CN115716713A - Ion exchange furnace and preparation method of glass with gradient refractive index - Google Patents

Abstract

The invention relates to the technical field of optical glass processing, in particular to an ion exchange furnace and a preparation method of gradient refractive index glass. The ion exchange furnace comprises a decomposing furnace, an exchange furnace and a recovery furnace, wherein the decomposing furnace is used for decomposing molten salt, the exchange furnace is used for carrying out ion exchange on the molten salt and optical glass, the recovery furnace is used for processing the molten salt after ion exchange, the decomposing furnace is communicated with the exchange furnace through a first high-temperature pipeline, the exchange furnace is communicated with the recovery furnace through a second high-temperature pipeline, the decomposing furnace is communicated with the recovery furnace through a third high-temperature pipeline, the first high-temperature pipeline, the second high-temperature pipeline and the third high-temperature pipeline can bear high temperature of at least 600 ℃, and pump control valves are arranged on the first high-temperature pipeline, the second high-temperature pipeline and the third high-temperature Wen Guandao. The ion exchange furnace provided by the invention can improve the exchange efficiency. The invention also provides a preparation method of the glass with the gradient refractive index prepared by using the ion exchange furnace.

Description

Ion exchange furnace and preparation method of gradient index glass

technical field

The invention relates to the technical field of optical glass processing, in particular to an ion exchange furnace and a preparation method for gradient refractive index glass.

Background technique

Ion exchange technology plays a vital role in the process of preparing gradient index glass, in which ion exchange technology is realized by ion exchange furnace. In the traditional process, molten salt decomposition, ion exchange, and molten salt treatment are all completed in the same furnace, and the molten salt decomposition stage takes a long time, resulting in reduced equipment utilization, long production cycle, high time cost, serious restrict production efficiency.

At the same time, in the process of using the traditional static ion exchange method to prepare gradient refractive index glass, the molten salt cannot be added twice during the ion exchange stage, and the cations in the molten salt continuously replace the cations in the glass filaments. , the content of cations in the molten salt continues to decay, and it is difficult to maintain a constant high concentration value, so that the ion exchange rate cannot be kept in a high-efficiency state, which eventually leads to a gradual decrease in the ion exchange rate and a prolonged exchange time. The performance and quality of can not show a good consistency.

Contents of the invention

Based on this, the invention provides an ion exchange furnace and a preparation method of gradient refractive index glass. The ion exchange furnace can ensure that in the ion exchange stage, the concentration of cations in the molten salt is maintained in a dynamic equilibrium state, which improves the ion exchange efficiency, thereby ensuring the consistency of performance and quality among gradient refractive index glasses.

In one aspect of the present invention, an ion exchange furnace is provided, which includes a decomposition furnace, an exchange furnace and a recovery furnace. The decomposition furnace is used for decomposing molten salt, and the exchange furnace is used for ion exchange between molten salt and optical glass. The recovery furnace is used to process molten salt after ion exchange, the decomposition furnace communicates with the exchange furnace through a first high-temperature pipeline, and the exchange furnace communicates with the recovery furnace through a second high-temperature pipeline, so The decomposition furnace and the recovery furnace are also communicated through a third high-temperature pipeline, the first high-temperature pipeline, the second high-temperature pipeline and the third high-temperature pipeline can withstand a high temperature of at least 600°C, and the first The high-temperature pipeline, the second high-temperature pipeline and the third high-temperature pipeline are respectively provided with pump control valves.

In a specific embodiment, there are multiple exchange furnaces and recovery furnaces, and the plurality of exchange furnaces correspond to multiple recovery furnaces one by one, wherein the first high-temperature pipeline is divided into multiple strands at the end close to the exchange furnace to be connected with the A plurality of exchange furnaces are connected, and the third high-temperature pipeline is divided into multiple strands at one end close to the recovery furnace to communicate with the plurality of recovery furnaces respectively.

In a specific embodiment, the furnace body structures of the decomposition furnace, the exchange furnace and the recovery furnace all include a base, a furnace body, a furnace cover, an outer crucible, an inner crucible and a heating element;

The furnace body has a furnace chamber, the furnace cover is adapted to the opening end of the furnace chamber for sealing the furnace chamber, the outer crucible is arranged in the furnace chamber, the inner crucible is arranged in the outer crucible, and there is a gap between the inner crucible and the outer crucible, The heating element is used to heat the furnace chamber;

The furnace body is provided with connecting pipes, wherein the connecting pipes are used to connect with high-temperature pipes and extend from the inner crucible to the furnace body.

In a specific embodiment, the heating element includes a first heating device arranged at the bottom of the furnace cavity and a second heating device arranged on the inner wall of the furnace body;

In a specific embodiment, a temperature sensor corresponding to the second heating device is provided on the outer wall of the outer crucible.

In a specific embodiment, the furnace body is provided with an insulating layer.

In a specific embodiment, the furnace cover is provided with an insulating layer.

In a specific embodiment, the base, the furnace body, the furnace cover, the inner crucible and/or the outer crucible are all made of stainless steel.

Another aspect of the present invention provides a method for preparing gradient refractive index glass using the above-mentioned ion exchange furnace, which includes the following steps:

The molten salt is heated and decomposed in the decomposition furnace, and the decomposed molten salt is transported to the exchange furnace through the first high-temperature pipeline;

Glass filaments are added to the exchange furnace, and the cations in the glass filaments are ion-exchanged with the cations in the molten salt to prepare gradient refractive index glass, and the exchanged molten salt is transported to the recovery furnace through the second high-temperature pipeline for molten salt recovery, and recovery The final molten salt is transported to the decomposition furnace through the third high-temperature pipeline.

In a specific embodiment, the molten salt is selected from at least one of KNO ₃ and NaNO ₃ .

In the present invention, the molten salt decomposition stage, the ion exchange stage and the molten salt treatment stage are respectively carried out in separate furnaces, and the furnace bodies are connected through high-temperature pipelines. In the ion exchange stage, the molten salt can be transported between the furnaces through pump-controlled high-temperature pipelines, thus ensuring that the cation concentration in the molten salt in the exchange furnace is stable and maintains a dynamic balance. That is, in the ion exchange stage, the molten salt in the decomposition furnace can be continuously transported to the exchange furnace, and the exchange product in the exchange furnace can be continuously transported to the recovery furnace for recovery, and the molten salt in the recovery furnace can be continuously transported to the decomposition furnace , thus forming a circulating exchange system. In this circulation system, since the recovery furnace still contains a large number of cations that can participate in the exchange, after recycling them, it can ensure that the concentration of cations in the molten salt in the exchange furnace is always maintained at a high-concentration dynamic equilibrium state, thereby It keeps the ion exchange rate in a stable and efficient state, shortens the exchange time and production cycle, improves the exchange efficiency and quality, and can maintain good product consistency. Moreover, the circulation system effectively eliminates the waiting time of the traditional single furnace in the decomposition stage, and enables the exchange furnace to work uninterruptedly to continuously produce products. Recycling molten salt can also reduce waste salt production, saving resources and costs.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

Figure 1 is a schematic diagram of the connection relationship among the decomposition furnace, the exchange furnace and the recovery furnace used in the preparation of gradient index glass in an embodiment of the present invention;

Fig. 2 is a schematic diagram of the connection relationship among the decomposition furnace, the exchange furnace and the recovery furnace used in the preparation of gradient index glass in another embodiment of the present invention;

Fig. 3 is a structural schematic diagram of a decomposition furnace, an exchange furnace and a recovery furnace used for preparing gradient index glass in an embodiment of the present invention;

In the figure: 1-calcining furnace; 11-base; 12-furnace body; 121-furnace cavity; 122-connecting pipe; 123-outer shell; 124-inner shell; handle; 132-outer shell; 133-inner shell; 134-second insulation layer; 14-outer crucible; 141-temperature sensor; 15-inner crucible; 16-heating element; 161-first heating device; 162-second Heating device; 2-exchange furnace; 3-recovery furnace; 4-first high-temperature pipeline; 5-second high-temperature pipeline; 6-third high-temperature pipeline; 7-pump control valve.

Detailed ways

Reference will now be made in detail to embodiments of the invention, one or more examples of which are described below. Each example is provided by way of explanation, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used on another embodiment to yield a still further embodiment.

Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the invention are disclosed in or are apparent from the following detailed description. It is to be understood by those of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended to limit the broader aspects of the invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Except as shown in the working examples or otherwise indicated, all numbers used in the specification and claims expressing amounts of ingredients, physicochemical properties, etc. are understood to be adjusted in all cases by the term "about". For example, therefore, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and appended claims are approximations that would enable those skilled in the art to seek to obtain the desired properties utilizing the teachings disclosed herein, as appropriate Change these approximations. The use of numerical ranges by endpoints includes all numbers within that range and any range within that range, eg, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc. .

The indefinite articles "a" and "an" preceding an element or component of the present invention do not limit the quantity requirement (ie, the number of occurrences) of the element or component. Thus "a" or "an" should be read to include one or at least one, and elements or components in the singular also include the plural unless it is clear that the number only refers to the singular.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the invention, "plurality" means at least two, such as two, three, etc., unless specifically defined otherwise. In the description of the present invention, "several" means at least one, such as one, two, etc., unless otherwise specifically defined.

The term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements but also other elements not expressly listed elements, or also elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

In the description of the present invention, unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated Connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

The terms "length", "width", "center", "top", "bottom", "left", "right", "front", "back", "vertical", "horizontal", "top", "Bottom", "inner", "outer", "clockwise", "counterclockwise", "radial", "axial", "longitudinal", "horizontal", "circumferential", etc. indicate the direction or positional relationship The term is based on the direction or positional relationship shown in the drawings, which is for convenience of description only, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a Invention Limitations.

In the patent of the present invention, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first and second feature through an intermediary if the first feature is "on" or "under" the second feature. indirect contact. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

As shown in FIG. 1 , one aspect of the present invention provides an ion exchange furnace, which includes a decomposition furnace 1 , an exchange furnace 2 and a recovery furnace 3 . Decomposition furnace 1 is used to decompose molten salt, exchange furnace 2 is used for ion exchange between molten salt and glass, and recovery furnace 3 is used to process molten salt after ion exchange. The decomposition furnace 1 communicates with the exchange furnace 2 through a first high-temperature pipeline 4 , and the exchange furnace 2 communicates with the recovery furnace 3 through a second high-temperature pipeline 5 . The decomposition furnace 1 and the recovery furnace 3 are also communicated through a third high-temperature pipeline 6 . The first high-temperature pipeline 4, the second high-temperature pipeline 5 and the third high-temperature pipeline 6 can withstand a high temperature of at least 600°C. The first high-temperature pipeline 4 , the second high-temperature pipeline 5 and the third high-temperature pipeline 6 are respectively provided with pump control valves 7 .

Usually, the molten salt after the ion exchange stage still contains molten salt cations that can be ion-exchanged. If these molten salt cations are not recycled, the production cost will be greatly wasted. In the present invention, the molten salt decomposition stage, the ion exchange stage and the molten salt treatment stage are divided into separate furnaces, and the first high-temperature pipeline 4, the second high-temperature pipeline 5 and the third high-temperature pipeline 6 are respectively used in the decomposition furnace 1, the exchange The molten salt is delivered between the furnace 2 and the recovery furnace 3, thereby forming a circular connection structure between the furnaces. This structure ensures the dynamic balance of the concentration of cations in the molten salt in the exchange furnace 2, so that the exchange rate between the cations in the molten salt and the cations in the glass remains stable and efficient, thereby improving the exchange efficiency and quality, and ensuring the final product quality. Consistency of performance and quality between the various products obtained. Moreover, since the molten salt cation concentration in the exchange furnace 2 is always in a high concentration state, the exchange furnace 2 can continuously produce products, shorten the exchange time, improve production efficiency, and also improve the utilization rate of the molten salt, reducing production. cost.

In the present invention, as a further illustration, the numbers of the decomposition furnace 1, the exchange furnace 2 and the recovery furnace 3 are not limited.

In the present invention, as a further illustration, there are multiple exchange furnaces 2 and recovery furnaces 3 . The multiple exchange furnaces 2 correspond to the multiple recovery furnaces 3 one by one. Wherein, the first high-temperature pipeline 4 is divided into multiple strands at the end close to the exchange furnace 2 to communicate with a plurality of exchange furnaces 2 respectively, and the third high-temperature pipeline 6 is divided into multiple strands at the end close to the recovery furnace 3 to communicate with the plurality of recovery furnaces 3 respectively. connected.

By increasing the number of furnaces, the production efficiency can be improved on the basis of ensuring the performance and quality consistency of the products produced.

Furthermore, in a specific example shown in FIG. 2 , there are three exchange furnaces 2 and three recovery furnaces 3 . The decomposition furnace 1 communicates with the three exchange furnaces 2 through the first high-temperature pipeline 4, the three exchange furnaces 2 communicate with the three recovery furnaces 3 through the second high-temperature pipeline 5, and the recovery furnace 3 communicates with the three exchange furnaces through the third high-temperature pipeline 6. Calciner 1 is connected. Wherein, the first high-temperature pipeline 4 is divided into three strands at the end close to the exchange furnace 2 , and the third high-temperature pipeline 6 is divided into three strands at the end close to the recovery furnace 3 .

As shown in Figure 3, in the present invention, as a further illustration, the body of furnace structure of calciner 1 comprises base 11, body of furnace 12, furnace cover 13, outer crucible 14, inner crucible 15 and heating element 16;

The body of furnace 12 has a furnace chamber 121, the furnace cover 13 is adapted to the opening end of the furnace chamber 121 for sealing the furnace chamber 121, the outer crucible 14 is arranged in the furnace chamber 121, the inner crucible 15 is arranged in the outer crucible 14, and the inner crucible 15 is arranged in the outer crucible 14. There is a gap between the crucible 15 and the outer crucible 14, and the heating element 16 is used to heat the furnace chamber 121;

The furnace body 12 is provided with a connecting pipe 122 , wherein the connecting pipe 122 is used for connecting with a high temperature pipe and extends from the inner crucible 15 to the outside of the furnace body 12 .

In the present invention, as a further illustration, the heating element 16 includes a first heating device 161 arranged at the bottom of the furnace cavity 121 and a second heating device 162 arranged on the inner wall of the furnace body 12;

In the present invention, as a further illustration, a temperature sensor 141 corresponding to the second heating device 162 is provided on the outer wall of the outer crucible 14 .

In the present invention, as a further illustration, the temperature sensor 141 is arranged vertically or horizontally at a position corresponding to the second heating device 162 .

In the present invention, as a further illustration, both the first heating device 161 and the second heating device 162 are resistance wires.

In the present invention, as a further illustration, a handle 131 may also be provided on the furnace cover 13 . Preferably, the handle 131 is made of stainless steel.

In the present invention, as a further illustration, both the furnace body 12 and/or the furnace cover 13 are provided with an insulating layer.

In the present invention, as a further illustration, the furnace body 12 further includes an outer shell 123 and an inner shell 124, and the first thermal insulation layer 125 is arranged between the outer shell 123 and the inner shell 124; and/or

The furnace cover 13 also includes an outer shell 132 and an inner shell 133 , and a second heat insulating layer 134 is disposed between the outer shell 132 and the inner shell 133 .

In some embodiments, the materials of the first insulation layer 125 and the second insulation layer 134 are not limited, and materials commonly used in the field can be used.

In the present invention, as a further illustration, the base 11 , the furnace body 12 , the furnace cover 13 , the inner crucible 15 and/or the outer crucible 14 are all made of stainless steel.

In the present invention, as a further illustration, the furnace body structure of the exchange furnace 2 and the recovery furnace 3 is basically the same as that of the calciner 1 .

In one aspect of the present invention, there is also provided a method for preparing gradient index glass using the ion exchange furnace described above, which includes the following steps:

The molten salt is heated and decomposed in the decomposition furnace 1, and the decomposed molten salt is transported to the exchange furnace 2 through the first high-temperature pipeline 4;

Glass filaments are added to the exchange furnace 2, and the cations in the glass filaments are ion-exchanged with the cations in the molten salt to prepare gradient refractive index glass, and the exchanged molten salt is transported to the recovery furnace 3 through the second high-temperature pipeline 5 for recovery, and The recovered molten salt is transported to the decomposition furnace through the third high-temperature pipeline.

The preparation method provided by the present invention can maintain the molten salt in the exchange furnace 2 in a dynamic equilibrium state, so that ion exchange can be performed in the molten salt in a dynamic circulation state, thereby improving the exchange efficiency.

In the present invention, as a further illustration, the molten salt is selected from nitrates. In some embodiments, the molten salt is selected from at least one of KNO ₃ and NaNO ₃ . In a preferred embodiment, the molten salt is selected from KNO ₃ .

In the present invention, as a further illustration, the thermal decomposition temperature of the molten salt is 450°C to 600°C. In a preferred embodiment, the thermal decomposition temperature of the molten salt is 600°C.

The ion exchange furnace and the preparation method of the gradient index glass of the present invention will be further described in detail below in conjunction with specific examples.

Unless otherwise specified, the drugs and instruments used in the examples are all conventional choices in the art. The experimental methods for which specific conditions are not indicated in the examples are implemented according to conventional conditions, such as the conditions described in literature, books or the method recommended by the manufacturer.

Embodiment 1 Preparation of Gradient Refractive Index Glass

In Example 1, the working process of preparing gradient index glass by using decomposition furnace 1, exchange furnace 2 and recovery furnace 3 is shown in Figure 1, and the structure of decomposition furnace 1, exchange furnace 2 and recovery furnace 3 is shown in Figure 3.

The preparation steps of the gradient index glass described in Example 1 are as follows:

Take KNO ₃ and place it in the decomposition furnace 1, heat it until it is decomposed, and continuously transport the KNO ₃ to the exchange furnace 2 through the first high-temperature pipeline 4 equipped with a pump control valve 6, and then add a diameter of 1.8 to the exchange furnace 2. The glass filaments of mm are ion-exchanged, and the finished product obtained by the exchange is taken out, and the molten salt continues to be continuously transported to the recovery furnace 3 through the second high-temperature pipeline 5 equipped with the pump control valve 7, and the recovered KNO ₃ is passed through the second high-temperature pipeline 5 equipped with the pump control valve 7 The three high-temperature pipelines 6 are continuously transported to the decomposition furnace 1 for further decomposition, and are continuously transported to the exchange furnace 2. It is found through calculation that it takes 83 hours to produce glass filaments with a diameter of 1.8 mm in this example. The positive deviation value of the refractive index distribution constant of the tested gradient index glass is 2.32‰, and the negative deviation value is -2.05‰.

Preparation of Comparative Example 1 Gradient Refractive Index Glass

In Comparative Example 1, the same glass filaments as in Example 1 were used to prepare gradient index glass. This comparative example adopts a traditional single ion exchange furnace, that is, the molten salt decomposition stage, ion exchange stage and molten salt treatment stage are all carried out in the same single furnace. It is found through calculation that it takes 97 hours to produce glass filaments with a diameter of 1.8 mm in this comparative example. The positive deviation value of the refractive index distribution constant of the tested gradient index glass is 7.53‰, and the negative deviation value is -5.61‰.

Through the exchange results of Example 1 and Comparative Example 1, it can be seen that the furnace connection structure adopted in the present invention, that is, a cyclic connection relationship is formed between the decomposition furnace 1, the exchange furnace 2 and the recovery furnace 3, so that the ion exchange stage is in the exchange system of dynamic circulation. in progress. Compared with the traditional single-furnace exchange, that is, static exchange, the method provided by the present invention ensures that the cation concentration in the molten salt in the exchange stage is always in a state of dynamic equilibrium high concentration, and the glass filament is in a dynamic equilibrium ion environment, and the ion exchange process is always maintained In the high-efficiency state, the exchange rate is improved and the exchange time is shortened.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. The utility model provides an ion exchange furnace, its characterized in that, includes dore furnace, exchange furnace and recovery furnace, the dore furnace is used for decomposing the fused salt, the exchange furnace is used for supplying fused salt and optical glass to carry out ion exchange, the recovery furnace is used for handling the fused salt after the ion exchange, the dore furnace with through first high temperature pipeline intercommunication between the exchange furnace, the exchange furnace with through second high temperature pipeline intercommunication between the recovery furnace, the dore furnace with still through third high temperature pipeline intercommunication between the recovery furnace, first high temperature pipeline second high temperature pipeline with third high temperature pipeline can bear 600 ℃ at least high temperature, first high temperature pipeline second high temperature pipeline with be equipped with pump control valve on the third high temperature pipeline respectively.

2. The ion exchange furnace according to claim 1, wherein there are a plurality of the exchange furnaces and the recovery furnace, a plurality of the exchange furnaces correspond to a plurality of the recovery furnaces one by one, the first high temperature duct is divided into a plurality of strands at an end near the exchange furnace to communicate with the plurality of the exchange furnaces, respectively, and the third high temperature duct is divided into a plurality of strands at an end near the recovery furnace to communicate with the plurality of the recovery furnaces, respectively.

3. The ion exchange furnace according to claim 1 or 2, wherein the furnace body structures of the decomposition furnace, the exchange furnace and the recovery furnace each include a base, a furnace body, a furnace cover, an outer crucible, an inner crucible and a heating element;

the furnace body is provided with a furnace chamber, the furnace cover is matched with the open end of the furnace chamber to be used for sealing the furnace chamber, the outer crucible is arranged in the furnace chamber, the inner crucible is arranged in the outer crucible, a gap is formed between the inner crucible and the outer crucible, and the heating element is used for heating the furnace chamber;

the furnace body is provided with a connecting pipeline, and the connecting pipeline is used for being connected with a high-temperature pipeline and extending from the inner crucible to the outside of the furnace body.

4. The ion exchange furnace of claim 3, wherein the heating element includes a first heating device disposed at a bottom of the furnace chamber and a second heating device disposed on an inner sidewall of the furnace body.

5. The ion exchange furnace of claim 4, wherein the outer side wall of the outer crucible is provided with a temperature sensor corresponding to the second heating device.

6. The ion exchange furnace of claim 3, wherein the furnace body is provided with an insulating layer.

7. The ion exchange furnace of claim 3, wherein the furnace cover is provided with an insulating layer.

8. The ion exchange furnace of claim 3, wherein the base, the furnace body, the furnace cover, the inner crucible, and/or the outer crucible are made of stainless steel.

9. A method for producing a glass having a graded refractive index by using the ion exchange furnace according to any one of claims 1 to 8, comprising the steps of:

placing the molten salt in a decomposing furnace for heating and decomposing, and conveying the decomposed molten salt to an exchange furnace through a first high-temperature pipeline;

and adding glass fibers into the exchange furnace, carrying out ion exchange on cations in the glass fibers and cations in the molten salt to prepare glass with the gradient refractive index, conveying the exchanged molten salt to the recovery furnace through the second high-temperature pipeline for molten salt recovery, and conveying the recovered molten salt to the decomposition furnace through the third high-temperature pipeline.

10. Method for producing a gradient index glass according to claim 9, characterized in that the molten salt is selected from KNO ₃ And NaNO ₃ At least one of (1).

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