Disclosure of Invention
In view of the problems in the prior art, the invention aims to provide a rare earth element adsorbent, and a preparation method and application thereof, and by improving the preparation method of the hydrotalcite-like adsorbent, a large amount of functional group hydrotalcite-like materials which can be applied to rare earth element recovery and purification can be prepared, so that the problems of low rare earth recovery efficiency, small equilibrium capacity, low extraction purity and the like of the adsorbent in the prior art are solved.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for preparing a rare earth element adsorbent, comprising the steps of:
(1) adding an auxiliary agent and a modifier into a solution containing divalent metal ions and trivalent metal ions to obtain an intermediate solution;
(2) and (2) carrying out modification reaction on the intermediate solution obtained in the step (1) to obtain the rare earth element adsorbent.
The preparation method provided by the invention takes metal ions as a main raw material, and is treated by a modifier rich in a specific functional group, so that a large amount of functional group hydrotalcite-like materials applied to rare earth element recovery and purification can be prepared, the adsorption balance is obviously improved, and the saturated adsorption capacity is between 0.5 and 5 g/g.
As a preferred technical solution of the present invention, the divalent metal ions in step (1) include 1 or a combination of at least 2 of divalent magnesium ions, divalent cobalt ions, ferrous ions, divalent nickel ions, divalent copper ions, divalent manganese ions, or divalent zinc ions. The combination may be a combination of divalent magnesium ions and divalent cobalt ions, a combination of divalent ferrous ions and divalent nickel ions, or a combination of divalent copper ions and divalent zinc ions, and the like, but is not limited to the listed combinations, and other combinations not listed in this range are also applicable.
Preferably, the trivalent metal ions of step (1) include 1 or a combination of at least 2 of trivalent aluminum ions, trivalent iron ions, trivalent manganese ions, trivalent chromium ions, or trivalent indium ions. The combination may be a combination of trivalent aluminum ions and trivalent iron ions, a combination of trivalent manganese ions and trivalent chromium ions, a combination of trivalent iron ions and trivalent silver ions, or the like, but is not limited to the listed combinations, and other combinations not listed in this range are also applicable.
In a preferred embodiment of the present invention, the molar ratio of the divalent metal element to the trivalent metal element in the solution in step (1) is 1 (0.3-3), and may be, for example, 1:0.3, 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8 or 1:3, but is not limited to the above-mentioned values, and other values not listed in this range are also applicable.
As a preferred technical scheme of the invention, the auxiliary agent in the step (1) comprises 1 or at least 2 of sodium hydroxide, sodium carbonate, melamine or urea. The combination may be a combination of sodium hydroxide and sodium carbonate, a combination of sodium carbonate and melamine or a combination of melamine and urea, etc., but is not limited to the listed combinations, and other combinations not listed within the scope are equally applicable.
In a preferred embodiment of the present invention, the amount of the auxiliary agent added in step (1) is 1 to 100% by mass of the divalent metal ion in the solution, and may be, for example, 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or the like, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.
As a preferred embodiment of the present invention, the modifying agent in step (1) comprises 1 or a combination of at least 2 of compounds containing at least 1 of hydroxyl, carboxyl, carbonyl, amino, imino, thio or sulfo. The combination may be a combination of a hydroxyl group and a carboxyl group, a combination of a carbonyl group and an amino group, a combination of an imino group and a mercapto group, or a combination of an amino group and a sulfo group, and the like, but is not limited to the listed combinations, and other combinations not listed in this range are also applicable.
In the present invention, the modifier includes a compound containing at least 1 of a hydroxyl group, a carboxyl group, a carbonyl group, an amino group, an imino group, a mercapto group, or a sulfo group, and may be an alcohol, a carboxylic acid, a sulfide, or a nitride.
The alcohols contain hydroxyl groups as much as possible and are liquid at normal temperature, such as methanol, ethanol or propanol.
The carboxylic acids should contain as many carboxyl groups as possible and should be liquid or solid at ordinary temperature, such as formic acid, acetic acid or oxalic acid.
The sulfide has oxidizing property, and is liquid or solid at normal temperature, such as sulfonate, sodium sulfamate, mercaptan, phenol sulfhydrate or benzene sulfonic acid.
The nitride has oxidizing property, and is liquid or solid at normal temperature, such as amino acid or imino acid.
As a preferred technical scheme of the invention, the modifier in the step (1) comprises a liquid modifier and/or a solid modifier.
Preferably, the modifying agent in step (1) is a liquid modifying agent, and the amount of the liquid modifying agent added is 1 to 30% of the mass of water in the solution, and may be, for example, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or 30%, and the like, but is not limited to the recited values, and other values not recited in the range are also applicable.
Preferably, the modifying agent in step (1) is a solid modifying agent, and the amount of the solid modifying agent added is 1-10% of the mass of water in the solution, and may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the recited values, and other values not recited in this range are also applicable.
Preferably, the modification reaction of step (2) is carried out in a reaction kettle.
Preferably, the volume of the solution in the reaction vessel in the modification reaction in step (2) is 50 to 70% of the volume of the reaction vessel, for example, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, or 70%, etc., but is not limited to the values listed, and other values not listed in this range are also applicable.
Preferably, the modification reaction in step (2) reaction temperature is 90-150 ℃, for example can be 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees or 150 degrees C, but not limited to the enumerated values, in the range of other values are also applicable.
Preferably, the modification reaction in step (2) is carried out for 2 to 8 hours, such as 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours, but not limited to the recited values, and other values not recited in the range are also applicable.
As a preferred technical scheme of the invention, the preparation method comprises the following steps:
(1) adding an auxiliary agent and a modifier into a solution containing divalent metal ions and trivalent metal ions to obtain an intermediate solution;
(2) carrying out modification reaction on the intermediate solution obtained in the step (1) to obtain the rare earth element adsorbent;
the modifier in the step (1) comprises 1 or the combination of at least 2 of compounds containing hydroxyl, carboxyl, carbonyl, amino, imino, sulfhydryl or sulfo, the modifier comprises a liquid modifier and/or a solid modifier, the modifier is a liquid modifier, the addition amount of the liquid modifier is 1-30% of the mass of water in the solution, the modifier is a solid modifier, and the addition amount of the solid modifier is 1-10% of the mass of water in the solution; the reaction temperature of the modification reaction is 90-150 ℃.
In a second aspect, the present invention provides the rare earth element adsorbent prepared by the method of the first method, wherein the adsorbent is a hydrotalcite-like adsorbent.
In a third aspect, the present invention provides the use of an adsorbent for a rare earth element, the use comprising adsorbing a solution containing a rare earth element with the adsorbent of the second aspect.
Preferably, the addition amount of the adsorbent and the liquid-solid ratio g/L of the rare earth element-containing solution are (0.5-1):1, and may be, for example, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1, but not limited to the values listed, and other values not listed in this range are also applicable.
Preferably, the pH of the rare earth element-containing solution is 2 to 13, and may be, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or the like, but is not limited to the recited values, and other values not recited in this range are also applicable, preferably 5 to 9.
Preferably, the rare earth element in the rare earth element-containing solution includes 1 or a combination of at least 2 of La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Sc, or Y. The combination may be a combination of La and Ce, a combination of Pr and Nd, a combination of Eu and Tb, a combination of Dy and Ho, or a combination of Tm and Sc, etc., but is not limited to the combinations enumerated, and other combinations not enumerated within this range are also applicable.
The mechanism of adsorbing, recovering and purifying the rare earth elements in the solution by the hydrotalcite-like adsorbent mainly relates to the following steps: electrostatic interaction, chelation and ion exchange, and the modified ion pairs or electron pairs can be used for adsorbing rare earth elements in the solution, and can be desorbed by low-concentration alkali liquor (such as 0.1-0.5M sodium hydroxide solution or potassium hydroxide solution) to recover the adsorbed elements.
Compared with the prior art, the invention at least has the following beneficial effects:
(1) the preparation method provided by the invention takes metal ions as a main raw material, and is modified by a modifier rich in a specific functional group, so that a large amount of functional group hydrotalcite-like material applied to rare earth element recovery and purification can be prepared, the adsorption equilibrium capacity is large, the equilibrium capacity is 0.5-5g/g, the recovery efficiency of rare earth is more than 98%, and the purity of desorption solution after desorption is as high as 99.9%.
(2) The hydrotalcite-like adsorbent prepared by the preparation method provided by the invention has the material morphology of sheet, lamellar, petal-shaped, sea urchin-like and the like, and the size is 0.1-10 mu m; the method has the advantages of wide application range, suitability for a slightly acidic environment, suitability for a neutral or alkaline environment, simple process and flow, short reaction time, wide parameter adjustable range and strong repeatability, and is beneficial to realizing industrial production.
Detailed Description
To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:
example 1
The embodiment provides a rare earth element adsorbent, which is prepared by the following method:
adding Mn (NO)3)2·6H2O、Al(NO3)3·9H2And preparing the O into a mixed solution according to the molar ratio of Mn to Al of 2: 1. Respectively reacting pentanediol and Na2CO3Adding into the mixed solution to obtain intermediate solution, wherein the addition amount of pentanediol is 10% of the water mass in the mixed solution, and Na2CO3The addition amount of Mn (NO)3)2·6H210% of the mass of O. Transferring the intermediate liquid into a high-pressure reaction kettle, carrying out modification synthesis reaction for 8 hours at 120 ℃, wherein the volume of the intermediate liquid accounts for 60% of the volume of the high-pressure reaction kettle, naturally cooling, filtering and drying the product to obtain the hydroxylated hydrotalcite-like adsorbent, wherein an SEM photograph is shown in figure 1, and the saturated adsorption capacity of the product to samarium ions is detailed in table 1.
Example 2
The embodiment provides a rare earth element adsorbent, which is prepared by the following method:
adding Mn (NO)3)2·6H2O、Mg(NO3)2·6H2O、Al(NO3)3·9H2And preparing the O into a mixed solution according to the molar ratio of Mn to Mg to Al of 1:1: 1. Respectively adding sodium sulfamate and urea into the mixed solution to obtain intermediate solution, wherein the addition amount of the sodium sulfamate is 3% of the mass of water in the mixed solution, and the addition amount of the urea is Mn (NO)3)2·6H2O and Mg (NO)3)2·6H250% of the total mass of O. Transferring the intermediate liquid into a high-pressure reaction kettle, performing modification synthesis reaction at 120 ℃ for 8 hours, wherein the volume of the intermediate liquid accounts for 60 percent of the volume of the high-pressure reaction kettle, naturally cooling, filtering and drying the product to obtain the sulfydrylThe saturated adsorption capacity of the base hydrotalcite-like adsorbent to samarium ions is detailed in table 1.
Example 3
The embodiment provides a rare earth element adsorbent, which is prepared by the following method:
adding Mn (NO)3)2·6H2O、Mg(NO3)2·6H2O、Al(NO3)3·9H2O、Fe(NO3)3·9H2And preparing the O into a mixed solution according to the molar ratio of Mn to Mg to Al to Fe of 2:2:1: 1. Respectively mixing glycerol, sodium sulfamate and Na2CO3Adding urea into the mixed solution to obtain an intermediate solution, wherein the addition amounts of glycerol and sodium sulfamate are respectively 5% and 2% of the mass of water in the mixed solution, and Na2CO3And urea in an amount of Mn (NO)3)2·6H2O and Mg (NO)3)2·6H25% and 25% of the total mass of O. Transferring the intermediate liquid into a high-pressure reaction kettle, carrying out modification synthesis reaction for 8 hours at 120 ℃, wherein the volume of the intermediate liquid accounts for 60% of the volume of the high-pressure reaction kettle, naturally cooling, filtering and drying the product to obtain the hydroxyl sulfhydrylation hydrotalcite-like adsorbent, and the saturated adsorption capacity to samarium ions is detailed in table 1.
Comparative example 1
The difference from example 1 is that no auxiliary agent or modifier is added, and after natural cooling, almost no product is produced, and hydroxylated hydrotalcite is not obtained.
Comparative example 2
The difference from example 1 is only that the molar ratio of the divalent metal element to the trivalent metal element in the solution is 20:1, and after natural cooling, almost no product is produced, and hydroxylated hydrotalcite-like compound cannot be obtained.
Comparative example 3
The difference from example 2 is that no modifier is added to obtain hydrotalcite-like adsorbent, and the SEM photograph is shown in FIG. 2.
Comparative example 4
The only difference from example 3 is that the temperature of the modification reaction was 60 ℃ to obtain a small amount of the hydroxysulfylated hydrotalcite-like compound.
Comparative example 5
The difference from example 1 is only that no auxiliary agent is added, and a small amount of hydrotalcite-like adsorbent is obtained.
Application example 1
0.5g of the adsorbents obtained in examples 1 to 3 and comparative examples 3 to 5 was added to a samarium ion solution having a pH of 7 and a concentration of 100mg/L to adsorb the samarium ions, and after the adsorption was completed, 0.1moL/L of sodium hydroxide solution was used to desorb the samarium ions, and the desorption results of the adsorption alloys are shown in table 1.
TABLE 1
|
Saturated adsorption capacity g/g
|
Percent recovery%
|
Purity of the analysis solution/%)
|
Analysis rate/%
|
Example 1
|
0.5
|
90
|
99.9
|
99.9
|
Example 2
|
0.8
|
98
|
99.9
|
99.9
|
Example 3
|
1.5
|
99
|
99.9
|
99.9
|
Comparative example 3
|
0.1
|
30
|
90
|
90
|
Comparative example 4
|
0.1
|
30
|
90
|
90
|
Comparative example 5
|
0.1
|
30
|
90
|
90 |
The results of the above examples and comparative examples show that a large amount of functional group hydrotalcite-like materials applied to rare earth element recovery and purification can be prepared by improving the preparation method of the hydrotalcite-like adsorbent, and the problems of low rare earth recovery efficiency, small equilibrium capacity, low extraction purity and the like of the adsorbent in the prior art are solved.
The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, additions of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.