Arsenic-free microcrystalline glassware and preparation system and method thereof

Abstract

The invention relates to an arsenic-free microcrystalline glass ware which is prepared from arsenic-free microcrystalline glass, and the arsenic-free microcrystalline glass is prepared from the following components in percentage by weight: 65.0 to 67.0 percent of SiO2, 19.5 to 20.5 percent of Al2O3, 3.7 to 4.3 percent of Li2O, 2.8 to 3.6 percent of TiO2, 1.5 to 1.8 percent of ZrO2, 1.0 to 1.3 percent of ZnO, 0.6 to 0.9 percent of MgO, 0.9 to 1.1 percent of B2O3, 0.5 to 0.7 percent of BaO, 0.5 to 0.7 percent of Na2O and 0.2 to 0.3 percent of K2O. The invention further discloses a special kiln system and a physical clarification method for the arsenic-free microcrystalline glassware. The method disclosed by the invention has the beneficial effects that toxic substances such as arsenic or antimony are completely abandoned, so that the arsenic residue of the product is zero, and green and harmless production of the microcrystalline glass ware is realized; a special kiln system and a physical clarification method replace the dependence of traditional chemical clarification, the clarification efficiency is high, and no pollution is caused; and energy conservation, controllability and safety of the production process are ensured.

Description

Technical Field

[0001] This invention belongs to the field of microcrystalline glass technology, and particularly relates to an arsenic-free microcrystalline glass vessel and its preparation system and method. Background Technology

[0002] Glass crystalline materials are glass materials with a microcrystalline structure, prepared from inorganic non-metallic materials through specific processes. Among them, low-expansion glass crystalline materials (especially the Li2O-Al2O3-SiO2 system, abbreviated as LAS glass crystalline materials) have extremely low coefficients of thermal expansion (±2~8×10). -8 ( / ℃) and is widely used in the field of high-end tableware.

[0003] However, the research and production of microcrystalline glassware in my country has long relied on arsenic trioxide (As₂O₃) as a clarifying agent. Arsenic is not a necessary component in microcrystalline glass; it is only used as a clarifying agent to remove air bubbles from the molten glass. This traditional process results in severely excessive arsenic residues in the finished product, failing to meet national safety limits for arsenic content in glassware (such as the EU standard requiring arsenic content <0.005%). Even more seriously, arsenic, as a highly toxic and hazardous chemical, has been included in the national list of strictly controlled substances, making it difficult for companies to obtain purchase permits. This not only increases production costs but also poses a potential threat to the environment and human health.

[0004] In existing technologies, although some attempts have been made to replace arsenic with other chemical clarifying agents (such as antimony compounds), the problem of toxic residues cannot be fundamentally solved, and new impurities may be introduced.

[0005] Therefore, developing a microcrystalline glass preparation technology that does not require arsenic-based clarifying agents and combines high-efficiency clarification with environmentally friendly characteristics has become a bottleneck that the industry urgently needs to overcome. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an arsenic-free microcrystalline glassware and its preparation system and method.

[0007] An arsenic-free microcrystalline glassware, made of arsenic-free microcrystalline glass, comprising, by weight percentage:

[0008] 65.0%–67.0% SiO2

[0009] 19.5%–20.5% Al2O3

[0010] 3.7–4.3% Li₂O,

[0011] 2.8–3.6% TiO2,

[0012] 1.5-1.8% ZrO2,

[0013] 1.0–1.3% ZnO,

[0014] 0.6-0.9% MgO,

[0015] 0.9–1.1% B2O3,

[0016] 0.5-0.7% BaO,

[0017] 0.5-0.7% Na₂O, and

[0018] 0.2-0.3% K₂O;

[0019] The rest are impurities.

[0020] Preferably, the impurity is Fe2O3.

[0021] A furnace system for preparing arsenic-free microcrystalline glassware includes a furnace body, a heating unit, and a temperature control unit.

[0022] The furnace body includes a feeding zone and a clarification zone. Along the material flow path, the clarification zone is located after the feeding zone.

[0023] The heating units are evenly distributed in the feeding zone and the clarification zone, and the heating units are electrically connected to the temperature control unit. The heating units are used to make the feeding zone and the clarification zone high-temperature zones with a temperature higher than the surrounding areas. The temperature control unit is used to control the heating units to make the feeding zone and the clarification zone respectively in a first temperature range and a second temperature range.

[0024] Within the first temperature range, the material can be melted into a liquid state; within the second temperature range, the heating unit in the clarification zone is in a constant resistance state, and under the action of the clarifying agent, the liquid arsenic-free microcrystalline glass can be clarified by high-temperature convection, and the liquid material is clarified in the clarification zone (i.e., the tiny bubbles therein are expelled).

[0025] Preferably, the first temperature range is 1180℃~1500℃, and the second temperature range is 1500℃~1650℃.

[0026] Preferably, the first temperature range is 1200℃~1413℃, and the second temperature range is 1560℃~1620℃.

[0027] Preferably, the heating unit comprises multiple bottom-inserted electrodes, which are electrodes that extend from the bottom of the furnace body into the furnace cavity; the multiple bottom-inserted electrodes are arranged at different intervals to form the first temperature range and the second temperature range.

[0028] Preferably, the heating unit comprises multiple side-inserted electrodes, which are electrodes arranged on the inner sidewall of the furnace cavity. The multiple side-inserted electrodes are arranged at different intervals to form the first temperature range and the second temperature range.

[0029] Preferably, the heating unit in the feeding zone is a plurality of bottom-inserted electrodes, which are electrodes extending from the bottom of the furnace body into the furnace cavity, and the plurality of bottom-inserted electrodes are arranged at different intervals to form the first temperature range; the heating unit in the clarification zone is a plurality of side-inserted electrodes, which are electrodes arranged on the inner side wall of the furnace cavity, and the plurality of side-inserted electrodes are arranged at different intervals to form the second temperature range.

[0030] Preferably, the furnace body is provided with a feeding port and a feeding channel, the feeding zone is connected to the feeding port for feeding materials, the feeding channel is located after the clarification zone, and the feeding channel is used for discharging materials.

[0031] A method for preparing arsenic-free microcrystalline glassware using a kiln system includes the following steps:

[0032] The temperature control unit and the heating unit are activated, and the temperature control unit controls the heating unit to heat the material feeding zone and the clarification zone, respectively, so that the material feeding zone and the clarification zone are in the first temperature range and the second temperature range.

[0033] The components of the arsenic-free microcrystalline glass are fed into the kiln, and a corresponding amount of clarifying agent (0.3-0.8% NaCl) is added to the kiln. The components of the arsenic-free microcrystalline glass melt into a liquid state within the first temperature range. The clarifying agent continuously undergoes liquid-gas and gas-liquid phase transformations between the first and second temperature ranges, forming strong convection and generating large bubbles. The large bubbles generated by the gaseous clarifying agent carry the residual microbubbles in the liquid components of the arsenic-free microcrystalline glass to the liquid surface for microbubble removal, achieving a good physical clarification effect.

[0034] After cooling and shaping, arsenic-free microcrystalline glassware is obtained.

[0035] The beneficial effects of this invention are:

[0036] This invention achieves three core breakthroughs through its unique arsenic-free microcrystalline glass formula, specialized furnace system, and physical clarification method:

[0037] First, by combining the basic components of the LAS system (such as SiO2, Al2O3, Li2O, etc.) with the environmentally friendly clarifying agent NaCl, toxic substances such as arsenic or antimony are completely eliminated, making the product arsenic residue zero and fully compliant with the most stringent environmental standards at home and abroad (such as the EU standard arsenic content <0.005%), thus realizing the green and harmless production of microcrystalline glassware.

[0038] Secondly, through the multi-zone temperature field design and electrode arrangement of the kiln system (such as the optimized arrangement of bottom / side inserted electrodes), the electrode arrangement and conduction method determine the thermal convection of the glass. By utilizing the liquid-gas phase change cycle of NaCl, strong convection is formed to eliminate microbubbles, replacing the reliance on traditional chemical clarification, resulting in high clarification efficiency and no pollution.

[0039] Finally, through the synergistic innovation of "formula-equipment-process", this invention ensures that the production process is energy-saving, controllable, and safe. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the electrode arrangement of the heating unit in Example 1;

[0041] Figure 2 This is a schematic diagram of the electrode arrangement of the heating unit in Example 2;

[0042] Figure 3 This is a schematic diagram of the electrode arrangement of the heating unit in Example 3;

[0043] Figure 4 The graph shows the temperature / resistivity change of the arsenic-free microcrystalline glass in Example 3.

[0044] Explanation of the attached diagram labels: 1. Feeding zone; 2. Clarification zone; 3. Feeding port; 4. Feeding channel; 5. Bottom electrode; 6. Side electrode. Detailed Implementation

[0045] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0046] From August 2023 to August 2025, the applicant spent two years developing a new approach, abandoning the traditional use of arsenic and instead developing an arsenic-free microcrystalline glass formula.

[0047] Small-scale test: Conduct melting experiments using the new formula multiple times, i.e., once a day. Stabilize the formula after obtaining a precise raw material ratio.

[0048] Pilot-scale test: Stable discharge was achieved for 30 days using a continuous feeding and discharging method for 24 consecutive hours to complete the pilot-scale formulation.

[0049] Example 1

[0050] A method for preparing arsenic-free microcrystalline glassware using a kiln system, the method comprising the following steps:

[0051] Start the temperature control unit and heating unit of the kiln system. The temperature control unit controls the heating unit and uses the current heating principle to heat the feeding zone and the clarification zone. The heating unit consists of multiple sets of bottom-inserted electrodes evenly arranged in the feeding zone and the clarification zone. The bottom-inserted electrodes are electrodes that extend into the furnace cavity from the bottom of the furnace body.

[0052] like Figure 1 As shown, each group of bottom electrodes includes six bottom electrodes 5, which are arranged symmetrically in three rows (two in each row). There is a certain distance between two adjacent bottom electrodes 5, and the diagonals of the upper and lower rows of bottom electrodes 5 intersect each other at 60° (acute angle 60°, obtuse angle 120°). This keeps the feeding zone and clarification zone inside the furnace at 1200℃~1413℃ and 1560℃~1620℃, respectively.

[0053] By weight percentage, the components of the arsenic-free microcrystalline glass are fed into the furnace according to the following formula:

[0054] 66% SiO2,

[0055] 20% Al2O3,

[0056] 4% Li2O,

[0057] 3.2% TiO2,

[0058] 1.5% ZrO2,

[0059] 1.2% ZnO,

[0060] 0.8% MgO,

[0061] 1.1% B2O3,

[0062] 0.7% BaO,

[0063] 0.5% Na₂O,

[0064] 0.2% K2O, and

[0065] 0.06% Fe2O3;

[0066] Add the corresponding amount of clarifying agent (0.44% NaCl) into the kiln; the components of the arsenic-free microcrystalline glass melt into liquid at a temperature above 1180℃ (1200℃~1413℃). NaCl continuously undergoes liquid-gas and gas-liquid transformations between 1200℃~1413℃ and 1560℃~1620℃: after the liquid NaCl enters the high-temperature zone (1560℃~1620℃) from the low-temperature zone (1200℃~1413℃), it vaporizes to produce a large amount of gas. The high-temperature sodium chloride gas transforms from gaseous to liquid after flowing through the region with a temperature below 1413℃, completing one liquid-gas and gas-liquid transformation. This cycle repeats, forming strong convection and generating large bubbles. The large bubbles generated by the gaseous clarifying agent carry the residual microbubbles in the components of the liquid arsenic-free microcrystalline glass to the liquid surface for microbubble removal, achieving a good physical clarification effect.

[0067] After cooling and shaping, arsenic-free microcrystalline glassware is obtained.

[0068] Example 2

[0069] Based on Example 1, in this example, the method for preparing arsenic-free microcrystalline glassware using a kiln system is as follows: Figure 2 As shown, the heating unit in the kiln system consists of multiple sets of side-inserted electrodes evenly arranged in the feeding zone and clarification zone. The side-inserted electrodes are electrodes arranged on the inner side wall of the furnace cavity. Each set of side-inserted electrodes includes three horizontally arranged side-inserted electrodes 6. The distance between the center points of the three side-inserted electrodes 6 is equal, and the line connecting the center points of each side-inserted electrode forms a 60° angle with each other.

[0070] Example 3

[0071] Based on Example 1, in the method of preparing arsenic-free microcrystalline glassware using a kiln system in this example, the kiln system used includes a furnace body, a heating unit and a temperature control unit. The inside of the furnace body includes a feeding zone 1 and a clarification zone 2. Along the material flow path, the clarification zone 2 is located after the feeding zone 1, which clearly divides the temperature control zone of the kiln into two main parts, front and back, to achieve zoned temperature control.

[0072] Heating units are evenly distributed in the feeding zone 1 and the clarification zone 2, and the heating units are electrically connected to the temperature control unit; for example Figure 3 As shown, the heating unit is used to make the feeding zone 1 and the clarification zone 2 high temperature zones with a higher temperature than the surrounding areas, and the temperature control unit is used to control the heating unit to make the feeding zone 1 and the clarification zone 2 be in the first temperature range (1200℃~1413℃) and the second temperature range (1560℃~1620℃), respectively.

[0073] In the first temperature range, the material melts into a liquid state; in the second temperature range, the heating unit in the clarification zone 2 is in a constant resistance state, and under the action of the clarifying agent, the liquid arsenic-free microcrystalline glass can be clarified by high-temperature convection. In the clarification zone 2, the liquid material is clarified (i.e., the tiny bubbles in it are discharged).

[0074] The electrode arrangement and conductivity method determine the heat convection of the glass; the heating unit in the charging zone 1 consists of six bottom-inserted electrodes 5, which are electrodes that extend from the bottom of the furnace body into the furnace cavity. The six bottom-inserted electrodes 5 are arranged at a certain distance, and the lines connecting the bottom-inserted electrodes 5 form two intersecting equilateral triangles; the heating unit in the refining zone 2 consists of six side-inserted electrodes 6, which are electrodes arranged on the inner side wall of the furnace cavity (three on each side); the refining zone uses a side-inserted arrangement to make the center temperature uniformly distributed laterally;

[0075] The furnace body is equipped with a feeding port 3 and a feeding channel 4. The feeding zone 1 is connected to the feeding port 3 for feeding materials. The feeding channel 4 is located after the clarification zone 2 and is used for discharging materials. The bottom insertion of the feeding port area is beneficial to the increase of the bottom temperature and prevents low-temperature crystallization.

[0076] By weight percentage, the components of the arsenic-free microcrystalline glass are fed into the furnace according to the following formula:

[0077] 66.5% SiO2,

[0078] 20.3% Al2O3,

[0079] 4.0% Li2O,

[0080] 3.1% TiO2,

[0081] 1.7% ZrO2,

[0082] 1.2% ZnO,

[0083] 0.8% MgO,

[0084] 1.0% B2O3,

[0085] 0.57% BaO,

[0086] 0.51% Na₂O,

[0087] 0.22% K2O, and

[0088] 0.04% CaO (impurities introduced from the raw material), 0.06% Fe2O3 (impurities introduced from the raw material);

[0089] The prepared arsenic-free microcrystalline glassware was tested, and the results were as follows: Figure 4The temperature / resistivity change curve of the microcrystalline glass shown is derived from... Figure 4 It is known that arsenic-free microcrystalline glassware does not melt below 1180℃, therefore the temperature of the feeding zone and the refining zone in the furnace needs to be kept above 1180℃. Within 60℃ of 1560℃ to 1620℃, the temperature / resistivity change curve of arsenic-free microcrystalline glassware is approximately a straight line segment, and the resistance value changes very little. Therefore, this temperature range is the optimal temperature range for refining the prepared arsenic-free microcrystalline glass.

Claims

1. An arsenic-free microcrystalline glassware, made of arsenic-free microcrystalline glass, characterized in that, The arsenic-free microcrystalline glass comprises, by weight percentage: 65.0%–67.0% SiO2 19.5%–20.5% Al2O3 3.7–4.3% Li₂O, 2.8–3.6% TiO2, 1.5-1.8% ZrO2, 1.0–1.3% ZnO, 0.6-0.9% MgO, 0.9–1.1% B2O3, 0.5-0.7% BaO, 0.5-0.7% Na₂O, and 0.2-0.3% K₂O; The rest are impurities.

2. The arsenic-free microcrystalline glassware according to claim 1, characterized in that: The impurity is Fe2O3.

3. A furnace system for preparing arsenic-free microcrystalline glassware as described in claim 1, comprising a furnace body, a heating unit, and a temperature control unit, characterized in that: The furnace body includes a feeding zone (1) and a clarification zone (2). Along the material flow path, the clarification zone (2) is located after the feeding zone (1). The heating units are evenly distributed in the feeding zone (1) and the clarification zone (2), and the heating units are electrically connected to the temperature control unit. The heating units are used to make the feeding zone (1) and the clarification zone (2) high temperature zones with higher temperatures than the surrounding areas. The temperature control unit is used to control the heating units to make the feeding zone (1) and the clarification zone (2) respectively in the first temperature range and the second temperature range. Within the first temperature range, the material melts into a liquid state; within the second temperature range, the heating unit in the clarification zone (2) is in a constant resistance state, and the liquid material is clarified in the clarification zone (2).

4. The kiln system according to claim 3, characterized in that: The first temperature range is 1180℃~1500℃, and the second temperature range is 1500℃~1650℃.

5. The kiln system according to claim 4, characterized in that: The first temperature range is 1200℃~1413℃, and the second temperature range is 1560℃~1620℃.

6. The kiln system according to claim 3, characterized in that: The heating unit consists of multiple bottom-inserted electrodes (5), which are electrodes that extend from the bottom of the furnace body into the furnace cavity; the multiple bottom-inserted electrodes (5) are arranged at different intervals to form the first temperature range and the second temperature range.

7. The kiln system according to claim 3, characterized in that: The heating unit consists of multiple side-inserted electrodes (6), which are electrodes arranged on the inner side wall of the furnace cavity. The multiple side-inserted electrodes (6) are arranged at different intervals to form the first temperature range and the second temperature range.

8. The kiln system according to claim 3, characterized in that: The heating unit in the feeding zone (1) consists of multiple bottom-inserted electrodes (5), which are electrodes that extend from the bottom of the furnace body into the furnace cavity. The multiple bottom-inserted electrodes (5) are arranged at different intervals to form the first temperature range. The heating unit in the clarification zone (2) consists of multiple side-inserted electrodes (6), which are electrodes arranged on the inner side wall of the furnace cavity. The multiple side-inserted electrodes (6) are arranged at different intervals to form the second temperature range.

9. The kiln system according to claim 3, characterized in that: The furnace body is provided with a feeding port (3) and a feeding channel (4). The feeding area (1) is connected to the feeding port (3) for feeding materials. The feeding channel (4) is located after the clarification area (2) and is used for discharging materials.

10. A method for preparing arsenic-free microcrystalline glassware using a kiln system as described in any one of claims 3-9, characterized in that, Includes the following steps: The temperature control unit and the heating unit are started, and the temperature control unit controls the heating unit to heat the material so that the feeding zone (1) and the clarification zone (2) are respectively in the first temperature range and the second temperature range; The components of the arsenic-free microcrystalline glass are fed into the kiln, and a corresponding amount of clarifying agent is added into the kiln. The components of the arsenic-free microcrystalline glass melt into a liquid state within the first temperature range, and the clarifying agent continuously undergoes liquid-gas and gas-liquid phase transformations between the first and second temperature ranges to achieve physical clarification. After cooling and shaping, arsenic-free microcrystalline glassware is obtained.

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