Synergistic extractant composition for extracting magnesium from wet-process phosphoric acid and use method

Abstract

The invention belongs to the field of extraction, and particularly relates to a synergistic extractant composition for extracting magnesium in wet-process phosphoric acid and a use method, the synergistic extractant composition comprises a sulfonic acid extractant and a diphosphoric acid extractant, the molar ratio of the sulfonic acid extractant to the diphosphoric acid extractant is 1: 10-10: 1, and the molar ratio of the sulfonic acid extractant to the diphosphoric acid extractant is 1: 10-10: 1. The application method comprises the following specific steps: (1) uniformly mixing the diluent and the phase regulator, adding the sulfonic acid extraction agent and the diphosphoric acid extraction agent, and stirring until a clear and transparent solution and a synergistic extraction system are obtained, namely an organic phase; (2) mixing the wet-process phosphoric acid solution, namely a water phase, with an organic phase, and extracting for 1-60 minutes at the temperature of 15-55 DEG C according to the volume ratio of the water phase to the organic phase being (1: 5)-(5: 1); (3) carrying out phase splitting on the extracted mixed solution to obtain an organic phase loaded with magnesium ions and raffinate; and (4) carrying out reverse extraction on the organic phase loaded with the magnesium ions by using a reverse extraction agent to obtain an aqueous solution containing the magnesium ions.

Description

Technical Field

[0001] The present application belongs to the field of extraction, and specifically relates to a synergistic extractant composition for extracting magnesium from wet-process phosphoric acid and a method of using the same. Background Art

[0002] As a basic mineral acid, phosphoric acid is widely used as a basic raw material in many fields such as feed, fertilizer and food additives. Among them, phosphate rock is the main source of phosphoric acid in phosphorus chemical industry. Wet-process phosphoric acid (WPA) is widely used in refined phosphoric acid because of its low energy consumption and low cost. The acid solution obtained by this method is mostly acid-lyzed with inorganic strong acids such as sulfuric acid, nitric acid and hydrochloric acid. Among them, the sulfuric acid method has a simple process and the by-product phosphogypsum is easy to separate, which can be industrialized on a large scale. The sulfuric acid method occupies a dominant position in the production of wet-process phosphoric acid, so the wet-process phosphoric acid process usually refers to sulfuric acid phosphoric acid. During the acidolysis process, a large amount of metal impurities (Fe, Al, Mg, etc.) will be dissolved in the acid solution, which will increase the viscosity of the acid solution, increase the mass transfer resistance, increase energy consumption, cause pipeline blockage, and cause product quality to decline, which will seriously affect the performance of products produced with phosphoric acid as raw material. At present, removing magnesium from the solution is still a global problem in separation and purification technology. Therefore, it is of great significance to study efficient methods for purifying and removing magnesium in the production process of wet-process phosphoric acid.

[0003] In today's hydrometallurgical industry, precipitation, adsorption and solvent extraction are commonly used to remove impurities from solutions. The precipitation method requires a large amount of precipitant, which not only has high production costs, but also cannot deeply remove impurities and will introduce other impurities. The adsorption method has a relatively limited loading capacity and can only be economically feasible when the impurity content is low. The solvent extraction method has a large processing capacity, high efficiency, and simple operation. Both the extractant and the extraction process are suitable for industrialization. In the past few decades, people have partially studied the technology of removing magnesium by solvent extraction.

[0004] Patent application number CN117187589A, "A method for extracting and purifying heavy metal sludge leachate", discloses a method for deep removal of magnesium from high-nickel P507 raffinate using Cyanex272. The invention requires 30 stages of extraction, a large number of extraction stages, and complicated process steps. The complicated process is not only not conducive to industrial production, but may also reduce the quality of phosphoric acid.

[0005] Patent application number CN113060778A, "Method for preparing battery-grade nickel sulfate solution", discloses a method for efficiently extracting magnesium from nickel sulfate solution using P507 and Cyanex272 saponified with an inorganic base. The method requires two extractants to extract magnesium ions in two steps, which has low efficiency and a complex process. The traditional acidic extractant is difficult to ionize in a strong acidic system, and the extraction effect will be greatly reduced as the acidity of the aqueous phase increases.

[0006] The concentrations of sulfuric acid and phosphoric acid in wet-process phosphoric acid are high, and the pH is relatively low, which makes it difficult to remove magnesium. Sulfonic acid extractants are currently commonly used to extract and remove magnesium from wet-process phosphoric acid. However, in a strongly acidic environment, sulfonic acid extractants have a strong binding ability with metal ions, which will cause the system to become more emulsified and fail to achieve production application. Therefore, it is urgent to develop an extractant and extraction system suitable for removing impurity magnesium from strongly acidic wet-process phosphoric acid. Summary of the invention

[0007] In order to solve the problems of the prior art, the present application provides a synergistic extractant composition for extracting magnesium from wet-process phosphoric acid and a method for using the same. The present application is implemented by the following scheme:

[0008] A synergistic extractant composition for extracting magnesium from wet-process phosphoric acid, characterized in that it comprises a sulfonic acid extractant and a diphosphoric acid extractant, wherein the molar ratio of the sulfonic acid extractant to the diphosphoric acid extractant is 1:10 to 10:1, and the structural formula is as follows:

[0009]

[0010] In the formula, R1 is a straight chain or branched chain alkyl group or an aromatic alkyl group, and R2 is a straight chain or branched chain hydrocarbon group having 8 to 18 carbon atoms.

[0011] Preferably, the sulfonic acid extractant is dodecylbenzenesulfonic acid (DBSA); and the bisphosphoric acid extractant is P,P'-[(octylimino)di(methylene)]di[p-phenylphosphinic acid] (OIBMBPPA).

[0012] A synergistic extraction system for extracting magnesium from wet-process phosphoric acid comprises a synergistic extraction agent composition, a diluent and a phase regulator, wherein the mass ratio of the diluent to the phase regulator is 2:1-10:1, and the mass proportion of the synergistic extraction agent composition in the synergistic extraction system is 5-40wt%.

[0013] Preferably, the diluent is one or more of dichloromethane, 1,2-dichloroethane, toluene, xylene, n-hexane, and kerosene; and the phase regulator is one or more of n-octanol, isooctyl alcohol, n-heptanol, and n-nonanol.

[0014] Preferably, the diluent is kerosene, and the phase regulator is n-octanol.

[0015] A method for using a synergistic extractant composition for extracting magnesium from wet-process phosphoric acid, wherein the magnesium ion concentration in the wet-process phosphoric acid is 0.2-7 g / L, the sulfuric acid concentration is 0.1-1 mol / L, and the phosphoric acid concentration is 0.2-8 mol / L.

[0016] Preferably, the steps are as follows: (1) mixing a diluent and a phase regulator evenly, adding a sulfonic acid extractant and a diphosphoric acid extractant, stirring until a clear and transparent solution is obtained, and a synergistic extraction system is formed, namely, an organic phase; (2) mixing and extracting a wet phosphoric acid solution, namely, an aqueous phase, with an organic phase, wherein the extraction time is 1 to 60 minutes, the extraction temperature is 15 to 55° C., and the volume ratio of the aqueous phase to the organic phase is 1:5 to 5:1; (3) separating the mixed solution after extraction to obtain an organic phase loaded with magnesium ions and a raffinate; and (4) stripping the organic phase loaded with magnesium ions with a stripping agent to obtain an aqueous solution containing magnesium ions.

[0017] Preferably, the stripping agent is a 2-6 mol / L sulfuric acid solution, the stripping time is 15-100 min, and the stripping temperature is 15-55°C.

[0018] Preferably, the volume ratio of the organic phase to the stripping agent is 1 to 5:1.

[0019] The general formula of the synergistic extractant composition of the present application is:

[0020]

[0021] Although patent CN112280982A also discloses a bisphosphonic acid extractant, the present application is essentially different from the patent. The patent uses a bisphosphonic acid extractant to extract iron ions from a phosphate rock leachate, while the present application uses a bisphosphonic acid extractant P,P'-[(octylimine)di(methylene)]di[p-phenylphosphinic acid] to extract magnesium from wet-process phosphoric acid. The extraction solutions and extraction conditions are completely different. The present application creatively combines the bisphosphonic acid extractant with a sulfonic acid extractant to generate hydrogen bonds, which not only improves the serious emulsification problem of the sulfonic acid extractant, but also shortens the extraction equilibrium time, accelerates the phase separation, and has high circulation performance.

[0022] Beneficial effects:

[0023] (1) Sulfonic acid extractants are highly acidic and have strong binding ability with metal ions. However, the extraction system composed of sulfonic acid extractants has high water solubility in the extraction process of magnesium, and there is a serious emulsification phenomenon, which makes it difficult to achieve efficient extraction of magnesium, resulting in that a single sulfonic acid extractant is difficult to be applied in actual industrial production. The present application uses sulfonic acid extractants and diphosphoric acid extractants as synergistic extractants, and the intermolecular hydrogen bond energy formed is greater than the hydrogen bond formed with water molecules, which reduces the hydrophilicity and reduces the solubility of the extractant in water. Not only do the two extractants have good oil solubility, but they also greatly reduce the emulsification degree in the extraction process, solving the emulsification problem of the extraction system;

[0024] (2) The synergistic extractant composition disclosed in the present application can effectively remove magnesium when extracting magnesium without changing the wet phosphoric acid process; and has a short extraction equilibrium time, fast phase separation, high cycle performance, and significantly better extraction performance than traditional extractants such as P204, P507, and Cyanex272;

[0025] (3) The present application uses a sulfonic acid extractant and a bisphosphonic acid extractant as a synergistic extractant, and this extractant composition still maintains an excellent extraction effect on magnesium ions in a strong acidic system;

[0026] (4) The synergistic extractant composition disclosed in the present application can completely remove magnesium from low-grade high-magnesium phosphate acid solution after five-stage extraction during magnesium extraction, which is conducive to industrialization and is a new type of synergistic extractant with promising application prospects;

[0027] (5) The preparation method of the sulfonic acid extractant and the diphosphoric acid extractant used in the present application is simple, and no three wastes are generated in the process, so they can be applied to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some of the preferred embodiments of the present application, not all of the embodiments. For the preferred embodiments in the present application, for ordinary technicians in this field, other embodiments and drawings can be obtained based on these embodiments and drawings without creative work, and they all belong to the protection scope of the present application.

[0029] Figure 1 This is a comparison chart of the emulsification degree after extraction with a synergistic extractant (left) and dodecylbenzenesulfonic acid (right). DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below. It should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings. The above definitions are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the structure referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0031] The extraction rate (E) of the embodiment of the present application is the ratio of the concentration of magnesium in the aqueous phase before and after extraction, which can intuitively show the extraction capacity of the extractant. The stripping rate (S) is the ratio of the concentration of magnesium in the aqueous phase after stripping with the stripping agent to the concentration in the original organic phase. The concentration of magnesium in this patent is determined by ICP-OES.

[0032] Example 1

[0033] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio to obtain a synergistic extraction system, and finally stirred until a clear and transparent solution was obtained, which was the organic phase, wherein the total concentration of the synergistic extractant was 30 wt%;

[0034] (2) kerosene and n-octanol were mixed in a mass ratio of 4:1, DBSA was added thereto, and finally stirred until a clear and transparent solution was obtained, which was the organic phase, in which the DBSA concentration was 30 wt%;

[0035] (3) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0036] (4) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed. The extraction time was 15 min and the extraction temperature was 25 °C. No emulsification occurred after extraction with the synergistic extractant (left), while emulsification occurred after extraction with DBSA single extractant (right). See attached Figure 1 ;

[0037] When the extractant composition added in this example is DBSA and OIBMBPPA in an equal molar ratio, the extraction rate is 52.30%.

[0038] Example 2

[0039] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 2:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0040] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0041] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 51.61%.

[0042] Example 3

[0043] (1) kerosene and n-octanol were mixed uniformly at a mass ratio of 10:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0044] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0045] (3) 2 mL of the aqueous phase and 2 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 51.80%.

[0046] Example 4

[0047] (1) xylene and n-heptanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0048] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0049] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 51.91%.

[0050] Example 5

[0051] (1) 1,2-dichloroethane and isooctyl alcohol are mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA are added thereto in an equal molar ratio in sequence, and finally stirred until a clear and transparent solution is obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition is 30 wt %;

[0052] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0053] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 50.07%.

[0054] Example 6

[0055] (1) mixing toluene and n-nonanol in a mass ratio of 4:1, adding DBSA and OIBMBPPA in equal molar ratios, and finally stirring until a clear and transparent solution is obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition is 30 wt %;

[0056] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0057] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 51.83%.

[0058] Example 7

[0059] (1) kerosene and n-octanol were mixed in a mass ratio of 4:1, and DBSA and OIBMBPPA were added in a molar ratio of 1:10, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0060] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0061] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the magnesium concentration in the raffinate was measured. The extraction rate was 12%.

[0062] Example 8

[0063] (1) kerosene and n-octanol were mixed in a mass ratio of 4:1, and DBSA and OIBMBPPA were added in a molar ratio of 1:5, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0064] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0065] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the magnesium concentration in the raffinate was measured. The extraction rate was 25.23%.

[0066] Example 9

[0067] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 20 wt %;

[0068] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0069] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the magnesium concentration in the raffinate was measured. The extraction rate was 41.33%.

[0070] Example 10

[0071] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 40 wt %;

[0072] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0073] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 57.67%.

[0074] Embodiment 11

[0075] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0076] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0077] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 1 min, the extraction temperature was 25° C., and the magnesium concentration in the raffinate was measured. The extraction rate was 49.12%.

[0078] Example 12

[0079] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0080] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0081] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 30 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 53.04%.

[0082] Example 13

[0083] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the concentration of the synergistic extractant composition was 30 wt %;

[0084] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0085] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed, the extraction time was 60 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 53.21%.

[0086] Embodiment 14

[0087] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0088] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0089] (3) 5 mL of the aqueous phase and 25 mL of the organic phase were taken and mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 92.42%.

[0090] Embodiment 15

[0091] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0092] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0093] (3) 5 mL of the aqueous phase and 15 mL of the organic phase were taken and mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 83.56%.

[0094] Example 16

[0095] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0096] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0097] (3) 25 mL of the aqueous phase and 5 mL of the organic phase were taken and mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the concentration of magnesium in the raffinate was measured. The extraction rate was 26.09%.

[0098] Embodiment 17

[0099] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0100] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0101] (3) 25 mL of the aqueous phase and the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the organic phase was back-extracted with an equal volume of 3 mol / L sulfuric acid solution. The back-extraction time was 15 min, the back-extraction temperature was 25° C., and the back-extraction rate was 89.12%.

[0102] Embodiment 18

[0103] (1) Kerosene and n-octanol were uniformly mixed in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio in sequence, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %.

[0104] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0105] (3) 25 mL of the aqueous phase and the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the organic phase was back-extracted with an equal volume of 3 mol / L sulfuric acid solution. The back-extraction time was 60 min, the back-extraction temperature was 25° C., and the back-extraction rate was 95.24%.

[0106] Embodiment 19

[0107] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then equal amounts of DBSA and OIBMBPPA were added thereto in sequence, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0108] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0109] (3) 25 mL of the aqueous phase and the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the organic phase was back-extracted with an equal volume of 3 mol / L sulfuric acid solution. The back-extraction time was 100 min, the back-extraction temperature was 25° C., and the back-extraction rate was 97.81%.

[0110] Embodiment 20

[0111] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0112] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0113] (3) 25 mL of the aqueous phase and the organic phase were mixed, the extraction time was 15 min, the extraction temperature was 25° C., and the extracted organic phase was back-extracted with an equal volume of 2 mol / L sulfuric acid solution. The back-extraction time was 90 min, the back-extraction temperature was 25° C., and the back-extraction rate was 61.55%.

[0114] Embodiment 21

[0115] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0116] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0117] (3) 25 mL of the aqueous phase and the organic phase were taken and mixed. The extraction time was 15 min and the extraction temperature was 25° C. The extracted organic phase was back-extracted with an equal volume of 4 mol / L sulfuric acid solution. The back-extraction time was 90 min and the back-extraction temperature was 25° C. The back-extraction rate was 98.67%.

[0118] Embodiment 22

[0119] (1) kerosene and n-octanol were mixed uniformly in a mass ratio of 4:1, and then DBSA and OIBMBPPA were added thereto in an equal molar ratio, and finally stirred until a clear and transparent solution was obtained to obtain a synergistic extraction system, i.e., an organic phase, wherein the total concentration of the synergistic extractant was 30 wt %;

[0120] (2) using a magnesium-containing wet-process phosphoric acid solution as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L;

[0121] (3) 25 mL of the aqueous phase and the organic phase were taken and mixed. The extraction time was 15 min and the extraction temperature was 25° C. The organic phase after extraction was back-extracted using a 6 mol / L sulfuric acid solution. The back-extraction time was 90 min and the back-extraction temperature was 25° C. The back-extraction rate was 99.11%.

[0122] Comparative Example

[0123] (1) Kerosene and n-octanol were mixed uniformly at a mass ratio of 4:1, and then equal amounts of P204, P538, P507, cyclohexane acid, CA-12, Cyanex 272, DBSA, and OIBMBPPA were added respectively, and finally stirred until a clear and transparent solution was obtained, which was the organic phase, wherein the concentration of the extractant was 30 wt%.

[0124] (2) A wet-process phosphoric acid solution containing magnesium is used as the aqueous phase, wherein the concentration of magnesium in the aqueous phase is 7 g / L, the concentration of sulfuric acid is 0.2 mol / L, and the concentration of phosphoric acid is 3 mol / L.

[0125] (3) 25 mL of the aqueous phase and 25 mL of the organic phase were mixed. The extraction time was 15 min and the extraction temperature was 25 °C. The extraction rate results are shown in Table 1.

[0126] Table 1

[0127]

[0128]

[0129] The extraction capacity of current commercial extractants is far inferior to that of the synergistic extractant of the present invention. From the results of DBSA and OIBMBPPA extraction alone, the present invention embodies a significant synergistic effect.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present application, which should be included in the scope of the claims of the present application.

Claims

1. A synergistic extractant composition for extracting magnesium from wet-process phosphoric acid, characterized in that: It comprises a sulfonic acid extractant and a diphosphoric acid extractant, wherein the molar ratio of the sulfonic acid extractant to the diphosphoric acid extractant is 1:10 to 10:1, and the structural formula is as follows: In the formula, R1 is a straight chain or branched chain alkyl group or an aromatic alkyl group, and R2 is a straight chain or branched chain hydrocarbon group having 8 to 18 carbon atoms.

2. A synergistic extractant composition for extracting magnesium from wet-process phosphoric acid according to claim 1, characterized in that: The sulfonic acid extractant is dodecylbenzenesulfonic acid (DBSA); the diphosphoric acid extractant is P,P'-[(octylimino)di(methylene)]di[p-phenylphosphinic acid] (OIBMBPPA).

3. A synergistic extraction system for extracting magnesium from wet-process phosphoric acid according to claim 1, characterized in that: The invention comprises a synergistic extractant composition, a diluent and a phase regulator, wherein the mass ratio of the diluent to the phase regulator is 2:1-10:1, and the mass proportion of the synergistic extractant composition in the synergistic extraction system is 5-40wt%.

4. A synergistic extraction system for extracting magnesium from wet-process phosphoric acid according to claim 3, characterized in that: The diluent is one or more of dichloromethane, 1,2-dichloroethane, toluene, xylene, n-hexane and kerosene; the phase regulator is one or more of n-octanol, isooctyl alcohol, n-heptanol and n-nonanol.

5. A synergistic extraction system for extracting magnesium from wet-process phosphoric acid according to claim 3, characterized in that: The diluent is kerosene, and the phase regulator is n-octanol.

6. The method for using the synergistic extractant composition for extracting magnesium from wet-process phosphoric acid according to claim 3, characterized in that: The magnesium ion concentration in the wet-process phosphoric acid is 0.2-7 g / L, the sulfuric acid concentration is 0.1-1 mol / L, and the phosphoric acid concentration is 0.2-8 mol / L.

7. The method for using the synergistic extractant composition for extracting magnesium from wet-process phosphoric acid according to claim 6, characterized in that: The steps are as follows: (1) mixing a diluent and a phase regulator evenly, adding a sulfonic acid extractant and a diphosphoric acid extractant, stirring until a clear and transparent solution is formed, and a synergistic extraction system is formed, namely, an organic phase; (2) mixing and extracting a wet phosphoric acid solution, namely, an aqueous phase, with an organic phase, wherein the extraction time is 1 to 60 minutes, the extraction temperature is 15 to 55° C., and the volume ratio of the aqueous phase to the organic phase is 1:5 to 5:1; (3) separating the mixed solution after extraction to obtain an organic phase loaded with magnesium ions and a raffinate; and (4) stripping the organic phase loaded with magnesium ions with a stripping agent to obtain an aqueous solution containing magnesium ions.

8. The method for using the synergistic extractant composition for extracting magnesium from wet-process phosphoric acid according to claim 7, characterized in that: The stripping agent is a 2-6 mol / L sulfuric acid solution, the stripping time is 15-100 min, and the stripping temperature is 15-55° C.

9. The method for using the synergistic extractant composition for extracting magnesium from wet-process phosphoric acid according to claim 8, characterized in that: The volume ratio of the organic phase to the stripping agent is 1 to 5:1.

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