A pressure transmission sealing medium raw material for synthesis of six-sided top press and its preparation method and application

Abstract

The present invention discloses a raw material for pressure transmission and sealing medium for synthesis of six-sided top press, and a preparation method and application thereof, and belongs to the field of synthesis technology of six-sided top press. With pyrophyllite as raw material, by removing impurities, crushing, and detecting components, and comparing the formula requirements, aluminum, iron, titanium and other elements are added to it so that the composition ratio reaches the ideal requirements, and then through screening, mixing, fermentation, pressing, drying and other process treatments, a pressure transmission and sealing medium block for synthesis of superhard materials is prepared. The pressure transmission and sealing medium block prepared according to this formula has good pressure transmission, sealing and heat preservation properties, can significantly reduce the operating pressure of the six-sided top press equipment, the fluctuation of heating power, improve the stability of the synthesis internal cavity, improve the quality of superhard material products, and at the same time reduce the consumption of the top hammer and the loss of the equipment, and reduce the production cost of synthetic superhard materials. The selection range of pyrophyllite ore sources for the raw materials of the synthetic pressure transmission and sealing medium is expanded, and the risk and procurement cost of enterprises in dealing with the shortage of high-quality pyrophyllite resources are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of a pressure transmission and sealing medium for synthesis of a six-sided top press, and in particular to a formula, a mixing and preparation method and an application of a pressure transmission and sealing medium raw material for synthesis of a six-sided top press. Background Art

[0002] Artificial diamond synthesis requires a specific high temperature and high pressure cavity. The pressure and temperature come from the top hammer of the six-sided top press. This requires a special pressure transmission and sealing medium, which is placed in the six-sided top press to apply pressure to achieve a high temperature and high pressure internal environment. The functions of the sealing medium include: sealing, heat preservation, insulation, pressure transmission, and support.

[0003] The pressure transmission sealing medium for diamond synthesis generally uses pyrophyllite as raw material. Pyrophyllite is a layered clay mineral with small internal friction coefficient, high refractoriness, small thermal conductivity, wide dehydration temperature range during heating, stable volume, and internal friction coefficient increases with increasing pressure. It meets all the requirements of the sealing medium of the six-sided top press and is an ideal sealing material.

[0004] On the one hand, talc is limited and has quality differences. It usually contains a certain amount of impurities. Depending on the origin, the ore composition varies to a certain extent, and has different associated minerals and impurities. The performance of talc pressure-transmitting sealing materials mainly depends on the mineral composition of the talc ore. The talc raw stone produced in Mentougou, Beijing is the best quality. After simple treatment, only a small amount of minerals need to be added for production. It is also the only variety currently used in the industry. However, due to the differences in the quality of each batch of ore sources, there are certain differences in its pressure transmission, sealing and thermal insulation properties, which are reflected in the synthesis of specific superhard materials. That is, different batches of talc cause obvious fluctuations in the pressure and power used in the synthesis, which has a great impact on product quality. In addition, the frequency of "blasting" accidents is different, and the hammer consumption fluctuates over a large range, making it impossible to accurately control production costs.

[0005] On the other hand, as one of the main raw materials, mineral resources are limited. Beijing pyrophyllite mine has been mined for many years, and high-quality minerals are gradually decreasing. Pyrophyllite has good physical and chemical properties and is often used in refractory materials, ceramic raw materials and other fields. As the scale of the diamond industry expands, demand is increasing, and the price of pyrophyllite continues to grow. Therefore, it is imperative for synthetic diamond companies to develop a relatively stable new raw material for the special pressure transmission and sealing medium of the six-sided top press, as well as a preparation method and application, to alleviate the demand for Beijing pyrophyllite ore sources, reduce the risk of irreplaceable resources, and at the same time reduce production costs and improve product stability.

[0006] In actual production, due to the differences in the components and contents of each batch of talc ore, the ratio of SiO2 and Al2O3 contents is unstable. In addition, the contents of iron and titanium elements, which are beneficial to the sealing and thermal insulation of the pressure transmission sealing medium block, are different. The prepared pressure transmission sealing medium blocks have certain differences in fluidity, sealing and thermal insulation. Therefore, it is necessary to sample and test the main components in the talc and stabilize the weight ratio within the optimal range. Summary of the invention

[0007] The purpose of the present invention is to solve the above technical problems and to provide a pressure transmission and sealing medium raw material specially used for a six-sided top press, and a preparation method and application thereof.

[0008] The technical solution of the present invention is:

[0009] A raw material for a pressure transmission and sealing medium for synthesis of a six-sided top press comprises the following components: SiO2 47-50wt%; Al2O3 37-39wt%; iron oxide 2.2-2.5wt%; titanium oxide 1.5-1.7wt%; ignition loss 6-9wt%; other impurity components 0-3wt%; and a ratio of Al2O3 to SiO2 of 0.74-0.83:1.

[0010] Preferably, the composition includes the following components: SiO2 49.87wt%; Al2O3 38.69wt%; iron oxide 2.43wt%; titanium oxide 1.56wt%; loss on ignition 6.68wt%; other impurity components 0.76wt%; the ratio of Al2O3 to SiO2 is 0.776:1.

[0011] Preferably, the composition includes the following components: SiO2 49.84wt%; Al2O3 37.74wt%; iron oxide 2.25wt%; titanium oxide 1.56wt%; loss on ignition 7.33wt%; other impurity components 1.29wt%; the ratio of Al2O3 to SiO2 is 0.757:1.

[0012] A pyrophyllite ore source is selected as a raw material for a pressure transmission sealing medium for the synthesis of a six-sided top press, and includes the following components: SiO2 44~60wt%; Al2O3 30~43wt%; iron oxide 0~3wt%; titanium oxide 0~2wt%; ignition loss 6~10wt%; other impurity components 0~3wt%; the ratio of Al2O3 to SiO2 is 0.50~0.98:1.

[0013] A method for preparing a pressure transmission and sealing medium raw material for synthesis of a six-sided top press comprises the following steps:

[0014] a. Physically remove impurities, crush and test the composition of the pyrophyllite ore source;

[0015] b. Adding SiO2 or Al2O3 or titanium oxide or iron oxide according to the content of the ingredients in step a, one or a combination thereof;

[0016] Or c. Mix two or more talc sources.

[0017] Preferably, the method comprises the following steps:

[0018] a. Physically remove impurities from the pyrophyllite ore source, cut off the visible impurities, and then crush it to 5-100 mesh, magnetically select the raw materials within 5000GS, and perform chemical composition analysis and X-ray diffraction detection on the raw materials after impurities removal;

[0019] b. Calculate according to the content of the ingredients in step a and the composition of the raw materials, and add one or different combinations of SiO2 or Al2O3 or titanium oxide or iron oxide according to the principle of minimum addition.

[0020] Preferably, the method comprises the following steps:

[0021] a. Physically remove impurities from two or more pyrophyllite sources, cut off the visible impurities, crush them into 5-100 mesh, magnetically select the raw materials within 5000GS, and perform chemical composition analysis and X-ray diffraction detection on the raw materials after impurities removal;

[0022] b. Calculate the content of the ingredients in step a and the composition of the raw materials, and proportion the pyrophyllite source according to the principle of minimum addition.

[0023] An application of a pressure transmission and sealing medium raw material for synthesizing a six-sided top press includes the following steps:

[0024] a. Screening the pressure transmission sealing medium raw material;

[0025] b. Mix the raw materials sieved in step a according to different particle sizes;

[0026] c. Add water glass and stir thoroughly;

[0027] d. Place the mixed raw materials in step c in a sealed environment for fermentation;

[0028] e. Pressing the fermented raw material in step d into a mold once;

[0029] f. Dry the pressure-transmitting sealing medium block pressed in step e.

[0030] Preferably, the method comprises the following steps:

[0031] a. Screening the pressure-transmitting sealing medium raw material;

[0032] b. Mix the raw materials sieved in step a according to different particle sizes;

[0033] c. Add 7-9% of the total weight of water glass and stir thoroughly;

[0034] d. Place the mixed raw materials in step c in a sealed environment and ferment for 12 to 24 hours at a fermentation temperature of 25 to 40°C;

[0035] e. The fermented raw material in step d is pressed once on a four-column press with a pressure setting of 35~45MPa, and the holding time is 3~5s;

[0036] f. Dry the pressure-transmitting sealing medium block pressed in step e in an oven at 240-270°C for 3-5 hours.

[0037] Preferably, in step a. screening, the coarse material is 5-10 mesh, the medium material is 10-60 mesh, and the fine material is 60-100 mesh;

[0038] The ratio of step b. is 16-20 for coarse, 20-30 for medium and 50-60 for fine.

[0039] The beneficial effects of the present invention are:

[0040] 1. Through the detection of different batches of pyrophyllite components, by trying to add beneficial elements, and the feedback of production experimental data, the optimal composition and ratio of pressure-transmitting sealing medium materials used in the field of superhard material synthesis are explored, and the selection range of pyrophyllite ore sources is expanded. Through component detection and analysis, some missing components are appropriately added, or pyrophyllite from different ore sources is reasonably proportioned to prepare the best raw materials for pressure-transmitting sealing medium that meets the requirements of the formula. It is not limited to specific high-quality pyrophyllite resources, which expands the selection range of raw materials for pressure-transmitting sealing medium for synthesis, reduces the dependence of diamond synthesis enterprises on high-quality pyrophyllite resources, and reduces the risk of enterprises coping with resource reduction. The pressure-transmitting sealing medium block prepared by this raw material ratio has stable pressure transmission, sealing and heat preservation effects, can effectively reduce the fluctuation of equipment pressure and power, reduce energy consumption, reduce top hammer consumption, and at the same time improve the stability of the internal cavity, improve the quality of superhard material synthesis, and at the same time significantly reduce the procurement cost and equipment loss of enterprises for pyrophyllite resources, and increase economic benefits.

[0041] 2. The impurity minerals in pyrophyllite are mainly composed of diaspore, alunite, feldspar, kaolinite, sericite, chlorite, quartz, hematite, ilmenite, limonite, rutile, etc. The minerals with layered structure are diaspore, alunite, feldspar, kaolinite, sericite, chlorite, etc., but the total amount does not exceed 10%, which will not affect the pressure transmission performance of the product. Alunite is unstable under high temperature and high pressure and is a harmful component. When the content of non-layered minerals such as feldspar and quartz is high, the static pressure rheological characteristics of pyrophyllite pressure transmission seal will be poor, which is a harmful component to the pressure transmission performance. The powder blocks made of very pure pyrophyllite have good performance, but the internal friction coefficient is small, the sealing performance is poor, and high-pressure extrusion and top hammer damage often occur. The presence of a small amount of hematite, ilmenite, limonite, and rutile minerals can improve its sealing and pressure transmission and thermal insulation performance. The iron oxide, ferrous oxide, titanium dioxide, aluminum oxide, etc. contained in these minerals can increase the sealing, pressure transmission and heat preservation properties of pyrophyllite on the basis of ensuring that it has a certain fluidity. Therefore, by selecting pyrophyllite from a suitable origin and modifying it by adding the above components, a suitable pressure transmission and sealing medium raw material can be prepared.

[0042] a. SiO2 is the key component that determines the pressure transmission of the pressure-transmitting sealing medium and plays a supporting role. Too much SiO2 will increase the pressure transmission and reduce the synthesis pressure, but its fluidity and sealing effect will decrease, causing a large number of blasting, which cannot meet the requirements of synthesis high temperature and high pressure. Its ratio is 47~50wt%;

[0043] b. Al2O3 is the key component that determines the sealing and fluidity of the pressure-transmitting sealing medium. Too much Al2O3 will improve the sealing and fluidity, but will significantly increase the synthesis pressure, and will cause the pressure-transmitting sealing medium block to be deformed during the pressing process. The ratio must be guaranteed to be 37~39wt%;

[0044] c. Al2O3 and SiO2 directly determine the pressure transmission and sealing effects of the pressure transmission and sealing medium. The appropriate ratio is beneficial for the pressure transmission and sealing medium to achieve an ideal balance between pressure transmission and sealing functions, ensuring the high temperature and high pressure environment required for synthesis while reducing the synthesis pressure as much as possible. The ratio must be guaranteed to be 0.74~0.83:1. The pressure transmission and sealing medium blocks prepared within this range have good pressure transmission performance and good fluidity;

[0045] d. The presence of a small amount of iron and titanium elements can increase the internal friction coefficient of the pressure-transmitting sealing medium and improve its sealing performance. The presence of oxides, the ratios are 2.2~2.5wt% and 1.5~1.7wt% respectively;

[0046] e. In practical applications, the appropriate ignition loss is 6~9wt%;

[0047] f. Other impurities must be kept below 3wt%.

[0048] 3. The pressure transmission sealing medium block prepared by the formula of the present invention is used in the six-sided top press to synthesize superhard materials. It has good pressure transmission performance, good pressure transmission stability of products from different batches, and the average pressure used is 1.5MPa lower than that of traditional pyrophyllite, and the fluctuation range is reduced by 1MPa; it has good thermal insulation performance, good stability of products from different batches, and the average power used is 150W lower than that of traditional pyrophyllite, and the fluctuation range is reduced by 100W; it has good sealing performance, and the hammer consumption per 10,000 carats is reduced by 0.06kg; the product quality is significantly improved, and the excellent crystal ratio is increased by 4%.

[0049] DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with embodiments, but the protection scope of the technical solution of the present invention is not limited thereto.

[0051] Embodiment 1:

[0052] We selected a batch of pyrophyllite ore from South Africa, physically removed impurities, cut off the visible impurities, crushed it to 5-100 mesh, and then magnetically separated the raw materials within 5000GS. The raw materials after impurities removal were subjected to chemical composition analysis and X-ray diffraction, and the main components were analyzed as follows:

[0053]

[0054] The SiO2 content of this batch of pyrophyllite is significantly higher, the Al2O3 content is lower, the Al2O3:SiO2 ratio is lower than the formula requirements, and the iron content is low. Compared with the formula adjustment, the ingredients need to be adjusted. According to the raw material formula table, mathematical calculations are performed according to the principle of minimum addition. It is calculated that 13wt% Al2O3 and 1.6wt% FeO+Fe2O3 can be added. The improved component content is as follows:

[0055]

[0056] The prepared raw materials of pressure transmission and sealing medium are screened to obtain three particle sizes: coarse, medium and fine. The coarse material is 5~10 mesh (excluding 10), the medium material is 10~60 mesh (excluding 60), and the fine material is 60~100 mesh (excluding 100). In specific applications, 100 mesh, 60 mesh, 10 mesh and 5 mesh sieves are used, and the weight ratio is 16 coarse: 30 medium: 54 fine. Add 8% of the total weight of water glass to the well-proportioned raw materials and stir them thoroughly. Place the mixed raw materials in a sealed plastic barrel at 38°C for fermentation for 18 hours. The fermented raw materials are pressed and formed on a 200T four-column press with a pressure setting of 40MPa, and the pressure holding time is 3s; the pressed pressure transmission and sealing medium block is dried in a 250°C oven for 5 hours.

[0057] After improvement and adjustment, the following technical effects are achieved:

[0058] 1. The batch of South African pyrophyllite that was originally unusable in production was adjusted to normal use to meet normal production needs, and all performances were stable and good. 2. The thermal insulation and sealing effects were improved, and the synthesis quality was significantly improved; the power used was effectively reduced by 180W; the hammer consumption was reduced by 0.57kg / 10,000 carats; and the excellent crystal ratio was increased by 9.1%.

[0059]

[0060] Embodiment 2:

[0061] A batch of pyrophyllite ore from Mentougou, Beijing was selected for physical impurity removal, and the visible impurities were cut off, and then crushed to 5~100 mesh, and then magnetically separated to obtain raw materials within 5000GS. The raw materials after impurity removal were subjected to chemical composition analysis and X-ray diffraction, and the main components were analyzed as follows:

[0062]

[0063] The SiO2 content in this batch of pyrophyllite is significantly lower than the formula requirements, the Al2O3:SiO2 ratio is higher than the optimal ratio, and the other ingredients meet the requirements. The ingredients are adjusted according to the formula. After calculation, 10% of the total weight of SiO2 is added, and the final ingredients are as follows:

[0064]

[0065] The prepared raw materials of pressure transmission and sealing medium are screened to obtain three particle sizes: coarse, medium and fine, of which 5~10 mesh (excluding 10), medium material 10~60 mesh (excluding 60), and fine material 60~100 mesh (excluding 100), and the weight ratio is 20:30:50. The raw materials with the good ratio are added with 7% of the total weight of water glass and fully stirred and mixed. The mixed raw materials are placed in a sealed plastic barrel at 28℃ for fermentation for 12 hours. The fermented raw materials are pressed and formed on a 200T four-column press with a pressure setting of 40MPa, and the pressure holding time is 3s; the pressed pressure transmission and sealing medium block is dried in a 250℃ oven for 5 hours.

[0066] After improvements and adjustments, 1. A batch of talc from Beijing that originally had poor production and use effects was adjusted to have good use effects, and various performance indicators were significantly better than before the improvements; 2. The pressure transmission performance, thermal insulation and pressure holding performance were improved, and equipment loss was reduced; 3. The use pressure was effectively reduced by 3.2MPa; the use power was reduced by 70W; the hammer consumption was reduced by 0.22kg / 10,000 carats; the excellent crystal ratio was increased by 3.2%; and normal production needs were met.

[0067]

[0068] Embodiment 3:

[0069] A batch of pyrophyllite ore from Mentougou, Beijing was selected for physical impurity removal, and the visible impurities were cut off, and then crushed to 5~100 mesh, and then magnetically separated the raw materials within 5000GS. The raw materials after impurity removal were subjected to chemical composition analysis and X-ray diffraction, and the main components were analyzed as follows:

[0070]

[0071] This batch of pyrophyllite has a low SiO2 content, a higher Al2O3:SiO2 ratio than the optimal ratio, a high iron content, a low TiO2 content, and all other components meet the requirements.

[0072] We selected a batch of pyrophyllite from South Africa, physically removed impurities, cut off the visible impurities, crushed them to 5-100 mesh, and then magnetically separated the raw materials within 5000GS. The raw materials after impurities removal were tested for composition, and the main components are as follows:

[0073]

[0074] The Al2O3 content of this batch of pyrophyllite is low, the Al2O3:SiO2 ratio is lower than the optimal ratio, the iron content is low, the TiO2 content is high, and the other components meet the requirements.

[0075] According to the mathematical calculation of the formula, a batch of pyrophyllite from Mentougou, Beijing and a batch from South Africa were mixed in a ratio of 6:4. The content of the ingredients after the improved ratio is as follows:

[0076]

[0077] The prepared raw materials of pressure transmission and sealing medium are screened to obtain three particle sizes of coarse, medium and fine, including 5~10 mesh (excluding 10), 10~60 mesh (excluding 60) of medium material, and 60~100 mesh (excluding 100) of fine material, and the weight ratio is 16:24:50 of coarse material. 9% of the total weight of water glass is added to the prepared raw materials and stirred thoroughly. The mixed raw materials are placed in a sealed plastic barrel at 40℃ for fermentation for 24 hours. The fermented raw materials are pressed and formed on a 200T four-column press with a pressure setting of 42MPa, and the pressure holding time is 4s; the pressed pressure transmission and sealing medium blocks are dried in a 250℃ oven for 5 hours.

[0078] After improvement and adjustment, the talc that could not be used directly originally was mixed according to the above-mentioned established proportions and met the formula requirements. The pressure transmission medium blocks prepared according to this formula 1. Mixed a batch of talc from South Africa that could not be used in production and a batch of talc from Beijing that had poor use effect, so that they have good production and use effects; 2. Compared with the talc blocks before improvement, the pressure transmission performance, thermal insulation and pressure holding performance are improved, the quality of the talc blocks is significantly improved, and the production quality and stability are improved; 3. The use pressure is significantly reduced by more than 0.8MPa; the hammer consumption per 10,000 carats is reduced by 0.07kg; and the superior crystal ratio is increased by more than 5%.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An application of a raw material for pressure transmission and sealing medium for synthesis of a six-sided top press, characterized in that: The steps include: a. Screening the pressure transmission sealing medium raw material; b. Mix the raw materials sieved in step a according to different particle sizes; c. Add 7-9% of the total weight of water glass and stir thoroughly; d. Place the mixed raw materials in step c in a sealed environment and ferment for 12 to 24 hours at a fermentation temperature of 25 to 40°C; e. The fermented raw material in step d is pressed once on a four-column press with a pressure setting of 35~45MPa, and the holding time is 3~5s; f. Dry the compressed pressure-transmitting sealing medium block in step e in an oven at 240 to 270°C for 3 to 5 hours; The step a. screening, wherein the coarse material is 5-10 mesh, the medium material is 10-60 mesh, and the fine material is 60-100 mesh; The step b. The ratio is 16-20 for coarse: 20-30 for medium: 50-60 for fine; The pressure transmission sealing medium raw material includes the following components: SiO2 47~50wt%; Al2O3 37~39wt%; iron oxide 2.2~2.5wt%; titanium oxide 1.5~1.7wt%; ignition loss 6~9wt%; other impurity components are 0~3wt%; the ratio of Al2O3 to SiO2 is 0.74~0.83:

1.

2. The use of the raw material for pressure transmission and sealing medium for synthesis of six-sided top press according to claim 1 is characterized in that: The pressure transmission sealing medium raw material includes the following components: SiO2 49.87wt%; Al2O3 38.69wt%; iron oxide 2.43wt%; titanium oxide 1.56wt%; ignition loss 6.68wt%; other impurity components 0.76wt%; the ratio of Al2O3 to SiO2 is 0.776:

1.

3. The use of the raw material for pressure transmission and sealing medium for synthesis of six-sided top press according to claim 1, characterized in that: The pressure transmission sealing medium raw material includes the following components: SiO2 49.84wt%; Al2O3 37.74wt%; iron oxide 2.25wt%; titanium oxide 1.56wt%; ignition loss 7.33wt%; other impurity components 1.29wt%; the ratio of Al2O3 to SiO2 is 0.757:

1.

4. The use of the raw material for pressure transmission and sealing medium for synthesis of six-sided top press according to claim 1, characterized in that: The method for preparing the pressure transmission sealing medium raw material comprises the following steps: a. Physically remove impurities, crush and test the composition of the pyrophyllite ore source; b. Adding SiO2 or Al2O3 or titanium oxide or iron oxide according to the content of the ingredients in step a, or different combinations thereof; or mixing two or more pyrophyllite ore sources.

5. The use of the raw material for pressure transmission and sealing medium for synthesis of six-sided top press according to claim 4, characterized in that: The method for preparing the pressure transmission sealing medium raw material comprises the following steps: a. Physically remove impurities from the pyrophyllite ore source, cut off the visible impurities, and then crush it to 5-100 mesh, magnetically select the raw materials within 5000GS, and perform chemical composition analysis and X-ray diffraction detection on the raw materials after impurities removal; b. Calculate according to the content of the ingredients in step a and the composition of the raw materials, and add one or different combinations of SiO2 or Al2O3 or titanium oxide or iron oxide according to the principle of minimum addition.

6. The use of the raw material for pressure transmission and sealing medium for synthesis of six-sided top press according to claim 4, characterized in that: The method for preparing the pressure transmission sealing medium raw material comprises the following steps: a. Physically remove impurities from two or more pyrophyllite sources, cut off the visible impurities, crush them into 5-100 mesh, magnetically select the raw materials within 5000GS, and perform chemical composition analysis and X-ray diffraction detection on the raw materials after impurities removal; b. Calculate according to the content of the ingredients in step a and the composition of the raw materials, and proportion the pyrophyllite source according to the principle of minimum addition.

7. The use of the raw material for the pressure transmission and sealing medium for the six-sided top press according to claim 6, characterized in that: The pyrophyllite source described in step b includes the following components: SiO2 44~60wt%; Al2O3 30~43wt%; iron oxide 0~3wt%; titanium oxide 0~2wt%; ignition loss of 6~10wt%; other impurity components of 0~3wt%; the ratio of Al2O3 to SiO2 is 0.50~0.98:1.

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