Preparation method of high-purity zirconium fluoride

Abstract

The invention discloses a preparation method of high-purity zirconium fluoride, which comprises the following steps: step S1, dissolving: dissolving a zirconium-containing substance with hydrofluoric acid according to a solid-to-liquid ratio of 1: 4 to 1: 10, after the zirconium-containing substance is dissolved, adding pure water to obtain a zirconium-containing solution, and forming a zirconium fluoride solution when the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100g / L; s2, impurity removal: introducing the zirconium-containing solution into a resin tower, and carrying out ion exchange adsorption; s3, concentration: performing electrodialysis concentration on the purified zirconium-containing solution through an electrodialyzer; step S4, freeze drying: carrying out primary drying on the concentrated zirconium-containing solution through freeze drying; and S5, high-temperature drying: performing high-temperature drying on the freeze-dried materials, and performing crushing and granulation. The preparation method of the high-purity zirconium fluoride is good in purification effect.

Description

Technical Field

[0001] The invention relates to the technical field of zirconium fluoride purification, and in particular to a method for preparing high-purity zirconium fluoride. Background Art

[0002] High-purity zirconium fluoride is an important raw material for preparing high-power mid-infrared optical fiber. The purity of zirconium fluoride affects the infrared transmittance of the optical fiber. The hydroxyl (OH) impurities contained in zirconium fluoride have a strong absorbance in the infrared region, which has a particularly significant impact on the quality of the optical fiber. Zirconium is easy to deliquesce and has a strong ability to absorb and complex oxygen. It is easy to form various forms of zirconium oxygen fluoride complexes (ZrF 3 OH, etc.). At present, high-purity zirconium fluoride is mainly prepared by ammonium fluorozirconate decomposition method, hydrated zirconium tetrafluoride dehydration method, and zirconium dioxide fluorination method, and the oxygen content limit of the product is 100ppm.

[0003] Molten salt energy storage technology uses molten salt and other raw materials as heat transfer media. It is generally combined with a solar thermal power generation system to enable the solar thermal power generation system to have energy storage and nighttime power generation capabilities to meet the peak load needs of the power grid. According to different thermal energy storage methods, solar high-temperature energy storage technology can be divided into sensible heat storage, latent heat storage and hybrid energy storage. Molten salt has high requirements for the content of anions and metal ions, among which the metal ion content is less than 100ppm and the anion content is less than 100ppm. However, it is difficult to achieve this with current purification methods. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing high-purity zirconium fluoride.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0006] A method for preparing high-purity zirconium fluoride comprises the following steps:

[0007] Step S1, dissolving: dissolving the zirconium-containing substance by hydrofluoric acid, wherein the solid-liquid ratio of the hydrofluoric acid is 1:4 to 1:10, and after the zirconium-containing substance is dissolved, adding pure water to obtain a zirconium-containing solution, wherein the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100 g / L, thereby forming a zirconium fluoride solution;

[0008] Step S2, impurity removal: passing the zirconium-containing solution into a resin tower for ion exchange adsorption;

[0009] Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer;

[0010] Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying;

[0011] Step S5, high temperature drying: the freeze-dried product is dried at high temperature and then crushed and granulated.

[0012] As a further improvement of the above technical solution:

[0013] Preferably, the zirconium-containing material is sponge zirconium.

[0014] Preferably, the zirconium sponge is 0.5-5 g, and the mass fraction of the hydrofluoric acid is 20%-45%.

[0015] Preferably, after the hydrofluoric acid and the zirconium-containing substance are mixed, they are left to stand for 72 hours, and the temperature during dissolution is 35°C.

[0016] Preferably, in step S2, the flow rate of the impurity-containing zirconium solution is 2 to 30 BV / h.

[0017] Preferably, in step S2, the pH value of the impurity-containing zirconium solution is adjusted to 3.

[0018] Preferably, in step S3, the feed flow rate of the zirconium-containing solution during the electrodialysis process is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm 2 .

[0019] Preferably, after drying, the content of alkali metal ions is less than 500 ppm, and the content of other metal ions is less than 150 ppm.

[0020] The method for preparing high-purity zirconium fluoride provided by the present invention has the following advantages compared with the prior art:

[0021] The preparation method of high-purity zirconium fluoride of the present invention dissolves zirconium-containing substances by hydrofluoric acid, has strong oxidizing and dehydrating properties, and zirconium can be more stable under acidic conditions to avoid hydrolysis to Zr(OH)4 precipitation. In addition, the present invention adopts electrodialysis concentration, and by monitoring the conductivity of the concentration chamber or sampling and analyzing the zirconium concentration, it can achieve 5 to 10 times of concentration after concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram of XRD analysis of the finished product in Example 2 of the present invention.

[0023] Figure 2 This is a diagram of XRD analysis of the finished product in Example 3 of the present invention.

[0024] Figure 3 This is a diagram of XRD analysis of the finished product in Example 4 of the present invention. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0026] Example 1

[0027] The method for preparing high-purity zirconium fluoride of this embodiment comprises the following steps:

[0028] Step S1, dissolving: dissolving the zirconium sponge by hydrofluoric acid, the solid-liquid ratio of hydrofluoric acid is 1:4, the zirconium sponge is 1g, the mass fraction of hydrofluoric acid is 20%, after the zirconium-containing substance is dissolved, pure water is added to obtain a zirconium-containing solution, the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100g / L, and a zirconium fluoride solution is formed; standing for 72 minutes, and maintaining the temperature at 35°C during dissolution.

[0029] Step S2, impurity removal: adjust the pH value of the zirconium-containing solution containing impurities to 3, pass the zirconium-containing solution into a resin tower, and perform separation. Ion exchange adsorption; the flow rate of the impurity-containing zirconium solution is 2 to 30 BV / h.

[0030] Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer; during the electrodialysis process, the feed flow rate of the zirconium-containing solution is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm 2 .

[0031] Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying.

[0032] Step S5, high temperature drying: the freeze-dried product is crushed and granulated after high temperature drying. After drying, the single ion content of alkali metal ions is less than 500ppm, and the single ion content of other metal ions does not exceed 150ppm.

[0033] Example 2

[0034] The method for preparing high-purity zirconium fluoride of this embodiment comprises the following steps:

[0035] Step S1, dissolving: dissolving the zirconium sponge by hydrofluoric acid, the solid-liquid ratio of hydrofluoric acid is 1:7, the zirconium sponge is 1g, the mass fraction of hydrofluoric acid is 25%, after the zirconium-containing substance is dissolved, pure water is added to obtain a zirconium-containing solution, the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100g / L, and a zirconium fluoride solution is formed; standing for 72 minutes, and maintaining the temperature at 35°C during dissolution.

[0036] Step S2, impurity removal: adjusting the pH value of the impurity-containing zirconium solution to 3, passing the zirconium-containing solution into a resin tower for ion exchange adsorption; the flow rate of the impurity-containing zirconium solution is 2 to 30 BV / h.

[0037] Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer; during the electrodialysis process, the feed flow rate of the zirconium-containing solution is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm2 .

[0038] Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying.

[0039] Step S5, high temperature drying: the freeze-dried product is crushed and granulated after high temperature drying. After drying, the single ion content of alkali metal ions is less than 500ppm, and the single ion content of other metal ions does not exceed 150ppm.

[0040] like Figure 1 As shown, XRD analysis of the dried finished product shows that pentafluorozirconic acid hydrate has the highest content.

[0041] Example 3

[0042] The method for preparing high-purity zirconium fluoride of this embodiment comprises the following steps:

[0043] Step S1, dissolving: dissolving the zirconium sponge by hydrofluoric acid, the solid-liquid ratio of hydrofluoric acid is 1:6, the zirconium sponge is 1g, the mass fraction of hydrofluoric acid is 30%, after the zirconium-containing substance is dissolved, pure water is added to obtain a zirconium-containing solution, the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100g / L, and a zirconium fluoride solution is formed; standing for 72 minutes, and maintaining the temperature at 35°C during dissolution.

[0044] Step S2, impurity removal: adjusting the pH value of the impurity-containing zirconium solution to 3, passing the zirconium-containing solution into a resin tower for ion exchange adsorption; the flow rate of the impurity-containing zirconium solution is 2 to 30 BV / h.

[0045] Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer; during the electrodialysis process, the feed flow rate of the zirconium-containing solution is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm 2 .

[0046] Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying.

[0047] Step S5, high temperature drying: the freeze-dried product is crushed and granulated after high temperature drying. After drying, the single ion content of alkali metal ions is less than 500ppm, and the single ion content of other metal ions does not exceed 150ppm.

[0048] like Figure 2 As shown, XRD analysis of the dried finished product shows that pentafluorozirconic acid hydrate has the highest content.

[0049] Example 4

[0050] The method for preparing high-purity zirconium fluoride of this embodiment comprises the following steps:

[0051] Step S1, dissolving: dissolving the zirconium sponge by hydrofluoric acid, the solid-liquid ratio of hydrofluoric acid is 1:5, the zirconium sponge is 1g, the mass fraction of hydrofluoric acid is 35%, after the zirconium-containing substance is dissolved, pure water is added to obtain a zirconium-containing solution, the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100g / L, and a zirconium fluoride solution is formed; standing for 72 minutes, and maintaining the temperature at 35°C during dissolution.

[0052] Step S2, impurity removal: adjusting the pH value of the impurity-containing zirconium solution to 3, passing the zirconium-containing solution into a resin tower for ion exchange adsorption; the flow rate of the impurity-containing zirconium solution is 2 to 30 BV / h.

[0053] Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer; during the electrodialysis process, the feed flow rate of the zirconium-containing solution is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm 2 .

[0054] Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying.

[0055] Step S5, high temperature drying: the freeze-dried product is crushed and granulated after high temperature drying. After drying, the single ion content of alkali metal ions is less than 500ppm, and the single ion content of other metal ions does not exceed 150ppm.

[0056] like Figure 3 As shown, XRD analysis of the dried finished product shows that pentafluorozirconic acid hydrate has the highest content.

[0057] Example 5

[0058] The method for preparing high-purity zirconium fluoride of this embodiment comprises the following steps:

[0059] Step S1, dissolving: dissolving the zirconium sponge by hydrofluoric acid, the solid-liquid ratio of the hydrofluoric acid is 1:4 to 1:10, the zirconium sponge is 1g, the mass fraction of the hydrofluoric acid is 40%, after the zirconium-containing substance is dissolved, pure water is added to obtain a zirconium-containing solution, the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100g / L, and a zirconium fluoride solution is formed; standing for 72 minutes, and maintaining the temperature at 35°C during dissolution.

[0060] Step S2, impurity removal: adjusting the pH value of the impurity-containing zirconium solution to 3, passing the zirconium-containing solution into a resin tower for ion exchange adsorption; the flow rate of the impurity-containing zirconium solution is 2 to 30 BV / h.

[0061] Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer; during the electrodialysis process, the feed flow rate of the zirconium-containing solution is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm 2 .

[0062] Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying.

[0063] Step S5, high temperature drying: the freeze-dried product is crushed and granulated after high temperature drying. After drying, the single ion content of alkali metal ions is less than 500ppm, and the single ion content of other metal ions does not exceed 150ppm.

[0064] Example 6

[0065] The method for preparing high-purity zirconium fluoride of this embodiment comprises the following steps:

[0066] Step S1, dissolving: dissolving the zirconium sponge by hydrofluoric acid, the solid-liquid ratio of the hydrofluoric acid is 1:4 to 1:10, the zirconium sponge is 1g, the mass fraction of the hydrofluoric acid is 45%, after the zirconium-containing substance is dissolved, pure water is added to obtain a zirconium-containing solution, the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100g / L, and a zirconium fluoride solution is formed; standing for 72 minutes, and maintaining the temperature at 35°C during dissolution.

[0067] Step S2, impurity removal: adjusting the pH value of the impurity-containing zirconium solution to 3, passing the zirconium-containing solution into a resin tower for ion exchange adsorption; the flow rate of the impurity-containing zirconium solution is 2 to 30 BV / h.

[0068] Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer; during the electrodialysis process, the feed flow rate of the zirconium-containing solution is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm 2 .

[0069] Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying.

[0070] Step S5, high temperature drying: the freeze-dried product is crushed and granulated after high temperature drying. After drying, the single ion content of alkali metal ions is less than 500ppm, and the single ion content of other metal ions does not exceed 150ppm.

[0071] In Examples 1-6, the states of the solutions under different solid-liquid ratios and different mass fractions of hydrofluoric acid are shown in Table 1.

[0072] Table 1 Solution state record under different solid-liquid ratios and different mass fractions of hydrofluoric acid

[0073]

[0074]

[0075] The above implementation cases are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, they are not intended to limit the present invention. Therefore, any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing high-purity zirconium fluoride, characterized in that: The following steps are involved: Step S1, dissolving: dissolving the zirconium-containing substance by hydrofluoric acid, wherein the solid-liquid ratio of the hydrofluoric acid is 1:4 to 1:10, and after the zirconium-containing substance is dissolved, adding pure water to obtain a zirconium-containing solution, wherein the mass content of zirconium fluoride in the zirconium-containing solution is greater than 100 g / L, thereby forming a zirconium fluoride solution; Step S2, impurity removal: passing the zirconium-containing solution into a resin tower for ion exchange adsorption; Step S3, concentration: the purified zirconium-containing solution is concentrated by electrodialysis through an electrodialyzer; Step S4, freeze drying: the concentrated zirconium-containing solution is preliminarily dried by freeze drying; Step S5, high temperature drying: the freeze-dried product is dried at high temperature and then crushed and granulated.

2. The method for preparing high-purity zirconium fluoride according to claim 1, characterized in that: The zirconium-containing material is zirconium sponge.

3. The method for preparing high-purity zirconium fluoride according to claim 1, characterized in that: The zirconium sponge is 0.5-5 g, and the mass fraction of the hydrofluoric acid is 20%-45%.

4. The method for preparing high-purity zirconium fluoride according to claim 3, characterized in that: After the hydrofluoric acid and the zirconium-containing substance are mixed, they are left to stand for 72 hours, and the temperature during the dissolution is 35°C.

5. The method for preparing high-purity zirconium fluoride according to claim 4, characterized in that: In the step S2, the flow rate of the zirconium-containing solution containing impurities is 2 to 30 BV / h.

6. The method for preparing high-purity zirconium fluoride according to claim 4, characterized in that: In the step S2, the pH value of the zirconium-containing solution containing impurities is adjusted to 3.

7. The method for preparing high-purity zirconium fluoride according to claim 4, characterized in that: In step S3, the feed flow rate of the zirconium-containing solution during the electrodialysis process is 2-5 cm / s, the solution temperature is 25-40°C, and the current density is 10-50 mA / cm 2 .

8. The method for preparing high-purity zirconium fluoride according to claim 4, characterized in that: After drying, the content of alkali metal ions is less than 500 ppm, and the content of other metal ions is less than 150 ppm.

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