.5% of the dry weight of the lithium slag. Since sodium dihydrogen phosphate is an acidic substance, there is no need to adjust the pH. The pH of the solution was measured to be 5.68 at this time. Continue stirring for 30 minutes.

[0092] Step 3: Separate the lithium slag slurry from the mud and water, wash away any residual phosphate in the lithium slag with water, filter to obtain solidified / stabilized lithium slag, and determine the leaching toxicity of the lithium slag according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007).

[0093] Example 5-2

[0094] The difference between this embodiment and Embodiment 5-1 is that the beryllium-containing waste residue used is different. Here, the beryllium-containing waste residue is waste residue from a beryllium smelting company. The pH of this waste residue is 6.6, and the concentration of beryllium is 521.3 mg / kg. The rest of the process is the same as in Embodiment 5-1.

[0095] Comparative Example 5-1

[0096] The difference between this comparative example and Example 5-1 is that in step 2, sulfuric acid is not added, but sodium hydroxide is added, and the pH of the slurry is adjusted to 8.9. The rest of the process is the same as in Example 5-1.

[0097] Comparative Example 5-2

[0098] The difference between this comparative example and Example 5-2 is that in step 2, sulfuric acid is not added, but sodium hydroxide is added, and the pH of the slurry is adjusted to 8.9. The rest of the process is the same as in Example 5-2.

[0099] Examples 5-1 and 5-2, along with comparative examples, are used to illustrate the general applicability of the present invention to beryllium-containing waste residues with different beryllium contents. As can be seen from Table 3, for the two types of beryllium-containing solid wastes with high beryllium concentrations, the beryllium leaching concentrations of the two waste residues after treatment using the technical means described in the present invention reached 3.2 μ / L and 3.38 μ / L, respectively.

[0100] Table 3

[0101]

[0102] Example 6:

[0103] The beryllium-containing waste residue is lithium slag from Plant A, with a pH of 8.06. The solidification / stabilization of the beryllium-containing waste residue was completed according to the following steps: An appropriate amount of water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; disodium hydrogen phosphate was added to the lithium slag slurry at a dosage of 0.5% of the oven-dry weight of the lithium slag, at which point the slurry pH was 6.2. After stirring for another 30 minutes, the slurry pH was adjusted to 8.5 with alkali; the lithium slag slurry was separated from the water, and any residual phosphate ions in the lithium slag were washed away with water. The solidified / stabilized lithium slag was obtained by filtration. The leaching toxicity of the lithium slag was determined to be 0.698 μg / L according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T 299-2007).

[0104] Therefore, the acidic conditions described in this invention refer to the reaction environment of phosphate and beryllium being acidic. Adjusting the beryllium-containing waste residue after curing to neutral or alkaline using alkali will not change the curing / stabilization effect described in this invention.

[0105] Example 7:

[0106] The beryllium-containing waste residue is lithium slag from Plant D. This waste residue has a pH of 7.83 and a water content of 18.85%. It contains 3.3% soluble sulfate. The solidification / stabilization of the beryllium-containing waste residue was completed according to the following steps: An appropriate amount of water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; 0.5% disodium hydrogen phosphate was added to the lithium slag, at which point the slurry pH was 7.82, and stirring was continued for 30 minutes; the lithium slag slurry was separated from the water, and any residual phosphate and sulfate ions were washed away with water. The solidified / stabilized lithium slag was obtained by filtration. The leaching toxicity of the lithium slag was determined to be 1.394 μg / L according to the "Identification of Leaching Toxicity of Solid Waste by Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007).

[0107] This embodiment illustrates the auxiliary role of sulfate in the process of phosphate solidification of beryllium-containing waste residue. When beryllium-containing solid waste contains soluble sulfate or sulfate is added to beryllium-containing solid waste, phosphate can achieve the same solidification / stabilization effect under neutral or alkaline conditions.

[0108] Example 8:

[0109] The beryllium-containing waste residue was lithium slag from Plant A, with a pH of 8.06 and a water content of 20.36%. The solidification / stabilization of the beryllium-containing waste residue was carried out according to the following steps: An appropriate amount of water was added to the lithium slag to obtain a lithium slag slurry, and the slurry was stirred until uniformly mixed; sodium dihydrogen phosphate was added to the lithium slag slurry at a dosage of 0.5% of the oven-dry weight of the lithium slag, at which point the solution pH was 6.2, and stirring was continued for 30 minutes; the lithium slag slurry was separated from the water, and any residual phosphate ions in the lithium slag were washed away with water, and the solidified / stabilized beryllium-containing waste residue was obtained by filtration. 300 μg / L of beryllium-containing wastewater was taken, and the solidified / stabilized beryllium-containing waste residue was added at a solid-liquid ratio of 1:2. After shaking and mixing for 12 hours, the residual beryllium concentration in the wastewater was determined to be 31 μg / L using ICP-MS.

[0110] Example 8 illustrates that the solidified product formed from beryllium-containing waste residue has a certain adsorption capacity for beryllium ions in the environment. This indicates that when beryllium ions invade the environment or other forms of beryllium in the beryllium-containing waste residue are dissolved by environmental factors, the present invention has a certain ability to resist secondary leakage of the hazardous element beryllium.

Claims

1. A beryllium mineralization reagent for lithium slag or beryllium-containing waste residue, characterized in that: The beryllium mineralizing agent contains one or more of phosphoric acid and phosphates. The solidified beryllium system containing the beryllium mineralizing agent is adjusted to acidic pH and then solidified.

2. The beryllium mineralization reagent for lithium slag or beryllium-containing waste slag according to claim 1, characterized in that: The phosphate is one or more of a compound or mixture containing phosphate, dihydrogen phosphate, hydrogen phosphate, pyrophosphate, and metaphosphate; or the phosphate is a polyphosphate.

3. The beryllium mineralization reagent for lithium slag or beryllium-containing waste slag according to claim 1, characterized in that: The phosphate is one or more of the following: dihydrogen phosphate, hydrogen phosphate, orthophosphate, pyrophosphate, polyphosphate, metaphosphate, and hypophosphate.

4. The beryllium mineralization reagent for lithium slag or beryllium-containing waste slag according to claim 1, characterized in that: The pH range is 0.01 to 6.

96.

5. The beryllium mineralization reagent for lithium slag or beryllium-containing waste slag according to claim 1, characterized in that: If the lithium slag or beryllium-containing waste contains sulfates, or if one or more of the following are added to the lithium slag or beryllium-containing waste: sulfates, acidic phosphates, hydrogen phosphates, dihydrogen phosphates, buffered phosphates, or hydrogen-releasing phosphates, or if the lithium slag or its slurry contains hydrogen phosphate, dihydrogen phosphate, buffered phosphates, or hydrogen-releasing phosphates after the addition of phosphates, then the pH may or may not be adjusted to acidity.

6. A beryllium mineralizing reagent for lithium slag or beryllium-containing waste slag according to any one of claims 1 to 5, characterized in that: The amount of beryllium mineralizing reagent added is more than 0.01% of the dry weight of lithium slag or beryllium-containing waste residue.

7. A method for solidifying beryllium using a beryllium mineralization reagent from lithium slag or beryllium-containing waste slag as described in any one of claims 1 to 5, characterized in that: The method for curing beryllium is carried out as follows: Add beryllium mineralization reagent to lithium slag or beryllium-containing waste residue, adjust the pH of the solidified beryllium system to acidic, and solidify beryllium under acidic conditions.

8. The method for curing beryllium according to claim 7, characterized in that: The addition of beryllium mineralizing reagent to lithium slag or beryllium-containing waste slag is carried out during the lithium extraction process from lithium ore, or in beryllium-containing waste slag or lithium slag or its water-immersed slurry, or in the treatment and disposal process of beryllium-containing waste slag or lithium slag, or in the preparation of materials, building materials or resource utilization processes of beryllium-containing waste slag or lithium slag.

9. The method for curing beryllium according to claim 7, characterized in that: The lithium slag or beryllium-containing waste residue containing beryllium mineralization reagents exhibits an acidic environment during the reaction phase. After solidifying beryllium, the pH value of the lithium slag or beryllium-containing waste residue may or may not increase.

10. The application of the beryllium mineralization reagent for lithium slag or beryllium-containing waste slag as described in any one of claims 1 to 5, characterized in that: The method described above utilizes beryllium mineralization reagents to solidify beryllium and extract lithium, potassium, rubidium, or cesium elements from lithium slag. Alternatively, beryllium mineralization reagents can be used to solidify beryllium or reduce the release of beryllium from the solidified lithium slag.

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