High-pressure liquid sintering modification method for low-quality natural jadeite

Abstract

The application discloses a high-pressure liquid phase sintering modification method of low-quality natural emerald, and belongs to the field of modification of ceramic materials. The high-pressure liquid phase sintering technology based on a cubic press is adopted, the size and assembly of a suitable high-temperature and high-pressure assembly are regulated and controlled, full atomic diffusion and component homogenization of low-quality emerald raw materials are promoted in a liquid phase temperature range, and a main component of hard jade (NaAlSi2O6) is obtained in a highly uniform molten state distribution. Then, densification sintering is completed under a temperature and pressure condition slightly lower than a solidus, directional growth and structural densification of hard jade single-phase crystals are effectively promoted, and finally, the emerald material with a smooth surface and significantly improved transparency is prepared. The gemmological characteristics and spectroscopy characteristics of the emerald modified by the method are basically consistent with those of natural emerald, the crystallinity is greater than 99.5%, the visible light transmittance is greater than 34.45%, and the porosity is less than 0.82%.

Description

Technical Field

[0001] This invention belongs to the field of ceramic material modification, specifically relating to a high-pressure liquid phase sintering modification method for low-quality natural jadeite. Background Technology

[0002] Jadeite is the second largest category in my country's jewelry market, after gold. With the continued growth in demand for high-quality jadeite, and given the non-renewable nature of natural resources, the supply-demand imbalance is becoming increasingly prominent. Against this backdrop, optimizing and modifying low-quality jadeite through physical or chemical means to enhance its aesthetic and commercial value has become an important direction in current jewelry materials science and technology research.

[0003] Currently, the mainstream enhancement techniques for low-quality jadeite mainly include heat treatment and acid washing-resin filling-dyeing. However, while traditional heat treatment can improve color to some extent, the high-temperature process easily induces the expansion of micro-cracks, leading to decreased transparency. Acid washing-resin filling-dyeing, although it can improve appearance in the short term, damages the microscopic integrity of the jadeite due to the residual network structure etched by strong acids. Furthermore, the organic polymers used for filling are prone to aging, precipitation, and even volatilization under long-term wear or environmental influences, affecting durability and posing potential environmental and health risks. Therefore, existing enhancement technologies still have significant limitations in terms of structural stability, optical performance improvement, and long-term service reliability.

[0004] High-temperature and high-pressure (HTHP) technology can induce lattice reconstruction, shorten interatomic spacing, and regulate electron cloud distribution by applying directional pressure, thereby achieving material densification and precise control of phase structure. It has demonstrated a mature application foundation and significant results in fields such as synthetic diamond synthesis, advanced ceramics, superhard materials, and functional composite materials. Given that natural jadeite itself forms in a high-temperature and high-pressure environment deep within the Earth's crust (research shows its minimum mineralization pressure is approximately 1.8 GPa, and the mineralization temperature window widens with increasing pressure), HTHP technology possesses natural suitability and theoretical feasibility in jadeite modification. However, traditional high-pressure solid-state sintering processes often struggle to achieve coordinated control of pressure and temperature, easily leading to problems such as microcrack formation, abnormal grain growth, or incomplete jadeite phase crystallization, which ultimately damages material quality. Therefore, how to construct a HTHP process system with controllable parameters and precise phase regions, guiding jadeite to simultaneously achieve structural densification and crystal integrity improvement within a stable jadeite single-phase range, has become a key scientific issue and technological challenge in overcoming the bottleneck of jadeite quality upgrading.

[0005] Chinese patent CN120210949A discloses a method for artificially synthesizing jadeite and its liquid-phase synthesis. This method employs a technical route of acid washing and purification followed by high-temperature and high-pressure synthesis. Its drawback is that while the strong acid purification process removes mineral impurities, it also simultaneously damages the original structure of the jadeite. Furthermore, the process lacks an anti-contamination mechanism for the high-temperature and high-pressure assembled components, allowing impurities such as carbon in the components to easily penetrate the jadeite during synthesis. This results in the synthesized jadeite having a darker color and an overall blackish appearance, failing to meet the standards of high-quality natural jadeite in terms of optical performance and appearance. Summary of the Invention

[0006] The purpose of this invention is to provide a high-pressure liquid-phase sintering modification method for low-quality natural jadeite. This method targets low-quality natural jadeite raw materials and optimizes pressure conduction and heat field distribution by precisely controlling the size design of the high-temperature, high-pressure assembly and the sintering process, aiming to achieve densification and high crystallinity of the loose jadeite structure. Simultaneously, the construction of this high-temperature, high-pressure assembly also serves as a physical barrier and prevents contamination, preventing impurities such as carbon from penetrating into the jadeite during the synthesis process. Jadeite treated by this method exhibits significantly improved transparency and meets the standards of high-quality natural jadeite in both optical performance and appearance.

[0007] The objective of this invention is achieved through the following technical solutions.

[0008] This invention provides a high-pressure liquid-phase sintering modification method for low-quality natural jadeite, comprising the following steps: (1) Natural low-quality jade scraps are crushed in an agate mortar and then sieved, and ferromagnetic impurities are removed by a magnetic separator. (2) Select pyrophyllite, zirconium oxide, graphite heating tubes, boron nitride crucibles and molybdenum foil of appropriate size to assemble into high temperature and high pressure assembly; (3) The jade precursor powder obtained in step (1) is cold-pressed into shape, the pressed blank is loaded into the high temperature and high pressure assembly in step (2), and dried; the dried assembly is placed in a six-sided top press for high pressure liquid phase melting and sintering crystal growth.

[0009] Preferably, in the above-mentioned high-pressure liquid-phase sintering modification method for natural low-quality jadeite, in step (1), the original natural low-quality jadeite sample has a relatively loose structure and a density of less than 3.25 g / cm³. 3 It contains certain iron impurities and has very low overall transparency, with a visible light transmittance of less than 20%.

[0010] Preferably, in the above-mentioned high-pressure liquid phase sintering modification method for natural low-quality jadeite, in step (1), the jadeite powder crushed by the agate mortar is sieved through a mesh screen and iron impurities are adsorbed by a magnetic separator.

[0011] Preferably, in the above-mentioned high-pressure liquid phase sintering modification method for natural low-quality jadeite, in step (2), the pyrophyllite in the high-temperature and high-pressure assembly has a size of 33×33mm-36×36mm, the zirconium oxide has a size of Ф12×Ф10×16mm-Ф15×Ф13×19mm, the graphite heating tube has a size of Ф9×Ф7×16mm-Ф12×Ф10×19mm, and the boron nitride crucible has a size of Ф7×Ф6.5×7×6.7mm-Ф10×Ф9.5×10×9.7mm.

[0012] More preferably, in step (2), the pyrophyllite has a size of 33×33mm-33.5×33.5mm, the zirconium oxide has a size of Ф12×Ф10×16mm-Ф12.2×Ф10.2×16.2mm, the graphite heating tube has a size of Ф9×Ф7×16mm-Ф9.2×Ф7.2×16.2mm, and the boron nitride crucible has a size of Ф7×Ф6.5×7×6.7mm-Ф7.2×Ф6.7×7.2×6.9mm.

[0013] Preferably, in the above-mentioned high-pressure liquid phase sintering modification method for natural low-quality jadeite, in step (2), the molybdenum foil is a rectangle with a size of 30×0.9mm-30.2×1.2mm and is rolled into a cylindrical shape to protect the jadeite raw material.

[0014] Preferably, in the above-mentioned high-pressure liquid phase sintering modification method for natural low-quality jadeite, in step (3), the pre-pressing molding adopts the cold pressing molding method of a tablet press, with a pressure of 10-20MPa.

[0015] Preferably, in the above-mentioned high-pressure liquid phase sintering modification method for natural low-quality jadeite, in step (3), after the pressed blank is loaded into the assembly, the drying temperature is 100-150℃ and the drying time is 10-12h.

[0016] Preferably, in the above-mentioned high-pressure liquid phase sintering modification method for natural low-quality jadeite, in step (3), the pressure of the high-pressure liquid phase melting is 4-6 GPa, the melting temperature is 1580-1660 ℃, the melting time is 10-30 min, the sintering temperature is 1400-1500 ℃, and the sintering time is 30-90 min.

[0017] The present invention also provides the above-mentioned high-pressure liquid phase sintering modified jadeite, which, in terms of appearance, has a dense structure, relatively high crystallinity, no blackening phenomenon, and is similar to the "glutinous type" of natural jadeite.

[0018] This invention employs high-pressure liquid-phase sintering technology based on a six-sided top press. By controlling the appropriate size and assembly of the high-temperature, high-pressure assemblies, it promotes sufficient atomic diffusion and component homogenization of low-quality jadeite raw materials within the liquid phase temperature range, resulting in a highly uniform molten distribution of the main component of jadeite (NaAlSi2O6). Subsequently, densification sintering is completed under temperature and pressure conditions slightly below the solidus line, effectively promoting the directional growth and structural densification of jadeite single-phase crystals, ultimately producing jadeite material with a smooth surface and significantly improved transparency. The gemological and spectroscopic characteristics of the jadeite modified by this invention are basically consistent with those of natural jadeite, with a crystallinity >99.5%, visible light transmittance >34.45%, and porosity <0.82%.

[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: (1) The raw materials are widely adaptable and can directly utilize natural low-quality jade scraps or fragments, which significantly improves the comprehensive utilization rate of resources. The process relies on a mature and cost-controllable six-sided top press system. The equipment is highly versatile and has high operational stability, providing a good foundation for industrialization and promotion.

[0020] (2) Compared with the traditional high-pressure solid-state sintering process, the present invention fully utilizes the mass transfer and wetting effect of the liquid phase medium by precisely controlling the temperature in the liquid phase-solid phase transition zone, providing a thermodynamically favorable anisotropic growth environment for jadeite crystals. Experimental results show that the density, relative crystallinity, and visible light transmittance of jadeite samples treated by the modification method of the present invention are significantly improved.

[0021] (3) By optimizing the size and assembly of the high-temperature and high-pressure assembly, the present invention effectively blocks the penetration of impurity carbon atoms into the sample cavity, solves the problem of jadeite turning black and becoming opaque during the synthesis process, and ensures that the modified jadeite is highly consistent with natural high-quality jadeite in terms of optical performance and appearance.

[0022] (4) The finished product obtained by the method of the present invention exhibits a typical vitreous luster. XRD and Raman test results show that the high-pressure liquid phase sintered jadeite is basically consistent with natural jadeite in terms of gemological and spectroscopic characteristics. SEM and X-Ray CT test results show that the high-pressure liquid phase sintering significantly improves the surface smoothness of jadeite and significantly improves the integrity of the microstructure. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0024] Figure 1 This is a stereoscopic optical microscope image of the original low-quality jadeite from Example 1.

[0025] Figure 2 This is a stereoscopic optical microscope image of the high-pressure liquid phase sintered modified jadeite of Example 1.

[0026] Figure 3 The image shows the XRD pattern of the high-pressure liquid phase sintered modified jadeite of Example 1.

[0027] Figure 4 The image shows the Raman diagram of the high-pressure liquid phase sintered modified jadeite of Example 1.

[0028] Figure 5 This is a surface SEM image of the high-pressure liquid phase sintered modified jadeite in Example 1.

[0029] Figure 6 The image shown is an X-ray CT image of the high-pressure liquid phase sintered modified jadeite of Example 1.

[0030] Figure 7 This is a stereoscopic optical microscope image of the high-pressure liquid phase sintered modified jadeite of Example 2.

[0031] Figure 8 This is a surface SEM image of the high-pressure liquid phase sintered modified jadeite in Example 3.

[0032] Figure 9 This is a stereoscopic optical microscope image of the high-pressure liquid phase sintered modified jadeite of Example 4.

[0033] Figure 10 The image shows the surface SEM image of the high-pressure solid-phase sintered modified jadeite in Example 5.

[0034] Figure 11 This is a stereoscopic optical microscope image of the high-pressure solid-phase sintered modified jadeite of Example 6.

[0035] Figure 12 This is a stereoscopic optical microscope image of the high-pressure liquid phase sintered modified jadeite of Comparative Example 1.

[0036] Figure 13 The image shows the surface SEM image of the high-pressure liquid phase sintered modified jadeite in Comparative Example 1.

[0037] Figure 14 This is a schematic diagram of the assembly components in the present invention. Wherein: 1. Steel cap; 2. Sample; 3. Molybdenum foil; 4. Boron nitride crucible; 5. Salt tube; 6. Graphite sheet; 7. Zirconia; 8. Boron nitride tube; 9. Graphite tube; 10. Pyrophyllite. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Figure 14 This is a schematic diagram of the high-temperature and high-pressure assembly of the present invention. Wherein: 1. Steel cap (as electrode contact and pressure seal); 2. Sample; 3. Molybdenum foil (protective layer for the sample); 4. Boron nitride crucible (heat-conducting device); 5. Salt tube (pressure-transmitting medium); 6. Graphite sheet (conductive bridge); 7. Zirconia (high-efficiency heat insulation layer); 8. Boron nitride tube (electrically insulating tube, preventing short circuits between the graphite tube and other metal components); 9. Graphite tube (heating tube); 10. Pyrophyllite (pressure-transmitting and sealing medium).

[0040] Example 1 Low-quality natural jadeite scraps were crushed using an agate mortar and pestle. The crushed jadeite was then sieved and magnetically separated to remove ferromagnetic impurities, yielding a high-pressure sintering precursor. The precursor was then cold-pressed into 6*6mm jadeite pieces using a tablet press under a pressure of 20MPa. The selected high-temperature, high-pressure assembly components were as follows: pyrophyllite (33×33mm), zirconia (Ф12×Ф10×16mm), graphite heating tube (Ф9×Ф7×16mm), boron nitride crucible (Ф7×Ф6.5×7×6.7mm), and molybdenum foil (30×0.9mm), all wound into a suitable shape to wrap the jadeite. The shaped jadeite was then... Figure 14 The assembly was installed into the component according to the shown assembly method, and then the component was dried at 150℃ for 12 hours. The dried component was then placed in a six-sided hydraulic press for pressure sintering. The high-pressure liquid phase sintering pressure was 6 GPa, the melting temperature was 1660℃, the melting time was 30 min, the sintering temperature was 1500℃, and the sintering time was 90 min. High-pressure liquid phase sintered modified jadeite was obtained.

[0041] Figure 1 This is a stereomicroscopic image of the original low-quality jadeite scraps from Example 1. It can be seen that the original sample has a loose overall structure, with large holes and cracks, and extremely poor transparency, belonging to low-grade raw materials in jadeite. Figure 2 The image shown is a stereomicroscopic image of the high-pressure liquid phase sintered modified jadeite in Example 1. It can be seen that the overall structure of the sample is relatively dense, the pores and cracks have basically disappeared, the transparency has been improved, and it has a vitreous luster very similar to that of natural high-quality jadeite.

[0042] Figure 3The image shows the XRD pattern of the high-pressure liquid phase sintered modified jadeite from Example 1. Comparison with the standard PDF card reveals that the sample is essentially consistent with the PDF 72-0174-NaAl(Si2O6) spectrum, exhibiting a single jadeite phase structure with no observed impurity phase formation.

[0043] Figure 4 This is the Raman spectral density (RSD) plot of the high-pressure liquid phase sintered modified jadeite from Example 1. Raman analysis reveals that the jadeite sample obtained through RSD has the same peak shape as natural jadeite, indicating that both are composed of pure jadeite phase. The sample obtained in Example 1 exhibits sharp peaks, demonstrating that the process successfully achieved a crystallization transformation and possesses excellent crystallinity.

[0044] Figure 5 This is a surface SEM image of the high-pressure liquid phase sintered modified jadeite from Example 1. The image shows that the jadeite surface obtained under this process is relatively smooth with only minor cracks, indicating that the sample has a high degree of densification.

[0045] Figure 6 This is an X-ray CT image of the high-pressure liquid phase sintered modified jadeite from Example 1. The image shows that the microstructure of the sample exhibits extremely low porosity, with only trace amounts of closed pores and virtually no open pores.

[0046] XRD, Raman, SEM, and X-ray CT tests show that the high-pressure liquid-phase sintering method of this invention significantly improves the surface smoothness and microstructural integrity of jadeite. The high-pressure liquid-phase sintered jadeite of Example 1 is essentially consistent with natural jadeite in terms of gemological properties and surface morphology. Its crystallinity is >99.5%, visible light transmittance is >31.45%, and porosity is <0.82%.

[0047] Example 2 The steps in this embodiment are basically the same as those in Embodiment 1, except that in step (2), the pyrophyllite size is 36×36mm, the zirconium oxide size is Ф15×Ф13×19mm, the graphite heating tube size is Ф12×Ф10×19mm, and the boron nitride crucible size is Ф10×Ф9.5×10×9.7mm. The stereomicroscopic image of the high-pressure liquid-phase sintered modified jadeite obtained by this process is shown below. Figure 7 As shown.

[0048] Example 3 The steps in this embodiment are basically the same as those in Embodiment 1, except that in step (3), the high-pressure sintering pressure is 4 GPa, the melting temperature is 1580℃, the melting time is 10 min, the sintering temperature is 1400℃, and the sintering time is 30 min. The surface SEM image of the high-pressure liquid-phase sintered modified jadeite obtained by this process is shown below. Figure 8 As shown.

[0049] Example 4 The steps in this embodiment are basically the same as those in Embodiment 3, except that in step (2), the pyrophyllite size is 36×36mm, the zirconium oxide size is Ф15×Ф13×19mm, the graphite heating tube size is Ф12×Ф10×19mm, and the boron nitride crucible size is Ф10×Ф9.5×10×9.7mm. The stereomicroscopic image of the high-pressure liquid-phase sintered modified jadeite obtained by this process is shown below. Figure 9 As shown.

[0050] Example 5 The steps in this embodiment are basically the same as those in Embodiment 1, except that in step (3), the high-pressure sintering pressure is 6 GPa, the sintering temperature is 1500℃, and the sintering time is 90 min. The surface SEM image of the high-pressure solid-phase sintered modified jadeite obtained by this process is shown below. Figure 10 As shown.

[0051] Example 6 The steps in this embodiment are basically the same as those in Embodiment 5, except that in step (2), the pyrophyllite size is 36×36mm, the zirconium oxide size is Ф15×Ф13×19mm, the graphite heating tube size is Ф12×Ф10×19mm, and the boron nitride crucible size is Ф10×Ф9.5×10×9.7mm. The stereomicroscopic image of the high-pressure solid-state sintered modified jadeite obtained by this process is shown below. Figure 11 As shown.

[0052] Comparative Example 1 The steps of this comparative example are basically the same as those of Example 1, except that the size of the molybdenum foil in step (2) is 0×0mm, that is, the jadeite is not protected by molybdenum foil during the high-pressure sintering process and is in direct contact with the boron nitride crucible. The stereomicroscopic image of the high-pressure liquid-phase sintered modified jadeite obtained by this process is shown in the figure. Figure 12 As shown, the surface SEM image is as follows Figure 13 As shown, the sample is generally black with obvious black spots and has extremely poor transparency.

[0053] Table 1 Gemological property data of jadeite after different examples and comparative treatments

[0054] A comparison of the results from Examples 1, 3, and 5 shows that, under the same sintering parameters, compared to solid-state sintering in Example 5, liquid-phase sintering, by introducing a small amount of molten jadeite phase at high temperature, can rapidly fill the pores inside the jadeite under capillary force, achieving rapid densification and improved visible light transmittance. Furthermore, the liquid-phase environment is conducive to the preferential growth of jadeite crystals along the c-axis, forming a highly crystalline mineral aggregate. Under liquid-phase sintering conditions, the modified jadeite obtained in Example 1 (pressure 6 GPa, melting temperature 1660℃, melting time 30 min, sintering temperature 1500℃, sintering time 90 min) exhibits better gemological properties than that obtained in Example 3 (pressure 4 GPa, melting temperature 1580℃, melting time 10 min, sintering temperature 1400℃, sintering time 30 min). This is because 6 GPa and 1660℃ significantly enhance the fluidity of the liquid phase and the compactness of the jadeite crystal lattice. Combined with more sufficient melting (30 min) and sintering time (90 min), the grains are more tightly bound, the structure is more uniform and stable, and the recrystallization process is more complete, thereby effectively improving the density, relative crystallinity and visible light transmittance of jadeite.

[0055] Comparing the experimental results of Examples 1 with those of Examples 2, 4, and 6, it is evident that under the same high-pressure sintering process conditions, changes in the size of the high-temperature, high-pressure assembly significantly affect the gemological properties of the jadeite samples. Experiments show that when larger assemblies are used (Examples 2, 4, and 6), the resulting jadeite samples exhibit a higher degree of porosity and are accompanied by noticeable black spots. The physical mechanism can be attributed to the pressure formula P=F / S. Under constant pressure F, increasing the assembly size leads to an increase in the force-bearing area S, thus reducing the actual pressure P on the sample and weakening the compaction effect during jadeite sintering, thereby reducing the density of the jadeite. Regarding the formation of black spots, the increased assembly size results in an uneven thermal field distribution between the center and both ends of the graphite tube heating element, creating a temperature gradient that induces a chemical potential difference. Driven by this chemical potential gradient, carbon atoms in the graphite tube penetrate the interfacial isolation layer and diffuse into the jadeite, ultimately forming carbon precipitation (i.e., black spots).

[0056] Therefore, this invention employs high-pressure liquid-phase sintering technology based on a six-sided top press. By controlling the appropriate size and assembly of the high-temperature and high-pressure assemblies, it promotes sufficient atomic diffusion and component homogenization of low-quality jadeite raw materials within the liquid phase temperature range, thereby achieving a highly uniform molten state distribution of the main component of jadeite (NaAlSi2O6). Densification sintering is completed under temperature and pressure conditions slightly below the solidus line, effectively promoting the directional growth and structural densification of jadeite single-phase crystals, ultimately producing jadeite materials with a smooth surface and significantly improved transparency. Optimal process conditions: High-pressure liquid phase sintering pressure is 6 GPa, melting temperature is 1660℃, melting time is 30 min, sintering temperature is 1500℃, and sintering time is 90 min; the dimensions of the high-temperature and high-pressure assembly are as follows: pyrophyllite is 33×33 mm, zirconium oxide is Ф12×Ф10×16 mm, graphite heating tube is Ф9×Ф7×16 mm, boron nitride crucible is Ф7×Ф6.5×7×6.7 mm, and molybdenum foil is 30×0.9 mm.

[0057] The comparative experiment between Example 1 and Comparative Example 1 verified the impact of the molybdenum foil isolation and wrapping process on the quality of jadeite under high-pressure sintering. Experimental data showed that Comparative Example 1, which did not use 30×0.9mm molybdenum foil to wrap the jadeite sample, produced products with obvious black spots in their gemological appearance. SEM surface morphology images confirmed that these black spots were carbon deposits formed by the graphite tubes in the assembly penetrating into the jadeite. Under high temperature and pressure conditions, without the protective barrier formed by the molybdenum foil wrapping, carbon atoms in the graphite tubes can easily penetrate the boron nitride crucible and permeate the surface of the jadeite. In contrast, Example 1, by completely wrapping the jadeite sample with molybdenum foil of a specific size, effectively established a dense isolation interface between the jadeite sample and the external graphite tubes, cutting off the diffusion path of carbon atoms. This process improvement ensured the excellent gemological appearance and commercial value of the modified jadeite.

Claims

1. A method for high-pressure liquid-phase sintering modification of low-quality natural jadeite, characterized in that, Includes the following steps: (1) Natural low-quality jade scraps are crushed, sieved, and magnetically separated to remove impurities; (2) Assemble pyrophyllite, zirconium oxide, graphite heating tube, boron nitride crucible, and molybdenum foil into a high-temperature and high-pressure assembly; (3) The jade precursor powder obtained in step (1) is cold-pressed into shape, the pressed blank is loaded into the high temperature and high pressure assembly in step (2), and dried; the dried assembly is placed into the top press for high pressure liquid phase melting and sintering crystal growth.

2. The high-pressure liquid-phase sintering modification method for low-quality natural jadeite according to claim 1, characterized in that, In step (1), the natural low-quality jade scraps are crushed in an agate mortar and then sieved.

3. The high-pressure liquid-phase sintering modification method for low-quality natural jadeite according to claim 1, characterized in that, In step (1), the magnetic separation for removing impurities involves using a magnetic separator to adsorb iron impurities.

4. The high-pressure liquid-phase sintering modification method for low-quality natural jadeite according to claim 1, characterized in that, In step (2), the pyrophyllite has a size of 33×33mm-36×36mm, the zirconium oxide has a size of Ф12×Ф10×16mm-Ф15×Ф13×19mm, the graphite heating tube has a size of Ф9×Ф7×16mm-Ф12×Ф10×19mm, and the boron nitride crucible has a size of Ф7×Ф6.5×7×6.7mm-Ф10×Ф9.5×10×9.7mm.

5. The high-pressure liquid-phase sintering modification method for low-quality natural jadeite according to claim 1, characterized in that, In step (2), the molybdenum foil is a rectangle with dimensions of 30×0.9mm-30.2×1.2mm and is wound into shape.

6. The high-pressure liquid-phase sintering modification method for low-quality natural jadeite according to claim 1, characterized in that, In step (3), the pre-compression molding is carried out by cold compression molding with a tablet press, and the pressure is 10-20MPa.

7. The high-pressure liquid-phase sintering modification method for natural low-quality jadeite according to claim 1, characterized in that, In step (3), after the pressed blank is loaded into the assembly, the drying temperature is 100-150℃ and the drying time is 10-12h.

8. The high-pressure liquid-phase sintering modification method for low-quality natural jadeite according to claim 1, characterized in that, In step (3), the pressure of the high-pressure liquid phase melting is 4-6 GPa, the melting temperature is 1580-1660℃, the melting time is 10-30 min, the sintering temperature is 1400-1500℃, and the sintering time is 30-90 min.

9. High-pressure liquid-phase sintered modified jadeite obtained by the modification method according to any one of claims 1 to 8.

10. The high-pressure liquid-phase sintering modified jadeite according to claim 9, characterized in that, The jadeite modified by the method of this invention has a single jadeite phase structure and spectroscopic characteristics consistent with natural jadeite, with a crystallinity >99.5%, visible light transmittance >31.45%, and porosity <0.82%.

Images