阅读说明：本技术 无硅盐浴提纯添加剂材料及其使用方法 (Silicon-free salt bath purification additive material and method of use thereof ) 是由 胡伟 谈宝权 覃文城 于 2019-10-16 设计创作，主要内容包括：一种无硅盐浴提纯添加剂材料及其使用方法。该无硅盐浴提纯添加剂材料,含34-60mol％的碱金属氧化物、30-60mol％的B-2O-3、和8-25mol％的其他氧化物,且所述盐浴提纯添加剂不含二氧化硅成分。该使用方法包括以下步骤：提供待提纯盐浴；将该无硅盐浴提纯添加剂材料添加至该待提纯盐浴中；待该无硅盐浴提纯添加剂材料与该待提纯盐浴的反应一定时间后取出该无硅盐浴提纯添加剂材料。将取出的该无硅盐浴提纯添加剂材料置入纯钠盐盐浴中；待该无硅盐浴提纯添加剂材料与该纯钠盐盐浴的反应一定时间后取出该无硅盐浴提纯添加剂材料待下一次使用。该无硅盐浴提纯添加剂材料具有可以快速吸收盐浴中的锂离子、钠离子,方便快捷取出,以及可重复多次利用的优点。(A silica-free salt bath purification additive material and a method of use thereof. The additive material for purifying silicon-free salt bath contains 34-60 mol% of alkali metal oxide and 30-60 mol% of B 2 O 3 And 8 to 25 mol% of other oxides, and the salt bath purification additive is free of silica components. The using method comprises the following steps: providing a salt bath to be purified; adding the silicon-free salt bath purification additive material to the salt bath to be purified; and taking out the additive material for purifying the silicon-free salt bath after the additive material for purifying the silicon-free salt bath reacts with the salt bath to be purified for a certain time. Putting the taken-out silicon-free salt bath purification additive material into a pure sodium salt bath; and taking out the additive material for purifying the silicon-free salt bath for the next use after the additive material for purifying the silicon-free salt bath reacts with the pure sodium salt bath for a certain time. The silicon-free salt bath purification additive material has the advantages of being capable of rapidly absorbing lithium ions and sodium ions in the salt bath, convenient and fast to take out, and capable of being repeatedly used for many times.)

1. A silica-free salt bath purification additive material, characterized in that: the additive material for purifying the silicon-free salt bath comprises 34-60 mol% of alkali metal oxide and 30-60 mol% of B in terms of molar percentage₂O₃And 8-25 mol% of other oxides, and the silicon-free salt bath purification additive material is free of silica.

2. The silicon-free salt bath purification additive material as claimed in claim 1, wherein: the molar content of the alkali metal oxide and B₂O₃The ratio of the molar content of (A) is more than 0.55; the other oxide includes Al₂O₃，Al₂O₃In an amount of B₂O₃10% or more of (A).

3. According to the claimsThe additive material for purifying the silicon-free salt bath according to claim 1, which is characterized in that: the alkali metal oxide includes and includes only Na₂O and/or K₂O。

4. The silicon-free salt bath purification additive material as claimed in claim 1, wherein: the other oxide includes Al₂O₃And also includes P₂O₅、ZrO₂、SnO₂、ZnO、Cr₂O₃、TiO₂At least one of (1).

5. The silicon-free salt bath purification additive material as claimed in claim 1, wherein: the additive material for purifying the silicon-free salt bath is granular, flaky or porous, and the orthographic projection of the additive material for purifying the silicon-free salt bath on any plane at least covers a square area with the length and width of 0.5 multiplied by 0.5 mm.

6. Use of a silicon-free salt bath for purifying an additive material according to any one of claims 1 to 5, comprising the steps of:

step S1, providing a salt bath to be purified, wherein the salt bath to be purified contains potassium ions or/and sodium ions or/and lithium ions;

step S2, adding the silicon-free salt bath purification additive material into the salt bath to be purified;

and step S3, taking out the additive material for purifying the silicon-free salt bath after the additive material for purifying the silicon-free salt bath reacts with the salt bath for purifying for a certain time.

7. The use method as claimed in claim 6, characterized in that the temperature of the salt bath to be purified is 350-550 ℃, the addition amount of the silicon-free salt bath purification additive material is 0.3-5 wt% of the mass of the salt bath to be purified, and the reaction time of the silicon-free salt bath purification additive material and the salt bath to be purified is at most 24 h.

8. Use according to claims 6-7, characterized in that it further comprises the following steps:

step S4, the silicon-free salt bath purification additive material taken out in the step S3 is placed in a pure sodium salt bath;

step S5, after the reaction between the silicon-free salt bath purification additive material and the pure sodium salt bath is carried out for a certain time, the silicon-free salt bath purification additive material is taken out for the next use, and the absorption efficiency of the silicon-free salt bath purification additive material obtained in the step S5 on lithium ions or sodium ions is reduced to be 50-95% of that of the silicon-free salt bath purification additive material in the step S2.

9. The use method as claimed in claim 8, wherein the temperature of the pure sodium salt bath is 350-550 ℃, and the reaction time of the silicon-free salt bath purification additive material and the pure sodium salt bath is 1-10 h.

Technical Field

The invention relates to the field of chemical industry, in particular to the technical field of purification of salt bath for glass chemical strengthening, and specifically relates to a silicon-free salt bath purification additive material and a use method thereof.

Background

In the process of placing the glass in the salt bath for chemical strengthening treatment, as the using time of the salt bath is prolonged and the number of the glass treated by the salt bath is increased, garbage ions Na in the salt bath⁺、Li⁺The content of (B) will increase, althoughBut only PPM level, but also be enough to seriously hinder the normal chemical tempering, lead to subsequent glass to go on through the CS value decline after the reinforcement, intensity descends by a wide margin, leads to final product quality to be difficult to manage and control. After the glass is chemically strengthened, the glass expands because the large ions in the salt bath replace the small ions in the glass, so that the compressive stress is formed on the surface of the glass, and the purpose of improving the strength of the glass is achieved. However, Li in the salt bath⁺The increase of the amount of the lithium aluminum silicon glass can seriously weaken the sodium-lithium exchange degree when the lithium aluminum silicon glass is chemically strengthened, so that the expansion degree after strengthening is reduced, the requirement of the chemically strengthened glass on the size of the glass in the cover plate of the mobile phone is within 20 microns, and Li in a salt bath is reduced⁺This increase in the number of steps will undoubtedly lead to an increase in the dimensional defect rate of the lithium aluminosilicate chemically strengthened glass. The above problems occurring in the field of strengthening are called "salt bath poisoning", and in order to solve the above problems, the conventional method is to replace a salt bath, but the process of replacing the salt bath is time-consuming and labor-consuming, and the cost is increased and the efficiency is reduced.

At present, a method for absorbing impurity ions (lithium ions) in a salt bath is proposed in the industry, wherein powdery sodium phosphate is put into the salt bath, the sodium phosphate is dissolved in the salt bath, and the phosphate and the lithium ions form lithium phosphate to precipitate so as to reduce the content of Li in garbage ions. However, the reaction after the lithium phosphate is introduced into the salt bath requires a chemical reaction time of more than 10 hours, the salt bath is turbid due to the formation of precipitates, and the lithium phosphate can be used after long-time clarification; therefore, salt bath and glass quality can not be managed in real time on line, and at best, batch management can only be realized; after the powdery sodium phosphate is added into the salt bath, a large amount of sodium ions are brought in, so that the effective proportion of the salt bath is changed; the sodium phosphate shows strong basicity and water absorption, and when the sodium phosphate is introduced into the salt bath, a large number of OH ions are introduced at the same time, so that the glass is strongly corroded, phosphate radicals invade silicon-oxygen bonds in a glass network structure, and the phosphate radicals and the silicon-oxygen bond structure change the network structure of the glass surface, so that the glass network is further damaged, and when the sodium phosphate is used for more than 30 hours, the glass strength cannot be increased, and the glass strength can be greatly reduced; when excessive sludge is formed at the bottom of the salt bath by the precipitated lithium phosphate, the effective working area of the salt bath is reduced, the yield is reduced, and the cleaning is difficult; after the lithium phosphate is used for a long time, the lithium phosphate is precipitated too much and is attached to the surface of the strengthened glass, so that the glass generates defects; the residual strong alkali phosphate in the salt bath is attached to the surface of the glass, and the glass is contacted with water in the air when being taken out of the salt bath, so that the glass is strongly corroded for the second time.

In addition, another absorption method for impurity ions (lithium ions) in a salt bath is proposed in the industry, in which a silicon-containing ion sieve is put into the salt bath, and the silicon-containing ion sieve is used for complexing and absorbing lithium ions in the salt bath. However, the silicon-containing ion sieve is formed on the basis of taking silicon-oxygen as a main backbone, and the backbone is small, so that the absorption efficiency and the rate are low; the silicon has a large atomic number and a large atomic mass, so that the active ingredients in the ion sieve are low, the use efficiency is low, and if a certain absorption efficiency is achieved, the consumption of the silicon-containing ion sieve is high, and the cost is high. In the long-term use process of the silicon-containing ion sieve, a small part of the silicon-containing ion sieve is pulverized under the action of high temperature, and the pulverized silicon-containing ion sieve contains a large amount of silicon component substances, and is easy to form bonding and crosslinking with a silicon dioxide component in the surface of glass at the high temperature of a salt bath, so that the surface of a strengthened glass finished product has granular defects, and the quality of the finished product is influenced.

In addition, in a glass processing plant, a salt bath furnace is generally 10 tons or even higher, the number of glass sheets treated in one strengthening process is as high as ten thousand, and in the ion exchange environment of the scale, if the salt bath is not subjected to environmental management and control, the strengthened glass is easily subjected to surface defects, the glass strength among batches is greatly reduced, and the salt bath is gradually failed.

Moreover, the main materials of the glass strengthening salt bath are potassium nitrate and sodium nitrate, and the potassium nitrate is a main component of a strong oxidant, inflammable and explosive; the sodium phosphate is strong base and weak acid salt, and has strong water absorption and corrosion; both of these are key materials of public safety regulations. In the glass processing process, the materials cannot be recycled, so that the use amount is large, which not only causes great damage to the environment, but also causes high production cost.

Therefore, the additive which has a large size and is convenient to take out from the salt bath and manages the salt bath on line in real time is urgently needed by people, impurity ions in the salt bath are effectively controlled, a stable ion exchange environment is provided for glass to be strengthened, and the stability and the strength of the batch production of the strengthened glass are ensured. In addition, the use amount of potassium nitrate and sodium nitrate can be greatly reduced, the pollution and damage degree to the environment can be effectively reduced, the production efficiency is improved, and the production cost is reduced. The characteristic of large size makes it have higher security and convenience in the operation process of saving, throwing in and fishing.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art and provides a silicon-free salt bath purification additive material and a using method thereof, wherein the silicon-free salt bath purification additive material can rapidly absorb lithium ions and sodium ions generated in a salt bath in a chemical strengthened glass process, so that the concentrations of the lithium ions and the sodium ions in the salt bath are ensured to be at a lower level, and the stability of the volume production size and the stability of the surface stress of the chemical strengthened glass are ensured. Furthermore, the additive material can be quickly, conveniently and quickly extracted in the silicon-free salt bath purification process, so that the influence on the production efficiency is reduced. Furthermore, the additive material for purifying the silicon-free salt bath can be repeatedly utilized after being treated to release absorbed impurity ions, so that the use amount is greatly reduced, and the cost is reduced. More particularly, the silica-free salt bath purification additive material does not contain silica, and it employs B₂O₃As a main structure, Al₂O₃As a secondary network architecture, compared with a silicon-free salt bath purification additive material containing silicon dioxide, the additive material has a lower synthesis temperature, the smelting temperature can be lower than 1000 ℃, so that the limitation condition of the smelting equipment is relaxed, and the smelting cost is greatly reduced. Still further, even if the additive material for purifying a silicon-free salt bath is partially pulverized at high temperature during long-term use, since it mainly contains a boron component substance rather than a silicon-containing component, it is not easily bonded or crosslinked with a silica component in the glass surface at high temperature of the salt bath, and prevents the silica component from being bonded or crosslinkedThe strengthened glass finished product has no granular defects, and the good quality of the product is ensured.

The technical scheme adopted by the invention for solving the technical problems is as follows: providing the silicon-free salt bath refining additive material, wherein the silicon-free salt bath refining additive material comprises 34-60 mol% of alkali metal oxide and 30-60 mol% of B in terms of molar percentage₂O₃And 8-25 mol% of other oxides, and the silicon-free salt bath purification additive material is free of silica.

As a preference for the silica-free salt bath purification additive material of the present invention, the molar content of the alkali metal oxide and B₂O₃The ratio of the molar content of (A) is more than 0.55; the other oxide includes Al₂O₃，Al₂O₃In an amount of B₂O₃10% or more of (A).

As a preference for the silicon-free salt bath purification additive material of the present invention, the alkali metal oxide includes and includes only Na₂O and/or K₂O。

As a preference for the silicon-free salt bath purification additive material of the present invention, the other oxide comprises Al₂O₃And also includes P₂O₅、ZrO₂、SnO₂、ZnO、Cr₂O₃、TiO₂At least one of (1).

Preferably, the additive material for purifying the silicon-free salt bath is granular, flaky or porous, and the orthographic projection of the additive material for purifying the silicon-free salt bath on any one plane at least covers a square area with the length and width of 0.5 multiplied by 0.5 mm.

In order to solve the technical problems, the invention also provides a using method of the additive material for purifying the silicon-free salt bath, which comprises the following steps:

step S1, providing a salt bath to be purified, wherein the salt bath to be purified contains potassium ions or/and sodium ions or/and lithium ions;

step S2, adding the silicon-free salt bath purification additive material into the salt bath to be purified;

and step S3, taking out the additive material for purifying the silicon-free salt bath after the additive material for purifying the silicon-free salt bath reacts with the salt bath for purifying for a certain time.

Preferably, the temperature of the salt bath to be purified is 350-550 ℃, the addition amount of the silicon-free salt bath purification additive material is 0.3-5 wt% of the mass of the salt bath to be purified, and the reaction time of the silicon-free salt bath purification additive material and the salt bath to be purified is at most 24 h.

As a preference of the use method provided by the present invention, the use method further comprises the steps of:

step S4, the silicon-free salt bath purification additive material taken out in the step S3 is placed in a pure sodium salt bath;

step S5, after the reaction between the silicon-free salt bath purification additive material and the pure sodium salt bath is carried out for a certain time, the silicon-free salt bath purification additive material is taken out for the next use, and the absorption efficiency of the silicon-free salt bath purification additive material obtained in the step S5 on lithium ions or sodium ions is reduced to be 50-95% of that of the silicon-free salt bath purification additive material in the step S2.

As the optimization of the using method provided by the invention, the temperature of the pure sodium salt bath is 350-550 ℃, and the reaction time of the silicon-free salt bath purification additive material and the pure sodium salt bath is 1-10 h.

Compared with the prior art, the additive material for purifying the silicon-free salt bath can quickly absorb lithium ions and sodium ions generated in the salt bath in the process of chemically strengthening glass, ensures that the concentrations of the lithium ions and the sodium ions in the salt bath are at a lower level, and ensures the stability of mass production size and the stability of surface stress of the chemically strengthened glass. Furthermore, the additive material can be quickly, conveniently and quickly extracted in the silicon-free salt bath purification process, so that the influence on the production efficiency is reduced. Furthermore, the additive material for purifying the silicon-free salt bath can be repeatedly utilized after being treated to release absorbed impurity ions, so that the use amount is greatly reduced, and the cost is reduced. More particularly, the silicon-free salt bath purification additiveThe additive material does not contain silicon dioxide, and B is adopted₂O₃As a main structure, Al₂O₃As a secondary network architecture, compared with a silicon-free salt bath purification additive material containing silicon dioxide, the additive material has a lower synthesis temperature, the smelting temperature can be lower than 1000 ℃, so that the limitation condition of the smelting equipment is relaxed, and the smelting cost is greatly reduced. Even if part of the additive material for purifying the silicon-free salt bath is pulverized under the action of high temperature in the long-term use process, the additive material is not easy to form bonding and crosslinking with a silicon dioxide component in the surface of glass at the high temperature of the salt bath because the additive material mainly contains a boron component substance but not a silicon-containing component, so that the particle defect of a glass finished product after being strengthened is avoided, and the good quality of the product is ensured.

Detailed Description

The invention provides a silicon-free salt bath purification additive material which can absorb lithium ions or sodium ions in a glass chemical strengthening salt bath. It is known that, in the glass strengthening process, after the glass chemical strengthening salt bath is used for a period of time, impurity metal ions (lithium ions or sodium ions) exchanged from the glass are increased in the salt bath, so that the glass chemical strengthening salt bath is inactivated and the effect of strengthening the glass is weakened. The additive material for purifying the silicon-free salt bath is added into the inactivated glass chemical strengthening salt bath, and after the additive material for purifying the silicon-free salt bath is reacted for a period of time at a certain temperature (the temperature is higher than the melting point of a molten salt compound), the additive material for purifying the silicon-free salt bath can absorb the impurity metal ions (lithium ions or sodium ions), so that the activity of the glass chemical strengthening salt bath is enhanced or recovered. More particularly, the additive material for purifying the silicon-free salt bath can release lithium ions or sodium ions after the lithium ions or the sodium ions are adsorbed, and the aim of recycling is fulfilled.

The additive material for purifying the silicon-free salt bath comprises 30-60 mol% of alkali metal oxide and 30-65 mol% of B in terms of molar percentage₂O₃And 8-25 mol% of other oxides, and the silicon-free salt bath purification additive material is free of silica. Wherein the molar content of the alkali metal oxide is equal to B₂O₃The ratio of the molar content of (A) is more than 0.6; the other oxide includes Al₂O₃，Al₂O₃In an amount of B₂O₃More than 10%; the other oxide further includes P₂O₅、ZrO₂、SnO₂、ZnO、Cr₂O₃、TiO₂At least one of (1). The alkali metal oxide comprises Na₂O and/or K₂O。

B₂O₃Is a backbone component of the additive material for purifying the silicon-free salt bath and is a necessary component.

Said other oxide and B₂O₃The selection of the composition and the content of the skeleton forming the covalent bond to form the salt bath purification additive network structure directly influences the adsorption performance of the salt bath purification additive network structure.

The metal element in the alkali metal oxide is intended to replace or extract the impurity metal ions in the salt bath, and it has been found through experiments that when the sum of the number of moles of the valence of at least one metal oxide in the alkali metal oxide (the alkali metal oxide participating in the reaction is not limited to the entire alkali metal oxide as long as part of the alkali metal oxide participating in the reaction can extract/replace the impurity metal ions in the salt bath to a predetermined concentration range) is equal to the sum of the number of moles of the valence of the impurity metal ions in the salt bath.

The alkali metal oxide includes a variety of cases, and may be a single monovalent metal oxide or a mixture of two or more monovalent metal oxides. Specifically, the metal element in the metal oxide is at least one of potassium and sodium; the monovalent metal oxide is selected from the group consisting of a carbonate, a fluoride, a sulfate, a nitrate, a phosphate, a hydroxide, an oxide, a chloride, or a mixture thereof. The raw materials of the monovalent metal oxide are reacted during the preparation of the salt bath purification additive according to the invention and finally present in the salt bath purification additive product in the form of the alkali metal oxide. For example, the source of potassium oxide may be potassium carbonate, potassium fluoride, potassium sulfate, potassium nitrate, potassium phosphate, potassium hydroxide, potassium oxide, potassium chloride, or mixtures thereof, and then the potassium oxide is ultimately present in the non-silicon salt bath refining additive material.

Preferably, the orthographic projection of the silicon-free salt bath purification additive material on any one plane at least covers a square area with the length and width dimensions of 0.5 multiplied by 0.5 mm. Therefore, the salt bath can be smoothly taken out under the normal working condition of the salt bath.

The silicon-free salt bath purification additive material provided by the invention can be prepared by the following steps: first, an alkali metal oxide and B are prepared₂O₃And other oxides, the components are fully mixed, the mole percentage content of the components in the obtained silicon-free salt bath purification additive material product is 30-60 mol%, B is alkali metal oxide₂O₃30-65 mol% and 8-25 mol% of other oxides. The amount of the starting material of the alkali metal oxide is such that the content of alkali metal oxide obtained after the reaction in the finally obtained silicate-free bath purification additive material is between 30 and 60 mol%. Then, the mixture is heated to 900 ℃ to 1000 ℃, stirred to a molten state, and a metastable salt bath purification additive precursor is formed. Optionally, after the metastable salt bath purification additive precursor is generated, introducing the metastable salt bath purification additive precursor into water at the temperature of 0-90 ℃ for quenching treatment, thereby obtaining the granular silicon-free salt bath purification additive material. Optionally, after the metastable salt bath purification additive precursor is generated, slowly cooling the metastable salt bath purification additive precursor to 400-900 ℃, and performing drawing forming or extrusion forming treatment through mechanical external force, thereby obtaining the flaky silicon-free salt bath purification additive material. Optionally, when a metastable liquid salt bath purification additive precursor is generated, a foaming agent is added to enable the interior and the surface of the precursor to be in a fine porous state, and after the precursor is cooled to room temperature, the precursor is crushed by mechanical external force to form a granular salt bath purification additive material with a porous structure in the interior.

The invention also provides a using method of the silicon-free salt bath for purifying the additive material, and the using method comprises a purifying part and an activating part.

Wherein, the purification part comprises the following steps:

step S1, providing a salt bath to be purified, wherein the salt bath to be purified contains potassium ions or/and sodium ions or/and lithium ions; wherein the salt bath to be purified is an inactivated glass chemical strengthening salt bath containing a large amount of lithium ions or sodium ions; preferably, the temperature of the salt bath to be purified is 350-550 ℃.

Step S2, adding the silicon-free salt bath purification additive material into the salt bath to be purified; preferably, the addition amount of the silicon-free salt bath purification additive material is 0.5-5 wt% of the mass of the salt bath to be purified,

step S3, taking out the additive material for purifying the silicon-free salt bath after the additive material for purifying the silicon-free salt bath reacts with the salt bath for purifying for a certain time; preferably, the reaction time of the silicon-free salt bath purification additive material with the salt bath to be purified is at most 24 h.

The use found that the absorption efficiency of lithium ions per 1 wt% of the silicon-free salt bath purification additive material in the first 6h was between 35PPm/h and 50PPm/h, and the absorption efficiency of sodium ions per 1 wt% of the silicon-free salt bath purification additive material in the first 6h was between 50PPm/h and 350 PPm/h.

The following is an activation part, which specifically comprises the following steps:

step S4, the silicon-free salt bath purification additive material taken out in the step S3 is placed in a pure sodium salt bath;

and step S5, taking out the silicon-free salt bath purification additive material for the next use after the silicon-free salt bath purification additive material reacts with the pure sodium salt bath for a certain time. Through use, the absorption efficiency of lithium ions or sodium ions of the silicon-free salt bath purification additive material obtained through the step S5 is reduced to 50-95% of that of the silicon-free salt bath purification additive material in the step S2. Preferably, the temperature of the pure sodium salt bath is 350-550 ℃ (if the pure sodium salt bath is recycled, the higher the temperature is better, so the lowest temperature is also required to be the IOX temperature), and the reaction time of the silicon-free salt bath purification additive material and the pure sodium salt bath is 1-10 h.

The invention also provides another using method of the additive material for purifying the silicon-free salt bath, which can be placed into a brand-new salt bath without impurity ions together with the glass to be strengthened, and continuously absorbs the impurity ions generated in the ion exchange process in the salt bath in the glass strengthening process, so that the impurity ions in the salt bath are always stabilized at a lower level. The method comprises the following specific steps:

step S1, providing a salt bath to be purified, which is a brand new salt bath that does not contain impurity ions (sodium ions and lithium ions); preferably, the temperature of the salt bath to be purified is 350-550 ℃.

Step S2, adding the silicon-free salt bath purification additive material into the salt bath to be purified; preferably, the addition amount of the silicon-free salt bath purification additive material is 0.3-5 wt% of the mass of the salt bath to be purified,

and step S3, the additive material to be purified by the silicon-free salt bath and the glass to be strengthened enter the salt bath at the same time and are taken out along with the glass, so that the strengthening is not influenced.

It was found that, in the salt bath control using the above-described method, the concentration of lithium ions and/or sodium ions as impurities in the salt bath was controlled to 400PPm or less, preferably 200PPm or less, and more preferably 100PPm or less.

In order to more clearly understand the technical features, objects, and effects of the present invention, specific embodiments of the present invention will now be described in detail. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples 1 to 6

In examples 1 to 6, 6 kinds of materials having different forms of components and being purified by the silicon-free salt bath purification additive were prepared by the above-mentioned preparation method using commercially available products as raw materials. The composition and morphology of the silicon-free salt bath purification additive materials of examples 1 to 6 are shown in table 1.

TABLE 1

In the table, β represents the alkali metal oxide content and B in the additive material for the silicate-free bath purification₂O₃The ratio of the contents of (A) to (B); theta refers to Al in the additive material without silicon salt bath purification₂O₃Content of (A) and (B)₂O₃The ratio of the sum of contents of (A) to (B).

Purification experiments 1 to 6

In order to obtain real experimental data to demonstrate that the silicon-free salt bath purification additive materials of examples 1 to 6 are capable of absorbing lithium ions and sodium ions in the deteriorated chemically strengthened salt bath, purification experiments were performed on the silicon-free salt bath purification additive materials of examples 1 to 6 in purification experiments 1 to 6 according to the steps of the purification part of the method of using the silicon-free salt bath purification additive materials mentioned hereinabove. The conditions during purification experiments 1 to 6 are shown in table 2.

TABLE 2

The above purification experiments 1 to 6 can fully prove that the additive material for purifying the silicon-free salt bath can rapidly absorb lithium ions and sodium ions generated in the salt bath in the process of chemically strengthening glass, the absorption efficiency in the first 6 hours is very high, and the minimum absorption rate is 31.0 ppm/h.

Purification experiments 1 to 2 were repeated

In order to obtain real experimental data to prove that the silicon-free salt bath purification additive material provided by the present invention can release absorbed lithium ions or sodium ions so as to be recycled, repeated purification experiments were performed on the silicon-free salt bath purification additive materials in examples 3 and 5 in activation experiments 1 to 2 according to the above-mentioned method of using the silicon-free salt bath purification additive materials. The conditions during the repetition of the purification experiments 1 to 2 are shown in table 3.

TABLE 3

As can be seen from the above repeated purification experiments 1 to 2, the silicon-free salt bath purification additive materials of examples 3 and 5 can be reused many times.

On-line purification experiments 1 to 2

In-line purification experiments 1 to 2 the in-line purification experiments were carried out on the additive materials purified by the silicon-free salt bath in examples 3 and 5 according to the above-mentioned alternative method of using the additive materials purified by the silicon-free salt bath. In addition, in order to confirm that the additive material for purifying the silicon-free salt bath can obtain the online purification effect, a blank experiment 1 and a blank experiment 2 are respectively performed, wherein the conditions of the blank experiment 1 are the same as those of the online purification experiment 1, except that the additive material for purifying the silicon-free salt bath in the embodiment 3 is not added in the blank experiment 1, and the conditions of the blank experiment 2 are the same as those of the online purification experiment 2, except that the additive material for purifying the silicon-free salt bath in the embodiment 5 is not added in the blank experiment 2. The conditions during the on-line purification experiments 1 to 2 and the blank experiments 1 to 2 are shown in table 4.

In the experimental process, a brand new salt bath without impurity ions is placed in a 12-ton-volume salt bath furnace, a silicon-free salt bath purification additive material and glass to be strengthened are fed into the salt bath simultaneously, 1.5 ten thousand pieces of glass to be strengthened are fed each time, and the strengthening time is 2-7 hours each time.

TABLE 4

As can be seen from the comparison of the data of the online purification experiment 1 and the blank experiment 1, the lithium ion concentration in the salt bath can be kept at a low level by adding the salt bath purifier material in each batch of strengthening process in the online purification experiment 1, the lithium ion concentration can still be controlled below 113.79ppm after seven times of strengthening, and the lithium ion concentration in the salt bath which is not added with the salt bath purifier material in the same batch in the blank experiment 1 is up to 860ppm and is at a poisoning level. It can be seen from the above online purification experiment 2 and blank experiment 2 that the sodium ion concentration in the salt bath can be kept at a low level by adding the salt bath purifier material in each batch of the online purification experiment 2, the sodium ion concentration can still be controlled below 193.10ppm after seven times of reinforcement, and the lithium ion concentration in the salt bath of the same batch of the blank experiment 2 without adding the salt bath purifier material is up to 1560ppm and is at a poisoning level. In conclusion, the salt bath purifying agent material and the glass to be strengthened are simultaneously put into the salt bath, and impurity ions generated in the ion exchange process in the salt bath are continuously absorbed in the glass strengthening process, so that the impurity ions in the salt bath are always stabilized at a lower level.

In summary, compared with the prior art, the additive material for purifying the silicon-free salt bath provided by the invention can rapidly absorb lithium ions and sodium ions generated in the salt bath in the process of chemically strengthening glass, ensure that the concentrations of the lithium ions and the sodium ions in the salt bath are at a lower level, and ensure the stability of mass production size and the stability of surface stress of the chemically strengthened glass. Moreover, the additive material for purifying the silicon-free salt bath can be repeatedly utilized after the absorbed impurity ions are released by treatment, so that the use amount can be greatly reduced, and the cost is reduced.

In addition, since the silicon-free salt bath purification additive material does not contain silica, it isBy using B₂O₃As a main structure, Al₂O₃As a secondary network architecture, compared with a silicon-free salt bath purification additive material containing silicon dioxide, the additive material has a lower synthesis temperature, the smelting temperature can be lower than 1000 ℃, so that the limitation condition of the smelting equipment is relaxed, and the smelting cost is greatly reduced.

Moreover, even if part of the additive material for purifying the silicon-free salt bath is pulverized under the action of high temperature in the long-term use process, the additive material is difficult to form bonding and crosslinking with a silicon dioxide component in the surface of glass at the high temperature of the salt bath because the additive material mainly contains a boron component substance but not a silicon-containing component, so that the particle defect of a glass finished product after being strengthened is avoided, and the good quality of the product is ensured.

While embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, which are intended to be illustrative rather than limiting, and many modifications may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.