CN113233788A

CN113233788A - Method for recycling tempered glass

Info

Publication number: CN113233788A
Application number: CN202110739701.7A
Authority: CN
Inventors: 袁小彬; 覃文城; 吕路; 王刚刚; 胡伟; 谈宝权
Original assignee: Chongqing Aureavia Hi Tech Glass Co Ltd
Current assignee: Chongqing Aureavia Hi Tech Glass Co Ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2021-08-10

Abstract

The invention discloses a method for recycling tempered glass, which comprises the following steps: 1) providing a strengthened glass having flaws, optionally mechanically polishing one or more surfaces of the glass having flaws; 2) carrying out different ion exchange treatments on the glass treated in the step 1) to obtain the glass without surface flaws. The invention combines mechanical polishing with different ion exchange to treat the glass with flaw on the surface, so that the treated glass meets the commercial requirement and the commercial value of the glass is finally improved.

Description

Method for recycling tempered glass

Technical Field

The invention relates to the technical field of glass products, in particular to a method for recycling tempered glass.

Background

The glass has the characteristics of transparency, high temperature resistance and the like, so the glass is widely applied in daily life. For example, in the fields of protection devices, decoration and the like, glass has certain defects, such as weak impact resistance, fragility and the like, so that the application of the glass in some fields is limited.

With the wide application of glass in aerospace materials, electronic display screen materials and other aspects, especially smart phone display screens. At present, the smart phone already occupies the main market of the mobile phone, but the smart phone is inevitably collided in daily life, so that screen breaking becomes a trouble for a large number of users. And the mechanical strength of the glass cover plate is greatly improved by the tempered glass. The strengthened glass is obtained by ion exchange of glass in a high-temperature salt bath, and the large-radius ions in the salt bath and the small-radius ions in the glass form an area difference on the surface of the glass, so that a certain tensile stress is formed on the surface of the glass to obtain the capacity of inhibiting or inhibiting the crack propagation of the glass, and the mechanical strength of the glass reaches a higher level.

However, surface flaws may be generated on the glass surface during the ion exchange process or the subsequent processes (cleaning, silk-screening, plating, etc.) after the ion exchange process, and the surface flaws may change the appearance and strength of the glass, and if the glass product cannot meet the aesthetic or functional requirements required in electronic devices due to the surface flaws, the glass product may not be used, or may even have to be discarded as a waste product, and the number of the glass products is large, and the yield of the glass products after the ion exchange process and the subsequent processes is only 7% to 15%, and the glass products with the surface flaws also need to be reprocessed for economic consideration. However, the strength of the glass after ion strengthening is greatly improved, the difficulty of reprocessing is also increased, and irreparable loss is likely to occur if the glass is not properly handled, and therefore, a method for effectively improving the value of such glass products with surface defects is required.

Disclosure of Invention

In view of the above-mentioned disadvantages of the prior art, the present invention provides a method for recycling strengthened glass, so as to solve the problem of difficulty in improving the value of glass products with surface defects in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for recycling tempered glass is characterized by comprising the following steps:

1) providing a strengthened glass having flaws, optionally mechanically polishing one or more surfaces of the glass having flaws, wherein the glass comprises a lithium aluminosilicate glass;

2) carrying out ion exchange treatment twice on the strengthened glass treated in the step 1) to obtain glass without surface flaws, wherein:

first ion exchange: heating a salt bath containing at least one monovalent salt to 410-450 ℃, and putting the polished glass into the salt bath for first ion exchange, wherein the time of the ion exchange is 10 min-5 h;

and (3) second ion exchange: heating a salt bath containing at least one monovalent salt different from the first ion exchange to 410-450 ℃, and putting the glass subjected to the first ion exchange treatment into the salt bath for second ion exchange, wherein the ion exchange time is 10 min-4 h.

The present invention also provides an electronic terminal as a consumer product, comprising:

a housing comprising a front surface, a rear surface, and side surfaces;

and an electronic assembly partially located within the housing, the electronic assembly including a display located at or adjacent a front surface of the housing;

the front surface or/and the back surface or/and the side surface comprise a glass product obtained by the method for recycling the tempered glass;

further comprising a cover article overlying the front surface of the housing or on the display, the cover article comprising a glass article obtained by the method of recycling strengthened glass according to the invention;

the electronic terminal used as the consumer goods comprises a mobile phone, a tablet computer or other electronic terminals.

Compared with the prior art, the invention has the following beneficial effects:

the invention combines mechanical polishing and ion exchange, firstly polishes the surface with flaw of the strengthened glass, polishes the surface flaw to remove the surface flaw, so that the surface of the glass with flaw does not have flaw, but the CS layer on the surface of the glass is polished, and the surface of the glass after mechanical polishing needs to be reprocessed. And treating the polished surface of the lithium aluminum silicate glass by adopting ion exchange, wherein the lithium aluminum silicate glass needs to be subjected to ion exchange twice, the first ion exchange endows the surface of the glass with a new deeper stress effect, and the second ion exchange endows the glass with a new surface CS, so that the polished surface of the lithium aluminum silicate glass has a composite stress layer. By the combined method of mechanical polishing and ion exchange, new stress effect can be endowed to the surface of the glass again, so that the resistance of the glass to cracking is increased, the treated glass meets the commercial requirement, and the commercial value of the treated glass is finally improved.

Drawings

FIG. 1 schematically illustrates the glass of the present invention in the form of one of the scratch defects.

In the figure: 1 is a flaw.

Detailed Description

The invention will be further explained with reference to the drawings and the embodiments.

First, the related proper names and related measurement methods related to the present invention are explained as follows

The term "glass article" as used herein is used in its broadest sense and includes any object made in whole or in part of glass, including glass-ceramics. The glass articles described herein may be formed from alkali aluminosilicate glass compositions that are susceptible to strengthening by ion exchange. Such compositions generally comprise SiO₂、Al₂O₃At least one alkaline earth metal oxide and one or more alkali metal oxides (e.g., Na)₂O and/or K₂O) in combination.

Strengthening glass: is chemically toughened glass treated by a high-temperature ion exchange process. The alkali metal ions with large ionic radius in the high-temperature molten salt replace the alkali metal ions with small ionic radius in the glass so as to generate exchange plasma accumulation difference, and high-to-low pressure stress is generated in the surface layer of the glass to hinder and delay the expansion of glass microcracks, thereby achieving the purpose of improving the mechanical strength of the glass.

Surface compressive stress CS: after the glass is chemically strengthened, the alkali metal ions with smaller radius on the surface are replaced by the alkali metal ions with larger radius, and the surface of the glass generates compressive stress due to the squeezing effect of the alkali metal ions with larger radius, which is called surface compressive stress.

Depth of compressive stress DOL-0: the distance from the surface of the strengthened glass to the position where the compressive stress is zero.

And (3) tensile stress linear density CT-LD: and obtaining the ratio of the tensile stress integral to the thickness of the glass under the thickness section of the glass according to SLP stress meter test. The stress of the chemically strengthened glass is in a balanced equal relationship with the tensile stress, and the SLP-1000 stress meter is more accurate to the tensile stress area of the glass, so that the stress magnitude contained under the unit thickness of the glass is represented by the ratio of the tensile stress integral to the thickness, and the stress degree of the chemically strengthened glass is represented.

Effective thickness: the glass article is the minimum thickness required for the product.

And (3) complete machine drop test: a method for testing the strength of strengthened glass includes sticking the strengthened glass piece to the sample of electronic device such as mobile phone, dropping the glass from high position, recording the height of broken glass, and testing the strength of strengthened glass.

Chemical strengthening limit experiment: in particular to the relationship between the time for exchanging sodium-lithium ions of the lithium aluminum silicon chemically strengthened glass and the stress. The lithium aluminosilicate glass plate is put into pure sodium nitrate salt at 430 ℃ for ion exchange. Taking out glass at intervals of 15min or 30min or 60min, performing stress test and recording by using an SLP1000 or SLP2000 stress instrument, placing the glass in a salt bath for continuous strengthening after the test is finished, and stopping the test until the stress CT-LD has a remarkably descending trend.

In the invention, the stress measurement can be respectively carried out on a surface high-pressure stress region and a deep low-pressure stress region by FSM6000 and SLP1000 produced by Orihara, and a stress curve is fitted by adopting PMC software to obtain corresponding test results. Of course, other stress testers capable of measuring the surface high-pressure stress region and the deep-layer low-pressure stress region can be adopted. In the invention, the flaws on the glass surface are selectively amplified and measured by a two-dimensional image measuring instrument.

Second, a method for recycling tempered glass

Currently, the prior art increases the resistance of strengthened glass to breakage by increasing the surface Compressive Stress (CS) of the glass and the depth of the stress layer. In order to provide a higher CS and increase the depth of the stress layer, the glass may be obtained by ion-exchanging in a high temperature salt bath. In the ion exchange treatment, glass containing at least one alkali metal ion with a smaller radius is brought into contact with a salt bath containing at least one alkali metal ion with a larger radius, the alkali metal ions with a smaller ionic radius being diffused from the glass surface into the salt bath, while the alkali metal ions with a larger ionic radius from the salt bath replace these ions with a smaller ionic radius in the glass surface. The substitution of such ions with larger ionic radii for ions with smaller ionic radii occurring in the glass creates a compressive stress layer on the glass surface, thereby increasing the glass' resistance to breakage. As the ion exchange treatment proceeds, the salt concentration of alkali metal ions of smaller ionic radius (i.e., ions diffusing from the glass as in the salt bath) in the salt bath increases, while the concentration of alkali metal ions of larger ionic radius (i.e., ions migrating from the salt bath into the glass) in the salt bath decreases. During the strengthening treatment (e.g., ion exchange treatment), a uniform surface compressive stress is ideally generated across the entire glass surface. However, the induced stresses are sometimes distributed unevenly, resulting in a high concentration of stresses in a certain local area, which may create flaws at the glass surface. As ion exchange proceeds, surface imperfections, such as pits or bumps, may form due to changes in ion volume, since smaller ions replacing larger ions leave voids or pits on the surface of the glass substrate, but this is not the primary cause of imperfections in the glass surface. Generally, the reason for the occurrence of defects on the surface of the strengthened glass is manifold, and in the ion exchange process and the subsequent processes after the ion exchange, in the subsequent treatment processes after the ion exchange, such as in the cleaning, silk-screen printing, coating and other processes, when the strengthened glass is subjected to the subsequent processing treatment, fine scratches or indentations may be left on the surface of the strengthened glass, so that the strengthened glass generates a certain number of glass products with defective surfaces after each process, and the number of the glass products with defective surfaces generated by the processes is far greater than the number of the glass products with defective surfaces generated by the chemical strengthening. Glass with pits, dots, scratches is often not commercially needed, which results in glass with these surface flaws no longer being commercially valuable. The treatment of the glass with the surface defects is difficult, because the glass with the surface defects is chemically strengthened, the strength of the glass is greatly improved, the glass is difficult to recycle, and finally the difficulty of improving the commercial value of the glass with the surface defects is high.

The embodiment of the invention is directed to the strengthened glass with flaws, and specifically comprises the following steps:

2) carrying out ion exchange treatment twice on the glass treated in the step 1) to obtain the glass without surface defects, wherein:

Generally, after the glass is chemically strengthened, the surface of the glass is inspected to determine whether the surface of the glass has flaws, which may be pits, bumps, or other forms. The commercial desirability of glasses with defects that are oversized and severely affect the commercial properties of the glass, for example, resulting in a glass with reduced resistance to breakage and thus glass breakage. But not all glasses with flaws, which are acceptable when the size of the flaws on the glass surface is within the range allowed by commercial products, do not affect the industrial properties of the glass.

In the present invention, one or more surfaces of the glass having flaws are optionally mechanically polished, on one hand, the flaws on the surface of the glass are polished off, and on the other hand, the mechanical polishing also polishes off the original surface CS layer of the glass, but after research, the mechanical polishing has been found to have a far greater effect on the stress effect of the glass when the glass is a lithium aluminosilicate glass. Experiments show that the original mechanically polished glass is subjected to one-time ion exchange to endow the glass with a new surface CS layer, but the drop resistance of a part of glass is reduced in a large range in a complete machine drop test, and the drop resistance height is even far inferior to that of the glass with flaws on the surface before mechanical polishing. After intensive research on the part of glass, the glass with the problem is lithium aluminum silicate glass, and after the intensive research, the glass is unexpectedly found to have great attenuation on deep stress, namely CT-LD, of the glass, the original mechanical polishing not only grinds off a surface CS layer, but also causes adverse effects on the deep stress of the glass, and particularly when the glass is lithium aluminum silicate glass, the adverse effects are more obvious. Therefore, when the glass is lithium-aluminum-silicon glass, the invention needs to endow the glass after mechanical polishing with a new surface CS layer and re-strengthen the deep stress of the glass, so that two times of ion exchange are needed, and the salt bath of the first time of ion exchange selects a salt bath containing sodium ions for Na⁺-Li⁺Ion exchange, which makes alkali metal ions with smaller radius diffuse into the salt bath from the glass surface, and at the same time, the alkali metal ions with larger radius from the salt bath replace the alkali metal ions with smaller radius on the glass surface,and because the content of lithium ions in the lithium-aluminum-silicon glass is high, and the exchange amount of sodium ions and lithium ions is large, the sodium ions in the salt bath can be exchanged with the lithium ions deeper in the glass, so that the glass can obtain a new and deeper stress effect after the first ion exchange, and the strength of the glass product is improved. After intensive research on the ion exchange process, it is found that the stress layers of the tempered glass with the surface defects are generally completely eliminated by the prior art, and then uniform ion exchange is carried out. The reason is that the depth of flaws of the glass is different, if the flaws are only removed by polishing, the thickness of the polished glass is different, the thickness of the stress layer of the polished glass is inconsistent, the process conditions of the polished glass are difficult to customize, if ion exchange is carried out according to the same condition, the thickness of the stress layer between the ion exchanged glass is deviated, some glass stress layers are too deep, other glass stress layers are too shallow, and finally the stress effect of the ion exchanged glass is uneven, and the quality of the product is difficult to control. The present invention focuses on the control of the first ion exchange time as to how to deal with this problem. The time of the first ion exchange can be adjusted according to the stress performance of the glass, firstly, a chemical strengthening limit experiment is carried out on the glass with qualified quality, the glass with qualified quality means that the size of a surface flaw of the glass is within the range allowed by a commercial product, and the stress effect meets the commercial requirement, so that the relation between the time of the ion exchange of the glass with qualified quality and the depth of a stress layer is obtained, a curve graph of the ion exchange time and the depth of the stress layer is further obtained, then the glass with the flaw on the surface and subjected to mechanical polishing is subjected to stress layer detection, and is compared with the curve graph of the depth of the stress layer obtained before, and further the time of the first ion exchange is obtained. For example, the glass product with surface flaw and mechanical polishing is tested for stress layer to obtain the depth of the stress layer of only 80 μm, and compared with the stress layer depth curve chart of the qualified glass product, the ion exchange time required for the depth of the stress layer of the qualified glass product to reach 80 μm is 1h, and the depth of the stress layer of the glass product needs to be measuredWhen the thickness of the stress layer of the glass product is increased to 120 μm and compared with the stress layer depth curve chart of the qualified glass product, the ion exchange time required for the stress layer depth of the qualified glass product to reach 120 μm is found to be 4 hours, and the first ion exchange time of the glass product with flaws on the surface and after mechanical polishing is found to be 3 hours. The time for the first ion exchange can include 10min to 5 hours and all ranges and subranges therebetween, e.g., 20min to 1 hour, 1h to 2 hours, 1h to 3 hours, 2h to 5 hours, 3h to 5 hours, 4h to 5 hours, 2h to 4 hours, 2h to 4.5 hours, 1.5h to 2.5 hours, 2.5h to 3.5 hours, 1.5h to 4.5 hours, 2.5h to 4.5 hours, 3.5h to 4.5 hours, 4.5h to 5 hours, 30min to 1 hour, 40min to 2 hours, 50min to 1 hour, 45min to 3 hours, 1.5h to 5 hours, 20min to 4.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours, etc. The temperature of the first ion exchange can include 410 deg.C to 450 deg.C and all ranges and subranges therebetween, such as 410 deg.C, 420 deg.C, 430 deg.C, 440 deg.C, 450 deg.C, 410 deg.C to 435 deg.C, 425 deg.C to 445 deg.C, 420 deg.C to 435 deg.C, 415 deg.C to 445 deg.C, and the like.

However, although the glass has a deeper stress effect after the first ion exchange, the strength of the CS surface is still insufficient, and a new CS surface needs to be added to the glass, so that a second ion exchange is required, and KNO is selected as the salt bath for the second ion exchange₃Mainly by performing K⁺-Na⁺And (3) exchanging, namely improving the surface of the glass subjected to the first ion exchange, and endowing the glass with a new surface CS, so that the resistance of the whole glass to breakage is further improved. The time for the second ion exchange is 10min to 4h, and may include 10min to 4h and all ranges and subranges therebetween, such as 10min to 20min, 10min to 2h, 10min to 30min, 10min to 3h, 10min to 50min, 20min to 3h, 20min to 4h, 20min to 50min, 20min to 1h, 30min to 2h, 30min to 50min, 30min to 1h, 40min to 3h, 40min to 1h, 15min to 25min, 15min to 35min, 25min to 45min, 25min to 55min, 10min, 15min, 20min, 25min, 30min, 40min, 50min, 1h, 2h, 3h or 4h, and the like. The temperature of the second ion exchange can include 410 deg.C to 450 deg.C and all ranges and subranges therebetween, e.g., 415 deg.C, 425 deg.C, 435 deg.C, 445 deg.C, 450 deg.C, 415 deg.C to 430 deg.C, 420 deg.C to 440 deg.C, 425 deg.C to 430 deg.C, 410 deg.C440 ℃, etc.

In some embodiments, after mechanical polishing and two ion exchanges, defects may still be formed on a portion of the glass surface due to the change in ion volume, the defects may include depressions or protrusions or other forms, the defects may be point-shaped or linear, and there is no limitation on the specific shape of the defects, and step 1) and step 2) may be repeated again for a plurality of times until glass without surface defects is obtained. The number of times step 1) and step 2) are repeated may be 2 times, or may be 3 times, or may be 4 times, or may be 5 times, or may be 6 times, or may be 7 times, or may be 8 times, or may be 9 times, or may be 10 times. The number of times of the two steps are alternately repeated is related to the thickness and the effective thickness of the glass product, and the requirement on the effective thickness of the glass product is different due to different final applications of the glass product.

In some embodiments, step 1) the glass has flaws including at least one surface flaw having a height or depth of greater than or equal to 2nm and a width or length of greater than or equal to 7 μm. Generally, after the glass is chemically strengthened, a series of subsequent treatment processes such as cleaning, silk-screen printing, film coating and the like are performed on the glass, and before each process, the surface of the glass is visually detected through a microscope to judge whether the surface of the glass has flaws. The flaws may be depressions or protrusions, but are not limited to these, and may be in other forms. The method is characterized in that a quadratic element image measuring instrument is adopted to observe glass with flaws on the surface, when the magnification is adjusted to 87.7 times, the attached drawing 1 is obtained, the scratch flaws on the surface of the glass are shown in the attached drawing 1, meanwhile, a plurality of fine black spots can be observed in the attached drawing 1, and the fine pits are probably formed on the surface of the glass, compared with the scratch flaws, the sizes of the fine pits are very small, the industrial performance of the glass cannot be influenced, and therefore the method is in an acceptable range. The defects are not limited to scratch defects shown in the attached drawings, and include point defects, linear defects, sensitive scratches, non-sensitive scratches, pockmarks, dirt and the like. Some flaws are oversized and seriously affect the industrial properties of the glass, for example, some flaws may lead to a reduction in the resistance of the glass to breakage, while some flaws may seriously affect the appearance of the glass product, for example, bright spots, black spots, inner stains, pinholes, jaggies, color spots, bubbles, white spots, etc. appearing on the surface of the glass product, and the glass with these flaws is considered to be an unacceptable glass product. For such defective glass products, it is necessary to reprocess them to make the surface flaws within the allowable range of commercial products. The invention is not limited to the shape of the flaws. In some embodiments, the flaws are visible to the naked eye. In other embodiments, the blemish may only be visible when placed under a green light, or using a microscope or other magnifying glass. In some embodiments, the glass surface has at least one flaw, and the flaw has a height or depth of greater than or equal to 2nm, which can be from 2nm to 100nm, or from 2nm to 200nm, or from 2nm to 300nm, or from 2nm to 400nm, or from 2nm to 500nm, or from 2nm to 600nm, or from 2nm to 700nm, or from 2nm to 800nm, or from 2nm to 10nm, or from 100nm to 500nm, or from 100nm to 1000nm, or from 200nm to 2000nm, or from 500nm to 1000nm, or from 1000nm to 10 μm, or from 100nm to 5 μm, or from 200nm to 50 μm, or from 2nm to 80 μm, or from 10nm to 60 μm, or from 100nm to 30 μm, or from 200nm to 30 μm, or from 500nm to 30 μm, or from 1000nm to 30 μm, or from 30 μm to 30 μm, or the like, or from 30 μm to 100 μm, or from 30 μm to 40 μm, or 40 μm to 50 μm, or 30 μm to 60 μm, or 30 μm to 70 μm, or 30 μm to 80 μm, or 30 μm to 90 μm, or 40 μm to 140 μm, or 30 μm to 150 μm, etc., or 10nm to 10mm, or 100nm to 15mm, or 100nm to 100 mm; the width or length of the flaw is greater than or equal to 7 μm, may be 0.03mm to 5.0mm, or 0.03mm to 7.0mm, or 0.03mm to 4.0mm, or 0.03mm to 9.0mm, or 0.06mm to 5.0mm, or 0.07mm to 9.0mm, or 0.09mm to 6.0mm, or 0.08mm to 9.0mm, or 0.07mm to 9.0mm, or 0.03mm to 10.0mm, or 0.07mm to 3.0mm, or 0.07mm to 9.6mm, or 0.06mm to 8.5mm, or 0.03mm to 6.5mm, or 7 μm to 100 μm, or 7 μm to 10 μm, or 7 μm to 20 μm, or 7 μm to 50 μm, or 7 μm to 200mm, or 7 μm to 1000 μm, or 7 μm to 500 μm; or 10 μm to 10mm, or 10 μm to 100mm, etc.

In some embodiments, step 1) the glass is polished to a thickness not less than the height or depth of the flaws that the glass has. When the flaw is a bump, the thickness of the glass subjected to optional mechanical polishing in the step 1) is not less than the height of the bump, and preferably the thickness of the glass subjected to optional mechanical polishing is equal to the height of the bump; when the flaw is a recess, the glass is subjected to optional mechanical polishing in the step 1) to a thickness not less than the depth of the recess, and preferably the thickness of the optional mechanical polishing is equal to the depth of the recess. When the flaws are in forms other than protrusions and depressions, step 1) the glass is optionally mechanically polished to a thickness that will completely polish the flaws off the glass surface. The glass is cleaned (e.g., by using a cleaning agent and ultrasonic cleaning) after mechanical polishing, and the surface is cleaned of dust particles for subsequent ion exchange. In actual production, the thickness of the mechanical polishing can be smaller than the height or depth of the flaw on the glass, but the height or depth of the flaw on the surface of the glass after polishing is small enough, namely the height or depth of the flaw is less than or equal to 2nm, so that the flaw on the surface of the glass can be prevented from being further enlarged in the subsequent processing process, and further unqualified glass products can be avoided. Therefore, through research, the method of the invention has found that the polishing thickness of the glass is optimal to remove the flaws on the surface of the glass, but the mechanical polishing thickness should not be too large from the subsequent process treatment and cost considerations, and the product of the thickness of each mechanical polishing and the number of mechanical polishing times is preferably smaller than the difference between the thickness of the glass product and the effective thickness.

In particular, the glass treated by the method has no surface flaws, the glass without surface flaws does not contain flaws with the height or depth of more than or equal to 2nm and the width or length of more than or equal to 0.007mm, and the CS of the surface of the glass without surface flaws is not less than 680 MPa. In practical applications, not all glasses with flaws are rejected, and some flaws are unacceptable, such as perceived scratches, pocks, spots, white spots, black spots and smudges, without limiting the cause of the formation of these flaws, which seriously affect the surface appearance of the glass article without being allowed to occur. But for other types of flaws whose size does not affect the industrial properties of the glass, the size of the flaw can be considered to be within the range allowed for commercial production, and such glass articles with surface flaws are acceptable, for example the fine depressions of fig. 1 are acceptable. The glass obtained by the method of the invention has a part of the surface of the glass which has no flaws, but may have flaws on the surface of the glass, but the size of the flaws is small, which does not affect the performance of the glass product, and the influence on the appearance of the glass product is negligible, so that the glass product can be used as commercial products. Therefore, the surface of the glass has flaws within the commercial product tolerance range, and the glass without the flaws can be regarded as surface flaw-free glass together with the glass without the flaws on the surface. In some embodiments, the height or depth of the flaws is less than or equal to 2nm, and may be 1nm to 2nm, or 1nm, or 2nm, etc., or even less; the width or length of the flaw is less than 7 μm, and may be 1 μm to 3 μm, or 2 μm to 4 μm, or 3 μm to 5 μm, or 4 μm to 6 μm, or 5 μm to 7 μm, or 1 μm to 2 μm, or 2 μm to 3 μm, or 3 μm to 4 μm, or 4 μm to 5 μm, or 5 μm to 6 μm, or 6 μm to 7 μm, or 1 μm to 4 μm, or 2 μm to 5 μm, or 3 μm to 6 μm, or 4 μm to 7 μm, or 1 μm to 5 μm, or 2 μm to 6 μm, or 3 μm to 7 μm, or 1 μm to 6 μm, or 2 μm to 7 μm, or the like; the surface CS of the glass without surface defects is not less than 680MPa, preferably 680MPa to 900MPa, preferably 680MPa to 920MPa, preferably 680MPa to 980MPa, preferably 680MPa to 990MPa, preferably 680MPa to 1000MPa, preferably 1100MPa to 1200MPa, preferably 1200MPa to 1300MPa, preferably 900MPa to 1200MPa, preferably 900MPa to 1100MPa, preferably 1000MPa to 1300 MPa.

In some embodiments, step 2) involves not less than 99wt% of NaNO in the salt bath used for the first ion exchange₃. After the optional mechanical polishing is performed on one or more surfaces of the glass with flaws, the flaws on the surface of the glass can be polished off, and the CS layer on the surface of the glass can also be polished off, and more seriously, the deep stress of the glass can be adversely affected, so that the deep stress of the glass after mechanical polishing is reduced, and therefore, for the glass product after mechanical polishing, a new deeper stress effect needs to be given again firstly, which can be realized by performing the first ion exchange. The first ion exchange salt bath is NaNO₃By reaction with Na⁺-Li⁺Ion exchange causes lithium ions of the glass having a smaller radius to diffuse from the surface of the glass into the salt bath, while sodium ions of a larger radius from the salt bath replace the lithium ions of the glass having a smaller radius. Moreover, because the lithium aluminosilicate glass has higher lithium ion content, the exchange amount of lithium ions of the glass product and sodium ions in the salt bath is larger, and the sodium ions can be exchanged with lithium ions deeper in the glass product, so that a new and deeper stress effect is formed on the surface of the glass, the resistance of the glass to breakage is further increased, and the glass obtains stronger and even better anti-falling performance again. NaNO in first ion exchange salt bath₃The amount of (B) is not less than 99wt%, including not less than 99wt% and all ranges and subranges therebetween, for example, 99wt% to 99.2 wt%, 99wt% to 99.4 wt%, 99wt% to 99.5wt%, 99wt% to 99.6 wt%, 99wt% to 99.7wt%, 99wt% to 99.8wt%, 99wt% to 99.9wt%, 99wt% to 99.99 wt%, 99wt% to 99.1 wt%, 99wt% to 100 wt%, 99.1 wt%, 99.2 wt%, 99.3 wt%, 99.4 wt%, 99.5wt%, 99.6 wt%, 99.7wt%, 99.8wt%, 99.9wt%, 100 wt%.

In some embodiments, step 2) uses a salt bath for the first ion exchange having a concentration of lithium ions of no more than 1000 ppm. Salt bath used in first ion exchangeThe concentration of lithium ions is strictly controlled because the first ion exchange is performed with Na⁺-Li⁺Ion exchange, the too high lithium ion concentration can seriously influence the effect of ion exchange for the first time in the salt bath, can lead to the lithium ion of glassware depths to be more difficult for being traded out to obtain the stress effect of deeper level to glass and cause harmful effects, lead to the stress layer thickness of glass lower, need control the lithium ion concentration in the salt bath that ion exchange used for the first time in certain extent. In some embodiments, this may be accomplished in a number of ways, for example, but not limited to, by adding an amount of ion sieve functional ceramic product "KmateTM" from Chongqingxin Jingshi specialty glass, Inc. or sodium phosphate to the first salt bath to reduce the concentration of lithium ions in the salt bath. In some embodiments, an ion sieve functional ceramic product may be added to the salt bath for adsorption of lithium ions in the salt bath. The ion sieve functional ceramic product is a crystal containing oxides of Si, Al and Na, a plurality of pores with uniform pore sizes are formed in the crystal after the zeolite is dehydrated through high-temperature activation, the structure has strong adsorption capacity, ions with diameters smaller than the pore sizes can be effectively sucked into the pores by utilizing the volume difference of the ions, and the ions with diameters larger than the pore sizes are blocked outside the crystal, so that the ions with different diameters can be separated, the addition amount of the ion sieve functional ceramic product is 0.5-1.5 wt% of the mass of the salt bath, and the adsorption time is 6-10 h. In other embodiments, sodium phosphate can be added to the salt bath in an amount of 0.1 wt% to 1 wt% of the mass of the salt bath to precipitate lithium ions from the salt bath. Thus, the lithium ion concentration in the salt bath used in the first ion exchange includes all ranges and subranges not exceeding 1000ppm and between, e.g., 100ppm to 1000ppm, 200ppm to 1000ppm, 300ppm to 1000ppm, 400ppm to 1000ppm, 500ppm to 1000ppm, 600ppm to 1000ppm, 700ppm to 1000ppm, 800ppm to 1000ppm, 900ppm to 1000ppm, 550ppm to 700ppm, 400ppm to 800ppm, 200ppm to 500ppm, 300ppm to 600ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm, 1000ppm, 210ppm, 420ppm, 530ppm, 640ppm, 850ppm, etc.

In some embodiments, step 2) uses a salt bath comprising not less than 99.9 wt.% KNO in the salt bath for the second ion exchange₃. Because the glass is endowed with new deeper stress effect after the first ion exchange, and simultaneously, the glass needs to be subjected to the second ion exchange to ensure that the glass is subjected to K⁺-Na⁺And exchanging to endow the glass with a new surface CS layer, and further improving the strength of the glass. KNO is used for the second ion exchange₃A salt bath containing KNO not less than 99.9wt%₃And all ranges and subranges therebetween, e.g., 99.91 to 99.92, 99.9 to 99.93, 99.9 to 99.94, 99.9 to 99.95, 99.9 to 99.96, 99.9 to 99.97, 99.9 to 99.98, 99.9 to 99.99, 99.9 to 100, etc.

The invention also provides a method for recycling the tempered glass, which comprises the following steps:

1) providing a strengthened glass having flaws, optionally mechanically polishing one or more surfaces of the glass having flaws, wherein the glass comprises a high alumina silica glass;

2) carrying out ion exchange treatment on the glass treated in the step 1) to obtain the glass without surface defects, wherein:

ion exchange: heating a salt bath containing at least one monovalent salt to 360-450 ℃, and putting the glass after mechanical polishing into the salt bath for ion exchange, wherein the ion exchange time is 30 min-5 h.

When the glass is high-alumina-silica glass, after one or more surfaces with flaw of the glass are subjected to optional mechanical polishing, because the content of lithium ions in the high-alumina-silica glass is very low and the exchange amount of sodium ions and lithium ions is almost zero, the high-alumina-silica glass only needs to be subjected to ion exchange once, a salt bath containing potassium ions is selected as the salt bath for the ion exchange, and K is carried out⁺-Na⁺The exchange of (1) causes alkali metal ions with smaller radius in the glass to diffuse from the surface of the glass into the salt bath, and simultaneously,the alkali metal ions with larger radius from the salt bath replace the alkali metal ions with smaller radius on the surface of the glass, thereby endowing the glass with new stress effect. The time of ion exchange is 30min to 5h, and can include 30min to 5h and all ranges and subranges therebetween, such as 30min to 50min, 30min to 40min, 30min to 1h, 50min to 2h, 1h to 1.5h, 40min to 2.5h, 45min to 3.5h, 1h to 4h, 55min to 1.5h, 30min to 2h, 35min to 4h, 35min to 3.5h, 1h, 2h, 30min, 40min, 50min, 3h, 4h, 5h, or 4.5h, and the like. The temperature of the ion exchange is 360 ℃ to 450 ℃, and can include 360 ℃ to 450 ℃ and all ranges and subranges therebetween, such as 360 ℃ to 370 ℃, 365 ℃ to 380 ℃, 370 ℃ to 380 ℃, 375 ℃ to 385 ℃, 365 ℃ to 385 ℃, 395 ℃ to 400 ℃, 370 ℃ to 420 ℃, 380 ℃ to 430 ℃, 360 ℃ to 440 ℃, 395 ℃ to 400 ℃, 360 ℃, 370 ℃, 380 ℃, 375 ℃, 385 ℃, 390 ℃, 395 ℃, 410 ℃, 430 ℃, or 450 ℃, and the like.

In some embodiments, after mechanical polishing and ion exchange, due to the change of ion volume, flaws including depressions or protrusions may still be formed on a portion of the glass surface, and the flaws may be point-shaped, linear, or in other forms, and do not limit the form of flaws, and then step 1) and step 2) may be repeated again for the glass still having surface flaws until the glass without surface flaws is obtained. The number of times step 1) and step 2) are repeated may be 2 times, or may be 3 times, or may be 4 times, or may be 5 times, or may be 6 times, or may be 7 times, or may be 8 times, or may be 9 times, or may be 10 times. The two steps are alternately repeated for a number of times, which is related to the thickness of the glass product and the effective thickness, and the product of the thickness of each polishing and the number of times of polishing is smaller than the difference between the thickness of the glass product and the effective thickness.

In some embodiments, step 1) the glass has flaws including at least one surface flaw having a height or depth of greater than or equal to 2nm and a width or length of greater than or equal to 7 μm. As ion exchange proceeds, flaws may form on the glass surface due to changes in ion volume. In some embodiments, the flaws are visible to the naked eye. In other embodiments, the blemish may only be visible when placed under a green light, or using a microscope or other magnifying glass. In some embodiments, the glass surface has at least one flaw, and the flaw has a height or depth of greater than or equal to 2nm, which can be from 2nm to 100nm, or from 2nm to 200nm, or from 2nm to 300nm, or from 2nm to 400nm, or from 2nm to 500nm, or from 2nm to 600nm, or from 2nm to 700nm, or from 2nm to 800nm, or from 2nm to 10nm, or from 100nm to 500nm, or from 100nm to 1000nm, or from 200nm to 2000nm, or from 500nm to 1000nm, or from 1000nm to 10 μm, or from 100nm to 5 μm, or from 200nm to 50 μm, or from 2nm to 80 μm, or from 10nm to 60 μm, or from 100nm to 30 μm, or from 200nm to 30 μm, or from 500nm to 30 μm, or from 1000nm to 30 μm, or from 30 μm to 30 μm, or the like, or from 30 μm to 100 μm, or from 30 μm to 40 μm, or 40 μm to 50 μm, or 30 μm to 60 μm, or 30 μm to 70 μm, or 30 μm to 80 μm, or 30 μm to 90 μm, or 40 μm to 140 μm, or 30 μm to 150 μm, etc., or 10nm to 10mm, or 100nm to 15mm, or 100nm to 100 mm; the width or length of the flaw is greater than or equal to 7 μm, may be 0.03mm to 5.0mm, or 0.03mm to 7.0mm, or 0.03mm to 4.0mm, or 0.03mm to 9.0mm, or 0.06mm to 5.0mm, or 0.07mm to 9.0mm, or 0.09mm to 6.0mm, or 0.08mm to 9.0mm, or 0.07mm to 9.0mm, or 0.03mm to 10.0mm, or 0.07mm to 3.0mm, or 0.07mm to 9.6mm, or 0.06mm to 8.5mm, or 0.03mm to 6.5mm, or 7 μm to 100 μm, or 7 μm to 10 μm, or 7 μm to 20 μm, or 7 μm to 50 μm, or 7 μm to 200mm, or 7 μm to 1000 μm, or 7 μm to 500 μm; or 10 μm to 10mm, or 10 μm to 100mm, etc.

In some embodiments, step 1), the glass is mechanically polished to a thickness not less than the height or depth of the flaws that the glass has. When the flaw is a bump, the thickness of the glass subjected to optional mechanical polishing in the step 1) is not less than the height of the bump; when the flaw is a depression, the glass of step 1) is optionally mechanically polished to a thickness not less than the depth of the depression. The glass is cleaned (e.g., ultrasonically) after mechanical polishing, and the surface is cleaned of dust particles for subsequent ion exchange.

In particular, the glass treated by the method has no surface flaws, the glass without surface flaws does not contain flaws with the height or depth of more than or equal to 2nm and the width or length of more than or equal to 0.007mm, and the CS of the surface of the glass without surface flaws is not less than 680 MPa. In the glass obtained after the treatment by the method of the present invention, a part of the glass surface does not have flaws, and another part of the glass surface has flaws within the range permitted by commercial products. In some embodiments, the height or depth of the flaws is less than or equal to 2nm, and may be 1nm to 2nm, or 1nm, or 2nm, etc., or even less; the width or length of the flaw is less than 7 μm, and may be 1 μm to 3 μm, or 2 μm to 4 μm, or 3 μm to 5 μm, or 4 μm to 6 μm, or 5 μm to 7 μm, or 1 μm to 2 μm, or 2 μm to 3 μm, or 3 μm to 4 μm, or 4 μm to 5 μm, or 5 μm to 6 μm, or 6 μm to 7 μm, or 1 μm to 4 μm, or 2 μm to 5 μm, or 3 μm to 6 μm, or 4 μm to 7 μm, or 1 μm to 5 μm, or 2 μm to 6 μm, or 3 μm to 7 μm, or 1 μm to 6 μm, or 2 μm to 7 μm, or the like; the surface CS of the glass without surface defects is not less than 680MPa, preferably 680MPa to 780MPa, preferably 900MPa to 950MPa, preferably 680MPa to 920MPa, preferably 680MPa to 980MPa, preferably 680MPa to 990MPa, preferably 680MPa to 1000MPa, preferably 680MPa to 870MPa, preferably 680MPa to 940MPa, preferably 900MPa to 910MPa, preferably 1000MPa to 1100MPa, preferably 1100MPa to 1200 MPa.

In some embodiments, step 2) involves ion-exchanging the salt bath comprising not less than 99.9 wt.% KNO₃. After one or more surfaces with flaws are subjected to optional mechanical polishing, the flaws on the surfaces of the glass can be polished off, and the original stress effect of the glass is also polished off, so that new stress effect needs to be given to the glassShould be used. Because the glass is high-alumina-silica glass, the lithium ion content in the glass is very low, and the exchange amount of Na and Li is almost zero, the ion exchange is only needed to be carried out once for the high-alumina-silica glass, and the salt bath of the ion exchange selects the salt bath containing potassium ions to carry out the exchange of K < + > -Na < + >. KNO in ion-exchange salt bath₃The amount of (b) is not less than 99wt%, including not less than 99wt% and all ranges and subranges therebetween, for example, 99wt% to 99.2 wt%, 99wt% to 99.4 wt%, 99wt% to 99.5wt%, 99wt% to 99.6 wt%, 99wt% to 99.7wt%, 99wt% to 99.8wt%, 99wt% to 99.9wt%, 99wt% to 99.99 wt%, 99wt% to 99.1 wt%, 99wt% to 100 wt%, 99.1 wt%, 99.2 wt%, 99.3 wt%, 99.4 wt%, 99.5wt%, 99.6 wt%, 99.7wt%, 99.8wt%, 99.9wt%, 100 wt%, etc.

The invention also discloses a consumer electronic terminal which comprises a shell and an electronic component, wherein the electronic component is partially positioned in the shell. The housing includes a front surface, a rear surface, and side surfaces; the electronic assembly includes a display located at or adjacent the front surface of the housing; the front surface or/and the back surface or/and the side surface comprise a glass product obtained by the method for recycling tempered glass of the present invention. Consumer electronics terminals include cell phones, tablets or other electronic terminals.

The glass articles obtained from the methods of recycling strengthened glass of the present invention can be included in other articles, such as articles having displays (or display articles) (e.g., consumer electronics products, including mobile phones, tablets, computers, navigation systems, etc.), construction articles, transportation articles (e.g., automobiles, trains, airplanes, marine craft, etc.), appliance articles, or any article that requires some transparency, scratch resistance, abrasion resistance, or combination thereof.

In some embodiments, a cover article may also be included that covers the front surface of the housing or is positioned over the display, and the cover article and/or a portion of the housing includes a glass article obtained from the method of recycling strengthened glass of the present invention.

Third, the present invention will be explained below by way of specific examples

Table 1 shows the composition of the lithium aluminosilicate glass of the present invention:

table 1 (calculation of mole percent)

Components	Example 1
		SiO₂	63
Al₂O₃	16.2
		P₂O₅	2.6
B₂O₃	0.8
		MgO	0.3
Na₂O	8.5
		Li₂O	8.6

Note: - -means free of this component.

The recycling method is suitable for the lithium aluminosilicate glass, the component content of the lithium aluminosilicate glass is not limited to the component content disclosed by the invention, and the components of the lithium aluminosilicate glass disclosed by the invention are only exemplified.

Table 2 shows the composition of the high aluminosilicate glass according to the present invention:

table 2 (calculation of mole percent)

Components	Example 6
		SiO₂	66
Al₂O₃	13.2
		P₂O₅	--
B₂O₃	4.5
		MgO	2.3
Na₂O	14
		Li₂O	--

Note: - -means free of this component.

The recycling method of the invention is also suitable for high alumina-silica glass, and the component content of the high alumina-silica glass is not limited to the component content disclosed by the invention, and the component of the high alumina-silica glass disclosed by the invention is only illustrated by way of example.

In the following table, D represents the diameter, W represents the width, L represents the length, H represents the depth, DS represents the distance between two adjacent flaws, N represents the number of flaws, and when the flaws on the surface of the glass are irregular, the distance between the farthest ends of the irregular shape is selected as the length; when the glass surface flaw is irregular but approximately circular, the distance between the furthest ends of the irregular shape is chosen to be the diameter. The length and/or width or diameter of the flaw is measured to determine whether the glass having the flaw needs to be recycled.

Examples 1 to 5 are lithium aluminosilicate glasses having the components shown in table 1, which were chemically strengthened and then screened before subsequent processes such as cleaning and/or transportation and/or screen printing and/or plating, and which had surface flaws of sizes considered to require recycling. Meanwhile, in the following examples, the present invention is not limited to the chemical strengthening process conditions performed before the subsequent process of the lithium aluminosilicate glass having a flaw on the surface, and the chemical strengthening process conditions of the lithium aluminosilicate glass given in the examples are only exemplified.

Taking example 1 as an example, the strengthened glass can be obtained by the following chemical strengthening process, but is not limited to the following chemical strengthening process:

1) preheating lithium-aluminum-silicon glass to 420 ℃, and then heating the lithium-aluminum-silicon glass to 430 ℃, wherein the lithium-aluminum-silicon glass contains 100 wt% of NaNO₃Ion exchange is carried out for 5 hours in the salt bath;

2) taking out the glass treated in the step 1), and then heating the glass to 430 ℃ and the glass containing 100 wt% of KNO₃Ion exchange is carried out for 40min in the salt bath;

3) taking out the glass treated in the step 2) and cooling to obtain the strengthened glass.

The chemical strengthening process is merely exemplary and the present invention is not limited to the way of obtaining strengthened glass.

Table 3 shows the results of the chemical strengthening of examples 1 to 5:

TABLE 3

Similarly, in examples 6 to 10, the high alumina silica glass having the components shown in table 2 was selected after chemical strengthening before subsequent processes such as cleaning and/or transportation and/or screen printing and/or plating, and the size of flaws on the surface was considered to be required to be recycled. Meanwhile, in the following examples, the present invention is not limited to the chemical strengthening process conditions performed before the subsequent process of the high aluminosilicate glass having a flaw on the surface, and the chemical strengthening process conditions of the high aluminosilicate glass given in the examples are only exemplified.

Taking example 6 as an example, the strengthened glass can be obtained by the following chemical strengthening process, but is not limited to the following chemical strengthening process:

1) preheating high-alumina-silicon glass to 460 ℃, putting the high-alumina-silicon glass into the high-alumina-silicon glass, heating the high-alumina-silicon glass to 430 ℃, wherein the high-alumina-silicon glass contains 100 wt% of KNO and₃ion exchange is carried out for 4 hours in the salt bath;

Table 4 shows the results of chemical strengthening in examples 6 to 10:

TABLE 4

Examples 6 to 10 are high alumina silica glass having the composition shown in table 2, which is chemically strengthened and then screened out before subsequent processes such as cleaning and/or transportation and/or screen printing and/or plating, and the surface of the high alumina silica glass has a defect size which is considered to require recycling.

As can be seen from tables 3 and 4, the surface of the glass has flaws after the subsequent processes such as cleaning and/or transportation and/or silk-screening and/or coating, but it can also be seen from CS or CT-LD on the surface of the glass product that these glass products still have high stress effect, but the surface of the glass product has flaws that exceed the allowable range of commercial products, so these glass products can be regarded as unqualified glass products. Since the direct discarding of this portion of glass products leads to a significant increase in production costs, it is necessary to recycle glass products that are regarded as defective due to surface flaws, to obtain acceptable glass products, and to reuse the acceptable glass products for commercial use. Therefore, the lithium aluminosilicate glass examples 1 to 5 and the high aluminosilicate glass examples 6 to 10 having different types of defects are selected and treated by the recycling method of the present invention.

The invention provides a method for recycling tempered glass, taking an example 1 as an example, and specifically comprises the following steps:

1) example 1 is a lithium aluminosilicate glass, the glass has flaws on the surface after strengthening, and is regarded as an unqualified glass product, and the surface with flaws in example 1 is mechanically polished by a polishing machine to a thickness not less than the depth of the surface flaws.

first ion exchange: will contain 100 wt% NaNO₃The salt bath was heated to 430 ℃ and the ion exchange time was 30 min. And monitoring the concentration of lithium ions in the first ion exchange salt bath, and if the concentration exceeds 1000ppm, adding an ion sieve functional ceramic product or sodium phosphate to control the concentration of the lithium ions, wherein the adding amount is 1 wt% of the mass of the salt bath. Alternatively, the concentration of lithium ions can be controlled by adding sodium phosphate in an amount of 1 wt% based on the mass of the salt bath.

And (3) second ion exchange: will contain 100 wt% KNO₃The salt bath was heated to 430 ℃ and the ion exchange time was 30 min.

TABLE 5

As can be seen from the comparative analysis of Table 3 and Table 5, the surface flaws of the strengthened glass are greatly improved in examples 1-5 after the mechanical polishing and the two-time ion exchange treatment according to the invention, and no flaws are detected on the surfaces of the glass products of the examples after the treatment according to the method of the invention, so that the glass products which originally have flaws and are not qualified have commercial value again. Furthermore, as can be seen from table 5, mechanical polishing not only polishes away the CS layer on the surface, but also adversely affects the deep stress of the glass, especially when the glass is a lithium aluminosilicate glass. When the glass is lithium-aluminum-silicon glass, the invention needs to endow the glass after mechanical polishing with a new surface CS layer and re-strengthen the deep stress of the glass. The invention carries out targeted polishing and grinding on glass according to different depths or thicknesses of flaws on the surface of the glass, takes example 1 as an example, carries out stress layer detection on the polished example 1 to obtain the depth of the stress layer of 101 mu m, and compares the depth with the stress layer depth curve graph of qualified glass products to obtain the ion exchange time t required by the depth of the stress layer of the qualified glass products reaching 100 mu m₁The depth of the stress layer of example 1 after polishing needs to be increased to 120 μm, and compared with the stress layer depth curve chart of the qualified glass product, the ion exchange time t needed for obtaining the depth of the stress layer of the qualified glass product to reach 120 μm is₂The time for the first ion exchange of example 1 after polishing was t₁And t₂The difference value of the DOL values is 30min, the polished glass product is subjected to targeted ion exchange, the DOL of the polished glass product can reach higher depth through the high lithium content of the lithium-aluminum-silicon glass in the first ion exchange and the reaction condition of the first ion exchange, the CS value of the surface of the glass product is improved through the second ion exchange, and a new CS value is endowed to the glass product again, so that the glass product without surface defects, which is obtained through the treatment of the method, has more excellent performanceThe stress performance of the reinforced glass is obviously improved, namely CT-LD and DOL-0 are obviously improved, and the anti-falling height of the reinforced glass is obviously improved. In example 4 and example 5, although the surface of the glass has defects after mechanical polishing and two times of ion exchange, the size of the defects is reduced to a certain extent after detection, and the condition of the defects on the surface of the glass is improved, but the glass cannot be regarded as a qualified commercial product, so that the mechanical polishing and the ion exchange treatment are repeated for a plurality of times on the surface of the glass in example 4 and example 5, the condition of the surface of the glass is greatly improved, and the treated surface of the glass does not have defects.

Taking the embodiment 6 as an example, the method specifically comprises the following steps:

1) example 6 is a high aluminosilicate glass, the glass has flaws on the surface after strengthening, and is considered to be an unacceptable glass product, and the surface with flaws in example 6 is mechanically polished by a polishing machine to a thickness not less than the depth of the flaws.

ion exchange: will contain 100 wt% KNO₃The salt bath is heated to 430 ℃, the glass after mechanical polishing is put into the salt bath for ion exchange, and the ion exchange time is 1 h.

TABLE 6

From the analysis of tables 4 and 6, it can also be seen that the surface flaws of the glass products are greatly improved in the examples after the mechanical polishing and the two ion exchanges according to the present invention, and no flaws are detected on the surfaces of the glass products of the examples after the mechanical polishing and the two ion exchanges according to the present invention, so that the glass products which are originally defective and cannot be qualified are endowed with commercial values again. Moreover, the glass product without surface flaws obtained after the treatment by the method still has excellent stress performance, CS and DOL are improved to different degrees, and the reaction is obviously improved in the anti-falling height of the glass, which also shows that the glass product treated by the method still can obtain the same or even better stress effect as before the treatment.

The invention combines mechanical polishing and ion exchange, firstly polishes the surface with flaw of the strengthened glass, and polishes the surface flaw to remove the surface flaw; treating the polished surface of the lithium aluminum silicate glass by adopting ion exchange, wherein the lithium aluminum silicate glass needs to be subjected to ion exchange twice, the first ion exchange endows the surface of the glass with a new deeper stress effect, and the second ion exchange endows the glass with a new surface CS, so that the polished surface of the lithium aluminum silicate glass has a composite stress layer; for the high-alumina-silica glass, only one ion exchange is needed, and a new surface CS is endowed to the high-alumina-silica glass through the ion exchange. By the combined method of mechanical polishing and ion exchange, new stress effect can be endowed to the surface of the glass again, so that the resistance of the glass to cracking is increased, the treated glass meets the commercial requirement, and the commercial value of the treated glass is finally improved.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the technical solutions, and those skilled in the art should understand that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all that should be covered by the claims of the present invention.

Claims

1. A method for recycling tempered glass is characterized by comprising the following steps:

2. A method for recycling tempered glass is characterized by comprising the following steps:

2) carrying out the following ion exchange on the strengthened glass treated in the step 1), wherein:

and (3) second ion exchange: heating a salt bath containing at least one monovalent salt different from the first ion exchange to 410-450 ℃, and putting the glass subjected to the first ion exchange treatment into the salt bath for second ion exchange, wherein the ion exchange time is 10 min-4 h;

3) and (3) sequentially repeating the step 1) and the step 2) to obtain the glass without surface flaws.

3. The method for recycling strengthened glass according to claim 1 or 2, wherein the glass in step 1) has defects comprising at least one surface defect having a height or depth of 2nm or more and a width or length of 7 μm or more.

4. The method for recycling the strengthened glass according to claim 3, wherein the glass is optionally mechanically polished to a thickness not less than the height or depth of the flaws in the glass in step 1).

5. The method of recycling strengthened glass according to claim 1 or 2, wherein the glass without surface flaws does not contain flaws with a height or depth of 2nm or more and a width or length of 0.007mm or more, and the surface CS of the glass without surface flaws is not less than 680 MPa.

6. The method for recycling strengthened glass according to claim 1 or 2, wherein the salt bath used in the first ion exchange in step 2) contains not less than 99wt% of NaNO₃Preferably, it contains not less than 99.5wt% of NaNO₃Preferably, it contains not less than 99.7wt% of NaNO₃Preferably, it contains not less than 99.8wt% of NaNO₃。

7. The method for recycling strengthened glass according to claim 6, wherein in step 2), the concentration of lithium ions in the salt bath used in the first ion exchange is not higher than 1000ppm, preferably not higher than 950ppm, preferably not higher than 900ppm, preferably not higher than 850 ppm.

8. The method for recycling the tempered glass according to claim 7, wherein an ion sieve is added into the salt bath used in the first ion exchange in the step 2) to control the concentration of lithium ions in the salt bath, the addition amount of the ion sieve is 0.5-1.5 wt% of the mass of the salt bath, and the adsorption time is 6-10 h.

9. The method for recycling strengthened glass according to claim 6, wherein the salt bath used in the second ion exchange in step 2) contains KNO in an amount of not less than 99.9wt%₃Preferably comprising not less than 99.95 wt.% KNO₃Preferably comprising not less than 99.97 wt.% KNO₃Preferably comprising not less than 99.98 wt.% KNO₃。

10. An electronic terminal as a consumer product, comprising:

a housing comprising a front surface, a rear surface, and side surfaces;

the front surface or/and the back surface or/and the side surface comprises a glass product obtained by the method for recycling the tempered glass according to any one of claims 1 to 9;

further comprising a cover article overlying the front surface of the housing or on the display, the cover article comprising a glass article obtained by the method of recycling tempered glass of any of claims 1-9;