A hydrophobic aminocarboxylic acid coordination system for comprehensive utilization of titanium, zirconium and hafnium in minerals

Abstract

The present invention belongs to the technical field of comprehensive utilization of chemical substances in mineral resources. Specifically, it discloses a hydrophobic aminocarboxylic acid coordination system for comprehensive utilization of titanium, zirconium, and hafnium. The system comprises a hydrophobic ligand, a hydrophobic solvent, and an aqueous solution of titanium, zirconium, and hafnium. The titanium, zirconium, or hafnium forms a complex with the hydrophobic ligand via a coordination bond or a feedback π bond. The complex effectively dissolves in the hydrophobic solvent to form a stable hydrophobic solution. The present invention utilizes the aforementioned hydrophobic aminocarboxylic acid coordination system for comprehensive utilization of titanium, zirconium, and hafnium. The system can form complexes of varying stability with titanium, zirconium, and hafnium. The system contains a hydrophobic ligand and a hydrophobic solvent that effectively dissolves these complexes. The system forms chelates of varying stability with titanium, zirconium, and hafnium through the coordination system, and then separates the titanium, zirconium, and hafnium from each other.

Description

Technical Field

[0001] The present invention relates to the field of comprehensive utilization of chemical substances in mineral resources, in particular to a hydrophobic aminocarboxylic acid coordination system for comprehensive utilization of titanium, zirconium and hafnium in minerals. Background Art

[0002] Among mineral resources, there is an important mineral sand, a crucial raw material for the production of metallic titanium, zirconium, and hafnium. This raw material undergoes separation through water separation, electrostatic separation, or magnetic separation, yielding minerals such as zircon sand, ilmenite, rutile, monazite, and xenotime. When zirconium and hafnium are extracted from zircon sand using processes such as alkaline dissolution-acid leaching, high-temperature chlorination-water, and fluoride-mixed acid leaching, the solution contains not only hydrated zirconium and hafnium ions but also hydrated titanium ions and their complex anions, such as [TiOCl4]. 2- 、[ZrCl6] 2- , [HfCl6] 2- 、[TiF6] 2- , [ZrF6] 2- and [HfF6] 2- When preparing high-purity zirconium and hafnium products from these leachates, it is necessary to separate the fourth subgroup elements from other elements, and it is also necessary to face the problem of separating zirconium and hafnium, as well as the problem of separating titanium from zirconium and hafnium. The chemical properties of the fourth subgroup elements are quite different from those of other elements, and they can usually be separated by conventional methods, and their separation difficulty is relatively low. Compared with the atomic radius and ionic radius of zirconium and hafnium, the two radii of titanium are less than 10 and 13pm respectively, while the radii of zirconium and hafnium are extremely close due to the lanthanide contraction. Therefore, it is easier to separate titanium from zirconium and hafnium, while it is more difficult to separate zirconium and hafnium. In order to achieve the separation of zirconium and hafnium, researchers have proposed many methods, and the most commercially valuable method is solvent extraction separation.

[0003] Patents currently covering the solvent extraction separation of zirconium and hafnium rarely address the separation of titanium from zirconium and hafnium. Instead, they primarily address solvents, separation media, or separation processes for the solvent extraction of zirconium and hafnium. Three commercially available methods primarily encompass these processes. One involves using zirconium (hafnium) oxychloride as the raw material, adding ammonium thiocyanate to the extraction system, and continuously extracting zirconium and hafnium using methyl isobutyl ketone (MIK) in a countercurrent extraction process to obtain zirconium and hafnium, respectively. A second solvent extraction method for separating zirconium and hafnium is performed in a nitric acid medium. Using tributyl phosphate (TBP) as the extractant, countercurrent extraction extracts the zirconium into the organic phase, while the hafnium remains in the aqueous solution. A third solvent extraction process uses a tertiary amine as the extractant in a sulfuric acid medium to separate zirconium and hafnium. For example, patent application number CN113234923A discloses a method for separating zirconium and hafnium using nitrogen dioxide (N235) in a sulfuric acid medium. Patent application number CN112593079A discloses a synergistic extractant and method for separating zirconium and hafnium. This method involves adding an alkaline amine extractant to a neutral phosphorus-containing extractant system to separate zirconium and hafnium from various media. Based on the three aforementioned separation methods, several new solvent extraction separation methods have been developed. For example, patent application number CN115710645A discloses a method for extracting and separating nuclear-grade zirconium and hafnium using a tridentate amide acid in a hydrochloric acid system. Patent application numbers CN115504901A and CN113981221A, respectively, disclose methods for separating and purifying zirconium and hafnium using ionic liquid systems. The cation is [A336] + , and the anions are several common anions.

[0004] Existing methods for separating zirconium and hafnium utilize commonly used and proven extractants, such as acidic phosphonic acid extractants, neutral phosphine oxide and ketone extractants, and alkaline amine extractants. To improve separation efficiency, complexing agents or extraction aids, such as ammonium thiocyanate or nitric acid, are added to the extraction system. However, some of these extractants suffer from limitations such as high water solubility, volatility, or difficulty in separating phases. In addition to the extractant, the added complexing agents or extraction aids in the raffinate increase the difficulty of wastewater comprehensive utilization or treatment. Summary of the Invention

[0005] The purpose of the present invention is to provide a hydrophobic aminocarboxylic acid coordination system for comprehensive utilization of titanium, zirconium and hafnium in minerals. The coordination agent can form a hydrophobic aminocarboxylic acid coordination system with different coordination stability with titanium, zirconium and hafnium. The system contains a hydrophobic ligand and a hydrophobic solvent that effectively dissolves these coordination complexes. The coordination system forms chelates of different stability with titanium, zirconium and hafnium, and then separates titanium, zirconium and hafnium from each other.

[0006] To achieve the above objectives, the present invention provides a hydrophobic aminocarboxylic acid coordination system for comprehensive utilization of titanium, zirconium and hafnium in minerals, comprising a hydrophobic ligand, a hydrophobic solvent, and aqueous solutions of titanium, zirconium and hafnium. Titanium, zirconium or hafnium forms a complex with the hydrophobic ligand via a coordination bond or a feedback π bond, and the complex effectively dissolves in the hydrophobic solvent to form a stable hydrophobic solution.

[0007] Preferably, the hydrophobic ligand is a monoalkylaminodicarboxylic acid, a dialkylaminomonocarboxylic acid, or a dialkyldiaminodicarboxylic acid, wherein the alkyl group in the alkylaminocarboxylic acid is a linear or branched saturated or unsaturated alkyl or aromatic hydrocarbon having 6 to 20 carbon atoms, and the carboxylic acid group is one of acetic acid, propionic acid, or butyric acid groups.

[0008] Preferably, the hydrophobic ligand is a di-alkyldiaminodicarboxylic acid, wherein the alkyl group is a straight-chain or branched saturated or unsaturated alkyl or aromatic hydrocarbon with 6-20 carbon atoms, the alkyl group between the two amino groups has 2-6 carbon atoms and is a straight-chain alkane, and the carboxylic acid group is one of acetic acid, propionic acid, and butyric acid groups.

[0009] Preferably, the hydrophobic solvent is a hydrophobic straight-chain or branched alkane, alkene or substituted aromatic hydrocarbon, and the number of carbon atoms is in the range of 8-20.

[0010] Preferably, the aqueous solution of titanium, zirconium and hafnium is one or two of sulfate, chloride and fluorine complexes, the concentration of titanium, zirconium and hafnium elements ranges from 0.0001 to 1.5 mol / L, and the hydrogen ion concentration ranges from 0.1 to 10 mol / L.

[0011] The advantages and beneficial effects of the hydrophobic aminocarboxylic acid coordination system of titanium, zirconium and hafnium using the above-mentioned mineral are as follows:

[0012] The system of the present invention contains a hydrophobic ligand and a hydrophobic solvent. Titanium, zirconium or hafnium forms a complex with the hydrophobic ligand via a coordination bond or a feedback π bond. The complex dissolves in the hydrophobic solvent to form a stable hydrophobic solution. The stability of the hydrophobic complex varies depending on the process conditions of the hydrophobic ligand, the hydrophobic solvent and the aqueous solution of titanium, zirconium and hafnium. This difference is utilized to achieve the separation of titanium, zirconium and hafnium from each other.

[0013] The technical solution of the present invention is further described in detail below through examples. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is further illustrated by the following examples.

[0015] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0016] Unless otherwise defined, the reagents used in the present invention are commercially available.

[0017] A hydrophobic aminocarboxylic acid coordination system of titanium, zirconium and hafnium for comprehensive mineral utilization is disclosed. The coordination system is used to separate metallic titanium, zirconium and hafnium from ore sands. The system comprises a hydrophobic ligand, a hydrophobic solvent, and an aqueous solution of titanium, zirconium and hafnium. Titanium, zirconium or hafnium forms a complex with the hydrophobic ligand via a coordination bond or a feedback π bond. The complex effectively dissolves in the hydrophobic solvent to form a stable hydrophobic solution.

[0018] The hydrophobic ligand is a monoalkylaminodicarboxylic acid, a dialkylaminomonocarboxylic acid, or a dialkyldiaminodicarboxylic acid, wherein the alkyl group in the alkylaminocarboxylic acid is a linear or branched saturated or unsaturated alkyl group or aromatic hydrocarbon having 6 to 20 carbon atoms, and the carboxylic acid group is an acetic acid, propionic acid, or butyric acid group, such as hexadecylaminodiacetic acid, di-hexadecylaminoacetic acid, octadecylaminodipropionic acid, di-octadecylaminopropionic acid, dodecylaminodibutyric acid, and dodecylaminobutyric acid.

[0019] The hydrophobic ligand is a di-alkyldiaminodicarboxylic acid, wherein the alkyl group is a linear or branched saturated or unsaturated alkyl group or aromatic hydrocarbon having 6 to 20 carbon atoms, the alkyl group between the two amino groups has 2 to 6 carbon atoms and is a linear alkane, and the carboxylic acid group is an acetic acid, propionic acid, or butyric acid group, such as di-hexadecylpropanediaminodiacetic acid, di-hexadecylbutanediaminodipropionic acid, di-octadecylethylenediaminodiacetic acid, di-octadecylethylenediaminomalonic acid, didodecylpropanediaminodibutyric acid, and didodecylethylenediaminodibutyric acid.

[0020] The hydrophobic solvent is a hydrophobic straight-chain or branched alkane, alkene or substituted aromatic hydrocarbon, and the number of carbon atoms ranges from 8 to 20.

[0021] The aqueous solution of titanium, zirconium and hafnium is one or two of the complexes of sulfate, chloride and fluorine. The concentration range of titanium, zirconium and hafnium elements is 0.0001-1.5 mol / L, and the hydrogen ion concentration range is 0.1-10 mol / L.

[0022] Example 1

[0023] Mineral sand containing titanium, zirconium, and hafnium is leached with hydrochloric acid to produce a hydrochloric acid solution containing titanium, zirconium, and hafnium. This solution is used as the raw material for the comprehensive utilization of titanium, zirconium, and hafnium in a hydrochloric acid medium. The hydrochloric acid medium contains a hydrogen ion concentration of 1.3 mol / L, and titanium, zirconium, and hafnium ion concentrations of 1.05 g / L (0.02 mol / L), 29.13 g / L (0.3 mol / L), and 0.81 g / L (0.0046 mol / L), respectively. The hydrophobic ligand is di-hexadecylaminoacetic acid at a concentration of 1.3 mol / L, and the hydrophobic solvent is dodecylbenzene. The hydrochloric acid medium is thoroughly mixed with the hydrophobic solvent at a volume ratio of 2:1 at 50°C and allowed to stand for separation.

[0024] Analysis results showed that 98% of the titanium ions remained in the aqueous solution, while 99.5% of the zirconium and 99.2% of the hafnium were transferred to the hydrophobic solvent, achieving separation of the titanium from the zirconium and hafnium. The organic solvent was washed with a 2.5 mol / L hydrochloric acid solution, and nearly 100% of the titanium remaining in the organic solution was washed into the washing solution, with zirconium and hafnium losses of 3% and 1%, respectively. The zirconium and hafnium organic solutions, after washing with hydrochloric acid, were thoroughly mixed with 3 mol / L hydrochloric acid and allowed to stand for separation, yielding a hafnium oxychloride solution. 98% of the hafnium and 0.12% of the zirconium were transferred to the aqueous solution, achieving separation of the zirconium and hafnium.

[0025] Example 2

[0026] The hafnium oxychloride solution obtained in Example 1 was concentrated to obtain a chloride solution containing 20.43 g / L of hafnium and 0.88 g / L of zirconium, with a hydrogen ion concentration of 3.7 mol / L. This solution was extracted with a 1:1.5 volume ratio of 32% by volume solution of di-dodecylethylenediaminodipropionic acid in dodecylbenzene. 99.8% of the zirconium and 98.5% of the hafnium were transferred to an organic solvent. The organic phase was washed with a 1:1 volume ratio of 3 mol / L hydrochloric acid solution. The 94% hafnium and 0.02% zirconium were transferred to an aqueous solution, resulting in a hafnium concentration of 18.92 g / L and a zirconium concentration of 0.00018 g / L.

[0027] Example 3

[0028] Mineral sand containing titanium, zirconium, and hafnium is leached with sulfuric acid to produce a sulfuric acid solution containing titanium, zirconium, and hafnium. This solution is used as a raw material for the comprehensive utilization of titanium, zirconium, and hafnium in a sulfuric acid medium. The aqueous solution of titanium, zirconium, and hafnium in a sulfuric acid medium has a hydrogen ion concentration of 3 mol / L, and titanium, zirconium, and hafnium ion concentrations of 1.31 g / L (0.025 mol / L), 38.59 g / L (0.40 mol / L), and 1.09 g / L (0.0050 mol / L), respectively. The hydrophobic ligand is di-hexadecylaminoacetic acid at a concentration of 1.30 mol / L, and the hydrophobic solvent is dodecylbenzene. The aqueous solution of titanium, zirconium, and hafnium in a sulfuric acid medium is thoroughly mixed with the hydrophobic solvent at a volume ratio of 2:1 at 50°C and allowed to stand for separation.

[0029] Analysis results showed that 99.50% of the titanium ions remained in the aqueous solution, while 98.0% of the zirconium and 95.0% of the hafnium were transferred to the organic solvent, achieving separation of the titanium from the zirconium and hafnium. The organic solvent was washed with a 1.5 mol / L sulfuric acid solution, and nearly 100% of the titanium remaining in the organic solution was washed into the washing solution, with zirconium and hafnium losses of 10.0% and 6.0%, respectively. The organic zirconium and hafnium solutions, washed with sulfuric acid, were thoroughly mixed with 3 mol / L hydrochloric acid and allowed to stand for separation. 98% of the hafnium, with 0.02% of the zirconium entering the aqueous solution, was obtained as a hafnium oxychloride solution, achieving separation of zirconium and hafnium.

[0030] Example 4

[0031] The hafnium oxychloride solution obtained in Example 3 was concentrated to obtain a chloride solution containing 15.32 g / L of hafnium and 0.11 g / L of zirconium, with a hydrogen ion concentration of 3.5 mol / L. This solution was extracted with a 25% solution of di-dodecylethylenediaminodipropionic acid in dodecylbenzene at a volume ratio of 1.5:1. 96% of the zirconium and 97% of the hafnium were transferred to an organic solvent. The organic phase was washed with a 3 mol / L hydrochloric acid solution, and the 95% hafnium and 0.01% zirconium were transferred to an aqueous solution, resulting in a hafnium concentration of 14.12 g / L and a zirconium concentration of 0.000011 g / L.

[0032] Example 5

[0033] Mineral sand containing titanium, zirconium, and hafnium is leached with a sulfuric acid-hydrofluoric acid mixture to produce a sulfuric acid-hydrofluoric acid solution containing titanium, zirconium, and hafnium. This solution is used as a raw material for the comprehensive utilization of titanium, zirconium, and hafnium. The titanium, zirconium, and hafnium aqueous solutions in a sulfuric acid-fluoride medium have a hydrogen ion concentration of 0.3 mol / L, and titanium, zirconium, and hafnium ion concentrations of 2.05 (0.04 mol / L), 40.26 (0.44 mol / L), and 1.13 g / L (0.0063 mol / L), respectively. The hydrophobic ligand is di-hexadecylaminoacetic acid at a concentration of 1.3 mol / L, and the hydrophobic solvent is dodecylbenzene. The sulfuric acid-fluoride medium is thoroughly mixed at 50°C with the hydrophobic solvent in a volume ratio of 3.5:1, and then allowed to stand to separate.

[0034] Analysis results showed that 98% of the titanium ions remained in the aqueous solution, while 99.5% of the zirconium and 99.2% of the hafnium were transferred to the organic solvent, effectively separating the titanium from the zirconium and hafnium. The organic solvent was washed with a 2.5 mol / L hydrochloric acid solution, and nearly 99.5% of the titanium remaining in the organic solution was washed into the washing solution, with zirconium and hafnium losses of 3% and 1%, respectively. The organic zirconium and hafnium solutions, after washing with hydrochloric acid, were thoroughly mixed with 3 mol / L hydrochloric acid and allowed to stand for separation, yielding a hafnium oxychloride solution. 98% of the hafnium and 0.012% of the zirconium were transferred to the aqueous solution, effectively separating the zirconium and hafnium.

[0035] Example 6

[0036] The hafnium oxychloride solution obtained in Example 5 was concentrated to obtain a chloride solution containing 26.22 g / L of hafnium and 0.11 g / L of zirconium, with a hydrogen ion concentration of 3.5 mol / L. This solution was extracted with a solution of 25% by volume of di-dodecylethylenediaminodipropionic acid in isomeric tetradecanol and hexadecanol (a mixture of isomeric tetradecanol and isohexadecanol) in a 1.2:1 volume ratio. 96% of the zirconium and 97% of the hafnium were transferred to an organic solvent. The organic phase was washed with 4 mol / L hydrochloric acid in a 1:1 volume ratio. The 95% hafnium and 0.01% zirconium were then transferred to an aqueous solution, resulting in hafnium concentrations of 14.12 g / L and zirconium concentrations of 0.000011 g / L.

[0037] Therefore, the present invention adopts the above-mentioned mineral comprehensive utilization titanium zirconium hafnium hydrophobic aminocarboxylic acid coordination system, which can form a hydrophobic aminocarboxylic acid coordination system with different coordination stability with titanium, zirconium and hafnium. The system contains a hydrophobic ligand and a hydrophobic solvent that effectively dissolves these coordination compounds. The coordination system forms chelates of different stability with titanium, zirconium and hafnium, and then separates titanium, zirconium and hafnium from each other.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A hydrophobic aminocarboxylic acid coordination system of titanium, zirconium and hafnium for comprehensive mineral utilization, characterized by: The invention comprises an aqueous solution of a hydrophobic ligand, a hydrophobic solvent, titanium, zirconium and hafnium, wherein the titanium, zirconium or hafnium forms a complex with the hydrophobic ligand via a coordination bond or a feedback π bond, and the complex effectively dissolves in the hydrophobic solvent to form a stable hydrophobic solution; The hydrophobic ligand is one of di-alkylaminomonocarboxylic acid and di-alkyldiaminodicarboxylic acid, wherein the alkyl group in the alkylaminocarboxylic acid is a linear or branched saturated or unsaturated alkyl or aromatic hydrocarbon with 6 to 20 carbon atoms, and the carboxylic acid group is one of acetic acid, propionic acid, and butyric acid groups.

2. The hydrophobic aminocarboxylic acid coordination system of titanium, zirconium and hafnium for comprehensive mineral utilization according to claim 1, characterized in that: The hydrophobic ligand is a di-alkyldiaminodicarboxylic acid, wherein the alkyl group is a straight-chain or branched saturated or unsaturated alkyl group or aromatic hydrocarbon with 6-20 carbon atoms, the alkyl group between the two amino groups has 2-6 carbon atoms and is a straight-chain alkane, and the carboxylic acid group is one of acetic acid, propionic acid, and butyric acid groups.

3. The hydrophobic aminocarboxylic acid coordination system of titanium, zirconium and hafnium for comprehensive mineral utilization according to claim 1, characterized in that: The hydrophobic solvent is a hydrophobic straight-chain or branched alkane, alkene or substituted aromatic hydrocarbon, and the number of carbon atoms ranges from 8 to 20.

4. The hydrophobic aminocarboxylic acid coordination system of titanium, zirconium and hafnium for comprehensive mineral utilization according to claim 1, characterized in that: The aqueous solution of titanium, zirconium and hafnium is one or two of sulfate, chloride and fluorine complexes; the concentration of titanium, zirconium and hafnium elements ranges from 0.0001 to 1.5 mol / L; and the hydrogen ion concentration ranges from 0.1 to 10 mol / L.