Rare earth extracting agent and application method thereof

Abstract

The invention belongs to the technical field of mineral extraction. The invention relates to a rare earth extraction agent, in particular to a rare earth extraction agent and an application method thereof. The rare earth extraction agent comprises the following raw materials in parts by weight: 30-40 parts of an organic extraction agent, 70-75 parts of a diluent, 6-8 parts of an interface stabilizer, and dioxane accounting for 5-10% of the mass of the organic extraction agent, wherein the organic extraction agent is selected from any one of 2-ethylhexyl phosphate mono-2-ethylhexyl ester, di (2-ethylhexyl) phosphate ester, naphthenic acid and di (2, 4, 4-trimethylpentyl) phosphonic acid, and the organic extraction agent is selected from any one of 2-ethylhexyl phosphate mono-2-ethylhexyl ester, di (2-ethylhexyl) phosphate ester, naphthenic acid and di (2, 4, 4-trimethylpentyl) phosphonic acid. The diluent is formed by mixing kerosene and palm oil according to the volume ratio of 1: 1; the interface stabilizer is formed by compounding a nonionic surfactant and gelatin according to the mass ratio of 1: (0.8-1.2); wherein the gelatin is selected from gelatin with an isoelectric point of 7.0; when the rare earth extraction agent is used, the pH value of a water phase is adjusted to 6.6 or below.

Description

Technical Field

[0001] The present invention belongs to the technical field of mineral extraction, and more specifically, relates to a rare earth extractant and an application method thereof. Background Art

[0002] Rare earth elements are affected by the "lanthanide contraction" effect and have very similar properties, making their separation and purification difficult. After rare earth ore is processed, a rare earth-containing leaching solution can be obtained, which can then be separated using a variety of classical methods. These methods mainly include fractional crystallization and precipitation, ion exchange and adsorption, solvent extraction, extraction chromatography, and liquid membrane separation.

[0003] Solvent extraction is the mainstream technology for the separation and enrichment of rare earth elements. Its principle is to use the difference in solubility of rare earth ions in two immiscible solvents to achieve extraction. Compared with solid-liquid extraction, liquid-liquid extraction is widely used in industry due to its simple operation. With the deepening of research, a variety of high-efficiency extractants have been discovered and gradually replaced traditional extractants. At present, although solvent extraction has the advantages of high efficiency, continuous production and large processing capacity, it has been widely used in the separation of rare earth elements, but it still faces many difficulties. Summary of the invention

[0004] The technical problem to be solved by the present invention is that although the extraction method of rare earth elements, especially the liquid-liquid extraction method, is simple to operate, there is still a bottleneck when the extraction effect needs to be further improved during the extraction process. In view of the existence of the above technical problems, the present invention provides a rare earth extractant and an application method thereof.

[0005] The purpose of the present invention is to provide a rare earth extractant.

[0006] Another object of the present invention is to provide an application method of the rare earth extractant.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions: A rare earth extractant, comprising the following raw materials in parts by weight: 30-40 parts of an organic extractant, 70-75 parts of a diluent and 6-8 parts of an interfacial stabilizer; Wherein, the organic extractant is selected from any one of: 2-ethylhexyl phosphate mono-2-ethylhexyl ester, di(2-ethylhexyl) phosphate, cyclohexane acid, and bis(2,4,4-trimethylpentyl)phosphonic acid; The diluent is a mixture of kerosene and palm oil in a volume ratio of 1:1; The interfacial stabilizer is prepared by compounding a nonionic surfactant and gelatin in a mass ratio of 1:0.8-1.2; Wherein, the gelatin is selected to have an isoelectric point of 7.0; When the rare earth extractant is used, the extraction temperature is 35-45° C., and the pH of the aqueous phase is adjusted to below 6.6.

[0008] Furthermore, the nonionic surfactant is selected from any one of Span 80, Span 60, Span 40 and Span 20.

[0009] Furthermore, the rare earth extractant further comprises 5-10% by mass of dioxane of the organic extractant.

[0010] A method for applying a rare earth extractant, the specific application steps comprising: Preparation of organic phase: The diluent is divided into two equal parts, one of which is stirred and mixed with the organic extractant to obtain a dilute extractant; and the other is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; adding sodium hydroxide solution to the diluted extractant for saponification to obtain a saponified organic phase; Adding the interfacial stabilizer dispersion to the saponified organic phase and stirring evenly to obtain an organic phase; Preparation of water phase: The pH of the solution containing rare earth ions to be extracted is adjusted to below 6.6 to obtain an aqueous phase; extraction: After the organic phase and the aqueous phase are mixed, the extraction is stirred at a temperature of 35-45°C and allowed to stand to separate the layers. The extraction is completed.

[0011] Furthermore, the preparation of the organic phase also includes: The diluent is divided into two equal parts, one of which is stirred and mixed with the organic extractant, and 5-10% of the mass of dioxane of the organic extractant is added to obtain a diluted extractant; the other part is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; Adding a sodium hydroxide solution with a concentration of 6-8 mol / L to the diluted extractant for saponification to obtain a saponified organic phase; Wherein, the amount of the sodium hydroxide solution is 50-60% of the mass of the organic extractant; Add the interfacial stabilizer dispersion to the saponified organic phase and stir evenly to obtain an organic phase.

[0012] Furthermore, the preparation of the organic phase also includes: The diluent is divided into two equal parts, one of which is stirred and mixed with the organic extractant to obtain a dilute extractant; and the other is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; Adding a sodium hydroxide solution with a concentration of 6-8 mol / L to the diluted extractant for saponification to obtain a saponified organic phase; Wherein, the amount of the sodium hydroxide solution is 50-60% of the mass of the organic extractant; Wherein, the preparation method of the interface stabilizer comprises: Dissolve gelatin in water to prepare a gelatin solution with a mass fraction of 10-15%; The gelatin solution and the nonionic surfactant are uniformly mixed to obtain an interfacial stabilizer; Add the interfacial stabilizer dispersion to the saponified organic phase and stir evenly to obtain an organic phase.

[0013] Furthermore, the gelatin is selected from low molecular weight gelatin with an average molecular weight of 5000-15000.

[0014] Furthermore, the rare earth ion is selected from any one of lanthanum ion, cerium ion, praseodymium ion, neodymium ion and samarium ion.

[0015] The beneficial effects of the present invention include: (1) For the extraction of rare earth ions by liquid-liquid extraction, the inventors found that emulsification would occur during the actual operation. The occurrence of emulsification would not only affect the extraction efficiency, but also cause certain environmental pollution. After in-depth research, it was found that the occurrence of emulsification was caused by the properties of the organic phase or the aqueous phase during the extraction process, and may also be related to the control of the operating conditions. Based on this, the inventors added an interfacial stabilizer to the organic phase of the extraction to improve the stability of the organic phase system and prevent emulsification from occurring during the extraction process. Specifically, by utilizing non-ionic surfactants, higher interfacial activity is provided, and a larger interfacial adsorption capacity is obtained. Therefore, the interfacial stability of the organic phase can be improved, thereby reducing the occurrence of emulsification. However, in the extraction process, in order to improve the extraction efficiency, a suitable extraction temperature needs to be selected. However, the adjustment of temperature will cause the stability of the extraction system to change. Based on this, gelatin is added to the interfacial stabilizer, and gelatin with an isoelectric point of 7.0 is selected. During the extraction process, the pH of the aqueous phase is controlled below 6.6. In this way, the amino groups in the gelatin molecular structure can be protonated, thereby causing electrostatic repulsion due to the same positive charge, allowing the gelatin molecular chains to fully stretch on the liquid film surface, thereby enhancing the stability of the organic phase, and further reducing the stability degradation caused by changes in operating conditions, such as extraction temperature, during the extraction process, thereby ensuring the extraction effect.

[0016] (2) Furthermore, by adding dioxane to the system and controlling its addition amount within a suitable range, the organic phase is diluted and the organic specific gravity is adjusted to a reasonable range, thereby adjusting the interfacial tension between the aqueous phase and the organic phase during the extraction process and reducing the possibility of emulsification. DETAILED DESCRIPTION

[0017] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0018] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0019] Example 1 Preparation of rare earth extractants: Calculated by weight, 30 parts of organic extractant, 70 parts of diluent and 6 parts of interfacial stabilizer are taken in sequence; and 5% of the weight of dioxane of the organic extractant; Wherein, the organic extractant is selected from: 2-ethylhexyl mono-2-ethylhexyl phosphate; The diluent is a mixture of kerosene and palm oil in a volume ratio of 1:1; The interfacial stabilizer is prepared by compounding a nonionic surfactant and gelatin in a mass ratio of 1:0.8; Wherein, the gelatin is selected to have an isoelectric point of 7.0; The gelatin is selected from low molecular weight gelatin with an average molecular weight of 5000; Specifically, when preparing the interface stabilizer, it includes: Dissolve gelatin in water to prepare a gelatin solution with a mass fraction of 10%; The gelatin solution and the nonionic surfactant are uniformly mixed to obtain an interfacial stabilizer; The nonionic surfactant is selected from Span 80; Preparation of organic phase: The diluent is divided into two equal parts, one of which is stirred and mixed with an organic extractant, and dioxane is added to obtain a diluted extractant; The other part is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; Adding a sodium hydroxide solution with a concentration of 6 mol / L to the diluted extractant for saponification to obtain a saponified organic phase; Wherein, the amount of the sodium hydroxide solution is 50% of the mass of the organic extractant; Preparation of water phase: Rare earth oxide and concentrated hydrochloric acid with a mass fraction of 30% were mixed in a mass ratio of 1:6, and heated and stirred at a temperature of 70°C and a stirring speed of 300 r / min for 2 hours, and then deionized water with a mass of 10 times that of the concentrated hydrochloric acid was added, and then the pH was adjusted to 6.6 to obtain an aqueous phase containing rare earth ions; The rare earth ions are selected from: lanthanum ions; extraction: The organic phase and the aqueous phase were mixed in a volume ratio of 1:1, and the mixture was stirred and extracted for 20 min at a temperature of 35°C and a stirring speed of 80 r / min. The mixture was allowed to stand for 2 h to separate the aqueous phase and the organic phase, and the extraction was completed.

[0020] Example 2 Preparation of rare earth extractants: Calculated by weight, 35 parts of organic extractant, 72 parts of diluent and 7 parts of interfacial stabilizer are taken in sequence; and 8% of the weight of dioxane of the organic extractant; Wherein, the organic extractant is selected from: di(2-ethylhexyl) phosphate; The diluent is a mixture of kerosene and palm oil in a volume ratio of 1:1; The interfacial stabilizer is prepared by compounding a nonionic surfactant and gelatin in a mass ratio of 1:1; Wherein, the gelatin is selected to have an isoelectric point of 7.0; The gelatin is selected from low molecular weight gelatin with an average molecular weight of 12000; Specifically, when preparing the interface stabilizer, it includes: Dissolve gelatin in water to prepare a gelatin solution with a mass fraction of 12%; The gelatin solution and the nonionic surfactant are uniformly mixed to obtain an interfacial stabilizer; The nonionic surfactant is selected from Span 60; Preparation of organic phase: The diluent is divided into two equal parts, one of which is mixed with an organic extractant by stirring, and dioxane is added to obtain a diluted extractant; The other part is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; Adding a sodium hydroxide solution with a concentration of 7 mol / L to the diluted extractant for saponification to obtain a saponified organic phase; Wherein, the amount of the sodium hydroxide solution is 55% of the mass of the organic extractant; Preparation of water phase: Rare earth oxide and concentrated hydrochloric acid with a mass fraction of 32% were mixed in a mass ratio of 1:6, and heated and stirred at a temperature of 75°C and a stirring speed of 400 r / min for 3 hours, and then deionized water with a mass of 10 times that of the concentrated hydrochloric acid was added, and then the pH was adjusted to 6.4 to obtain an aqueous phase containing rare earth ions; The rare earth ions are selected from: cerium ions; extraction: The organic phase and the aqueous phase were mixed in a volume ratio of 1:1, and the mixture was stirred and extracted for 25 minutes at a temperature of 40°C and a stirring speed of 90 r / min. The mixture was allowed to stand for 2.5 hours to separate the aqueous phase and the organic phase, and the extraction was completed.

[0021] Example 3 Preparation of rare earth extractants: Calculated by weight, take 40 parts of organic extractant, 75 parts of diluent and 8 parts of interfacial stabilizer in sequence; and 10% of the weight of dioxane of the organic extractant; Wherein, the organic extractant is selected from: cyclohexane acid; The diluent is a mixture of kerosene and palm oil in a volume ratio of 1:1; The interfacial stabilizer is prepared by compounding a nonionic surfactant and gelatin in a mass ratio of 1:1.2; Wherein, the gelatin is selected to have an isoelectric point of 7.0; The gelatin is selected from low molecular weight gelatin with an average molecular weight of 15000; Specifically, when preparing the interface stabilizer, it includes: Dissolve gelatin in water to prepare a gelatin solution with a mass fraction of 15%; The gelatin solution and the nonionic surfactant are uniformly mixed to obtain an interfacial stabilizer; The nonionic surfactant is selected from Span 40; Preparation of organic phase: The diluent is divided into two equal parts, one of which is stirred and mixed with an organic extractant, and dioxane is added to obtain a diluted extractant; The other part is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; Adding a sodium hydroxide solution with a concentration of 8 mol / L to the diluted extractant for saponification to obtain a saponified organic phase; Wherein, the amount of the sodium hydroxide solution is 60% of the mass of the organic extractant; Preparation of water phase: Rare earth oxide and concentrated hydrochloric acid with a mass fraction of 35% were mixed in a mass ratio of 1:6, and heated and stirred for 4 hours at a temperature of 80°C and a stirring speed of 500 r / min, and then deionized water with a mass of 10 times that of the concentrated hydrochloric acid was added, and then the pH was adjusted to 6.2 to obtain an aqueous phase containing rare earth ions; The rare earth ions are selected from: praseodymium ions; extraction: The organic phase and the aqueous phase were mixed in a volume ratio of 1:1, and the mixture was stirred at 45°C and a stirring speed of 100 r / min for 30 min. The mixture was allowed to stand for 3 h to separate the aqueous phase and the organic phase, and the extraction was completed.

[0022] Example 4 The difference between this embodiment and embodiment 1 is that no dioxane is added, and the other conditions remain unchanged.

[0023] Comparative Example 1 The difference between this comparative example and Example 1 is that an equal amount of cyclodextrin is used to replace gelatin, and other conditions remain unchanged.

[0024] Comparative Example 2 The difference between this comparative example and Example 1 is that gelatin is not added, and other conditions remain unchanged.

[0025] Comparative Example 3 The difference between this comparative example and Example 1 is that no interface stabilizer is added, and other conditions remain unchanged.

[0026] The extraction results of the above embodiments and comparative examples were tested, and the specific test methods and test results are as follows: After the extraction is completed, the lower aqueous phase is collected and centrifuged at 8000r / min for 25min. The concentration of rare earth ions in the aqueous phase is determined by an ultraviolet spectrophotometer. The change in ion concentration before and after extraction is then calculated and used as the extraction rate. In addition, the raffinate was collected and centrifuged at 5000 r / min for 10 min, and the supernatant was collected to measure the oil content using an infrared oil meter. The detailed test results are shown in Table 1; Table 1: Extraction results analysis It can be seen from the test results in Table 1 that the extractant and extraction method used in the present invention can effectively extract rare earth metal ions.

[0027] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A rare earth extractant, characterized in that: The method comprises the following raw materials in parts by weight: 30-40 parts of an organic extractant, 70-75 parts of a diluent and 6-8 parts of an interfacial stabilizer; Wherein, the organic extractant is selected from any one of: 2-ethylhexyl phosphate mono-2-ethylhexyl ester, di(2-ethylhexyl) phosphate, cyclohexane acid, and bis(2,4,4-trimethylpentyl)phosphonic acid; The diluent is a mixture of kerosene and palm oil in a volume ratio of 1:1; The interfacial stabilizer is prepared by compounding a nonionic surfactant and gelatin in a mass ratio of 1:0.8-1.2; Wherein, the gelatin is selected to have an isoelectric point of 7.0; When the rare earth extractant is used, the extraction temperature is 35-45° C., and the pH of the aqueous phase is adjusted to below 6.

6.

2. A rare earth extractant according to claim 1, characterized in that: The nonionic surfactant is selected from any one of Span 80, Span 60, Span 40 and Span 20.

3. A rare earth extractant according to claim 1, characterized in that: The rare earth extractant also includes 5-10% of the mass of dioxane of the organic extractant.

4. A method for using the rare earth extractant according to any one of claims 1 to 3, characterized in that: The specific application steps include: Preparation of organic phase: The diluent is divided into two equal parts, one of which is stirred and mixed with the organic extractant to obtain a dilute extractant; and the other is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; adding sodium hydroxide solution to the diluted extractant for saponification to obtain a saponified organic phase; Adding the interfacial stabilizer dispersion to the saponified organic phase and stirring evenly to obtain an organic phase; Preparation of water phase: The pH of the solution containing rare earth ions to be extracted is adjusted to below 6.6 to obtain an aqueous phase; extraction: After the organic phase and the aqueous phase are mixed, the extraction is stirred at a temperature of 35-45°C and allowed to stand to separate the layers. The extraction is completed.

5. The application method of a rare earth extractant according to claim 4, characterized in that: The preparation of the organic phase also includes: The diluent is divided into two equal parts, one of which is stirred and mixed with an organic extractant, wherein the organic extractant contains 5-10% of dioxane by weight to obtain a diluted extractant; the other is stirred and mixed with an interfacial stabilizer to obtain an interfacial stabilizer dispersion; Adding a sodium hydroxide solution with a concentration of 6-8 mol / L to the diluted extractant for saponification to obtain a saponified organic phase; Wherein, the amount of the sodium hydroxide solution is 50-60% of the mass of the organic extractant; Add the interfacial stabilizer dispersion to the saponified organic phase and stir evenly to obtain an organic phase.

6. The application method of a rare earth extractant according to claim 5, characterized in that: The preparation of the organic phase also includes: The diluent is divided into two equal parts, one of which is stirred and mixed with the organic extractant, and 5-10% of the mass of dioxane of the organic extractant is added to obtain a diluted extractant; the other part is stirred and mixed with the interfacial stabilizer to obtain an interfacial stabilizer dispersion; Adding a sodium hydroxide solution with a concentration of 6-8 mol / L to the diluted extractant for saponification to obtain a saponified organic phase; Wherein, the amount of the sodium hydroxide solution is 50-60% of the mass of the organic extractant; Wherein, the preparation method of the interface stabilizer comprises: Dissolve gelatin in water to prepare a gelatin solution with a mass fraction of 10-15%; The gelatin solution and the nonionic surfactant are uniformly mixed to obtain an interfacial stabilizer; Add the interfacial stabilizer dispersion to the saponified organic phase and stir evenly to obtain an organic phase.

7. The application method of a rare earth extractant according to any one of claims 5 or 6, characterized in that: The gelatin is selected from low molecular weight gelatin with an average molecular weight of 5000-15000.

8. The application method of a rare earth extractant according to claim 4, characterized in that: The rare earth ion is selected from any one of lanthanum ion, cerium ion, praseodymium ion, neodymium ion and samarium ion.

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