Method for synthesizing polycrystalline jadeite

Abstract

A method for synthesizing polycrystalline jadeite. The powdery raw materials of aluminum silicate, sodium silicate, and silicon dioxide are comprised. The method comprises: firstly, respectively weighing the raw materials according to the proportion, adding a coloring agent, and uniformly mixing; heating the mixture to 150°C at a certain pressure and heating speed, and then keeping the temperature for 0.5-1 hour, continuously heating to 1200-1800°C, sintering and melting, and then cooling to room temperature at a certain rate; next, heating the product obtained in the previous step to 1200-1800°C at a certain pressure and heating speed, sintering and melting, and then cooling to room temperature at a certain cooling rate, and repeating the step for multiple times; and finally, keeping the temperature of the product obtained in the previous step at a certain pressure and temperature, and then cooling to normal temperature and reducing the pressure to normal pressure.

Description

A method for synthesizing polycrystalline jadeite Technical Field

[0001] The present invention relates to the field of material synthesis, in particular to a method for synthesizing polycrystalline jadeite. Background Art

[0002] Jadeite, known in mineralogical terms as jadeite, is primarily composed of sodium aluminum silicate, with the mineral formula: NaAlSi2O6. It is a rare and precious gemstone whose physical and chemical properties are closely related to geological evolution. Natural jadeite is a polycrystalline aggregate of jadeite formed in high-temperature, high-pressure geological environments. Currently, natural jadeite is primarily produced in countries such as Myanmar, Guatemala, and Russia. In today's era of powerful large-scale mechanized mining, lands containing large quantities of jadeite can become depleted or depleted over time, compromising effective land utilization and environmental protection.

[0003] Currently, artificial jadeite synthesis plays a significant role in protecting the land and the environment. Existing methods for synthesizing jadeite require crushing the jadeite glass into a powder. Due to the high hardness of jadeite glass, the crushing process, whether manual or mechanical, can easily introduce impurities, causing pollution. Furthermore, re-molding the ground powder can also lead to the formation of pores within the powder, compromising the quality of the resulting synthetic jadeite and making it difficult to obtain high-quality synthetic jadeite. Technical issues

[0004] In view of the existing deficiencies, the present invention provides a method for synthesizing polycrystalline jadeite and an engineering chip. Technical Solutions

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for synthesizing polycrystalline jadeite, comprising the following powdered raw materials: aluminum silicate, sodium silicate and silicon dioxide; the steps are as follows:

[0006] S1, weighing aluminum silicate, sodium silicate and silicon dioxide in a molar ratio of aluminum silicate: sodium silicate: silicon dioxide = 1:1:1.5, and adding 0.01-3wt% of the total weight of the raw materials to a colorant and mixing for 10-120 minutes;

[0007] S2, heating the mixture obtained in step S1 at a pressure of 0.1-5 GPa at a heating rate of 3-50°C / min to 150°C, holding the temperature for 0.5-1 hour, then further heating the temperature to 1200-1800°C, sintering and melting the mixture for 0.5-24 hours, and cooling the melted sample to room temperature at a rate of 3-50°C / min to obtain a slightly transparent or translucent amorphous jadeite block;

[0008] S3, heating the slightly transparent or translucent amorphous jadeite block obtained in step S2 to 1200-1800°C at a pressure of 0.1-5 GPa at a heating rate of 3-50°C / min, then sintering and melting the block for 0.5-24 hours, cooling the melted sample to room temperature at a rate of 3-50°C / min, and repeating this step multiple times to obtain a dense transparent amorphous jadeite block;

[0009] S4, keeping the transparent amorphous jadeite block obtained in step S3 at a pressure of 0.1-5 GPa and a temperature of 1200-2000°C for 0.1-48 hours, and then cooling and reducing the pressure to room temperature and pressure to obtain translucent jadeite crystals.

[0010] Preferably, the colorant is any one or more oxides of the following elements: Cr, Fe, Mn, V, Ti, Ni, Mg, Co, Cu, Nd, Lu, Ce, and Sn.

[0011] Preferably, in step S3, the slightly transparent or translucent amorphous jadeite block obtained in step S2 is first placed in a mold and then sintered and melted to form it.

[0012] Preferably, the temperature is increased at a heating rate of 5°C / min in both step S2 and step S3, the temperature is decreased at a cooling rate of 5°C / min in step S2, and the temperature is decreased at a cooling rate of 10°C / min in step S3. The pressure in both step S2 and step S3 is 1 GPa.

[0013] Preferably, the specific steps of step S4 are:

[0014] S4a, first increase the pressure to 1 / 2 of the maximum pressure and then increase the temperature to 1 / 2 of the maximum temperature at this pressure, and then increase the pressure to the maximum pressure at this temperature;

[0015] S4b, raising the temperature to a maximum temperature under the maximum pressure, and maintaining the temperature and pressure at the maximum temperature and maximum pressure for 0.1 to 48 hours;

[0016] S4c, after the heat and pressure are maintained, the temperature is lowered to 1000-1100°C and the pressure is released to 1 / 4 of the maximum pressure, then the temperature is lowered to room temperature at the pressure, and finally the pressure is released to normal pressure.

[0017] Preferably, the maximum pressure is 4 GPa and the maximum temperature is 1600°C.

[0018] Preferably, the temperature is increased at a rate of 3-50°C / min in steps S4a and S4b, and the temperature is first decreased to 1000-1100°C at a rate of 50-100°C / min in step S4c, and then decreased to room temperature at a rate of 3-50°C / min.

[0019] Preferably, step S3 is repeated 1-5 times. Beneficial effects

[0020] The beneficial effects of the present invention are as follows: the invention adopts powdered raw materials, which do not need to be crushed during the entire synthesis process, thus avoiding pollution; and high pressure is adopted from the initial stage to facilitate the melting of the raw materials, so that the various components can be fused more evenly, and the synthesized product has greater hardness and a denser structure; and heat preservation is carried out at low temperatures, so that the moisture is better evaporated, and the moisture is prevented from evaporating too late to escape and forming bubbles remaining in the final product; slow heating is adopted during the heating process, which further avoids the formation of coke during sintering, and will not cause excessive sintering of particles to affect quality; different cooling rates are also adopted for cooling to ensure that dense translucent jadeite crystals are finally obtained, which have various parameter standards of gem-grade jadeite and can be processed and polished into various gem craft accessories, with huge economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a diagram of polycrystalline jadeite synthesized in Example 1 of the present invention;

[0022] FIG2 is a SEM image of polycrystalline jadeite synthesized in Example 1 of the present invention;

[0023] FIG3 is an XRD pattern of the polycrystalline jadeite synthesized in Example 1 of the present invention. Modes for Carrying Out the Invention

[0024] In order to more clearly illustrate the purpose, technical solutions and advantages of the embodiments of the present invention, the present invention will be further described below in conjunction with the embodiments for a clear and complete description. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] A method for synthesizing polycrystalline jadeite, comprising the following powdered raw materials: aluminum silicate, sodium silicate, and silicon dioxide; and the following steps: Example 1

[0026] S1, weigh 32g of aluminum silicate, 24g of sodium silicate, and 17.1g of silicon dioxide, and then add 0.7g of chromium trioxide, a colorant, and mix for 90 minutes. The colorant can also be any one or more of the following elements: Fe, Mn, V, Ti, Ni, Mg, Co, Cu, Nd, Lu, Ce, and Sn oxides. Different colors are formed according to the colorant, such as Cr, which makes jade green. 3+ , Mn, which makes jade appear purple 3+ , Fe2O3 which makes jadeite red, and 2Fe2O3·3H2O which makes jadeite yellow.

[0027] S2, heating the mixture obtained in step S1 at a pressure of 1 GPa at a heating rate of 5°C / min to 150°C, holding the temperature for 0.5 hours, then further heating the temperature to 1300°C and sintering and melting for 12 hours. The melted sample is cooled to room temperature at a rate of 5°C / min to obtain a green, slightly transparent or translucent amorphous jadeite block;

[0028] S3, heating the slightly transparent or translucent amorphous jadeite block obtained in step S2 to 1500°C at a heating rate of 5°C / min under a pressure of 1 GPa, and then sintering and melting the block for 12 hours. Cooling the melted sample to room temperature at a rate of 10°C / min, and repeating this step four times to obtain a dense transparent amorphous jadeite block;

[0029] S4, keeping the transparent amorphous jadeite block obtained in step S3 at a pressure of 4 GPa and a temperature of 1600°C for 48 hours, and then cooling and reducing the pressure to room temperature and pressure to obtain translucent jadeite crystals.

[0030] The specific steps are:

[0031] S4a, first increase the pressure to 2 GPa and then increase the temperature at a rate of 10°C / min to 800°C, at which temperature the pressure is increased to 4 GPa;

[0032] S4b, the temperature was raised to 1600 °C at a rate of 10 °C / min under a pressure of 4 GPa and kept at this temperature and pressure for 48 h;

[0033] S4c, after the heat preservation and pressure holding is completed, the temperature is cooled to 1100℃ at a cooling rate of 80℃ / min and then the pressure is released to a pressure of 1 GPa. Then, the temperature is cooled to room temperature at a cooling rate of 10℃ / min at the same pressure, and finally the pressure is released to normal pressure.

[0034] The jadeite crystals prepared in this embodiment are shown in Figures 1 to 3, which are gem-grade jadeite jade. The color is mostly green to emerald green, with a glassy luster, a relative density of 3.26 to 3.38, a Mohs hardness of 6.5-7.1, and a refractive index of 1.67 measured by the point measurement method. After XRD analysis, the sample composition is consistent with natural jadeite, and the crystallinity reaches 98%; the scanning electron microscope analysis results of the sample cross-sectional morphology are basically consistent with the cross-sectional morphology of natural jadeite. Example 2

[0035] S1: Weigh 32 g of aluminum silicate, 24 g of sodium silicate, and 17.1 g of silicon dioxide separately, then add 1.0 g of chromium trioxide (a colorant) and mix for 100 min.

[0036] S2, heating the mixture obtained in step S1 at a pressure of 2 GPa at a heating rate of 5°C / min to 150°C, holding the temperature for 1 hour, then further heating the temperature to 1300°C and sintering and melting for 12 hours. The melted sample is cooled to room temperature at a rate of 5°C / min to obtain a green, slightly transparent or translucent amorphous jadeite block;

[0037] S3, placing the slightly transparent or translucent amorphous jadeite block obtained in step S2 into a high-temperature and high-pressure resistant forming mold, then heating the amorphous jadeite block and the forming mold to 1500°C at a heating rate of 5°C / min under a pressure of 2 GPa, and then sintering and melting the sample for 12 hours. The melted sample is cooled to room temperature at a rate of 10°C / min, and this step is repeated five times to obtain a dense transparent amorphous jadeite block;

[0038] S4, keeping the transparent amorphous jadeite block obtained in step S3 at a pressure of 4 GPa and a temperature of 1600°C for 48 hours, and then cooling and reducing the pressure to room temperature and pressure to obtain translucent jadeite crystals.

[0039] The specific steps are as follows: S4a, first increasing the pressure to 2 GPa and then increasing the temperature at a heating rate of 10°C / min at this pressure to 800°C, and then increasing the pressure to 4 GPa at this temperature;

[0040] S4b, the temperature was raised to 1600 °C at a rate of 10 °C / min under a pressure of 4 GPa and kept at this temperature and pressure for 48 h;

[0041] S4c, after the heat preservation and pressure holding is completed, the temperature is cooled to 1100℃ at a cooling rate of 100℃ / min and then the pressure is released to a pressure of 1 GPa. Then, the temperature is cooled to room temperature at a cooling rate of 10℃ / min at the same pressure, and finally the pressure is released to normal pressure.

[0042] It should be understood that those skilled in the art may make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for synthesizing polycrystalline jadeite, characterized in that : It includes the following powdery raw materials: aluminum silicate, sodium silicate, and silicon dioxide; the steps are as follows: S1, Weigh aluminum silicate, sodium silicate, and silicon dioxide respectively according to the molar ratio of aluminum silicate:sodium silicate:silicon dioxide = 1:1:1.5, and at the same time add a colorant accounting for 0.01 - 3wt% of the total mass of the raw materials and mix for 10 - 120 minutes; S2, Under the pressure of 0.1 - 5GPa, heat the mixture obtained in step S1 at a heating rate of 3 - 50°C / min. After heating to 150°C, keep it warm for 0.5 - 1 hour, and then continue to heat to 1200 - 1800°C and sinter and melt for 0.5 - 24 hours. Cool the melted sample to room temperature at a rate of 3 - 50°C / min to obtain a slightly transparent or semi - transparent amorphous jadeite block; S3, Under the pressure of 0.1 - 5GPa, heat the slightly transparent or semi - transparent amorphous jadeite block obtained in step S2 at a heating rate of 3 - 50°C / min to 1200 - 1800°C and sinter and melt for 0.5 - 24 hours. Cool the melted sample to room temperature at a rate of 3 - 50°C / min. Repeat this step multiple times to obtain a dense transparent amorphous jadeite block; S4, Keep the transparent amorphous jadeite block obtained in step S3 under the pressure of 0.1 - 5GPa and at the temperature of 1200 - 2000°C for 0.1 - 48 hours, and then cool and reduce the pressure to normal temperature and pressure to obtain a semi - transparent jadeite crystal.

2. The method for synthesizing polycrystalline jadeite according to claim 1, wherein : The colorant is any one or more of the oxides of the following elements: Cr, Fe, Mn, V, Ti, Ni, Mg, Co, Cu, Nd, Lu, Ce, Sn.

3. The method for synthesizing polycrystalline jadeite according to claim 1, wherein : In step S3, the slightly transparent or semi - transparent amorphous jadeite block obtained in step S2 is first placed in a mold and then sintered and melted into shape.

4. The method for synthesizing polycrystalline jadeite according to claim 1, characterized in that : In both step S2 and step S3, the heating rate is 5°C / min for heating, the cooling rate in step S2 is 5°C / min for cooling, the cooling rate in step S3 is 10°C / min for cooling, and the pressure in both step S2 and step S3 is 1GPa.

5. The method for synthesizing polycrystalline jadeite according to claim 1, wherein : The specific steps of step S4 are as follows: S4a, First increase the pressure to 1 / 2 of the maximum pressure and heat to 1 / 2 of the maximum temperature at this pressure. At this temperature, increase the pressure to the maximum pressure; S4b, Increase the temperature to the maximum temperature at the maximum pressure, and keep the pressure and temperature constant for 0.1 - 48 hours at the maximum temperature and maximum pressure; S4c, After keeping the pressure and temperature constant, cool to 1000 - 1100°C and then reduce the pressure to 1 / 4 of the maximum pressure, then cool to room temperature at this pressure, and finally reduce the pressure to normal pressure.

6. The method for synthesizing polycrystalline jadeite according to claim 5, characterized in that : The maximum pressure is 4GPa, and the maximum temperature is 1600°C.

7. The method for synthesizing polycrystalline jadeite according to claim 5, wherein : In steps S4a and S4b, the heating rate is 3 - 50°C / min for heating. In step S4c, first cool at a cooling rate of 50 - 100°C / min to 1000 - 1100°C, and then cool to normal temperature at a cooling rate of 3 - 50°C / min.

8. The method for synthesizing polycrystalline jadeite according to claim 1, characterized in that : The number of times step S3 is repeated is 1 - 5 times.

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