High-temperature-resistant and High-stability Ion Sieve and Preparation Method and Application thereof

Abstract

A high-temperature-resistant and high-stability ion sieve and a preparation method and application thereof are provided. Based on a molar percentage of each oxide in the ion sieve, a composition of the ion sieve includes: SiO.sub.2: 46-60 mol %, Al.sub.2O.sub.3: 3-16 mol %, Y.sub.2O.sub.3: 0-3 mol %, and R.sub.2O: 33-45 mol %, where R.sub.2O is an alkali metal oxide; and the ion sieve satisfies: S.sub.Q.sub.3/S.sub.Q.sub.2 is not lower than 1.

Claims

1. A high-temperature-resistant and high-stability ion sieve, comprising, based on a molar percentage of each oxide in the ion sieve, a composition of: SiO.sub.2: 46-60 mol %, Al.sub.2O.sub.3: 3-16 mol %, Y.sub.2O.sub.3: 0-3 mol %, and R.sub.2O: 33-45 mol %, where R.sub.2O is an alkali metal oxide; and the ion sieve satisfies: S.sub.Q.sub.3/S.sub.Q.sub.2 is not lower than 1, where S.sub.Q.sub.3 is an area corresponding to Q.sup.3 after Gaussian deconvolution fitting is performed on a spectrum band within a range of 830-1230 cm.sup.1 in a Raman spectrum of the ion sieve, and Q.sup.3 is an SiO.sup. stretching vibration peak in a silicon-oxygen tetrahedron with only one non-bridging oxygen; S.sub.Q.sub.2 is an area corresponding to Q.sup.2 after Gaussian deconvolution fitting is performed on a spectrum band within the range of 830-1230 cm.sup.1 in the Raman spectrum of the ion sieve, and Q.sup.2 is an SiO.sup. stretching vibration peak in a silicon-oxygen tetrahedron with only two non-bridging oxygens.

2. The ion sieve according to claim 1, wherein a crystal content in the ion sieve is less than 10 wt % after the ion sieve is placed in a 480 C. salt bath for 24 h.

3. The ion sieve according to claim 1, wherein 3S.sub.Q.sub.3/S.sub.Q.sub.21.

4. The ion sieve according to claim 1, wherein the composition of the ion sieve satisfies: 52.00.85SiO.sub.2+0.15Al.sub.2O.sub.3+1.65Y.sub.2O.sub.345.3, based on the molar percentage of each oxide in the ion sieve.

5. The ion sieve according to claim 4, wherein the composition of the ion sieve further satisfies: 20.00.50R.sub.2O16.0, based on the molar percentage of each oxide in the ion sieve, where R.sub.2O is Na.sub.2O and/or K.sub.2O, and optionally, R.sub.2O is Na.sub.2O.

6. The ion sieve according claim 1, wherein in the ion sieve, the molar percentage of SiO.sub.2 is 49-60 mol %; and/or the molar percentage of Al.sub.2O.sub.3 is 3-15 mol %; and/or the molar percentage of Y.sub.2O.sub.3 is 1-3 mol %; and/or the molar percentage of R.sub.2O is 33-40 mol %.

7. The ion sieve according to claim 1, further comprising, based on the molar percentage of each oxide in the ion sieve, the composition of: ZnO: 0-3 mol %, CaO: 0-3 mol %, MgO: 0-3 mol %, P.sub.2O.sub.5: 0-3 mol %, B.sub.2O.sub.3: 0-3 mol %, wherein a sum of the molar percentages of ZnO+CaO+MgO+P.sub.2O.sub.5+B.sub.2O.sub.3 does not exceed 5 mol %.

8. The ion sieve according to claim 7, wherein the ion sieve is substantially free of P.sub.2O.sub.5 and/or B.sub.2O.sub.3.

9. The ion sieve according to claim 1, wherein based on a mass of the salt bath, the ion sieve in a mass proportion of 1 wt % is added to a 480 C. salt bath containing 10510 ppm impurity lithium ions; and a curve of change of lithium ion concentration y in the salt bath over time x satisfies a function of: y=A.sub.1exp(x/b.sub.1)+A.sub.2exp(x/b.sub.2)+C.sub.0, where exp is an exponential function, and 100>A.sub.1>30, 0<A.sub.2<31, 0<b.sub.1<5, 0<b.sub.2<25, 0<C.sub.0<50, and unit of x is h.

10. The ion sieve according to claim 1, wherein the ion sieve is granular, sheet-shaped or porous, optionally granular, and optionally a granular ion sieve has a particle size of 1-10 mm.

11. A method for preparing the ion sieve according to claim 1, comprising steps of: taking various raw materials according to a formula and mixing the same uniformly, then performing melting at 1300-1650 C., so as to obtain a liquid material; and then making the liquid material granular, sheet-shaped or porous.

12. The preparation method according to 11, wherein a granular ion sieve is formed by water quenching, wherein a temperature of the water quenching is 10-80 C.

13. The preparation method according to 11, wherein a sheet-shaped ion sieve is made by rolling or drawing with an external force.

14. The preparation method according to 11, wherein a porous ion sieve is made by feeding a blowing agent.

15. A purification method of a salt bath for glass chemical strengthening, comprising steps of: introducing the ion sieve according to claim 1 into a to-be-purified salt bath at 350-550 C., so as to perform an adsorption reaction of an impurity ion.

16. The purification method according to claim 15, wherein a usage amount of the ion sieve is 0.5-5.0 wt % of the to-be-purified salt bath, and/or a duration of the adsorption reaction is 0.1-48.0 h.

17. The purification method according to claim 16, wherein an impurity ion content in the to-be-purified salt bath is 1-1000 ppm.

18. (canceled)

19. The ion sieve according to claim 2, wherein 3S.sub.Q.sub.3/S.sub.Q.sub.21.

20. The ion sieve according to claim 2, wherein the composition of the ion sieve satisfies: 52.00.85SiO.sub.2+0.15Al.sub.2O.sub.3+1.65Y.sub.2O.sub.345.3, based on the molar percentage of each oxide in the ion sieve

21. The ion sieve according to claim 3, wherein the composition of the ion sieve satisfies: 52.00.85SiO.sub.2+0.15Al.sub.2O.sub.3+1.65Y.sub.2O.sub.345.3, based on the molar percentage of each oxide in the ion sieve.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate technical solutions of embodiments of the present disclosure, drawings which need to be used in the embodiments will be introduced briefly below, and it should be understood that the drawings below merely show some embodiments of the present disclosure, therefore, they should not be considered as limitation to the scope, and a person ordinarily skilled in the art still could obtain other relevant drawings according to these drawings, without using any inventive efforts.

[0040] FIG. 1a is an initial XRD pattern of ion sieves of Example 1-4;

[0041] FIG. 1b is an initial XRD pattern of ion sieves of Comparative Example 1-4.

[0042] FIG. 2a is an XRD pattern of the ion sieves of Examples 1-4 after absorbing lithium ions in a 480 C. test salt bath for 24 h;

[0043] FIG. 2b is an XRD pattern of the ion sieves of Comparative Examples 1-4 after absorbing lithium ions in a 480 C. test salt bath for 24 h.

[0044] FIG. 3a is a chart of changing trend of lithium ion concentration of the ion sieves of Examples 1-4 in a 480 C. test salt bath over time;

[0045] FIG. 3b is a chart of changing trend of lithium ion concentration of the ion sieves of Comparative Examples 1-4 in a 480 C. test salt bath over time;

[0046] FIG. 4 is a fitting result chart of the changing trend of the lithium ion concentration of Example 1 over time.

[0047] FIG. 5 is a fitting result chart of the changing trend of the lithium ion concentration of Example 2 over time.

[0048] FIG. 6 is a fitting result chart of the changing trend of the lithium ion concentration of Example 3 over time.

[0049] FIG. 7 is a fitting result chart of the changing trend of the lithium ion concentration of Example 4 over time.

[0050] FIG. 8 is a picture of a surface of a finished product of the strengthened glass obtained after the ion sieve of Example 1 directly participates in a chemical strengthening process.

[0051] FIG. 9 is a picture of a surface of a finished product of the strengthened glass obtained after the ion sieve of Comparative Example 1 directly participates in a chemical strengthening process.

[0052] FIG. 10 is a picture of a surface of a finished product of the strengthened glass obtained after the ion sieve of Comparative Example 2 directly participates in a chemical strengthening process.

DETAILED DESCRIPTION OF EMBODIMENTS

[0053] Endpoints and any values of ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to contain values proximate to those ranges or values. For numerical ranges, one or more new numerical ranges can be obtained by combining endpoint values of various ranges, endpoint values and individual point values of various ranges, and individual point values with each other, and these numerical ranges should be considered as being specifically disclosed herein. The terms optional and optionally both mean possibly including or not (or possibly being present or possibly being not present).

[0054] Corresponding test methods involved in the present disclosure are as follows:

1. Ion Sieve Raman Spectrum Test

[0055] An ion sieve is sieved and ground into fine powder, so as to make a particle size thereof less than 75 m, and then the powder is tested using a laser Raman spectrometer to obtain a Raman spectrum.

[0056] Test conditions are as follows: a wave number range is 100-1500 cm.sup.1, and spectral resolution is 1-2 cm.sup.1.

[0057] The laser Raman spectrometer used in the present disclosure is manufactured by British company RENISHAW, with model number INVIA.

2. Ion Sieve XRD Spectrogram Test

(1) XRD Spectrogram Test of Initial Ion Sieve

[0058] An initial ion sieve which has not participated in salt bath purification is sieved and ground into fine powder, so as to make a particle size thereof less than 75 m, and then the powder is tested using an X-ray diffractometer to obtain an XRD diffraction peak curve, i.e., an XRD spectrogram.

[0059] Test conditions are as follows: an incident angle range is 2=10-80, a scan speed is 6/min, a working voltage is 40 kV, and a working current is 30 mA.

(2) XRD Spectrogram Test of the Ion Sieve Having Participated in the Salt Bath Purification

[0060] The initial ion sieve is placed in a 480 C. test salt bath containing impurity lithium ions of below 1000 ppm, subjected to purification for 24 h and then taken out. The ion sieve taken out is sieved and ground into fine powder, so as to make a particle size thereof less than 75 m, and then the powder is tested using an X-ray diffractometer to obtain an XRD diffraction peak curve, i.e., XRD spectrogram. The test salt bath used in the present disclosure is a sodium nitrate salt bath containing 10510 ppm impurity lithium ions.

[0061] Test conditions are as follows: an incident angle range is 2=10-80, a scan speed is 6/min, a working voltage is 40 kV, and a working current is 30 mA.

[0062] The X-ray diffractometer used in the present disclosure is Shimadzu XRD_6100.

3. Test of Crystal Content in the Ion Sieve

[0063] The crystal content in the ion sieve is measured by a proportion of peak area of crystal phase in the XRD spectrogram of the ion sieve having participated in the salt bath purification, i.e., the ratio of the peak area of the crystal phase fitted based on the XRD spectrogram to all the fitted peak areas is the crystal content.

[0064] In the present disclosure, the ion sieve having participated in the salt bath purification is tested using the X-ray diffractometer, and a test result file (RAW format) of the X-ray diffractometer is imported into X-ray diffraction data Rietveld refinement software (such as Jade, Gsas, Fullprof, and Maud) for fitting and calculation. In the present disclosure, the test result file (RAW format) of the X-ray diffractometer is imported into Jade for fitting and calculation, so as to obtain the crystal content in the ion sieve.

4. Test of Lithium Ion Concentration (or Referred to as Content) in the Salt Bath

[0065] After the ion sieve is added to the to-be-purified salt bath, the concentration of lithium ions in the salt bath at different time is detected using an atomic absorption spectrophotometer, with time as a variable.

[0066] In a first aspect, the present disclosure provides a high-temperature-resistant and high-stability ion sieve, wherein based on molar percentage of each oxide in the ion sieve, composition of the ion sieve includes: SiO.sub.2: 46-60 mol %, Al.sub.2O.sub.3: 3-16 mol %, Y.sub.2O.sub.3: 0-3 mol %, and R.sub.2O: 33-45 mol %, where R.sub.2O is an alkali metal oxide; and the ion sieve satisfies: S.sub.Q.sub.3/S.sub.Q.sub.2 is not lower than 1, where S.sub.Q.sub.3 is an area corresponding to Q.sup.3 after Gaussian deconvolution fitting is performed on a spectrum band within a range of 830-1230 cm.sup.1 in a Raman spectrum of the ion sieve, and Q.sup.3 is an SiO.sup. stretching vibration peak in a silicon-oxygen tetrahedron with only one non-bridging oxygen; S.sub.Q.sub.2 is an area corresponding to Q.sup.2 after Gaussian deconvolution fitting is performed on the spectrum band within the range of 830-1230 cm.sup.1 in a Raman spectrum of the ion sieve, and Q.sup.2 is an SiO.sup. stretching vibration peak in a silicon-oxygen tetrahedron with only two non-bridging oxygens. It can be understood that a unit of area S.sub.Q.sub.2 is the same as S.sub.Q.sub.3.

[0067] In the above, working principles of oxides of various components are as follows.

[0068] SiO.sub.2 is used for forming covalent bonds, and constituting a skeleton of an ion sieve network structure, and selection of composition and content thereof directly affects adsorption performance of the ion sieve network structure and thermal stability of the ion sieve in a high-temperature environment. A too low content of SiO.sub.2 may lead to poor formability of the ion sieve, but excessive SiO.sub.2 may lead to high viscosity of the composition, causing difficulty in melting. Therefore, in the present disclosure, the molar percentage of SiO.sub.2 is 46-60 mol %. In some embodiments, the content of SiO.sub.2 may be 46 mol %, 47 mol %, 48 mol %, 49 mol %, 50 mol %, 51 mol %, 52 mol %, 53 mol %, 54 mol %, 55 mol %, 56 mol %, 57 mol %, 58 mol %, 59 mol %, 60 mol % and etc., and all ranges and sub-ranges therebetween. It should be appreciated that in embodiments, any of the above ranges can be combined with any other range.

[0069] Al.sub.2O.sub.3 is a constituent part of network architecture, and meanwhile is beneficial to enhance absorption rate of the ion sieve for the impurity ions in the process of adsorbing impurity ions and improve anti-decomposition capability of the ion sieve at a high temperature, but excessive aluminum oxide will cause difficulty in forming of the ion sieve. Therefore, in the present disclosure, the molar percentage of Al.sub.2O.sub.3 is 3-16 mol %. In some embodiments, the content of Al.sub.2O.sub.3 may be 3 mol %, 4 mol %, 5 mol %, 6 mol %, 7 mol %, 8 mol %, 9 mol %, 10 mol %, 11 mol %, 12 mol %, 13 mol %, 14 mol %, 15 mol %, 16 mol % and etc., and all ranges and sub-ranges therebetween. It should be appreciated that in the embodiments, any of the above ranges can be combined with any other range.

[0070] An appropriate amount of Y.sub.2O.sub.3 can improve hardness and chemical stability of the ion sieve, but when the Y.sub.2O.sub.3 content is relatively high, the ion sieve has increased tendency of crystallization. Therefore, in the present disclosure, the molar percentage of Y.sub.2O.sub.3 is 0-3 mol %. In some embodiments, the content of Y.sub.2O.sub.3 may be 0, 0.5 mol %, 1 mol %, 1.5 mol %, 2 mol %, 2.5 mol %, 3 mol % and etc., and all ranges and sub-ranges therebetween. It should be appreciated that in the embodiments, any of the above ranges can be combined with any other range.

[0071] The alkali metal oxide R.sub.2O, on one hand, can provide alkali metal ions to participate in ion exchange, which is beneficial to ensure the absorption ability of the ion sieve to impurity ions, and on the other hand, can also provide free oxygen, which affects structural stability of the ion sieve. That is, the content of R.sub.2O directly affects the ability of the ion sieve to adsorb the impurity ions and the stability of the ion sieve in a high-temperature salt bath. Therefore, in the present disclosure, the molar percentage of R.sub.2O is 33-45 mol %. In some embodiments, the content of R.sub.2O may be 33 mol %, 34 mol %, 35 mol %, 36 mol %, 37 mol %, 38 mol %, 39 mol %, 40 mol %, 41 mol %, 42 mol %, 43 mol %, 44 mol %, 45 mol % and etc., and all ranges and sub-ranges therebetween. It should be appreciated that in the embodiments, any of the above ranges can be combined with any other range.

[0072] In some optional embodiments, after the ion sieve is placed in a 480 C. salt bath for 24 h, the crystal content in the ion sieve is less than 10 wt %, wherein the crystal content is measured by a proportion of peak area of crystal phase in the XRD spectrum of the ion sieve.

[0073] In the present disclosure, the Gaussian deconvolution fitting refers to importing a laser Raman spectrometer test result file (.txt format) into Origin (e.g. version 2022 of Origin), selecting a spectrum band within a range of 830-1230 cm.sup.1, and performing deconvolution fitting and calculation using Gaussian function, so as to obtain areas corresponding to Q.sup.3 and Q.sup.2, where a ratio of fitted Q.sup.3 area to fitted Q.sup.2 area is S.sub.Q.sub.3/S.sub.Q.sub.2.

[0074] In some optional embodiments, 3S.sub.Q.sub.3/S.sub.Q.sub.21.

[0075] In some embodiments, a value of S.sub.Q.sub.3/S.sub.Q.sub.2 may be 1.00, 1.05, 1.30, 1.50, 2.00, 2.30, 2.50, 2.80, 3.00 and etc., and all ranges and sub-ranges therebetween. It should be appreciated that in the embodiments, any of the above ranges can be combined with any other range. The inventors found through research and verification that the ion sieve having a specific composition and satisfying specific structural requirements has excellent high-temperature resistance and high-temperature stability, and after being placed in the high-temperature salt bath for a relatively long time, the ion sieve substantially has no obvious crystal phase transformation, and has a stable structure.

[0076] In some optional embodiments, the composition of the ion sieve satisfies: 52.00.85SiO.sub.2+0.15Al.sub.2O.sub.3+1.65Y.sub.2O.sub.345.3, based on molar percentage of each oxide in the ion sieve. In this optional solution, the inventors of the present disclosure found through a lot of researches that oxides of key components affect high-temperature stability to different degrees, and when they meet the above condition, the ion sieve of a specific structure with S.sub.Q.sub.3/S.sub.Q.sub.2 being not lower than 1 can be obtained, so that the structural stability of the ion sieve can be significantly improved, and meanwhile the melting and forming of the ion sieve are facilitated.

[0077] In some embodiments, a value of 0.85SiO.sub.2+0.15Al.sub.2O.sub.3+1.65Y.sub.2O.sub.3 may be 45.3, 46.0, 47.0, 48.0, 49.0, 50.0, 51.0, 51.5, 52.0 and etc., and all ranges and sub-ranges therebetween. It should be appreciated that in the embodiments, any of the above ranges can be combined with any other range.

[0078] In the above optional solutions, Y.sub.2O.sub.3 may or may not be contained. In cases where Y.sub.2O.sub.3 is contained, the effect of the Y.sub.2O.sub.3 contained on the structural stability of the ion sieve is much greater than that of SiO.sub.2 and Al.sub.2O.sub.3, and controlling of the content of Y.sub.2O.sub.3 under the above condition is more beneficial to improve the high-temperature stability.

[0079] In the present disclosure, in cases where the above 52.00.85SiO.sub.2+0.15Al.sub.2O.sub.3+1.65Y.sub.2O.sub.345.3 is satisfied, the ion sieve may further contain other components.

[0080] In some optional embodiments, the composition of the ion sieve satisfies: 20.00.50R.sub.2O16.0, based on molar percentage of each oxide in the ion sieve, where R.sub.2O is Na.sub.2O and/or K.sub.2O. The alkali metal oxide, on one hand, can provide alkali metal ions to participate in ion exchange, which is beneficial to ensure the absorption capacity of the ion sieve to impurity ions, and on the other hand, also will provide free oxygen, and affect the structural stability of the ion sieve. In the present disclosure, with 0.50R.sub.2O being 16.0-20.0, the structural stability of the ion sieve can be ensured while realizing that the ion sieve has an excellent adsorption capability. It should be understood that, when conventional glass is subjected to chemical strengthening, it is mainly Na ions and Li ions contained in the glass that are exchanged with K ions and Na ions in the salt bath. The impurity ions existing in the salt bath are mainly Li ions released from the glass into the salt bath. R.sub.2O in the ion sieve is Na.sub.2O and/or K.sub.2O, which can better realize absorption and purification of the impurity ions in the salt bath.

[0081] More optionally, R.sub.2O is Na.sub.2O. It should be understood that when the glass is subjected to chemical strengthening, NaLi exchange is performed, so that a compressive stress layer with a greater depth can be obtained, which is more beneficial to improve impact resistance of the glass. To accomplish this, Li ions in the glass are exchanged by Na ions in the salt bath and enter the salt bath to become impurity ions. Meanwhile, the inventors found through research that too high concentration of impurity lithium ions in the salt bath will bring an extremely adverse effect on the glass strengthening. When R.sub.2O in the ion sieve are all Na.sub.2O, the absorption and purification of the lithium ions in the salt bath can be better realized.

[0082] More optionally, the molar percentage of SiO.sub.2 in the ion sieve is 49-60 mol %.

[0083] More optionally, the molar percentage of Al.sub.2O.sub.3 in the ion sieve is 3-15 mol %.

[0084] More optionally, the molar percentage of Y.sub.2O.sub.3 in the ion sieve is 1-3 mol %.

[0085] More optionally, the molar percentage of R.sub.2O in the ion sieve is 33-40 mol %.

[0086] The ion sieve of the present disclosure also may contain other metal oxides, and further optionally, based on the molar percentage of each oxide in the ion sieve, the composition of the ion sieve further includes: ZnO: 0-3 mol %, CaO: 0-3 mol %, MgO: 0-3 mol %, P.sub.2O.sub.5: 0-3 mol %, and B.sub.2O.sub.3: 0-3 mol %.

[0087] More optionally, the sum of the molar percentages of ZnO+CaO+MgO+P.sub.2O.sub.5+B.sub.2O.sub.3 does not exceed 5 mol %. In this optional solution, it is more beneficial to the high-temperature stability of the ion sieve, and reduction of an amount of crystal precipitation; and meanwhile, it is more beneficial to avoid weakening the absorption efficiency of the ion sieve.

[0088] In the present disclosure, P.sub.2O.sub.5 and B.sub.2O.sub.3 may be contained in the components of the ion sieve. However, when the contents of these components are excessive, the chemical durability of the ion sieve tends to deteriorate, and when they are used in a high-temperature salt bath, it is more likely to cause random erosion phenomenon to surfaces of glass and glass ceramic. Therefore, the ion sieve of the present disclosure is optionally substantially free of P.sub.2O.sub.5 and/or B.sub.2O.sub.3. Herein, substantially free of means that P.sub.2O.sub.5 and/or B.sub.2O.sub.3 are not actively added or proportioned into the ion sieve, but may be present in a quite small amount as contaminants or impurities.

[0089] In the present disclosure, the ion sieve is substantially free of Li.sub.2O. If the ion sieve contains Li.sub.2O, it is easy to bring about adverse influence to the effect of adsorbing the impurity lithium ions by the ion sieve.

[0090] In some optional embodiments, based on a mass of the salt bath, the ion sieve in a mass proportion of 1 wt % is added to a 480 C. salt bath containing 10510 ppm impurity lithium ions; and [0091] a curve of change of lithium ion concentration y in the salt bath over time x satisfies the following function: y=A.sub.1exp(x/b.sub.1)+A.sub.2exp(x/b.sub.2)+C.sub.0, where exp is an exponential function, and 100>A.sub.1>30, 0<A.sub.2<31, 0<b.sub.1<5, 0<b.sub.2<25, 0<C.sub.0<50, where unit of x is h. This optional solution shows that the ion sieve of the present disclosure can continuously absorb the impurity lithium ions in a high-temperature salt bath for a long time, that is, the ion sieve of the present disclosure has excellent high-temperature stability and an excellent impurity ion absorption capacity.

[0092] It can be understood that, in the above function, a data relationship (mathematical model) is established with discrete data points of given y and x, and a series of tiny straight line segments are obtained to connect these interpolation points into a curve, so that a smooth curve can be formed. This curve can be represented by exp (exponential function), and A.sub.1, A.sub.2, b.sub.1, b.sub.2, and C.sub.0 are all coefficients determined by the given discrete data points.

[0093] A person skilled in the art could select the shape and particle size of the ion sieve according to practical requirements.

[0094] In some optional embodiments, the ion sieve is granular, sheet-shaped or porous, optionally granular, and optionally a granular ion sieve has a particle size of 1-10 mm. In some embodiments, the particle size of the granular ion sieve may be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm and etc., and all ranges and sub-ranges therebetween. More optionally, the particle size of the granular ion sieve is 2-5 mm. It should be appreciated that in the embodiments, any of the above ranges can be combined with any other range. The particle size of the ion sieve herein refers to the maximum diameter of the ion sieve particles.

[0095] In a second aspect, the present disclosure provides a preparation method of the ion sieve of the first aspect, including the following steps: taking various raw materials according to a formula and mixing the same uniformly, and melting at 1300-1650 C., so as to obtain a liquid material; and then making the liquid material granular, sheet-shaped or porous.

[0096] In some optional embodiments, the melting lasts for more than 1 h, so as to ensure that various raw materials are melted sufficiently and mixed uniformly.

[0097] In the present disclosure, the granular ion sieve can be formed by water quenching, and optionally, a temperature of the water quenching is 10-80 C. In some embodiments, the temperature of the water quenching may be 10 C., 15 C., 20 C., 22 C., 25 C., 30 C., 35 C., 45 C., 50 C., 60 C., 65 C., 70 C., 75 C., 80 C. and etc., and all ranges and sub-ranges therebetween. It should be appreciated that in the embodiments, any of the above ranges can be combined with any other range. The size of the ion sieve particles can be controlled by controlling the temperature, so that the particle size of the ion sieve particles satisfies 1-10 mm.

[0098] In some optional embodiments, a sheet-shaped or porous ion sieve can be made according to use requirements. Exemplarily, the sheet-shaped ion sieve can be made by rolling or drawing with an external force. Optionally, the sheet-shaped ion sieve is of an irregular sheet shape, and the sheet-shaped ion sieve is controlled to have the shortest side of at least 0.3 cm, the largest side of less than 20 cm, and the thickness of 0.3-1.0 mm. Exemplarily, the porous ion sieve can be made by feeding a blowing agent, optionally, a pore diameter is 1-10 mm, and optionally, a porous ion sieve block has the shortest side of at least 0.5 cm, and the largest side of less than 10 cm.

[0099] The ion sieve of the present disclosure can be used for purifying a salt bath containing impurity ions, and can also directly participate in a process of chemical strengthening treatment, and adsorb/absorb lithium ions in the salt bath in the process of chemical strengthening treatment, with wide applications.

[0100] In a third aspect, the present disclosure provides a purification method of a salt bath for glass chemical strengthening, including the following steps: introducing the ion sieve of the first aspect into a to-be-purified salt bath, so as to perform an impurity ion adsorption reaction. A temperature of the to-be-purified salt bath can be chosen to be 350-550 C., which is more conducive to giving full play to adsorption/absorption performance of the ion sieve to lithium ions. The impurity ions adsorbed/absorbed by the ion sieve are mainly lithium ions.

[0101] It should be understood that impurity ions herein refer to ions that are not actively introduced into the salt bath when the initial salt bath is formulated, such as lithium ions. The term adsorption reaction herein refers to that alkali metal ions with a large ionic radius in the ion sieve, such as K.sup.+ or Na.sup.+, may react with impurity alkali metal ions with a small ionic radius in the salt bath, such as Li.sup.+, so as to adsorb the impurity alkali metal ions in the salt bath into the ion sieve, thus realizing purification of the salt bath.

[0102] In the present disclosure, purification of salt bath may be on-line purification, and also may be purification of a salt bath subjected to the glass strengthening or a salt bath with excessive impurity ions. In the above, the on-line purification refers to that the ion sieve is directly introduced into the initial salt bath free of impurity ions, for example, the ion sieve can be loaded into a carrier (such as a metal mesh) and placed into the salt bath, so that the ion sieve purification process (absorbing impurity ions in the salt bath) is performed at the same as the glass strengthening process. Purification of salt bath subjected to glass strengthening or the salt bath with excessive impurity ions refers to introducing the ion sieve into the salt bath containing impurity ions, while the strengthening process is in progress or after the strengthening process is stopped, so as to perform adsorption treatment of the impurity ions.

[0103] In some optional embodiments, the usage amount of ion sieve is 0.5-5.0 wt % of the to-be-purified salt bath. The present disclosure can effectively purify the salt bath using a relatively low amount of ion sieve, and has excellent high-temperature resistance and high-temperature stability.

[0104] The to-be-purified salt bath in the present disclosure can be a pure potassium salt bath, a pure sodium salt bath or a mixed sodium and potassium salt bath (i.e., a mixed salt bath containing lithium (impurity ions), sodium, and potassium) containing a lot of impurity lithium ions, and a nitrate salt bath can be selected as the above salt bath.

[0105] The content of impurity lithium ions in the to-be-purified salt bath in the present disclosure can be selected in a relatively wide range, and can all be purified using the ion sieve in the present disclosure. For example, the content of impurity ions in the to-be-purified salt bath can be 1-1000 ppm.

[0106] In some optional embodiments, the reaction lasts for 0.1-48.0 h. The ion sieve of the present disclosure has an excellent capability of absorbing impurity ions, and can efficiently purify a salt bath containing impurity ions in a relatively short period of time. Meanwhile, the ion sieve of the present disclosure has excellent high-temperature stability, can still maintain a stable structure in a high-temperature salt bath, and is not prone to obvious crystal form transformation. Therefore, the ion sieve can stably absorb impurity ions in the 480 C. salt bath for 24 h, better realize the on-line purification, and avoid frequent replacement of the salt bath or the ion sieve material, which is more conducive to improving the mass production efficiency of the chemically strengthened glass and reducing the costs.

[0107] In a fourth aspect, the present disclosure provides a method of preparing chemically strengthened glass, including: introducing to-be-strengthened glass and the ion sieve of the first aspect into a salt bath for glass chemical strengthening that is free of impurity ions, and chemically strengthening the to-be-strengthened glass to prepare the chemically strengthened glass. It should be understood that what is realized by the preparation method herein is on-line purification of the ion sieve, wherein it is realized that the ion sieve purification process is carried out at the same time as the glass strengthening process, without the need of suspending the strengthening process, or frequently replacing the salt bath, thus improving the production efficiency of the chemically strengthened glass and reducing the production costs of the chemically strengthened glass.

[0108] In this preparation method, in the process of performing the chemical strengthening, the ion sieve of the present disclosure can constantly and stably absorb impurity ions generated in the ion exchange process in the salt bath, so that the impurity ions in the salt bath are always stable at a relatively low level, and the quality of the strengthened glass is ensured, moreover, the ion sieve substantially has no obvious crystal phase transformation and has a stable structure, and it will not release a large amount of impurity substances to contaminate the salt bath, thus avoiding appearance of obvious defects such as granular defect on a surface of a finished product of the strengthened glass.

[0109] The salt bath free of impurity ions refers to a brand new salt bath substantially free of impurity ions, i.e., an initial salt bath, and this salt bath has not been used for chemically strengthening the glass.

[0110] The present disclosure is further described in detail below in combination with specific examples.

Example 1

[0111] An ion sieve, S.sub.Q.sub.3/S.sub.Q.sub.2 and oxide composition thereof are as shown in following Table 1, where S.sub.Q.sub.3 is an area corresponding to Q.sup.3 after Gaussian deconvolution fitting is performed on a spectrum band within a range of 830-1230 cm.sup.1 in a Raman spectrum of the ion sieve, Q.sup.3 is an SiO.sup. stretching vibration peak in a silicon-oxygen tetrahedron with only one non-bridging oxygen; S.sub.Q.sub.2 is an area corresponding to Q.sup.2 after Gaussian deconvolution fitting is performed on a spectrum band in the range of 830-1230 cm.sup.1 in a Raman spectrum of the ion sieve, and Q.sup.2 is an SiO.sup. stretching vibration peak in a silicon-oxygen tetrahedron with only two non-bridging oxygens. An initial XRD pattern of the ion sieve, i.e., the XRD pattern of the initial ion sieve having not been used for salt bath purification, is as shown in FIG. 1a.

[0112] A preparation method thereof is as follows: proportioning raw material components of the ion sieve according to the formula in Table 1, and mixing the same uniformly, then perform melting at 1500 C. for more than 1 h to form a liquid state, and forming a granular ion sieve with a particle size of 2-5 mm by water quenching, wherein a temperature of the water quenching was 25 C.

Examples 2-4

[0113] They were carried out with reference to Example 1, respectively, and differences lie in that formulas of the ion sieves are different, and S.sub.Q.sub.3/S.sub.Q.sub.2 in the ion sieves is different, specifically realized by controlling contents of various oxides and content relationships between various oxides, specifically as shown in Table 1. An initial XRD pattern of the ion sieves thereof, i.e., an XRD pattern of initial ion sieves having not been used for salt bath purification, is as shown in FIG. 1a.

Comparative Examples 1-4

[0114] They were carried out with reference to Example 1, respectively, and differences lie in that formulas of the ion sieves are different, and S.sub.Q.sub.3/S.sub.Q.sub.2 in the ion sieves is different, specifically realized by controlling contents of various oxides and content relationships between various oxides, specifically as shown in Table 1. An initial XRD pattern of the ion sieves thereof, i.e., an XRD pattern of initial ion sieves having not been used for salt bath purification, is as shown in FIG. 1b.

Application Example 1

[0115] The ion sieves prepared in the above examples and comparative examples were each placed in a 480 C. test salt bath containing 10510 ppm lithium ions, and subjected to a lithium ion adsorption reaction. Each ion sieve was used in an amount of 1 wt % of weight of the test salt bath.

[0116] In the above test salt bath, change situation of the lithium ion concentration y over time x is as shown in the following Table 2 and FIG. 3a and FIG. 3b, in wherein fitting result charts of change curves of Examples 1-4 are as shown in FIG. 4, FIG. 5, FIG. 6, and FIG. 7.

[0117] After the ion sieve absorbed lithium ions in the test salt bath for 24 h, a crystal content in the obtained ion sieve is as shown in the following Table 1, wherein the crystal content is measured by a proportion of an area of peak area of crystal phase in an XRD spectrogram of the obtained ion sieve after 24 h of salt bath purification.

[0118] XRD patterns of the ion sieves obtained after 24 h of salt bath purification are as shown in FIG. 2a and FIG. 2b, respectively.

TABLE-US-00001 TABLE 1 Composition of Ion Sieve Comparative Comparative Comparative Comparative (mol %) Example 1 Example 2 Example 3 Example 4 Example 1 Example 2 Example 3 Example 4 SiO.sub.2 53 46 47 50 54 60 49 55 Al.sub.2O.sub.3 1 15 15 4 7 3 15 3 Na.sub.2O 44 37 35 43 38 37 33 39 Y.sub.2O.sub.3 / / / 1 1 / 1 / ZnO / 1 / / / / / 2 CaO 2 / 2 / / / 2 1 MgO / 1 1 2 / / / / Total 100 100 100 100 100 100 100 100 0.85 SiO.sub.2 + 45.2 41.35 42.2 44.75 48.6 51.45 45.55 47.2 0.15 Al.sub.2O.sub.3 + 1.65 Y.sub.2O.sub.3 0.50 Na.sub.2O 22 18.5 17.5 21.5 19 18.5 16.5 19.5 S.sub.Q3 1647.46 17153.15 22032.05 5234.86 32415.69 32571.43 21941.95 30726.36 S.sub.Q2 43352.63 26116.66 27404.84 40268.14 11454.31 11428.57 20936.10 13019.64 S.sub.Q3/S.sub.Q2 0.04 0.66 0.80 0.13 2.83 2.85 1.05 2.36 Crystal 78.51 32.13 13.16 53.64 4.15 3.97 8.76 6.32 content/ wt % in the ion sieve in 480 C. test salt bath, after 24 h of adsorption of Li.sup.+

TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Comparative Ion Sieve Example 1 Example 2 Example 3 Example 4 Example 1 Example 2 Example 3 Example 4 Li.sup.+ 106.48 96.80 107.12 108.28 113.96 109.08 108.92 102.00 content in initial test salt bath (ppm) Li.sup.+ 50.24 91.80 102.12 56.24 84.24 79.76 87.48 69.48 content in salt bath after 0.5 h (ppm) Li.sup.+ 37.45 84.92 91.88 45.400 73.68 76.20 81.16 58.92 content in salt bath after 1 h (ppm) Li.sup.+ 37.16 80.64 83.48 42.16 65.40 67.20 72.44 53.12 content in salt bath after 1.5 h (ppm) Li.sup.+ 41.12 71.08 70.44 25.56 57.36 51.08 69.2 50.44 content in salt bath after 2 h (ppm) Li.sup.+ 46.72 71.96 64.12 21.48 53.23 46.76 66.24 47.19 content in salt bath after 3 h (ppm) Li.sup.+ 56.36 69.52 61.36 19.36 50.16 42.28 64.80 45.40 content in salt bath after 4 h (ppm) Li.sup.+ 61.28 65.68 60.56 19.12 47.81 37.40 60.52 42.47 content in salt bath after 5.5 h (ppm) Li.sup.+ 63.48 65.4 52.68 20.16 45.4 31.20 54.96 37.64 content in salt bath after 9 h (ppm) Li.sup.+ 68.56 48.00 45.84 23.60 37.46 30.04 47.64 32.82 content in salt bath after 22 h (ppm) Li.sup.+ 71.28 49.00 47.16 35.84 34.2 29.12 46.68 32.53 content in salt bath after 24 h (ppm)

[0119] It can be seen from Tables 1 and 2 that compared with the comparative examples, all the ion sieves in the examples of the present disclosure have the formula with S.sub.Q.sub.3/S.sub.Q.sub.2 being greater than 1, and can adsorb the lithium ions constantly and stably for 24 h in the 480 C. test salt bath, and after the lithium ions are absorbed for 24 h, the crystal content in the ion sieve is less than 10 wt %. It is indicated that the ion sieve using the solutions of the examples of the present disclosure maintains a stable capability of absorbing the lithium ions in the high-temperature salt bath, and can maintain a stable structure in the high-temperature salt bath for a long time substantially, without incurring or incurring little crystal form change, so that it will not contaminate the high-temperature salt bath or shorten the lifetime of the salt bath due to the long-term introduction of the ion sieve.

[0120] It can be seen from FIG. 1a, FIG. 1b, FIG. 2a, and FIG. 2b that, after the ion sieve of the examples of the present disclosure continuously performs purification in the 480 C. salt bath for 24 h, the ion sieve has substantially no crystal form change, and the structure remains stable. However, after the ion sieves of the comparative examples continuously performs purification in the 480 C. salt bath for 24 h, an obvious crystal form change occurs, producing many crystals not contained in the initial ion sieves. This indicates that the ion sieve having the specific composition and specific structure in the present disclosure has excellent high-temperature stability, and can be placed in the high-temperature salt bath for performing impurity ion purification for a long time.

[0121] It can be seen from FIG. 3a and FIG. 3b and FIG. 4-7 that after the ion sieves of the examples are placed in the 480 C. test salt bath for performing lithium ion purification, the change of the lithium ion concentration y over time x in the salt bath satisfies the following function: y=A.sub.1exp(x/b.sub.1)+A.sub.2exp(x/b.sub.2)+C.sub.0, and 100>A.sub.1>30, 0<A.sub.2<31, 0<b.sub.1<5, 0<b.sub.2<25, 0<C.sub.0<50, exp being an exponential function. This indicates that the ion sieves having a specific composition and structure in the examples of the present disclosure can stably adsorb lithium ions in a high-temperature salt bath for a long time.

[0122] However, the ion sieves of the comparative examples do not satisfy the above function of the lithium ion concentration over time in the 480 C. salt bath. For example, a corresponding fitting function of Comparative Example 2 is y=29exp(x/1.52)10.92exp(x/22.00)+79.89. After the ion sieves of Comparative Example 1 and Comparative Example 4 perform the purification for less than 10 h, lithium ions are even reversely precipitated into the salt bath, so that the lithium ion concentration in the salt bath is increased, which indicates that the ion sieves in the comparative examples which do not satisfy the specific composition or the specific structure of the present disclosure cannot constantly and stably adsorb the lithium ions in the high-temperature salt bath for a long time, and even release the lithium ions into the salt bath due to structural change in the later stage.

Application Example 2

[0123] Taking Example 1, Comparative Example 1, and Comparative Example 2 as examples, respective ion sieve thereof and the to-be-strengthened lithium-aluminum-silicon glass were simultaneously placed in a brand new 460 C. sodium nitrate salt bath for successive batch strengthening, with strengthening time per batch being 8 h. After the strengthening of one batch of glass was completed, the strengthened glass was taken out of the salt bath together with the ion sieve, and then a new batch of the to-be-strengthened glass and a new ion sieve were added. The ion sieve added to the salt bath each time with the to-be-strengthened glass was in an amount of 1 wt % of the weight of the salt bath. When an eighth batch had been strengthened, pictures of finished products of glass respectively obtained from Example 1 and Comparative Examples 1 and 2 are as shown in FIG. 8, FIG. 9, and FIG. 10.

[0124] It can be seen from FIG. 8 that when the ion sieve of Example 1 of the present disclosure is used for salt bath purification, the surface of the glass obtained after the strengthening is smooth without defects. When the ion sieves in Comparative Examples 1 and 2 are used for salt bath purification, obvious granular defects appear on the surface of the glass obtained after the strengthening, as shown within dashed circles in FIGS. 9 and 10.

[0125] The optional embodiments of the present disclosure are described in detail in the above, but the present disclosure is not limited thereto. Within the scope of technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, including combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as contents disclosed in the present disclosure, and all belong to the scope of protection of the present disclosure.

INDUSTRIAL APPLICABILITY

[0126] The present disclosure belongs to the technical field of ion sieves, in particular to the technical field of purification of salt bath for glass chemical strengthening, and specifically to a high-temperature-resistant and high-stability ion sieve and a preparation method and application thereof. Based on the molar percentage of each oxide in the ion sieve, the composition of the ion sieve includes: SiO.sub.2: 46-60 mol %, Al.sub.2O.sub.3: 3-16 mol %, Y.sub.2O.sub.3: 0-3 mol %, and R.sub.2O: 33-45 mol %, where R.sub.2O is an alkali metal oxide; and the ion sieve satisfies: S.sub.Q.sub.3/S.sub.Q.sub.2 is not lower than 1. The ion sieve in the present disclosure has excellent high-temperature resistance and high-temperature stability, and after being placed in the high-temperature salt bath for a relatively long time, the ion sieve substantially has no obvious crystal phase transformation and has a stable structure, and it will not release a large amount of impurity substances to contaminate the salt bath, and will not cause appearance of obvious defects on the surface of the finished product of strengthened glass. The ion sieve of the present disclosure can constantly and stably absorb impurity ions in the 480 C. salt bath for 24 h.

[0127] Besides, it can be understood that the high-temperature-resistant and high-stability ion sieve and the preparation method and application thereof in the present disclosure can be reproduced, and can be used in a variety of industrial applications. For example, the high-temperature-resistant and high-stability ion sieve and the preparation method and application thereof in the present disclosure can be used in the technical field of ion sieves.