A method for extracting and separating molybdenum and rhenium ions in a solution by an aqueous two-phase system

Abstract

A method for extracting and separating molybdenum and rhenium ions in a solution by an aqueous two-phase system. An aqueous two-phase system composed of isodecyl polyoxyethylene ether, ammonium sulfate and water is prepared, wherein the mass percentage concentrations of isodecyl polyoxyethylene ether and ammonium sulfate are 10% - 40%, and the mass ratio of isodecyl polyoxyethylene ether, ammonium sulfate and water is 1:(1 - 4):(0.5 - 8). Add 1 part by mass of the above aqueous two-phase system to 1 - 5 parts by mass of the molybdenum and rhenium solution to be separated to obtain a mixed solution. Adjust the pH of the mixed solution to 1 - 7, stir and react at 10 - 60 °C for 2 - 30 min, stand for 10 min - 3 h, and separate into two phases to obtain an aqueous two-phase system. Measure the concentrations of molybdenum and rhenium ions in the upper and lower phases to obtain the separation factor of rhenium / molybdenum. The aqueous two-phase system used in the present invention avoids the use of organic solvents and has prominent advantages such as fast phase separation speed, high separation efficiency for molybdenum and rhenium ions, safe operation and environmental protection in the process.

Description

Technical Field

[0001] The present invention provides a method for extracting and separating molybdenum and rhenium ions in a solution by using an aqueous two-phase system, belonging to the technical field of separating metal ions in a solution, and specifically designing a method for separating molybdenum and rhenium ions in an aqueous solution by using an aqueous two-phase system composed of isodecyl polyoxyethylene ether and ammonium sulfate. Background Art

[0002] Molybdenum metal has high melting and boiling points, relatively strong electrical and thermal conductivities, stable properties and is easy to process. It is widely used in fields such as steel, non-ferrous metal alloys, electricity, aerospace, etc., and is an irreplaceable strategic material in national defense construction and national economic development. The content of rhenium in the earth's crust is only 7%-10%. Rhenium hardly exists independently in natural minerals and is usually dispersed in molybdenite and chalcopyrite in the form of sulfides. The silver-white metal rhenium has good ductility, wear resistance, corrosion resistance, high temperature resistance, and very high melting and boiling points, and is widely used in fields such as aerospace, electronics, petrochemical, etc.

[0003] Currently, the most commonly used method for separating molybdenum and rhenium ions in a solution system is solvent extraction. Extractants used for separating molybdenum and rhenium ions include amine, alcohol, and phosphorus extractants, etc. However, most of the extractants used are volatile and toxic organic substances, and organic solvents are used as diluents. Traditional solvent extraction is likely to cause the loss of organic solvents and extractants, thus bringing pollution to the environment. The characteristic of using an aqueous two-phase system to separate metal ions in a solution is to avoid the use of organic solvents and there is no problem of organic solvent residue, which is a green and environmentally friendly separation method.

[0004] Using the fact that a solution will automatically separate into two aqueous phases under certain additive concentrations and certain temperature conditions with non-ionic surfactants, the distribution of metal ions between different aqueous phases can be achieved. Non-ionic surfactants can be classified into polyoxyethylene type, polyol type, polyether type, etc. according to the structure of the hydrophilic group. Examples include polyethylene glycol (Rare Metal Materials and Engineering, 2011, 40(06): 1102-1104; Hydrometallurgy, Volume 219, 2023, 106077:0304-386X), polyether L35 (Journal of Cleaner Production, 2021, 297:126452), F68 (Yanshan University, 2020.), TritonX-100 (polyethylene glycol octyl phenyl ether) (Separation & Purification Technology, 2016, 169:151-157; CIESC Journal, 2006, 57(9):6), polypropylene oxide, etc. Zhenning Lou et al. (Hydrometallurgy, Volume 157, 2015) used TritonX-100 as a surfactant to selectively extract and separate Re(II) from Mo(VI) with N235 / isopentanol / n-heptane / NaCl under acidic conditions, and the separation factor of rhenium / molybdenum was 7.07–217.39. The above experiments provided the application of the aqueous two-phase microemulsion system containing non-ionic surfactants in the separation of metal anions such as molybdenum and rhenium, but there were defects such as the loss of organic solvents and a relatively long phase separation time.

[0005] The present invention uses an aqueous two-phase system composed of isodecyl polyoxyethylene ether and ammonium sulfate to extract and separate molybdenum and rhenium ions, avoiding the use of organic solvents, and having prominent advantages such as fast phase separation speed, high separation efficiency for molybdenum and rhenium ions, safe operation, and environmental protection during the process. Summary of the Invention

[0006] Aiming at the deficiencies of traditional solvent extraction separation, the present invention provides an aqueous two-phase system composed of a non-ionic surfactant, isodecyl polyoxyethylene ether, and ammonium sulfate to achieve the separation of molybdenum and rhenium ions in an aqueous solution. Using the method of the present invention to separate molybdenum and rhenium ions in a solution has the advantages of short phase separation time, high separation efficiency, simple operation, and environmental friendliness.

[0007] The purpose of the present invention is to provide a method for extracting and separating molybdenum and rhenium ions in a solution with an aqueous two-phase system. The aqueous two-phase system is composed of isodecyl polyoxyethylene ether, ammonium sulfate, and water, wherein the mass concentrations of isodecyl polyoxyethylene ether and ammonium sulfate are 10% - 40%, and the mass ratio of isodecyl polyoxyethylene ether, ammonium sulfate, and water is 1:(1 - 4):(0.5 - 8).

[0008] Add 1 part by mass of the above-mentioned aqueous two-phase system to 1 - 5 parts by mass of the molybdenum-rhenium solution to be separated to obtain a mixed solution. Adjust the pH of the mixed solution to 1 - 7, stir and react at 10 - 60 °C for 2 - 30 min, and let it stand for 10 min - 3 h to form two phases by layering. Measure the concentrations of molybdenum and rhenium ions in the upper and lower phases to obtain a rhenium / molybdenum separation factor that can be as high as over 660.

[0009] The present invention utilizes the salting-out effect of ammonium sulfate to break the hydrogen bonds formed between the C-O-C groups in the structure of isodecyl polyoxyethylene ether and water molecules, increase the hydrophobicity of isodecyl polyoxyethylene ether, and promote phase separation of the system. Due to the difference in the interaction forces between the upper and lower two phases (isodecyl polyoxyethylene ether-rich aqueous phase and ammonium sulfate-rich aqueous phase) and molybdenum and rhenium ions, the distribution of molybdenum and rhenium ions in the two phases is different, thus realizing the separation of molybdenum and rhenium ions.

[0010] In the molybdenum-rhenium solution to be separated, the mass concentration of molybdenum is 0.05% - 5%, and the mass concentration of rhenium is 0.005% - 0.5%.

[0011] Compared with the prior art, the present invention uses an aqueous two-phase system composed of isodecyl polyoxyethylene ether and ammonium sulfate to extract and separate molybdenum and rhenium ions in a solution, avoiding the use and loss of organic solvents, and also having prominent advantages such as fast phase separation speed, high separation efficiency for molybdenum and rhenium ions, safe operation, and environmental protection in the process. Specific Embodiments

[0012] To make the purpose and technical solutions of the invention clearer, the present invention will be further described in detail below with specific examples. The specific examples described here are used to explain the present invention, but do not limit the present invention. Example 1

[0013] The aqueous two-phase extraction system consists of isodecyl polyoxyethylene ether and ammonium sulfate with a mass percentage concentration of 20% each, and the rest is water. The target solution consists of molybdenum with a mass percentage concentration of 1% and rhenium with a mass percentage concentration of 0.1%. Mix the aqueous two-phase extraction system and the target solution in a volume ratio of 1:1 to form a mixed solution, adjust the pH of the solution to 4, shake at 40 °C for 20 min, and let it stand at 40 °C for 2 h to form two phases by layering. Dilute the upper and lower phases after the solution is layered respectively, measure the concentrations of molybdenum and rhenium in the two phases, and calculate to obtain a rhenium / molybdenum separation factor of 57.23. Example 2

[0014] The aqueous two-phase extraction system consists of isodecyl polyoxyethylene ether and ammonium sulfate, each with a mass percentage concentration of 20%, and the rest is water. The target solution consists of 1% molybdenum and 0.1% rhenium by mass percentage concentration. The aqueous two-phase extraction system and the target solution are combined into a mixed solution at a volume ratio of 1:1, the pH of the solution is adjusted to 5, shaken at 40 °C for 20 min, left standing at 40 °C for 2 h, and two-phase solutions are obtained by stratification. The upper and lower phases after the solution is stratified are respectively taken for dilution, the concentrations of molybdenum and rhenium in the two phases are measured, and the rhenium / molybdenum separation factor is calculated to be 93.43. Example 3

[0015] The aqueous two-phase extraction system consists of isodecyl polyoxyethylene ether and ammonium sulfate, each with a mass percentage concentration of 20%, and the rest is water. The target solution consists of 1% molybdenum and 0.1% rhenium by mass percentage concentration. The aqueous two-phase extraction system and the target solution are combined into a mixed solution at a volume ratio of 1:1, the pH of the solution is adjusted to 7, shaken at 40 °C for 20 min, left standing at 40 °C for 2 h, and two-phase solutions are obtained by stratification. The upper and lower phases after the solution is stratified are respectively taken for dilution, the concentrations of molybdenum and rhenium in the two phases are measured, and the rhenium / molybdenum separation factor is calculated to be 108.53. Example 4

[0016] The aqueous two-phase extraction system consists of 30% isodecyl polyoxyethylene ether and 40% ammonium sulfate by mass percentage concentration, and the rest is water. The target solution consists of 1% molybdenum and 0.1% rhenium. The aqueous two-phase extraction system and the target solution are combined into a mixed solution at a volume ratio of 1:1, the pH of the solution is adjusted to 7, shaken at 40 °C for 20 min, left standing at 40 °C for 2 h, and two-phase solutions are obtained by stratification. The upper and lower phases after the solution is stratified are respectively taken for dilution, the concentrations of molybdenum and rhenium in the two phases are measured, and the rhenium / molybdenum separation factor is calculated to be 660.15. Example 5

[0017] The aqueous two-phase extraction system consists of isodecyl polyoxyethylene ether and ammonium sulfate, each with a mass percentage concentration of 20%, and the rest is water. The target solution consists of 1% molybdenum and 0.1% rhenium by mass percentage concentration. The aqueous two-phase extraction system and the target solution are combined into a mixed solution at a volume ratio of 1:1, the pH of the solution is adjusted to 7, shaken at 50 °C for 20 min, left standing at 40 °C for 2 h, and two-phase solutions are obtained by stratification. The upper and lower phases after the solution is stratified are respectively taken for dilution, the concentrations of molybdenum and rhenium in the two phases are measured, and the rhenium / molybdenum separation factor is calculated to be 157.78. Example 6

[0018] The aqueous two-phase extraction system consists of isodecyl polyoxyethylene ether and ammonium sulfate, each with a mass percentage concentration of 20%, and the rest is water. The target solution consists of 1% molybdenum and 0.1% rhenium by mass percentage concentration. The aqueous two-phase extraction system and the target solution are combined to form a mixed solution at a volume ratio of 1:1, the pH of the solution is adjusted to 7, shaken at 60 °C for 20 min, left standing at 40 °C for 2 h, and two-phase solutions are obtained by stratification. The upper and lower phases after the solution is stratified are respectively taken for dilution, the concentrations of molybdenum and rhenium in the two phases are measured, and the rhenium / molybdenum separation factor is calculated to be 263.01. Example 7

[0019] The aqueous two-phase extraction system consists of isodecyl polyoxyethylene ether and ammonium sulfate, each with a mass percentage concentration of 20%, and the rest is water. The target solution consists of 1% molybdenum and 0.1% rhenium by mass percentage concentration. The aqueous two-phase extraction system and the target solution are combined to form a mixed solution at a volume ratio of 1:1, the pH of the solution is adjusted to 7, shaken at 40 °C for 20 min, left standing at 40 °C for 15 min, and two-phase solutions are obtained by stratification. The upper and lower phases after the solution is stratified are respectively taken for dilution, the concentrations of molybdenum and rhenium in the two phases are measured, and the rhenium / molybdenum separation factor is calculated to be 106.01. Example 8

[0020] The aqueous two-phase extraction system consists of isodecyl polyoxyethylene ether and ammonium sulfate, each with a mass percentage concentration of 20%, and the rest is water. The target solution consists of 1% molybdenum and 0.1% rhenium by mass percentage concentration. The aqueous two-phase extraction system and the target solution are combined to form a mixed solution at a volume ratio of 1:2, the pH of the solution is adjusted to 7, shaken at 40 °C for 20 min, left standing at 40 °C for 2 h, and two-phase solutions are obtained by stratification. The upper and lower phases after the solution is stratified are respectively taken for dilution, the concentrations of molybdenum and rhenium in the two phases are measured, and the rhenium / molybdenum separation factor is calculated to be 123.27.

[0021] The above are only some embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for extracting and separating molybdenum and rhenium ions in a solution by an aqueous two-phase system, characterized in that, The described aqueous two-phase system is composed of isodecyl polyoxyethylene ether, ammonium sulfate and water. The mass percentage concentrations of isodecyl polyoxyethylene ether and ammonium sulfate are 10% - 40% respectively, and the mass ratio of isodecyl polyoxyethylene ether, ammonium sulfate and water is 1:(1 - 4):(0.5 - 8); the specific steps are as follows: Add 1 part by mass of the above aqueous two-phase system to 1 - 5 parts by mass of the molybdenum-rhenium solution to be separated to obtain a mixed solution; adjust the pH of the mixed solution to 4 - 7, stir and react at 40 - 60 °C for 2 - 30 min, stand for 10 min - 3 h, and layer to obtain an aqueous two-phase; measure the concentrations of molybdenum and rhenium ions in the upper and lower phases to obtain the separation factor of rhenium / molybdenum; the mass percentage concentration of molybdenum in the molybdenum-rhenium solution to be separated is 0.05% - 5%, and the mass percentage concentration of rhenium is 0.005% - 0.5%.