An oxidation catalyst and a method for preparing glyceric acid by catalytic oxidation of glycerol

Abstract

The present application belongs to the technical field of biomass catalytic conversion and comprehensive utilization of mineral resources, and particularly relates to an oxidation catalyst and a method for preparing glyceric acid by catalytic oxidation of glycerol. The present application utilizes the components of low-grade lithium ore to prepare a catalyst, activates the synergistic catalytic action of Li, Al, Si and associated K, F and other components in the ore by a composite pretreatment process of intensified mechanical activation-high concentration acid leaching-high temperature step roasting, constructs a Li-Al-Si-K-F composite oxide heterogeneous catalyst, and realizes the efficient conversion of glycerol to glyceric acid in pure water medium with oxygen as the oxidant.

Description

Technical Field

[0001] This invention belongs to the technical field of biomass catalytic conversion and comprehensive utilization of mineral resources, specifically relating to an oxidation catalyst and a method for catalytic oxidation of glycerol to prepare glyceric acid. Background Technology

[0002] Glyceric acid is a simple organic acid and an intermediate product of glycerol metabolism. It is naturally found in some fruits (such as pineapple and banana). As a multifunctional and highly valuable fine chemical, its role spans multiple fields from basic metabolism to commercial applications, showing significant application potential in many areas and experiencing continuous growth in demand.

[0003] Currently, there are many pathways for the conversion of glycerol, and compared with other pathways, oxidation is an effective way to generate high value-added products. Typical catalysts used for glycerol oxidation to obtain value-added products are the three noble metals Au, Pt, and Pd, and their corresponding alloys. However, these noble metal-supported catalysts suffer from problems such as dependence on alkaline conditions, harsh reaction conditions (alkaline media, high pressure), easy deactivation of active sites, and low recovery rates. The presence of noble metals also leads to high overall process costs. Therefore, the exploration of catalysts for glyceric acid oxidation has received more attention.

[0004] Lithium ore is the core carrier of lithium resources, but low-grade lithium ore (Li₂O < 2%) is often stored as tailings due to poor economics in lithium extraction, resulting in significant resource waste. Current research focuses on lithium extraction or catalytic applications of high-grade lithium ore (such as spodumene with Li₂O ≥ 6%), and has not yet addressed the construction of catalytic systems for low-grade lithium ore. This field anticipates the development of more new applications, which will have a positive impact on the comprehensive utilization of lithium ore. Summary of the Invention

[0005] The first objective of this invention is to provide an alkali-free atmospheric pressure oxidation catalyst prepared from the natural components of low-grade lithium ore. The catalyst can catalytically oxidize glycerol to glyceric acid under alkali-free, atmospheric pressure and mild conditions, which can effectively reduce costs, simplify the process and realize the high value of low-grade mineral resources.

[0006] The second objective of this invention is to provide a method for preparing glyceric acid by catalytic oxidation of glycerol under non-alkaline, normal pressure and mild conditions, which effectively solves the problems of existing technologies relying on precious metals, harsh reaction conditions and insufficient utilization of low-grade lithium ore resources.

[0007] To address the aforementioned technical problems, this invention provides a method for preparing an oxidation catalyst, comprising the following steps:

[0008] (1) Low-grade lithium ore is crushed and activated to obtain activated mineral powder;

[0009] (2) The activated mineral powder is added to acid solution for impregnation and strengthening, and the filter residue is collected by solid-liquid separation;

[0010] (3) Under a protective atmosphere, the filter residue is pre-calcined at 350-450°C and calcined at 700-800°C to obtain the desired oxidation catalyst.

[0011] Specifically, in the preparation method of the oxidation catalyst, in step (1), the low-grade lithium ore is a lithium polymetallic ore containing 1.5%-2.0wt% Li2O, and the main chemical components include SiO2≥60wt%, Al2O315-20wt%, and associated K2O and F elements;

[0012] Preferably, the crushing step includes crushing the low-grade lithium ore to 300-400 mesh.

[0013] Specifically, in the preparation method of the oxidation catalyst, step (1) includes the activation treatment step of performing mechanical activation treatment;

[0014] Preferably, the activation treatment step controls the ball-to-material ratio to be 15:1-20:1;

[0015] Preferably, the activation process step controls the rotation speed to be 150-200 rpm;

[0016] Preferably, the activation process is performed for 4-6 hours.

[0017] Specifically, in the preparation method of the oxidation catalyst, in step (2), the acid solution includes a dilute sulfuric acid solution or a phosphoric acid solution;

[0018] Preferably, the acid solution comprises a dilute sulfuric acid solution with a mass concentration of 10-15 wt% or a phosphoric acid solution with a mass concentration of 12-18%.

[0019] Preferably, the liquid-solid mass ratio of the activated mineral powder to the acid solution is 8:1-10:1;

[0020] Preferably, the temperature of the impregnation strengthening step is 70-95°C;

[0021] Preferably, the impregnation strengthening step takes 8-12 hours.

[0022] In some specific embodiments, the acid solution comprises a dilute sulfuric acid solution with a mass concentration of 10-15 wt%, and the temperature of the impregnation strengthening step is 70-90°C.

[0023] In some specific embodiments, the acid solution comprises a phosphoric acid solution with a mass concentration of 12-18%, and the temperature of the impregnation strengthening step is 80-95°C.

[0024] Specifically, in the preparation method of the oxidation catalyst, in step (3):

[0025] The pre-calcination step takes 2-3 hours; and / or,

[0026] The roasting step takes 3-4 hours; and / or,

[0027] The protective atmosphere comprises an inert gas with a flow rate of 0.8-1.5 L / min.

[0028] The present invention also discloses the oxidation catalyst prepared by the method.

[0029] The present invention also discloses the application of the oxidation catalyst in the process of oxidative catalysis to prepare glyceric acid from glycerol.

[0030] The present invention also discloses a method for preparing glyceric acid from glycerol by oxidation catalysis, comprising the step of carrying out an oxidation reaction using glycerol and oxygen as raw materials in the presence of the oxidation catalyst.

[0031] Specifically, the method for oxidative catalysis to prepare glyceric acid from glycerol:

[0032] The glycerol has a mass concentration of 10-30 wt%; and / or,

[0033] The molar ratio of oxygen to glycerol is 30:1 to 60:1, and / or,

[0034] The mass ratio of the catalyst to glycerol is 0.3:1 to 0.5:1; and / or,

[0035] The oxidation reaction is carried out at a temperature of 70-90°C; and / or,

[0036] The oxidation reaction is carried out at atmospheric pressure; and / or,

[0037] The oxidation reaction takes 24-36 hours.

[0038] Specifically, the method for oxidative catalysis to prepare glyceric acid from glycerol further includes the step of adding a co-catalyst;

[0039] Preferably, the co-catalyst comprises potassium oxalate and / or MnSO4;

[0040] Preferably, the amount of the co-catalyst added accounts for 1-3 wt% of the amount of glycerol used.

[0041] The oxidation catalyst of this invention is based on low-grade lithium ore as raw material. It involves enhanced mechanical activation to disrupt the dense structure of the ore, selectively dissolving active components such as Li, Al, and K through high-concentration acid leaching and regulating the Si-based framework, and further promoting the reconstruction of the Li-Al-Si-KF composite active phase through high-temperature stepwise roasting. Although the low-grade lithium ore has a low Li content, it has a high proportion of SiO2 and Al2O3, and is associated with elements such as K and F. Among these, Li... + K + The active site electron density is synergistically regulated, F-modified surface acidity enhances glycerol adsorption, and the Si-based framework ensures structural stability. This oxidation catalyst can catalyze the oxidation of glycerol to glyceric acid under alkaline-free, normal-pressure, and mild conditions. Breaking through raw material limitations, the catalyst utilizes Li, Al, Si, and associated K and F components in low-grade lithium ore. Through process optimization, a highly efficient catalytic system is constructed, achieving synergistic utilization of glycerol oxidation and mineral resources. This effectively reduces costs, simplifies the process, and realizes the high-value utilization of low-grade mineral resources.

[0042] The oxidation catalyst described in this invention is designed for low-grade lithium ores with low Li content but high SiO2 and Al2O3 content, and associated elements such as K and F. During mechanical activation, by extending the time (4-6h), increasing the ball-to-material ratio (15:1-20:1), and increasing the rotation speed (150-200rpm), the ore lattice defects are significantly increased, and the Li-O and KO bond energies are reduced, thus providing a foundation for subsequent acid leaching.

[0043] The oxidation catalyst described in this invention is designed for low-grade lithium ores with low Li content but high proportions of SiO2 and Al2O3, and associated elements such as K and F. In the enhanced acid leaching process, by increasing the acid concentration (10%-15% dilute sulfuric acid), liquid-solid ratio (8:1-10:1), and temperature (70-90℃), it ensures the full dissolution of low-content Li and K while preserving the integrity of the Si-based framework.

[0044] The oxidation catalyst described in this invention is designed for low-grade lithium ores with low Li content but high proportions of SiO2 and Al2O3, and associated elements such as K and F. In the high-temperature roasting step, a step-by-step roasting method is adopted. Impurities and moisture are removed by pre-roasting (350-450℃), and the main roasting (700-800℃) promotes the crystallization of Li-Al-Si-KF composite oxide to form a stable catalytically active phase.

[0045] The oxidation catalyst described in this invention can be used as raw material for the Velasto lithium ore in the Velasto mining area of ​​Keshiketeng Banner, Inner Mongolia Autonomous Region, which has a Li2O content of 1.71%. It utilizes the high SiO2 (60.52%), Al2O3 (17.12%) and associated K2O (5.44%) and F (6.33%) to activate the synergistic catalytic effect through process optimization, resulting in better raw material adaptability.

[0046] The method for preparing glyceric acid by catalytic oxidation of glycerol according to the present invention uses the oxidation catalyst to carry out the catalytic reaction. By appropriately increasing the amount of catalyst (0.3:1-0.5:1), the reaction temperature (70-90℃), and the time (24-36h), the activity and selectivity are balanced. The introduction of oxygen or a large flow of air ensures the oxygen supply, which effectively guarantees the conversion efficiency and reaction selectivity of glycerol.

[0047] This invention is the first to utilize low-grade lithium ore (Li2O≤2%) in a catalytic system, realizing the high-value utilization of tailings-level mineral resources and expanding raw material sources. Furthermore, the catalyst's Li-Al-Si-KF composite structure is wear-resistant, anti-sintering, has good reusability, and stable catalytic performance, meeting the requirements of continuous industrial production. The method for catalytically preparing glyceric acid from glycerol requires no precious metals, utilizes natural mineral components, involves an alkali-free, atmospheric pressure reaction, reduces wastewater and equipment investment, and simplifies product separation, offering cost and environmental advantages.

[0048] The oxidation catalyst described in this invention uses low-grade lithium ore (tailings grade) with low Li content as raw material. The prepared oxidation catalyst is identical to traditional high-grade lithium ore catalysts and traditional precious metal catalytic reactions. It can oxidize glycerol to glyceric acid in pure water medium, and the entire reaction can be completed under normal pressure. The catalytic reaction not only has a similar effect to that of existing high-grade lithium ore catalysts and precious metal catalysts, but also realizes the resource utilization of low-grade lithium ore, breaking the resource limitation of high-grade lithium ore. At the same time, it solves the cost limitation of traditional carbon nanotubes and other catalyst supports requiring the loading of precious metals such as Pt / Au, resulting in superior process application value.

[0049] This invention discloses a method for catalytically oxidizing glycerol to glyceric acid under alkaline-free, ambient pressure, and mild conditions by preparing a catalyst using the inherent components of low-grade lithium ore. Through a composite pretreatment process involving enhanced mechanical activation, high-concentration acid leaching, and high-temperature stepwise roasting, the synergistic catalytic effects of Li, Al, Si, and associated K and F components in the ore are activated, constructing a Li-Al-Si-KF composite oxide heterogeneous catalyst. Using oxygen as the oxidant, the efficient conversion of glycerol to glyceric acid is achieved in a pure water medium. This invention overcomes the raw material limitations of high-grade lithium ore, offers low-cost and environmentally friendly catalyst preparation, and solves the problems of low-grade lithium ore resource utilization and the dependence on precious metals and harsh reaction conditions in existing glycerol oxidation technologies. Attached Figure Description

[0050] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0051] Figure 1The image shows the XRD pattern of the catalyst prepared from low-grade lithium ore in Example 1, which shows that the ore forms a LiAlO2-SiO2-KF composite phase after processing. Detailed Implementation

[0052] In the following embodiments of the present invention, an oxidation catalyst is provided. Specifically, the oxidation catalyst prepared using low-grade lithium tailings ore with low Li content as raw material has the same reaction performance as traditional high-grade lithium ore catalysts and traditional precious metal catalysts, and can realize the oxidation of glycerol to glyceric acid in pure water medium.

[0053] In the following embodiments 1-3 of the present invention, as an exemplary implementation, lithium polymetallic ore from the Vilasto mining area in Keshiketeng Banner, Inner Mongolia Autonomous Region was selected, and its composition information is shown in Tables 1-2 below.

[0054] Table 1. Semi-quantitative analysis results of X-ray fluorescence spectra of raw ore, %

[0055]

[0056] Table 2. Results of multi-element chemical analysis of the ore, %

[0057]

[0058] Example 1

[0059] This study uses lithium polymetallic ore from the Vilastow mining area in Keshiketeng Banner, Inner Mongolia Autonomous Region as raw material to prepare an oxidation catalyst, which is then used to catalyze the oxidation of glycerol and the preparation of glyceric acid.

[0060] The preparation method of the oxidation catalyst described in this embodiment includes the following steps:

[0061] (1) Raw material pretreatment: Lithium polymetallic ore from the Vilasto mining area (Li2O content 1.71%) in Keshiketeng Banner, Inner Mongolia Autonomous Region, was crushed to 350 mesh, mechanically activated for 5 hours, and the ball-to-material ratio was adjusted to 18:1 and the rotation speed was 180 rpm.

[0062] (2) Enhanced acid leaching: Add activated mineral powder to 12wt% dilute sulfuric acid solution and mix, adjust the liquid-solid ratio to 10:1, stir and react at 80℃ for 10h, filter and collect the filter residue;

[0063] (3) Stepwise calcination: Under an inert atmosphere (argon, flow rate of 1.2 L / min), the filter residue was pre-calcined at 400 °C for 2 h, and then heated to 750 °C for 3 h. After the reaction was completed, it was cooled and pulverized to 250 mesh to obtain the desired Li-Al-Si-KF composite oxide catalyst.

[0064] The XRD pattern of the oxidation catalyst prepared in this embodiment is attached. Figure 1As shown, the ore, after processing, forms a LiAlO2-SiO2-KF composite phase. Characteristic peaks of LiAlO2 appear at 2θ values ​​of 22.2 and 33.3, belonging to the (101) and (102) crystal planes respectively; characteristic peaks of SiO2 appear at 22.0 and 28.4, belonging to the (101) and (111) crystal planes respectively; and characteristic peaks of KF appear at 33.4 and 47.9, belonging to the (200) and (220) crystal planes respectively. LiAlO2 serves as the active site for catalytic oxidation, and the Al on the surface... 3+ and O 2- The bond can activate molecular oxygen and adsorb the hydroxyl groups of glycerol molecules, which is the core active center for the oxidation of glycerol to glyceric acid; SiO2, as a framework with a high specific surface area, uniformly disperses the LiAlO2 active phase, avoids the aggregation of active sites, and ensures sufficient contact between active sites and glycerol and oxygen in the reaction; KF can regulate the electronic environment on the catalyst surface, reduce the generation of by-products, and thus improve the selectivity of glyceric acid.

[0065] In this embodiment, glycerol acid is prepared by oxidative catalysis of glycerol using the catalyst prepared above.

[0066] Prepare a glycerol solution with ω%=12.5% ​​according to the raw material ratio of 10g glycerol and 70g pure water. Add 4g of the above catalyst (catalyst to glycerol mass ratio 0.4:1) and mix. Heat the entire reaction system to 80℃ and introduce oxygen at normal pressure (gas flow rate to glycerol molar ratio 50:1) and stir for 24h.

[0067] Example 2

[0068] This study uses lithium polymetallic ore from the Vilastow mining area in Keshiketeng Banner, Inner Mongolia Autonomous Region as raw material to prepare an oxidation catalyst, which is then used to catalyze the oxidation of glycerol and the preparation of glyceric acid.

[0069] The preparation method of the oxidation catalyst described in this embodiment includes the following steps:

[0070] (1) Raw material pretreatment: Lithium polymetallic ore from the Vilasto mining area (Li2O content 1.71%) in Keshiketeng Banner, Inner Mongolia Autonomous Region, was crushed to 300 mesh, mechanically activated for 4 hours, and the ball-to-material ratio was adjusted to 15:1 and the rotation speed was 150 rpm.

[0071] (2) Enhanced acid leaching: Add activated mineral powder to 10wt% dilute sulfuric acid solution and mix, adjust the liquid-solid ratio to 8:1, stir and react at 70℃ for 8h, filter and collect the filter residue;

[0072] (3) Stepwise calcination: Under an inert atmosphere (argon, flow rate of 0.8 L / min), the filter residue was pre-calcined at 350 °C for 3 h, and then heated to 700 °C for 4 h. After the reaction was completed, it was cooled and pulverized to 250 mesh to obtain the desired Li-Al-Si-KF composite oxide catalyst.

[0073] In this embodiment, glycerol acid is prepared by oxidative catalysis of glycerol using the catalyst prepared above.

[0074] Prepare a glycerol solution with ω%=10.0% according to the raw material ratio of 10g glycerol and 90g pure water. Add 3g of the above catalyst (catalyst to glycerol mass ratio of 0.3:1) and mix. Heat the entire reaction system to 70℃ and introduce oxygen at normal pressure (gas flow rate to glycerol molar ratio of 30:1) and stir for 30h.

[0075] Example 3

[0076] This study uses lithium polymetallic ore from the Vilastow mining area in Keshiketeng Banner, Inner Mongolia Autonomous Region as raw material to prepare an oxidation catalyst, which is then used to catalyze the oxidation of glycerol and the preparation of glyceric acid.

[0077] The preparation method of the oxidation catalyst described in this embodiment includes the following steps:

[0078] (1) Raw material pretreatment: Lithium polymetallic ore from the Vilasto mining area (Li2O content 1.71%) in Keshiketeng Banner, Inner Mongolia Autonomous Region, was crushed to 400 mesh, mechanically activated for 6 hours, and the ball-to-material ratio was adjusted to 20:1 and the rotation speed was 200 rpm.

[0079] (2) Enhanced acid leaching: Add activated mineral powder to 18wt% phosphoric acid solution and mix, adjust the liquid-solid ratio to 8:1, stir and react at 95℃ for 12h, filter and collect the filter residue;

[0080] (3) Stepwise calcination: Under an inert atmosphere (argon, flow rate of 1.5 L / min), the filter residue was pre-calcined at 450 °C for 2 h, and then heated to 800 °C for 3 h. After the reaction was completed, it was cooled and pulverized to 250 mesh to obtain the desired Li-Al-Si-KF composite oxide catalyst.

[0081] In this embodiment, glycerol acid is prepared by oxidative catalysis of glycerol using the catalyst prepared above.

[0082] Prepare a glycerol solution with an ω% of 30.0% by mixing raw materials: 30g glycerol and 70g pure water. Add 15g of the above catalyst (catalyst to glycerol mass ratio 0.5:1) and mix. Heat the entire reaction system to 90℃ and introduce oxygen at normal pressure (gas flow rate to glycerol molar ratio 60:1) and stir for 36h.

[0083] Example 4

[0084] The preparation method of the oxidation catalyst described in this embodiment is the same as that in Embodiment 1.

[0085] The method for preparing glyceric acid by catalytic oxidation of glycerol in this embodiment is the same as in Example 1, except that a co-catalyst is added to enhance and promote the reaction.

[0086] In this embodiment, the principle of promoting molecular oxygen activation and selective oxidation of glycerol by synergistic interaction between potassium oxalate and the active sites on the surface of the oxidation catalyst is utilized. Specifically, in the catalytic reaction stage described in Example 1, potassium oxalate accounting for 2% of the mass fraction of glycerol is added as a co-catalyst, while the other conditions remain unchanged.

[0087] Comparative Example 1

[0088] The preparation method of the oxidation catalyst described in this comparative example is the same as that in Example 1, except that a one-step calcination method is used.

[0089] In the entire preparation method, the raw material pretreatment and enhanced acid leaching are the same as in the original Example 1. During roasting, the filter residue A is directly roasted at 750℃ for 5 hours (the total time is consistent with the original "pre-roasting 2 hours + main roasting 3 hours"). After cooling, it is pulverized to 250 mesh to obtain the catalyst roasted in one step.

[0090] The process of preparing glyceric acid by oxidative catalysis of glycerol using the catalyst prepared above is the same as in Example 1.

[0091] Comparative Example 2

[0092] The preparation method of the oxidation catalyst described in this comparative example is the same as that in Example 1, except that the ore raw material is only crushed and not mechanically activated, while the other steps are the same as in Example 1.

[0093] The process of preparing glyceric acid by oxidative catalysis of glycerol using the catalyst prepared above is the same as in Example 1.

[0094] Comparative Example 3

[0095] The preparation method of the oxidation catalyst described in this comparative example is the same as that in Example 1, except that the ore raw material is not subjected to acid leaching treatment, and the other steps are the same as in Example 1.

[0096] The process of preparing glyceric acid by oxidative catalysis of glycerol using the catalyst prepared above is the same as in Example 1.

[0097] Comparative Example 4

[0098] The preparation method of the oxidation catalyst described in this comparative example is the same as that in Example 4, except that the added co-catalyst is replaced with manganese sulfate, and the other steps are the same as in Example 1.

[0099] The comparative example uses the catalyst prepared above to catalyze the oxidation of glycerol to prepare glyceric acid, and the process is the same as in Example 4.

[0100] Experimental Example

[0101] 1. Catalytic performance

[0102] In Examples 1-4 and Comparative Examples 1-4 above, the glycerol conversion rate, glyceric acid selectivity, and glyceric acid yield (conversion rate × selectivity) of the entire catalytic reaction were tested after the glycerol conversion reaction was completed; among them,

[0103] Glycerol conversion rate = (n 初始 -n 剩余 ) / n 初始 ×100%, which is the molar ratio of glycerol consumed in the reaction to the initial total amount of glycerol;

[0104] Glyceric acid selectivity = n 生成 / (n 初始 -n 剩余 ) × 100%, which is the molar ratio of glyceric acid produced by the reaction to glycerol consumed in the reaction;

[0105] Glyceric acid yield = glycerol conversion rate × glyceric acid selectivity.

[0106] The test results are recorded in Table 3 below.

[0107] Table 3 Experimental Results

[0108]

[0109] It is evident that the oxidation catalyst prepared by the present invention based on low-grade lithium ore as raw material and through a composite pretreatment process including enhanced mechanical activation, high-concentration acid leaching, and high-temperature stepwise roasting can achieve efficient conversion of glycerol to glyceric acid.

[0110] 2. Repeatability

[0111] This embodiment uses the oxidation catalyst prepared in Example 1 as an example to verify the reusability of the catalyst.

[0112] The catalyst prepared in Example 1 was recovered. The reaction products were collected and separated. After the reaction was complete, the remaining reactants were poured into a Buchner funnel and filtered. The filter residue was the recovered catalyst. This filter residue contained some glycerol solution, glyceric acid, and other glycerol conversion products, requiring washing to remove impurities. It was washed 2-3 times with appropriate amounts of deionized water and anhydrous ethanol. The washed catalyst was then placed in an oven and dried at 80-100°C for 4-6 hours. After drying, it was ground to below 200 mesh for later use.

[0113] The recovered catalyst was directly used in a new round of reaction according to the scheme in Example 1.

[0114] After repeating the catalytic reaction five times, the glycerol conversion rate remained above 55% and the glyceric acid selectivity remained around 60% throughout the entire reaction, indicating that the catalyst has good stability.

[0115] In summary, this invention overcomes the raw material limitations of high-grade lithium ore, has low catalyst preparation cost and is environmentally friendly, and solves the problems of low-grade lithium ore resource utilization and the dependence on precious metals and harsh reaction conditions of existing glycerol oxidation technologies.

[0116] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing an oxidative catalyst for the oxidative catalysis of glycerol to glyceric acid, characterized in that, Includes the following steps: (1) Low-grade lithium ore is crushed and mechanically activated to obtain activated mineral powder; The low-grade lithium ore contains 1.5%-2.0 wt% Li2O, ≥60 wt% SiO2, and 15-20 wt% Al2O3, and is associated with K2O and F elements. In the mechanical activation treatment step: The activation process controls the ball-to-material ratio to be 15:1-20:

1. The activation process is controlled at a rotation speed of 150-200 rpm; The activation process is controlled to take 4-6 hours. (2) The activated mineral powder is added to acid solution for impregnation and strengthening, and the filter residue is collected by solid-liquid separation; The acid solution includes a dilute sulfuric acid solution with a mass concentration of 10-15 wt% or a phosphoric acid solution with a mass concentration of 12-18%. The liquid-solid mass ratio of the activated mineral powder to the acid solution is 8:1-10:1; The temperature for the impregnation strengthening step is 70-95℃; The impregnation and strengthening step takes 8-12 hours; (3) Under a protective atmosphere, the filter residue is pre-calcined at 350-450°C and calcined at 700-800°C to obtain the desired oxidation catalyst.

2. The method for preparing the oxidation catalyst for the process of oxidizing glycerol to glyceric acid according to claim 1, characterized in that, In step (1), the crushing step includes crushing the low-grade lithium ore to 300-400 mesh.

3. The method for preparing the oxidation catalyst for the process of oxidizing glycerol to glyceric acid according to claim 1 or 2, characterized in that, In step (3): The pre-calcination step takes 2-3 hours; and / or, The roasting step takes 3-4 hours; and / or, The protective atmosphere comprises an inert gas with a flow rate of 0.8-1.5 L / min.

4. An oxidation catalyst prepared by the method according to any one of claims 1-3 for the oxidative catalysis of glycerol to glyceric acid.

5. The application of the oxidation catalyst as described in claim 4 for the oxidative catalytic process of glycerol to glyceric acid in the oxidative catalytic process of glycerol to glyceric acid.

6. A method for oxidatively catalyzing the preparation of glyceric acid from glycerol, characterized in that, The step includes an oxidation reaction using glycerol and oxygen as raw materials in the presence of the oxidation catalyst described in claim 4.

7. The method for preparing glyceric acid by oxidative catalysis of glycerol according to claim 6, characterized in that: The glycerol has a mass concentration of 10-30 wt%; and / or, The molar ratio of oxygen to glycerol is 30:1 to 60:1, and / or, The mass ratio of the catalyst to glycerol is 0.3:1 to 0.5:1; and / or, The oxidation reaction is carried out at a temperature of 70-90°C; and / or, The oxidation reaction is carried out at atmospheric pressure; and / or, The oxidation reaction takes 24-36 hours.

8. The method for preparing glyceric acid by oxidative catalysis of glycerol according to claim 6 or 7, characterized in that, The method further includes the step of adding a co-catalyst; wherein... The co-catalyst comprises potassium oxalate and / or MnSO4; and / or, The amount of the co-catalyst added accounts for 1-3 wt% of the amount of glycerol used.

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