Method for synthesizing jadeite under normal pressure
By using a method of multiple sintering and mixing elemental powders under normal pressure, the problems of expensive and complex operation of high-pressure and high-temperature synthetic jadeite equipment have been solved, enabling the mass production and promotion of high-quality synthetic jadeite. The product density, hardness, and transparency meet gem-grade requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2026-03-27
Smart Images
Figure CN121735544A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of material synthesis, and in particular to a method for synthesizing jadeite under normal pressure. Background Technology
[0002] Jadeite, mineralogically known as jade, is primarily composed of sodium aluminum silicate, with the chemical formula NaAlSi₂O₆. It is a rare and precious gemstone. Based on the various conditions under which natural jadeite forms, research on synthetic jadeite mainly focuses on how to artificially simulate the natural formation process. This research is conducted by universities, research institutes, and precision manufacturing companies worldwide. Recently, some domestic precision manufacturing companies have used six-sided presses under high pressure and low temperature conditions, as well as in specific sodium and aluminum mineral chemical environments, to synthesize jadeite. While the resulting products have achieved similarities to natural jadeite in composition, structure, hardness, and density, these synthetic jadeite pieces are of poor quality, with inaccurate color and poor transparency, failing to meet gem-quality requirements.
[0003] Currently, all methods for synthesizing jadeite involve high pressure and high temperature. However, the equipment used requires advanced manufacturing technology, high operational precision, and is very expensive. The transition from experimental results to mass production takes time, and initial production costs are close to those of natural jadeite, making it difficult to promote and popularize high-quality synthetic jadeite. The high cost and technical difficulty of synthetic jadeite hinder its market promotion and widespread adoption. Summary of the Invention
[0004] To address the shortcomings of existing methods, this invention provides a method for synthesizing jadeite under normal pressure.
[0005] The technical solution adopted by this invention to solve its technical problem is: a method for synthesizing jadeite under normal pressure, the steps of which are as follows:
[0006] S1, Mixing: Powdered aluminum silicate, sodium carbonate and silicic acid are weighed according to the theoretical mass fraction of each element in the molecular formula of jadeite NaAlSi2O6 and then mixed to obtain the initial mixture.
[0007] S2, First sintering: After pressing the initial mixture into a block, it is kept at atmospheric pressure and 800-1300℃ for no less than 30 minutes. After sintering, it is cooled to room temperature to obtain the first sintered product.
[0008] S3, Second sintering: The first sintered material is crushed and ground to form a primary sintering powder mixture. The primary sintering powder mixture is then pressed into blocks and held at atmospheric pressure and a temperature of 800-1300℃ for no less than 30 minutes. After sintering, it is cooled to room temperature to obtain the second sintered material.
[0009] S4, Third sintering: The second sintered material is crushed and ground to form a secondary sintered powder mixture. Bismuth oxide powder is mixed into the secondary sintered powder mixture to obtain a first mixture. The first mixture is then pressed into a block and held at atmospheric pressure and a temperature of 800-1400℃ for no less than 30 minutes. After sintering, it is cooled to room temperature to obtain the third sintered material. The bismuth oxide accounts for 30-40% of the weight of the first mixture.
[0010] S5, Fourth sintering: The third sintered material is crushed and ground to form a mixture of three sintered powders. A colorant powder is mixed into the three sintered powder mixture to obtain a second mixture. The second mixture is then pressed into a block and held at a temperature of 800-1400℃ for no less than 30 minutes under normal pressure. After sintering, it is cooled to room temperature to obtain the fourth sintered material. The colorant accounts for 0.1-5% of the weight of the second mixture.
[0011] S6, the fifth sintering, the fourth sintering material is crushed and ground to form a mixture of four sintering powders, and a clarifying agent powder is mixed into the mixture of four sintering powders to obtain a third mixture. The third mixture is then pressed into blocks and kept at a temperature of 800-1500℃ for no less than 30 minutes under normal pressure. After sintering, it is cooled to room temperature to obtain synthetic jadeite, wherein the clarifying agent accounts for 0.3-5% of the weight of the third mixture.
[0012] Preferably, the preparation of the initial mixture includes the following steps:
[0013] S1a, dissolve and mix the weighed aluminum silicate, sodium carbonate and silicic acid in deionized water to form a mixture;
[0014] S1b, the mixture is dried in a constant temperature oven at a temperature of 160±10℃ to obtain dried block material;
[0015] S1c, the dried block material is crushed and ground into powder to obtain the primary mixture.
[0016] Preferably, the colorant is any one or more of basic chromium sulfate, chromium oxide, cobalt oxide, manganese oxide, copper oxide, nickel oxide, iron oxide, praseodymium oxide, erbium oxide, titanium oxide, neodymium oxide, lutetium oxide, cerium oxide, selenite, erbium oxide, and cuprous oxide.
[0017] Preferably, in steps S2 to S6, the temperature is increased to the target temperature at a rate of 1-6℃ / min.
[0018] Preferably, the heat preservation time for steps S2, S4, and S5 is 30-240 min, the heat preservation time for step S3 is 30-200 min, and the heat preservation time for step S6 is 30-1500 min.
[0019] Preferably, the cooling rate in steps S2 to S5 is 3-20℃ / min, and the cooling rate in step S6 is no greater than 3℃ / min.
[0020] Preferably, in step S6, the temperature is first reduced to 300°C at a cooling rate of no more than 3°C / min, and then cooled to room temperature by natural cooling.
[0021] Preferably, the clarifying agent is a mixture of cerium oxide and sodium sulfate, wherein the weight ratio of cerium oxide to sodium sulfate is 1:0.5-5.
[0022] Preferably, in steps S2 to S6, the mixture is pressed into blocks by cold isostatic pressing.
[0023] The beneficial effects of this invention are as follows: it is prepared under normal pressure, requires less equipment investment, has a simple process operation, a short production cycle, and produces a product with a density of 3.25–3.45 g / cm³. 3 With a hardness of 6.3–7.0 and a refractive index of 1.62–1.67, it reaches gem-quality jadeite. Synthetic jadeite has low cost, which is conducive to the promotion and popularization of the product. Attached Figure Description
[0024] Figure 1 This is an optical photograph of the product prepared according to the embodiments of the present invention, magnified 15,000 times under a SEM electron microscope;
[0025] Figure 2 This is an optical photograph of the product prepared according to the embodiments of the present invention, magnified 5000 times under a SEM electron microscope;
[0026] Figure 3 These are photographs of the products prepared according to embodiments of the present invention;
[0027] Figure 4 These are decorative items carved from the products prepared in the embodiments of the present invention; Detailed Implementation
[0028] To more clearly illustrate the objectives, technical solutions, and advantages of the embodiments of the present invention, the present invention will be further described below in conjunction with the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.
[0029] A method for synthesizing jadeite under normal pressure, the steps of which are as follows:
[0030] S1, Mixing: Aluminum silicate (Al2SiO5), sodium carbonate (Na2CO3), and silicic acid (H2SiO3) are weighed according to the theoretical mass fraction ratio of each element in the molecular formula of jadeite NaAlSi2O6, and then mixed to obtain the initial mixture. The specific mixing process is as follows:
[0031] S1a, dissolve and mix the weighed aluminum silicate, sodium carbonate and silicic acid in deionized water to form a mixture;
[0032] S1b, the mixture is dried in a constant temperature oven at a temperature of 160±10℃ to obtain dried block material;
[0033] S1c, the dried block material is crushed and ground into powder to obtain the primary mixture;
[0034] S2, First sintering: The initial mixture is pressed into blocks by cold isostatic pressing and then placed in a high-temperature resistant crucible. It is then sintered in a high-temperature furnace under normal pressure and a temperature of 800-1300℃ for at least 30 minutes. For example, the sintering conditions are: heating rate of 3℃ / min, holding at 1000℃ for 60 minutes and then cooling to room temperature to obtain the first sintered material. The cooling rate is 10℃ / min. After cooling, it is taken out of the crucible.
[0035] S3, Second sintering: The first sintered material is crushed and ground to form a primary sintering powder mixture. The primary sintering powder mixture is then pressed into blocks by cold isostatic pressing and placed in a high-temperature crucible. It is then sintered in a high-temperature furnace under normal pressure and a temperature of 800-1300℃ for at least 30 minutes. The sintering conditions are a heating rate of 3℃ / min and a holding temperature of 1000℃ for 60 minutes. After sintering, it is cooled to room temperature to obtain the second sintered material, which is a jade microcrystalline glass-like product. The cooling rate is 10℃ / min. After cooling, it is taken out of the crucible.
[0036] S4, Third sintering: The second sintered material is crushed and ground to form a secondary sintering powder mixture. High-purity bismuth oxide powder is mixed into the secondary sintering powder mixture to obtain a uniformly mixed first mixture. For example, bismuth oxide accounts for 38% of the weight of the first mixture. The first mixture is then pressed into blocks by cold isostatic pressing and placed in a high-temperature crucible. It is then sintered in a high-temperature furnace under normal pressure and a temperature of 800-1400℃ for no less than 30 minutes. The sintering conditions are a heating rate of 3℃ / min and a holding temperature of 1200℃ for 90 minutes. After sintering, it is cooled to room temperature to obtain the third sintered material, which is a sodium aluminum silicate material rich in bismuth. It is made into a high-density, high-hardness glassy crystal. The cooling rate is 10℃ / min. After cooling, it is taken out of the crucible.
[0037] S5, Fourth Sintering: The material from the third sintering is pulverized and ground to form a mixture of three sintered powders. A colorant powder is mixed into this mixture to obtain a second mixture. The colorant is any one or more of the following: basic chromium sulfate, chromium oxide, cobalt oxide, manganese oxide, copper oxide, nickel oxide, iron oxide, praseodymium oxide, erbium oxide, titanium oxide, neodymium oxide, lutetium oxide, cerium oxide, selenite, erbium oxide, and cuprous oxide. The colorant accounts for 0.1-5% of the weight of the second mixture; if chromium oxide is selected, it accounts for 1% of the weight of the second mixture. The mixture is mixed evenly, and the resulting product is bright green. The second mixture is then pressed into blocks by cold isostatic pressing and placed in a high-temperature resistant crucible. It is then held at atmospheric pressure and 800-1400℃ for at least 30 minutes. At this time, the sintering conditions are set with a heating rate of 3℃ / min and a holding temperature of 1200℃ for 120 minutes. After sintering, the mixture is cooled to room temperature to obtain the fourth sintered product, which is a high-density, high-hardness glassy bright green microcrystalline mixture. The cooling rate is 10℃ / min. After cooling, the mixture is removed from the crucible.
[0038] S6, the fifth sintering: The material from the fourth sintering is pulverized and ground to form a mixture of four-sintering powders. A clarifying agent powder is mixed into this mixture to obtain a third mixture. The clarifying agent is a mixture of cerium oxide and sodium sulfate. The clarifying agent is used for degassing. The weight ratio of cerium oxide to sodium sulfate is 1:0.5-5. At this point, the clarifying agent accounts for 0.3-5% of the weight of the third mixture. For example, if the weights of cerium oxide and sodium sulfate are 1.0% and 2.0% respectively, they are mixed evenly. The third mixture is then pressed into blocks by cold isostatic pressing and placed... The material is held at a temperature of 800-1500℃ for at least 30 minutes in a high-temperature resistant crucible under normal pressure. The sintering conditions are: a heating rate of 2℃ / min and a holding temperature of 1200℃ for 120 minutes. After sintering, it is cooled to room temperature to obtain synthetic jadeite. Alternatively, it can be cooled to 300℃ at a rate not exceeding 3℃ / min, followed by natural cooling to room temperature. If a cooling rate of 1℃ / min is chosen, the jadeite is removed from the crucible after cooling. This process produces high-quality, high-density, high-hardness, well-colored, vitreous, and oily microcrystalline synthetic jadeite. Figure 3 and Figure 4 As shown in the image.
[0039] The above steps produce microcrystalline synthetic jade rich in bismuth, with a density of 3.34 g / cm³. 3 It has a Mohs hardness of 6.5 and a refractive index of approximately 1.64. For example... Figure 1 and Figure 2As shown in the image, the sample, viewed under an electron microscope, exhibits a microcrystalline state with uniform fusion of various elements. This indicates that the prepared product is a sodium aluminum silicate material rich in elements such as sodium, aluminum, and silicon. The composition, structure, hardness, density, and refractive index of this product are identical to natural jadeite, achieving the same performance characteristics. It possesses a pure and diverse color, a greasy luster, a warm and bright appearance, high density and hardness, and a fine, oily, and transparent texture, making it suitable for high-end jewelry and valuable handicrafts. This method, performed under normal pressure, effectively solves the problems associated with traditional high-temperature and high-pressure jadeite production, reducing production requirements and costs, and facilitating the mass production and widespread application of synthetic jadeite.
[0040] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. A method for synthesizing jadeite under normal pressure, characterized in that, The steps are as follows: S1, Mixing: Aluminum silicate, sodium carbonate and silicic acid are weighed according to the theoretical mass fraction of each element in the molecular formula of jadeite NaAlSi2O6 and then mixed to obtain a powdered primary mixture. S2, First sintering: After pressing the initial mixture into a block, it is kept at atmospheric pressure and 800-1300℃ for no less than 30 minutes. After sintering, it is cooled to room temperature to obtain the first sintered product. S3, Second sintering: The first sintered material is crushed and ground to form a primary sintering powder mixture. The primary sintering powder mixture is then pressed into blocks and held at atmospheric pressure and a temperature of 800-1300℃ for no less than 30 minutes. After sintering, it is cooled to room temperature to obtain the second sintered material. S4, Third sintering: The second sintered material is crushed and ground to form a secondary sintered powder mixture. Bismuth oxide powder is mixed into the secondary sintered powder mixture to obtain a first mixture. The first mixture is then pressed into a block and held at atmospheric pressure and a temperature of 800-1400℃ for no less than 30 minutes. After sintering, it is cooled to room temperature to obtain the third sintered material. The bismuth oxide accounts for 30-40% of the weight of the first mixture. S5, Fourth sintering: The third sintered material is crushed and ground to form a mixture of three sintered powders. A colorant powder is mixed into the three sintered powder mixture to obtain a second mixture. The second mixture is then pressed into a block and held at a temperature of 800-1400℃ for no less than 30 minutes under normal pressure. After sintering, it is cooled to room temperature to obtain the fourth sintered material. The colorant accounts for 0.1-5% of the weight of the second mixture. S6, the fifth sintering, the fourth sintering material is crushed and ground to form a mixture of four sintering powders, and a clarifying agent powder is mixed into the mixture of four sintering powders to obtain a third mixture. The third mixture is then pressed into blocks and kept at a temperature of 800-1500℃ for no less than 30 minutes under normal pressure. After sintering, it is cooled to room temperature to obtain synthetic jadeite, wherein the clarifying agent accounts for 0.3-5% of the weight of the third mixture.
2. The method for synthesizing jadeite under normal pressure according to claim 1, characterized in that, The preparation of the initial mixture includes the following steps: S1a, dissolve and mix the weighed aluminum silicate, sodium carbonate and silicic acid in deionized water to form a mixture; S1b, dry the mixture in a constant temperature oven at 160±10℃ to obtain dried block material; S1c, the dried block material is crushed and ground into powder to obtain the primary mixture.
3. The method for synthesizing jadeite under normal pressure according to claim 1, characterized in that... The colorant is any one or more of the following: basic chromium sulfate, chromium oxide, cobalt oxide, manganese oxide, copper oxide, nickel oxide, iron oxide, praseodymium oxide, erbium oxide, titanium oxide, neodymium oxide, lutetium oxide, cerium oxide, selenite, erbium oxide, and cuprous oxide.
4. The method for synthesizing jadeite under normal pressure according to claim 1, characterized in that... In steps S2 to S6, the temperature is increased to the target temperature at a rate of 1-6℃ / min.
5. The method for synthesizing jadeite under normal pressure according to claim 1, characterized in that... The heat preservation time for steps S2, S4, and S5 is 30-240 min, the heat preservation time for step S3 is 30-200 min, and the heat preservation time for step S6 is 30-1500 min.
6. The method for synthesizing jadeite under normal pressure according to claim 1, characterized in that... The cooling rate in steps S2 to S5 is 3-20℃ / min, and the cooling rate in step S6 is no greater than 3℃ / min.
7. The method for synthesizing jadeite under normal pressure according to claim 6, characterized in that... In step S6, the temperature is first reduced to 300°C at a rate of no more than 3°C / min, and then cooled to room temperature by natural cooling.
8. The method for synthesizing jadeite under normal pressure according to claim 1, characterized in that... The clarifying agent is a mixture of cerium oxide and sodium sulfate, wherein the weight ratio of cerium oxide to sodium sulfate is 1:0.5-5.
9. The method for synthesizing jadeite under normal pressure according to claim 1, characterized in that... In steps S2 to S6, the mixture is pressed into blocks by cold isostatic pressing.