Ammoniated lignin biomass collecting agent and preparation method and application thereof
Ammoniated lignin biomass collectors were prepared by strong alkali pretreatment and low-temperature amine addition followed by high-temperature aldehyde addition, which solved the problem of insufficient performance of existing collectors and realized a highly efficient and environmentally friendly low-cost flotation separation process for spodumene.
Patent Information
- Application Number
- CN202511879502.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-02-24
AI Technical Summary
Existing chemically synthesized collectors suffer from poor collection performance, high production costs, and poor environmental compatibility in spodumene flotation. Unmodified lignin has limited interaction sites with the spodumene surface, making it difficult to meet the requirements of industrial applications.
Ammoniated lignin biomass collectors were prepared by activating lignin through strong alkali pretreatment, followed by low-temperature amine addition and high-temperature aldehyde addition. The collection rate and selectivity of spodumene were improved by utilizing electrostatic attraction and chelation. The modified lignin can form chelates with aluminum ions on the surface of spodumene.
It significantly improves the recovery rate and selectivity of spodumene, and has the advantages of being environmentally friendly and low-cost, making it suitable for flotation separation processes of spodumene ore.
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Abstract
Description
Technical Field
[0001] This application relates to the field of mineral processing, specifically to an ammonified lignin biomass collector, its preparation method, and its application. Background Technology
[0002] Lithium, as a strategic metal, is an indispensable core raw material for industries such as new energy vehicle power batteries, energy storage equipment, advanced ceramics, and glass. In recent years, with the acceleration of the global energy transition, the demand for lithium resources in the power battery and energy storage fields has experienced explosive growth. Spodumene, as one of the lithium minerals with the highest lithium content and the widest distribution, is currently the preferred raw material for industrial lithium extraction, and its beneficiation and purification efficiency directly determines the utilization level of lithium resources.
[0003] In the separation and purification process of spodumene, flotation has become the mainstream technology for separating spodumene from gangue minerals such as albite, quartz, and mica due to its advantages of simple operation, strong adaptability, and high separation efficiency. Currently, the collectors used in spodumene flotation are mainly chemically synthesized reagents, including fatty acid derivatives, hydroxamic acids, and amine compounds. Although these reagents can achieve preliminary separation of spodumene under specific conditions, they suffer from problems such as poor collection performance, high production costs, and poor environmental compatibility in practical applications.
[0004] Lignin, a major byproduct of the pulp and paper industry, is a stable, inexpensive, and fully biodegradable natural polymer biomass resource. Its molecules contain abundant active functional groups, allowing it to adsorb onto mineral surfaces through chemical reactions, thus possessing the potential to become a green collector. However, unmodified lignin has limited interaction sites with the spodumene surface, making it difficult to meet industrial production requirements and limiting its practical application in spodumene flotation. Summary of the Invention
[0005] To address the performance deficiencies of existing chemically synthesized collectors and the limitations of direct lignin application, this application provides an ammoniated lignin biomass collector. This method involves activating lignin through strong alkali pretreatment, followed by a "low-temperature amine addition-high-temperature aldehyde addition" process to ensure the smooth progress of the Mannich reaction, thereby preparing the ammoniated lignin biomass collector. The modified lignin significantly improves the collection rate and selectivity of spodumene through electrostatic attraction and the synergistic effect of forming chelates with aluminum ions on the spodumene surface. Furthermore, it offers advantages such as environmental friendliness and low cost, making it suitable for flotation separation processes in spodumene ore.
[0006] In a first aspect, this application provides an ammoniated lignin biomass collector, employing the following technical solution: A method for preparing an ammoniated lignin biomass collector includes the following steps: Pretreatment: Lignin is placed in an activator solution with a pH range of 9-12 and ultrasonically mixed to obtain a lignin mixture; the activator solution includes at least one of NaOH solution, KOH solution, Na2CO3 solution and K2CO3 solution; Modification: The lignin mixture is stirred, and after the initial temperature is raised to 50-60℃, amino alkanes are added. Then, the temperature is raised to 70-90℃ and aldehyde additives are added dropwise to react. After cooling, an aminated lignin modification solution is obtained. The amino alkanes are amino alkane compounds with a carbon chain length of 3-6. Extraction: The pH of the aminated lignin-modified solution was adjusted to 1-3, and then filtered, washed and dried to obtain the aminated lignin biomass collector.
[0007] By employing the above technical solution, the β-O-4 ether and ester bonds in lignin are first broken using the strongly alkaline environment of the activator, exposing phenolic hydroxyl groups (-OH) and carboxyl groups (-COOH). The phenolic hydroxyl groups then ionize into phenoxy anions, enhancing nucleophilicity. The temperature is initially raised to 50-60℃ before adding amine-based alkanes to ensure the amine groups are "in place" and activated, dominating the reaction. Then, the temperature is raised to 70-90℃ before adding aldehyde additives. Under conditions of excess and activated amine groups, the aldehyde additives preferentially react with the amines to form intermediates, rather than reacting randomly with other components, ensuring the smooth progress of the Mannich reaction, thereby preparing an ammoniated lignin biomass collector.
[0008] During the flotation separation of spodumene and quartz, the protonated amine groups on ammoniated lignin can attract the negative charge on the spodumene surface through electrostatic attraction. Furthermore, compared to silicon ions on the quartz surface, the phenolic hydroxyl and amine groups on ammoniated lignin preferentially form chelates with aluminum ions on the spodumene surface, resulting in better spodumene capture.
[0009] This application utilizes strong alkali pretreatment to activate lignin, followed by a "low-temperature amine addition-high-temperature aldehyde addition" process to ensure the smooth progress of the Mannich reaction, thereby preparing an ammoniated lignin biomass collector. The modified lignin significantly enhances the collection rate and selectivity of spodumene through electrostatic attraction and the synergistic effect of forming chelates with aluminum ions on the spodumene surface. It also boasts advantages such as environmental friendliness and low cost, making it suitable for flotation separation processes in spodumene ore.
[0010] Preferably, the amino alkane includes at least one of diethylenetriamine and tris(hydroxymethyl)aminomethane.
[0011] Preferably, the amino alkane is an amino mixture of diethylenetriamine and tris(hydroxymethyl)aminomethane.
[0012] By adopting the above technical solution, diethylenetriamine contains two primary amino groups and one secondary amino group. Multiple amino groups can simultaneously crosslink with lignin phenolic hydroxyl groups and aldehydes, increasing the nitrogen content and chelation sites of the modified product and enhancing its ability to collect metal ions. The resulting ammonified lignin can efficiently complex Ca... 2+ Mg 2+ These properties significantly enhance scale inhibition and collection performance. The amino groups on tris(hydroxymethyl)aminomethane can also cross-link with lignin phenolic hydroxyl groups and aldehydes, increasing the nitrogen content and chelation sites of the modified product and improving its ability to collect metal ions. Furthermore, tris(hydroxymethyl)aminomethane stabilizes the system in an alkaline environment (pH 9-12), preventing side reactions (such as condensation or degradation) of lignin due to pH fluctuations during modification.
[0013] The addition of diethylenetriamine and tris(hydroxymethyl)aminomethane in combination is superior to adding either one alone. This is likely because tris(hydroxymethyl)aminomethane can stabilize the pH environment (reducing potential side reactions caused by higher alkalinity of diethylenetriamine), while diethylenetriamine provides high-density amine groups to enhance crosslinking. The hydroxyl groups of tris(hydroxymethyl)aminomethane can inhibit excessive crosslinking, maintaining the product's molecular weight within a suitable range (improving solubility and dispersibility).
[0014] Preferably, the ratio between the volume of diethylenetriamine and the mass of trihydroxymethylaminomethane in the amine mixture is 1 mL: (0.6-1.2) g.
[0015] By adopting the above technical solution, when the mass ratio of tris(hydroxymethyl)aminomethane is too low, diethylenetriamine will be excessively cross-linked, resulting in reduced product dispersibility and thus reduced collection effect; when the mass ratio of tris(hydroxymethyl)aminomethane is too high, the degree of cross-linking of lignin phenolic hydroxyl groups and aldehydes is reduced, decreasing the nitrogen content and chelation sites of the modified product and reducing the collection ability for metal ions. Therefore, after extensive research and experimental verification, the applicant finally determined that the ratio between the volume of diethylenetriamine and the mass of tris(hydroxymethyl)aminomethane in the amine mixture of this application should be as described above.
[0016] Preferably, the aldehyde additive includes at least one of acetaldehyde and phenylacetaldehyde.
[0017] Preferably, the aldehyde additive is an aldehyde mixture of acetaldehyde and phenylacetaldehyde.
[0018] By employing the above technical solution, acetaldehyde rapidly undergoes a Mannich reaction with amino alkanes to generate a linear hydroxymethyl structure, increasing the nitrogen content of lignin (by increasing the amino grafting rate). The benzene ring of phenylacetaldehyde inhibits excessive cross-linking, generating a more stable secondary amine structure and improving the thermal stability of the product. Furthermore, the benzene ring imparts a hydrophobic surface to the collector, enhancing its adsorption capacity and improving flotation recovery.
[0019] When acetaldehyde and phenylacetaldehyde are added in combination, it is superior to adding either aldehyde additive alone. This may be because acetaldehyde introduces a hydrophilic chain, while phenylacetaldehyde provides a hydrophobic aromatic ring, forming an amphoteric structure that simultaneously improves harvesting efficiency.
[0020] Preferably, the volume ratio of acetaldehyde to phenylacetaldehyde in the aldehyde mixture is 1:0.6-1.
[0021] By adopting the above technical solution, when the volume ratio of phenylacetaldehyde is too low, acetaldehyde is prone to self-condensation to generate 2-butenal, which reduces the performance of the collector; when the volume ratio of phenylacetaldehyde is too high, the Mannich reaction rate decreases, and the collection effect of the prepared ammoniated lignin biomass collector is only slightly improved. Therefore, after extensive research and experimental verification, the applicant finally determined that the volume ratio of acetaldehyde to phenylacetaldehyde in the aldehyde mixture of this application should be as described above.
[0022] Preferably, the drying method is freeze drying.
[0023] By adopting the above technical solutions, ordinary drying will cause shrinkage, agglomeration, and pore collapse inside the material, while freeze drying retains the internal pore structure of the ammonified lignin biomass collector. This porous morphology not only increases the contact area between the collector and spodumene, but also provides sufficient sites for the binding of hydrophobic groups and bubbles, thereby enhancing the effect of the collector.
[0024] Secondly, this application provides an ammoniated lignin biomass collector, employing the following technical solution: An ammoniated lignin biomass collector is prepared by the above-mentioned method for preparing an ammoniated lignin biomass collector.
[0025] Thirdly, this application provides an ammoniated lignin biomass collector for the flotation separation of spodumene and quartz, employing the following technical solution: An application of the above-mentioned ammoniated lignin biomass collector in the flotation separation of spodumene and quartz includes the following steps: Grinding and pulping: The pegmatite is ground into a mineral sample, which is then added to water to form a slurry; Flotation: Sodium silicate inhibitor, ammoniated lignin biomass collector, and methyl isobutyl methanol are added sequentially to the slurry. The mixture is stirred and floated, and then skimmed and washed to obtain spodumene concentrate.
[0026] In summary, this application has the following beneficial effects: This application utilizes strong alkali pretreatment to activate lignin, followed by a "low-temperature amine addition-high-temperature aldehyde addition" process to ensure the smooth progress of the Mannich reaction, thereby preparing an ammoniated lignin biomass collector. The modified lignin significantly enhances the collection rate and selectivity of spodumene through electrostatic attraction and the synergistic effect of forming chelates with aluminum ions on the spodumene surface. It also boasts advantages such as environmental friendliness and low cost, making it suitable for flotation separation processes in spodumene ore. Detailed Implementation
[0027] The raw materials in this application include the following: Lignin: Commercially available product with CAS number 8068-05-1 is used; Tris(hydroxymethyl)aminomethane: Uses commercially available products with CAS number 77-86-1; Diethylenetriamine: Use commercially available product with CAS number 111-40-0; Sodium silicate: Use commercially available product with CAS number 1344-09-8; Methyl isobutyl methanol: Use the commercially available product with CAS number 108-11-2; The present application will be further described in detail below with reference to embodiments and comparative examples.
[0028] Example 1 A method for preparing an ammoniated lignin biomass collector includes the following steps: Pretreatment: 1g of lignin was placed in 50mL of NaOH solution with pH 11. After sonication for 5min, the mixture was homogenized to obtain a lignin mixture. Since the activator solution mainly provides a strongly alkaline environment, this application only uses NaOH solution as an example. Any one of NaOH solution, KOH solution, Na2CO3 solution and K2CO3 solution can be used alone or in combination, and will not be listed in detail. Modification: The lignin mixture was stirred at 300 rpm, and after the initial temperature was raised to 50℃, 0.67 g of tris(hydroxymethyl)aminomethane was added. Then the temperature was raised to 90℃ and 0.76 mL of acetaldehyde was added dropwise. After reacting for 5 h, the mixture was cooled to room temperature to obtain the aminated lignin modified solution. Extraction: Add 0.1M HCl to the aminated lignin modified solution to adjust the pH to 2, then filter and wash until neutral, and freeze-dry at -25℃ (or within the range of -20℃ to -30℃) for 8 hours to obtain the aminated lignin biomass collector.
[0029] An ammoniated lignin biomass collector is used for the flotation separation of spodumene and quartz, comprising the following steps: Grinding and pulping: Grind the pegmatite into a mineral sample with a particle size of 80-180 mesh accounting for 70%. Add 2.5 kg of mineral sample to 7.5 kg of water to form a slurry with a mineral sample mass concentration of 25 wt%. Stir for 2 min, adjust the pH of the slurry to 4 with 10% hydrochloric acid, and continue stirring for 2 min. Flotation: Subsequently, 15g of sodium silicate inhibitor, 5g of ammoniated lignin biomass collector, and 0.3mL of methyl isobutyl methanol were added. The mixture was stirred and floated at 300rpm for 8min, with the air flow rate controlled at 0.7m. 3 The spodumene concentrate was obtained by scraping and washing the spodumene at a speed of 1000 m / min.
[0030] Example 2-3 Examples 2-3 are based on the preparation method of the ammonified lignin biomass collector in Example 1, with adjustments made to the reaction conditions in the preparation method of the ammonified lignin biomass collector. The specific adjustments are shown in Table 1.
[0031] Comparative Examples 1-5 Comparative Example 1 is based on the application of the aminated lignin biomass collector in Example 1 for the flotation separation of spodumene and quartz, but the aminated lignin biomass collector is replaced with lignin.
[0032] Comparative Example 2, based on the application of the aminated lignin biomass collector in Example 1 for the flotation separation of spodumene and quartz, replaces the aminated lignin biomass collector with sodium oleate.
[0033] Comparative Example 3, based on the application of the ammoniated lignin biomass collector in Example 1 for the flotation separation of spodumene and quartz, replaces the ammoniated lignin biomass collector with oleic acid.
[0034] Comparative Example 4 modifies the modification steps based on the preparation method of Example 1 as follows: Modification: The lignin mixture was stirred at 300 rpm, and after the initial temperature was raised to 50°C, tris(hydroxymethyl)aminomethane was added. Then, 0.76 mL of acetaldehyde was added dropwise, and the temperature was raised to 90°C and reacted for 5 h. After cooling to room temperature, the aminated lignin modified solution was obtained.
[0035] Comparative Example 5 modifies the modification steps based on the preparation method of Example 1 as follows: Modification: The lignin mixture was stirred at 300 rpm, and after the initial temperature was raised to 50°C, 0.76 mL of acetaldehyde was added dropwise. Then, the temperature was raised to 90°C and tris(hydroxymethyl)aminomethane was added. The reaction was carried out for 5 hours. After cooling to room temperature, the aminated lignin modified solution was obtained.
[0036] Performance testing The spodumene concentrates of Examples 1-3 and Comparative Examples 1-5 were subjected to the following performance tests, and the test results are shown in Table 1.
[0037] Li2O grade and recovery rate The mass of Li₂O in the spodumene concentrate (A), the mass of the spodumene concentrate (B), and the mass of Li₂O in the ore sample (C) were determined. The Li₂O grade was calculated as (A / B) * 100%, and the recovery rate was calculated as (A / C) * 100%.
[0038] Table 1. Reaction conditions and performance testing in the preparation methods of ammoniated lignin biomass collectors in Examples 1-3 and Comparative Examples 1-5.
[0039] Referring to Table 1, comparing Examples 1-3 and Comparative Examples 1-5, it can be seen that when lignin is activated by NaOH solution, an ammoniated lignin biomass collector is prepared through the interaction of tris(hydroxymethyl)aminomethane and acetaldehyde. Compared with unmodified lignin, it can effectively improve the Li₂O grade and the recovery rate of spodumene concentrate. Furthermore, compared with traditional collectors sodium oleate and oleic acid, the ammoniated lignin biomass collector has a higher spodumene concentrate recovery rate, and the biodegradability of sodium oleate and oleic acid is poor, far inferior to that of the ammoniated lignin biomass collector.
[0040] Comparative Examples 1-3 and 4-5 revealed that, in the ammoniation of lignin, it is necessary to first add tris(hydroxymethyl)aminomethane at a lower temperature, followed by the dropwise addition of acetaldehyde at a higher temperature, in order to effectively modify the lignin. The reason is that first raising the temperature to 50-60°C before adding tris(hydroxymethyl)aminomethane ensures that the amino groups are "in place" and activated, dominating the reaction; then raising the temperature to 70-90°C before adding acetaldehyde, under conditions of excess and activated amino groups, allows acetaldehyde to preferentially react with the amine to form an intermediate, rather than reacting randomly with other components, ensuring the smooth progress of the Mannich reaction, thereby preparing the ammonified lignin biomass collector.
[0041] Furthermore, comparing Examples 1-3, it was found that Example 1 had the best performance; therefore, Example 1 was preferred.
[0042] Examples 4-6 Example 4 is based on the preparation method of Example 1, except that 0.67 g of tris(hydroxymethyl)aminomethane is replaced with 0.67 mL of diethylenetriamine.
[0043] Example 5 is based on the preparation method of Example 1, but 0.67g of tris(hydroxymethyl)aminomethane is replaced with an amino mixture consisting of 0.335mL of diethylenetriamine and 0.335g of tris(hydroxymethyl)aminomethane.
[0044] Example 6 is based on the preparation method of Example 1, but the modification steps are adjusted as follows: the lignin mixture is stirred at 300 rpm, the temperature is initially raised to 50°C and 0.335 g of tris(hydroxymethyl)aminomethane is added, 0.335 mL of diethylenetriamine is added after 10 min, the temperature is raised to 90°C and 0.76 mL of acetaldehyde is added dropwise and reacted for 5 h. After cooling to room temperature, the aminated lignin modified solution is obtained.
[0045] The spodumene concentrates from Examples 4-6 were subjected to the above performance tests, and the test results are shown in Table 2.
[0046] Table 2. Types of amino alkanes and their performance tests in Examples 1 and 4-6.
[0047] Referring to Table 2, a comparison of Examples 1 and 4-6 shows that both diethylenetriamine and tris(hydroxymethyl)aminomethane can be used in this application, and the effect is even better when added in combination. This may be because tris(hydroxymethyl)aminomethane can stabilize the pH environment (reducing side reactions that may be caused by the higher alkalinity of diethylenetriamine), while diethylenetriamine provides high-density amine groups to enhance crosslinking. The hydroxyl groups of tris(hydroxymethyl)aminomethane can inhibit excessive crosslinking and maintain the molecular weight of the product within a suitable range (improving solubility and dispersibility).
[0048] When adding both, adding tris(hydroxymethyl)aminomethane first, followed by diethylenetriamine, yields better results. This is because it ensures that diethylenetriamine dominates the cross-linking process, while tris(hydroxymethyl)aminomethane provides auxiliary stabilization. It also effectively prevents the hydroxyl groups of tris(hydroxymethyl)aminomethane from condensing with the primary amino groups of diethylenetriamine to form Schiff bases, thus consuming available amino groups.
[0049] Examples 7-8 Examples 7-8 are based on the preparation method of Example 6, but the volume of diethylenetriamine and the mass of tris(hydroxymethyl)aminomethane are adjusted. The specific adjustments are shown in Table 3.
[0050] The spodumene concentrates from Examples 7-8 were subjected to the above performance tests, and the test results are shown in Table 3.
[0051] Table 3. Volume of diethylenetriamine and mass of tris(hydroxymethyl)aminomethane in Examples 1 and 6-8, and performance test results.
[0052] Referring to Table 3, a comparison of Examples 1 and 6-8 shows that as the mass of tris(hydroxymethyl)aminomethane increases, the Li₂O grade and spodumene recovery rate in spodumene concentrate initially increase and then decrease. This is because as the mass of tris(hydroxymethyl)aminomethane increases, its hydroxyl groups inhibit excessive cross-linking, maintaining the product's molecular weight within a suitable range (improving solubility and dispersibility), thus increasing the Li₂O grade and spodumene recovery rate. However, beyond a certain range, the degree of cross-linking between lignin phenolic hydroxyl groups and aldehydes decreases, reducing the nitrogen content and chelation sites of the modified product, and decreasing its ability to collect metal ions, thereby reducing the Li₂O grade and spodumene recovery rate.
[0053] Examples 9-11 Example 9 is based on the preparation method of Example 1, except that 0.76 mL of acetaldehyde is replaced with 0.76 mL of phenylacetaldehyde.
[0054] Example 10 is based on the preparation method of Example 1, except that 0.76 mL of acetaldehyde is replaced with 0.76 mL of an aldehyde mixture of acetaldehyde and phenylacetaldehyde, and the volume ratio of acetaldehyde to phenylacetaldehyde in the aldehyde mixture is 1:0.8.
[0055] Example 11: Based on the preparation method of Example 1, the modification steps were adjusted as follows: The lignin mixture was stirred at 300 rpm, and after the initial temperature was raised to 50°C, 0.67 g of tris(hydroxymethyl)aminomethane was added. Then, after the temperature was raised to 90°C, 0.422 mL of acetaldehyde was added dropwise and reacted for 0.5 h. Then, 0.338 mL of phenylacetaldehyde was added dropwise and reacted for 4.5 h. After cooling to room temperature, the ammonified lignin modified solution was obtained. The total volume of acetaldehyde and phenylacetaldehyde was 0.76 mL, and the volume ratio of acetaldehyde to phenylacetaldehyde was 1:0.8.
[0056] The spodumene concentrates from Examples 9-11 were subjected to the above performance tests, and the test results are shown in Table 4.
[0057] Table 4. Types of aldehyde additives and their performance test results in Examples 1 and 9-11.
[0058] Referring to Table 4, a comparison of Examples 1 and 9-11 shows that both acetaldehyde and phenylacetaldehyde can be used in this application, and the combined addition of the two yields even better results. This may be because acetaldehyde rapidly undergoes the Mannich reaction with tris(hydroxymethyl)aminomethane to generate a linear hydroxymethyl structure, increasing the lignin nitrogen content (increasing the amine grafting rate). The benzene ring of phenylacetaldehyde inhibits excessive cross-linking, generating a more stable secondary amine structure and improving the thermal stability of the product. In addition, the benzene ring imparts a hydrophobic surface to the collector, enhancing its adsorption capacity and improving the flotation recovery rate.
[0059] When adding both aldehydes together, adding acetaldehyde first, followed by phenylacetaldehyde, yields better results. This is because some of the mixed aldehydes may undergo aldol condensation under alkaline conditions, forming insoluble resins. Adding them in stages effectively prevents aldol condensation, thus ensuring the reaction's effectiveness and improving the collection efficiency of the ammoniated lignin biomass collector.
[0060] Examples 12-13 Examples 12-13 are based on the preparation method of Example 11, but the volume ratio of acetaldehyde and phenylacetaldehyde in the aldehyde mixture is adjusted. The specific adjustments are shown in Table 5.
[0061] The spodumene concentrates from Examples 12-13 were subjected to the above performance tests, and the test results are shown in Table 5.
[0062] Table 5. Volume ratio of acetaldehyde and phenylacetaldehyde and performance test results for Examples 1 and 11-13.
[0063] Referring to Table 5, a comparison of Examples 1 and 11-13 shows that as the volume percentage of phenylacetaldehyde increases, the Li₂O grade and the recovery rate of spodumene concentrate initially increase and then decrease. This is because, with a larger volume percentage of phenylacetaldehyde, the benzene ring of phenylacetaldehyde can better suppress excessive cross-linking, generating a more stable secondary amine structure and improving the thermal stability of the product. Furthermore, the benzene ring imparts a hydrophobic surface to the collector, enhancing its adsorption capacity, thus increasing the Li₂O grade and the recovery rate of spodumene concentrate. However, beyond a certain range, the Mannich reaction rate decreases, which in turn reduces the Li₂O grade and the recovery rate of spodumene concentrate. Example
[0064] Example 14 is based on the preparation method of Example 1, but the drying method is changed from freeze drying at -25°C for 8 hours to drying at 80°C for 8 hours.
[0065] The spodumene concentrate from Example 14 was subjected to the above performance tests, and the test results are shown in Table 6.
[0066] Table 6. Drying methods and performance test results for Examples 1 and 14.
[0067] Referring to Table 6, a comparison of Examples 1 and 14 shows that freeze-drying is more advantageous for preparing ammoniated lignin biomass collectors. This is because ordinary drying causes shrinkage, agglomeration, and pore collapse within the material, while freeze-drying preserves the internal pore structure of the ammoniated lignin biomass collector. This porous morphology not only increases the contact area between the collector and spodumene but also provides ample sites for the binding of hydrophobic groups and air bubbles, enhancing the collector's effectiveness.
[0068] Examples 15-17 Example 15: Based on the application of the ammoniated lignin biomass collector in Example 1 for the flotation separation of spodumene and quartz, the following adjustments were made: An ammoniated lignin biomass collector is used for the flotation separation of spodumene and quartz, comprising the following steps: Grinding and pulping: Grind the pegmatite into a mineral sample with a particle size of 80-180 mesh accounting for 70%. Add 3 kg of mineral sample to 7 kg of water to form a slurry with a mineral sample mass concentration of 30 wt%. Stir for 2 min, adjust the pH of the slurry to 4 with 10% hydrochloric acid, and continue stirring for 2 min. Flotation: Subsequently, 10g of sodium silicate inhibitor, 10g of ammoniated lignin biomass collector, and 0.2mL of methyl isobutyl methanol were added. The mixture was stirred and floated at 300rpm for 8min, with the air flow rate controlled at 0.7m. 3 The spodumene concentrate was obtained by scraping and washing the spodumene at a speed of 1000 m / min.
[0069] Example 16 is an adjustment based on the application of the ammoniated lignin biomass collector in Example 1 for the flotation separation of spodumene and quartz: An ammoniated lignin biomass collector is used for the flotation separation of spodumene and quartz, comprising the following steps: Grinding and pulping: Grind the pegmatite into a mineral sample with a particle size of 80-180 mesh accounting for 70%. Add 2 kg of mineral sample to 8 kg of water to form a slurry with a mineral sample mass concentration of 20 wt%. Stir for 2 min, adjust the pH of the slurry to 5 with 10% hydrochloric acid, and continue stirring for 2 min. Flotation: Subsequently, 10g of sodium silicate inhibitor, 5g of ammoniated lignin biomass collector, and 0.3mL of methyl isobutyl methanol were added. The mixture was stirred and floated at 400rpm for 8min, with the air flow rate controlled at 0.7m. 3 The spodumene concentrate was obtained by scraping and washing the spodumene at a speed of 1000 m / min.
[0070] Example 17 is an adjustment based on the application of the ammoniated lignin biomass collector in Example 1 for the flotation separation of spodumene and quartz: An ammoniated lignin biomass collector is used for the flotation separation of spodumene and quartz, comprising the following steps: Grinding and pulping: Grind the pegmatite into a mineral sample with a particle size of 80-180 mesh accounting for 70%. Add 2.5 kg of mineral sample to 7.5 kg of water to form a slurry with a mineral sample mass concentration of 25 wt%. Stir for 2 min, adjust the pH of the slurry to 4 with 10% hydrochloric acid, and continue stirring for 2 min. Flotation: Subsequently, 20g of sodium silicate inhibitor, 10g of ammoniated lignin biomass collector, and 0.5mL of methyl isobutyl methanol were added. The mixture was stirred and floated at 300rpm for 5min, with the air flow rate controlled at 0.7m. 3 The spodumene concentrate was obtained by scraping and washing the spodumene at a speed of 1000 m / min.
[0071] Table 7. Conditions and performance tests for the application of spodumene and quartz flotation separation in Examples 1 and 15-17.
[0072] Referring to Table 7, a comparison of Examples 1 and 15-17 shows that during the flotation process, the amounts of sodium silicate inhibitor, ammoniated lignin biomass collector, and methyl isobutyl methanol need to be moderate. Excessive addition will reduce the Li2O grade in the spodumene concentrate and the recovery rate of the spodumene concentrate. This is because: excessive sodium silicate inhibitor increases pulp viscosity, hindering separation; excessive ammoniated lignin biomass collector will adsorb onto the surface of gangue minerals, causing gangue to float with the foam, reducing the Li2O grade; and excessive methyl isobutyl methanol makes the foam too stable and thick, carrying a large amount of fine mud and gangue particles. Furthermore, excessive foam is difficult to control, leading to mixing of concentrate and tailings during foam scraping, reducing the recovery rate.
[0073] Furthermore, the ammoniated lignin biomass collector and sodium silicate inhibitor can synergistically reduce gangue interference through the combination of sodium silicate inhibitor inhibiting gangue and ammoniated lignin biomass collector targeting and collecting lithium minerals. Similarly, the ammoniated lignin biomass collector and methyl isobutyl methanol can synergistically improve lithium mineral flotation efficiency through the combination of ammoniated lignin biomass collector enhancing mineral hydrophobicity and methyl isobutyl methanol bridging bubbles. However, excessive amounts of any of these three additives can easily turn the synergistic effect into an antagonistic one, leading to a deterioration in separation efficiency. Therefore, flotation reagents need to achieve a balance between inhibition, collection, and foaming through optimized formulation, rather than simply increasing the dosage.
[0074] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A method for preparing an ammonified lignin biomass collector, characterized in that, Includes the following steps: Pretreatment: Lignin is placed in an activator solution with a pH range of 9-12 and ultrasonically mixed to obtain a lignin mixture; the activator solution includes at least one of NaOH solution, KOH solution, Na2CO3 solution and K2CO3 solution; Modification: The lignin mixture is stirred, and after the initial temperature is raised to 50-60℃, amino alkanes are added. Then, the temperature is raised to 70-90℃ and aldehyde additives are added dropwise to react. After cooling, an aminated lignin modification solution is obtained. The amino alkanes are amino alkane compounds with a carbon chain length of 3-6. Extraction: The pH of the aminated lignin-modified solution was adjusted to 1-3, and then filtered, washed and dried to obtain the aminated lignin biomass collector.
2. The method for preparing the ammonified lignin biomass collector according to claim 1, characterized in that: The amino-based alkanes include at least one of diethylenetriamine and tris(hydroxymethyl)aminomethane.
3. The method for preparing the ammonified lignin biomass collector according to claim 2, characterized in that: The amino-based alkane is an amino mixture of diethylenetriamine and tris(hydroxymethyl)aminomethane.
4. The method for preparing the ammonified lignin biomass collector according to claim 3, characterized in that: The ratio between the volume of diethylenetriamine and the mass of trihydroxymethylaminomethane in the amine mixture is 1 mL: (0.6-1.2) g.
5. The method for preparing the ammonified lignin biomass collector according to claim 1, characterized in that: The aldehyde additives include at least one of acetaldehyde and phenylacetaldehyde.
6. The method for preparing the ammonified lignin biomass collector according to claim 5, characterized in that: The aldehyde additive is an aldehyde mixture of acetaldehyde and phenylacetaldehyde.
7. The method for preparing the ammonified lignin biomass collector according to claim 6, characterized in that: The volume ratio of acetaldehyde to phenylacetaldehyde in the aldehyde mixture is 1:0.6-1.
8. The method for preparing the ammonified lignin biomass collector according to claim 1, characterized in that: The drying method is freeze drying.
9. An ammonified lignin biomass collector, characterized in that: It is prepared by the method of preparing the ammonified lignin biomass collector according to any one of claims 1-8.
10. An application of the ammonified lignin biomass collector according to claim 9 in the flotation separation of spodumene and quartz, characterized in that, Includes the following steps: Grinding and pulping: The pegmatite is ground into a mineral sample, which is then added to water to form a slurry; Flotation: Sodium silicate inhibitor, ammoniated lignin biomass collector, and methyl isobutyl methanol are added sequentially to the slurry. The mixture is stirred and floated, and then skimmed and washed to obtain spodumene concentrate.