Alkaline-earth metal saponifying agent and use thereof

Abstract

The present application relates to the technical field of hydrometallurgy, and discloses an alkaline-earth metal saponifying agent and the use thereof. The saponifying agent is a compound powder of an alkaline earth metal, wherein the maximum particle size of the powder is smaller than 200 μm; and the purity of the powder is not less than 80%. The alkaline-earth metal saponifying agent and an acidic extractant solution are mixed, and are then subjected to saponification to obtain a saponified organic phase. The alkaline-earth metal saponifying agent or a saponifying method provided by the present application can be used for metal extraction. Compared with a traditional process, the present application uses the alkaline-earth metal saponifying agent for direct saponification, which does not produce any saponification wastewater during the process; moreover, the conversion rate of an alkaline-earth metal is high, and the problem of solid residues is avoided; and the obtained saponified organic phase has a good flowability, and is stable. The saponifying agent provided by the present application is widely available and can be recycled, thereby greatly reducing the saponification costs.

Description

Alkaline earth metal saponifying agents and their applications

[0001] Cross-referencing

[0002] This application claims priority to Chinese Patent Application No. 202410928603.1, filed on July 11, 2024, entitled "Alkaline Earth Metal Saponifying Agent and Its Application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of hydrometallurgical technology, specifically to an alkaline earth metal saponifying agent and its application. Background Technology

[0004] Extraction is an important method for the deep separation and enrichment of metals and has been widely used in the hydrometallurgical industry. The main extraction process includes steps such as saponification, extraction, washing, and back-extraction. Traditional saponification mainly uses alkaline solutions such as liquid alkali and ammonia as saponifying agents. Its advantages are high technical maturity, wide application, simple operation, and very little saponification wastewater. However, traditional saponification processes are costly, the alkaline solutions used cannot be recycled, and the resulting sodium sulfate and ammonium sulfate wastewater requires significant treatment.

[0005] Existing magnesium soap processes are mainly divided into two categories: conversion soap and direct magnesium soap. Conversion soap refers to using a magnesium salt solution to replace sodium / ammonia in the saponified organic phase within the existing sodium or ammonia soap system, thus obtaining a magnesium-loaded organic phase. This method does not fundamentally solve the problems of high saponification costs and high processing pressure from sodium / ammonium sulfate. Direct magnesium soap refers to directly saponifying blank organic phase using a magnesium-containing slurry. This method solves the problems of high saponification costs and high processing pressure from sodium / ammonium sulfate, but it introduces new problems: First, because the solubility of magnesium inorganic salts in water is generally low, there is a large amount of saponification wastewater, resulting in low magnesium conversion rates and the need for excessive slurry use. Furthermore, the residual magnesium slurry is difficult to collect, hindering industrial-scale application. Second, because most magnesium compounds cannot be completely dissolved, some powder is carried into the extraction section along with the organic phase, affecting extraction. Currently, the use of solid powder for direct saponification has been mentioned, but this is merely a suggestion without in-depth research, specifying the type of solid powder to use, or demonstrating its technical benefits.

[0006] CN 116949289A discloses a phosphonohydroxycarboxylic acid and its use and method for separating yttrium. It mainly describes the general chemical formula of the phosphonohydroxycarboxylic acid and the operational method for separating yttrium. The patent mentions that solid powder can be directly saponified, but it does not describe the solid powder in detail, and its examples do not use solid powder to saponify the extractant.

[0007] CN 117735579A discloses a highly active ultrafine composite phase magnesium oxide, its preparation method, and its applications. This composite phase magnesium oxide contains basic magnesium chloride. When this composite phase magnesium oxide is used to saponify an extractant, in practical applications, it not only generates chloride ion pollution, but the basic magnesium chloride also produces magnesium chloride and water, which are poorly soluble in organic matter. During large-scale saponification, a certain amount of saponification wastewater is generated. Furthermore, the embodiments explicitly state that there are no three-phase substances at the oil-water interface, therefore, saponification wastewater is generated during the saponification process.

[0008] Therefore, there is an urgent need to develop a saponifying agent that is universally applicable, requires a small dosage, has good saponification effect, good subsequent extraction effect, produces no wastewater, and can be recycled. Summary of the Invention

[0009] The purpose of this application is to overcome the problems existing in the prior art and provide an alkaline earth metal saponifying agent and its application.

[0010] To achieve the above objectives, the first aspect of this application provides an alkaline earth metal saponifying agent, wherein the saponifying agent is an alkaline earth metal compound powder;

[0011] The maximum particle size of the powder is less than 200 μm; the purity of the powder is not less than 80%.

[0012] The second aspect of this application provides the application of the alkaline earth metal saponifying agent described in the first aspect in the saponification of acidic extractants.

[0013] A third aspect of this application provides a method for saponification using the alkaline earth metal saponifying agent described in the first aspect, wherein the method includes: mixing the alkaline earth metal saponifying agent with an acidic extractant solution and then performing saponification to obtain a saponified organic phase.

[0014] The fourth aspect of this application provides a saponified organic phase obtained according to the method described in the third aspect, wherein the saponified organic phase is an organic acid salt solution of an alkaline earth metal with a concentration of 0.1-2 mol / L.

[0015] The fifth aspect of this application provides the application of the method described in the third aspect in metal extraction.

[0016] The beneficial technical effects achieved by this application through the above technical solution are as follows:

[0017] (1) The alkaline earth metal saponifying agent provided in this application has a specific maximum particle size and purity, which can further obtain better saponification effects (such as actual saponification degree, precipitation, saponification time, phase separation time, etc.) and is easy to industrialize.

[0018] (2) The alkaline earth metal saponifying agent provided in this application can be used to saponify a variety of acidic extractants. The resulting saponified organic phase has excellent extraction effect and can achieve complete separation of nickel, cobalt and magnesium (carboxylic acid extractant) with a separation efficiency of over 99%.

[0019] (3) Compared with traditional processes, this application uses alkaline earth metal saponifying agents for direct saponification. The process does not generate any saponification wastewater, and the conversion rate of alkaline earth metals is high. There is no problem of solid residue. The obtained saponified organic phase has good fluidity and stability.

[0020] (4) The saponifying agent provided in this application is widely available and can be recycled, which greatly reduces the cost of saponification. Attached Figure Description

[0021] Figure 1 is a flowchart of the extraction process of this application. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] The first aspect of this application provides an alkaline earth metal saponifying agent, wherein the saponifying agent is an alkaline earth metal compound powder;

[0024] The maximum particle size (D100) of the powder is less than 200 μm; the purity of the powder is not less than 80%.

[0025] This application achieves a saponification effect superior to existing technologies by limiting the maximum particle size and purity of the saponifying agent powder, resulting in less precipitation during the saponification process and shorter saponification and phase separation times.

[0026] The alkaline earth metal compound powders described in this application can be directly purchased commercially (e.g., analytical grade or industrial grade purity) or custom-made, or regenerated through one or more combinations of spray pyrolysis, roasting, calcination, reduction pyrolysis, and precipitation. In this application, powders with the corresponding maximum particle size can be obtained by grinding and sieving large-particle-size powders. When self-made using the above processes, the purity (which can be industrial grade purity) can be tested by a combination of XRD and SEM.

[0027] In some embodiments of this application, the maximum particle size of the powder is, for example, 180 μm, 106 μm, 75 μm, 44 μm, 20 μm, or any value within the range of any two of the above values. In some embodiments of this application, the maximum particle size of the powder is less than 120 μm, preferably less than 50 μm. In this application, the smaller the maximum particle size, the shorter the saponification time.

[0028] In some embodiments of this application, the purity of the powder is, for example, 80%, 85%, 92%, 98%, or any value within the range of any two of the above values. In some embodiments of this application, the purity of the powder is not less than 85%, preferably not less than 90%. In this application, the higher the purity, the less precipitation and the shorter the phase separation time.

[0029] In some embodiments of this application, the alkaline earth metal is magnesium and / or calcium.

[0030] In some embodiments of this application, the compound is a basic compound.

[0031] In some embodiments of this application, the alkaline compound is selected from at least one of oxides, hydroxides, carbonates, and bicarbonates.

[0032] In some embodiments of this application, the alkaline earth metal compound powder is selected from at least one of magnesium oxide powder, magnesium hydroxide powder, magnesium carbonate powder, magnesium bicarbonate powder, calcium oxide powder, calcium hydroxide powder, and calcium carbonate powder.

[0033] In some embodiments of this application, the alkaline earth metal compound powder does not contain F or Cl impurity ions.

[0034] In some embodiments of this application, the contents of Fe, Al, Zn, Cu, and Cd impurity ions in the alkaline earth metal compound powder are each less than 0.01%.

[0035] The second aspect of this application provides the application of the alkaline earth metal saponifying agent described in the first aspect in the saponification of acidic extractants.

[0036] The third aspect of this application provides a method for saponifying the alkaline earth metal saponifying agent described in the first aspect, wherein the method includes: mixing the alkaline earth metal saponifying agent with an acidic extractant solution and then saponifying it to obtain a saponified organic phase.

[0037] In some embodiments of this application, the acidic extractant solution has a volume fraction of 25%.

[0038] In some embodiments of this application, the saponification conditions include: stirring; and a time of 1-10 minutes. In this application, the specific stirring time is determined to achieve the saponification limit and stability. Specifically, this means the extractant has a uniform color, no further reaction occurs, and there are no bubbles. Based on actual testing, different stirring times are compared for each new saponification condition or saponifying agent to determine the stability under different saponification times (after stopping, no precipitation or stratification occurs, and the metal loading no longer changes with time, indicating that saponification is complete).

[0039] In some embodiments of this application, the acidic extractant is a carboxylic acid extractant and / or a phosphoric acid extractant.

[0040] In some embodiments of this application, the carboxylic acid extractant is selected from... and / or Where R1 and R2 are independently C3-C 12 Straight-chain or branched alkyl groups, R3 is a C4-C9 straight-chain or branched alkyl group, and R4 is a C3-C9 straight-chain or branched alkyl group. 10 Straight-chain or branched alkyl groups, preferably

[0041] The carboxylic acid extractant is selected from at least one of BC196, BC191, BC194 and BC211.

[0042] In some embodiments of this application, the phosphoric acid extractant is P204.

[0043] The fourth aspect of this application provides a saponified organic phase obtained according to the method described in the third aspect.

[0044] In some embodiments of this application, the saponified organic phase is a carboxylate solution of alkaline earth metals with a concentration of 0.1-2 mol / L.

[0045] The saponified organic phase described in this application exhibits excellent extraction performance, achieving complete separation of nickel-cobalt from calcium and magnesium when using a carboxylic acid extractant, with a separation efficiency exceeding 99%. Furthermore, the saponified organic phase possesses a high degree of saponification (up to 100%), good fluidity, and greater stability.

[0046] In traditional saponification processes using lye, the degree of saponification typically cannot exceed 70%, otherwise over-saponification will occur, significantly reducing the extraction performance of the organic phase. The degree of saponification in traditional saponification methods is usually 50-55%, with an organic phase loading of 11-14 g / L. Further increasing the degree of saponification may lead to reduced organic phase fluidity, decreased extraction performance, and poorer stability. If a slurry is used, it is often impossible to achieve a high actual degree of saponification.

[0047] Using the alkaline earth metal saponifying agent of this application, the actual degree of saponification can reach 100%, and the organic phase loading can reach 22-28 g / L or more. At the same time, the organic phase will not have any problems (no over-saponification). This means that the processing capacity of the same amount of organic phase is increased by 50% compared with traditional saponification. This can greatly improve the extraction efficiency of saponified organic phase and greatly increase the processing capacity, which is a very big step forward in the extraction industry.

[0048] In addition, the raffinate obtained from subsequent extraction can be recycled to recover alkaline earth metals and prepare high-purity compounds, which can be sold directly as products or returned to the front end as saponifying agents for direct saponification.

[0049] The fifth aspect of this application provides the application of the method described in the third aspect in metal extraction.

[0050] Specifically, as shown in Figure 1, the saponified organic phase obtained by the method is mixed with a feed solution (e.g., a magnesium-containing feed solution) for extraction to obtain a carboxylate solution loaded with other metals and a raffinate containing alkaline earth metals. The carboxylate solution loaded with other metals is mixed with inorganic acids of different concentrations and subjected to washing-back-extraction-regeneration to obtain an extractant, which is recycled. The raffinate containing alkaline earth metals is regenerated through a regeneration process to obtain alkaline earth metal compound powder. The regeneration process includes one or a combination of precipitation, calcination, reduction, and spray pyrolysis.

[0051] The present application will be described in detail below through examples.

[0052] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0053] Example 1

[0054] This embodiment illustrates a method for saponifying an acidic extractant using magnesium oxide powder.

[0055] Magnesium oxide powder: obtained by spray pyrolysis of magnesium nitrate solution, with a maximum particle size of less than 20 μm and a purity of 98%.

[0056] Acidic extractant solution: including BC196 extractant The volume fraction of the extractant, Escaid 110 and BC196, was 25%.

[0057] Magnesium oxide powder was mixed with an acidic extractant solution and saponified for 2.5 min under stirring to obtain a saponified organic phase. The amount of magnesium oxide powder used was based on achieving a theoretical saponification degree of 100% with a 25% (v / v) acidic extractant (BC196).

[0058] The obtained saponified organic phase has good flowability, no solid powder precipitate after standing for more than 48 hours, and is clear and transparent after standing, with good stability.

[0059] Example 2

[0060] Saponification was performed according to the method in Example 1, except that the extractant was replaced with BC194 extractant.

[0061] Example 3

[0062] Saponification was carried out according to the method of Example 1, except that the purity of the magnesium oxide powder was 80%.

[0063] Example 4

[0064] Saponification was carried out according to the method of Example 1, except that the purity of magnesium oxide powder was 92%, and it was obtained by spray pyrolysis of magnesium chloride solution.

[0065] Example 5

[0066] Saponification was carried out according to the method of Example 1, except that the purity of the magnesium oxide powder was 85%.

[0067] Example 6

[0068] Saponification was carried out according to the method of Example 1, except that the maximum particle size of magnesium oxide powder was 75 μm, and it was obtained by evaporation and reduction calcination of magnesium sulfate solution.

[0069] Example 7

[0070] Saponification was carried out according to the method of Example 1, except that the maximum particle size of magnesium oxide powder was 44 μm, and magnesium sulfate solution was obtained by precipitation and calcination.

[0071] Example 8

[0072] Saponification was performed according to the method of Example 1, except that the maximum particle size of the magnesium oxide powder was 106 μm.

[0073] Example 9

[0074] Saponification was performed according to the method of Example 1, except that the maximum particle size of the magnesium oxide powder was 180 μm.

[0075] Example 10

[0076] Saponification was performed according to the method of Example 1, except that the extractant was replaced with P204.

[0077] Example 11

[0078] Saponification was performed according to the method of Example 1, except that magnesium oxide powder was replaced with magnesium hydroxide powder.

[0079] Example 12

[0080] Saponification was carried out according to the method of Example 1, except that magnesium oxide powder was replaced with magnesium carbonate powder.

[0081] Example 13

[0082] Saponification was carried out according to the method of Example 1, except that magnesium oxide powder was replaced with magnesium bicarbonate powder.

[0083] Example 14

[0084] Saponification was performed according to the method of Example 1, except that magnesium oxide powder was replaced with calcium oxide powder.

[0085] Example 15

[0086] Saponification was carried out according to the method of Example 1, except that magnesium oxide powder was replaced with calcium hydroxide powder.

[0087] Example 16

[0088] Saponification was carried out according to the method of Example 1, except that magnesium oxide powder was replaced with calcium carbonate powder.

[0089] Comparative Example 1

[0090] Saponification was carried out according to the method of Example 1, except that magnesium oxide powder was replaced with magnesium hydroxide slurry (20% light magnesium oxide aqueous solution).

[0091] The obtained saponified organic phase had good flowability, but produced a large amount of saponification wastewater. Meanwhile, most of the light magnesium oxide remained undissolved in the water and sank to the bottom, failing to be utilized. After separating the saponified organic phase and placing it in a separate beaker, solid powder precipitated at the bottom of the organic phase after more than 48 hours, and the organic phase remained turbid and did not clarify.

[0092] Comparative Example 2

[0093] Saponification was carried out according to the method of Example 3, except that the maximum particle size of the magnesium oxide powder was 600 μm.

[0094] Comparative Example 3

[0095] Saponification was performed according to the method of Example 3, except that the maximum particle size of the magnesium oxide powder was 212 μm.

[0096] Comparative Example 4

[0097] Saponification was performed according to the method of Example 3, except that the maximum particle size of the magnesium oxide powder was 325 μm.

[0098] Comparative Example 5

[0099] Saponification was carried out according to the method of Example 1, except that magnesium oxide powder was replaced with a 10.8% liquid alkali solution.

[0100] The obtained saponified organic phase had poor flowability and was turbid, exhibiting excessive alkalinity. It flowed slowly and unstable in the extraction tank, making it impossible to conduct experiments within the extraction tank. When a portion of the organic phase was transferred to a separatory funnel for extraction, a large amount of nickel-cobalt precipitate was generated after mixing with the feed solution. The organic extraction performance was poor and could not meet the extraction requirements. Furthermore, the loading capacity could not be investigated, and the experiment could not proceed normally.

[0101] Comparative Example 6

[0102] Saponification was carried out according to the method of Example 1, except that the purity of the magnesium oxide powder was 50%.

[0103] Comparative Example 7

[0104] Saponification was performed according to the method of Example 1, except that the purity of the magnesium oxide powder was 75%.

[0105] Comparative Example 8

[0106] Saponification was carried out according to the method of Example 1, except that the purity of the magnesium oxide powder was 60%.

[0107] Comparative Example 9

[0108] Saponification was carried out according to the method of Example 1, except that the extractant was replaced with P507 and the magnesium oxide powder was replaced with a mixture of MgO (92%) and Mg(OH)Cl (8%).

[0109] Because the Mg(OH)Cl in the extractant forms MgCl2, which is insoluble in the organic phase, it affects the actual saponification effect, resulting in an actual saponification degree of only 90%. Furthermore, some MgCl2 will remain suspended in the organic phase, slowing down phase separation after saponification and introducing impurities into the extraction system, causing liquid contamination. A small amount of wastewater will also be generated.

[0110] Test case

[0111] The saponified organics obtained in Examples 1-16 and Comparative Examples 1-9 were subjected to eight-stage continuous extraction using the extractable solutions shown in Table 1.

[0112] Table 1

[0113] After extraction, the loaded organics were sampled and back-extracted using 7N sulfuric acid at a 1:1 ratio to determine the organic loading.

[0114] The organic loading of Example 1 is shown in Table 2, and the ion concentration of the raffinate is shown in Table 3.

[0115] Table 2

[0116] Table 3

[0117] Therefore, it can be seen that after continuous and stable operation, the organic loading of 26.71 g / L can still be perfectly maintained, and the extraction tank operates well. This value is basically the limit of the organic loading at this concentration of BC196 with 100% saponification, and the extractant has reached its limit. At this time, the magnesium carboxylate concentration is 0.5 mol / L, and the separation efficiency of nickel, cobalt and magnesium is above 99%.

[0118] The organic loading of Comparative Example 1 is shown in Table 4, and the ion concentration of the raffinate is shown in Table 5.

[0119] Table 4

[0120] Table 5

[0121] Therefore, the organic loading is 9.93 g / L, which is basically the limit loading at this concentration of BC196 with 40% saponification. This loading is consistent with the organic phase loading in traditional saponification and existing magnesium soap processes. The magnesium carboxylate concentration at this point is only 0.2 mol / L.

[0122] The test results of Examples 1-16 and Comparative Examples 1-9 are summarized in Table 6.

[0123] Table 6

[0124] The theoretical degree of saponification refers to the value that can be theoretically achieved by adding the corresponding saponifying agent; the actual degree of saponification refers to the actual value after adding the corresponding saponifying agent according to the theoretical degree of saponification. This value represents the maximum conversion rate of the saponifying agent under these conditions. The higher the value, the higher the conversion rate and the better the saponification effect, which directly affects the ease of industrialization and the cost after industrialization.

[0125] Organic loading is a quantitative representation of the actual degree of saponification and is directly related to it. The higher the organic loading, the better the subsequent extraction effect.

[0126] Precipitation refers to the sediment generated during the saponification process, which directly affects the ease of industrialization and operation. The greater the amount of sediment, the more difficult the industrialization, the greater the operational difficulty, and the higher the requirements for equipment.

[0127] Saponification time refers to the time required for the saponification process to reach the saponification limit (the organic phase remains stable after saponification stops, and the organic load does not change with saponification time) and stabilize under these conditions. It directly affects the ease of industrialization. Usually, this value should be less than 5 minutes, and the smaller the better.

[0128] Phase separation time refers to the time required for the phases to separate after saponification. It directly affects the ease of industrialization. Usually, this value should be less than 3 minutes, and the smaller the better.

[0129] Based on the results in Table 6, the analysis is as follows:

[0130] Examples 1 and 2 demonstrate that the effects of different extractants are basically the same, illustrating the universality of the extractants in this application.

[0131] Examples 1, 3, 4, and 5 compared the purity of different saponifying agents and generally achieved good results, but the precipitation and phase separation time increased as the purity decreased.

[0132] Examples 1, 6, 7, 8, and 9 compare the maximum particle size of different saponifying agents and all achieve good results, but the saponification time increases with the increase of the maximum particle size.

[0133] Examples 1, 4, 6, and 7 compare different sources of saponifying agent, and the source of saponifying agent has no effect, demonstrating the universality of this application regarding the source of saponifying agent.

[0134] Furthermore, a comparison of Example 1 with Comparative Examples 6, 7, and 8 shows that the purity of the saponifying agent is outside the range described in this application, resulting in a significant increase in precipitation and phase separation time, which has a considerable impact.

[0135] A comparison of Example 3 with Comparative Examples 2, 3, and 4 shows that the particle size of the saponifying agent is outside the range described in this application, resulting in a significant increase in saponification time and causing considerable impact.

[0136] A comparison of Example 1 with Comparative Examples 1 and 5 shows that neither the slurry nor the liquid alkali can achieve the effect of this application, and the difference in effect is significant.

[0137] Examples 1 and 10 compare different extractants, showing that this application is also applicable to phosphoric acid extractants.

[0138] Examples 1, 11, 12, 13, 14, 15, and 16 compare different types of saponifying agents and show that other alkaline earth metal compounds can also complete saponification.

[0139] As can be seen from Comparative Example 9, when saponifying agent is added according to the theoretical requirement of magnesium, the actual degree of saponification cannot reach the theoretical saponification. At the same time, a certain amount of wastewater is generated, and impurity ions are introduced simultaneously, which will greatly affect the difficulty of industrial operation.

[0140] The preferred embodiments of this application have been described in detail above; however, this application is not limited thereto. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in this application and are all within the protection scope of this application. Industrial applicability

[0141] This application relates to the field of hydrometallurgical technology and discloses an alkaline earth metal saponifying agent and its application. The saponifying agent is a compound powder of an alkaline earth metal; wherein the maximum particle size of the powder is less than 200 μm; and the purity of the powder is not less than 80%. The alkaline earth metal saponifying agent is mixed with an acidic extractant solution and then saponified to obtain a saponified organic phase. The alkaline earth metal saponifying agent or saponification method provided in this application can be used for metal extraction. Compared with traditional processes, this application uses an alkaline earth metal saponifying agent for direct saponification, which does not generate any saponification wastewater, has a high conversion rate of alkaline earth metals, avoids the problem of solid residue, and yields a saponified organic phase with good fluidity and stability. The saponifying agent provided in this application is widely available and can be recycled, significantly reducing saponification costs.

Claims

1. An alkaline earth metal saponifying agent, characterized in that, The saponifying agent is a compound powder of an alkaline earth metal; The maximum particle size of the powder is less than 200 μm; the purity of the powder is not less than 80%.

2. The alkaline earth metal saponifying agent according to claim 1, wherein, The maximum particle size of the powder is less than 120 μm, preferably less than 50 μm; Preferably, the purity of the powder is not less than 85%, and more preferably not less than 90%.

3. The alkaline earth metal saponifying agent according to claim 1 or 2, wherein, The alkaline earth metal is magnesium and / or calcium; Preferably, the compound is a basic compound; Preferably, the alkaline compound is selected from at least one of oxides, hydroxides, carbonates, and bicarbonates; Preferably, the alkaline earth metal compound powder is selected from at least one of magnesium oxide powder, magnesium hydroxide powder, magnesium carbonate powder, magnesium bicarbonate powder, calcium oxide powder, calcium hydroxide powder, and calcium carbonate powder.

4. The application of the alkaline earth metal saponifying agent according to any one of claims 1-3 in the saponification of acidic extractants.

5. A method for saponification using any one of the alkaline earth metal saponifying agents according to claims 1-3, characterized in that, The method includes: mixing the alkaline earth metal saponifying agent with an acidic extractant solution and then saponifying it to obtain a saponified organic phase.

6. The method according to claim 5, wherein, The saponification conditions include: stirring; time is 1-10 min.

7. The method according to claim 5 or 6, wherein, The acidic extractant is a carboxylic acid extractant and / or a phosphoric acid extractant; Preferably, the carboxylic acid extractant is selected from... and / or Where R1 and R2 are independently C3-C 12 Straight-chain or branched alkyl groups, R3 is a C4-C9 straight-chain or branched alkyl group, and R4 is a C3-C9 straight-chain or branched alkyl group. 10 Straight-chain or branched alkyl groups, preferably Preferably, the phosphoric acid extractant is P2O4.

8. A saponified organic phase obtained by the method according to any one of claims 5-7.

9. The saponified organic phase according to claim 8, wherein, The saponified organic phase is an organic acid salt solution of alkaline earth metals with a concentration of 0.1-2 mol / L.

10. The application of the method according to any one of claims 5-7 in metal extraction.

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