First, the history of synthetic diamond production In 1954, the United States GE company successfully developed the world's first synthetic diamond. In October 1960, China issued a task for the development of synthetic diamonds as a national key scientific research project. The task was jointly undertaken by the Institute of Abrasives Grinding, the General Machinery Research Institute and the former Institute of Geological Sciences. After cooperating, on December 6, 1963, on the domestically produced 300-ton type 61 double-faced ultra-high pressure device, high-purity graphite powder was used as raw material, and nickel-chromium alloy was used as catalyst to successfully produce the first artificial man-made in China. Diamond. In April 1964, the 6×6MNDS-023A hinged six-face press was designed by the Institute of Abrasives Grinding and the Institute of Casting and Forging. In April 1965, the former First Ministry of Machinery Industry issued the National Science and Technology Commission's “Intermediate Test Taskbook on Synthetic Diamondsâ€. In August 1965, the six-face press was made and installed at the Abrasives Grinding Research Institute, 1966. On July 3, the synthetic process test was officially carried out and put into mass production. In the same year, 10,000 carats of synthetic diamond was produced. At the same time, the grinding abrasive grinding research institute participated in the site selection, design and preparation of the first professional diamond and its products in China. The production plant, the sixth grinding wheel factory, and the sixth grinding wheel factory were completed and put into production in 1969. So far, China has gradually formed a 6×6 mega-newton (MN) six-face top equipment featuring a synthetic diamond production industrial system.
In foreign countries, in the late 1980s, German Winter Company successfully developed a process of powder catalyst synthesis of coarse-grained high-strength diamond on a double-faced ultra-high pressure device, realizing the breakthrough of powder-catalyst industrial production of high-grade diamond. [1] Since the powder catalyst synthetic diamond has the advantages of high yield, good quality, and low consumption of raw and auxiliary materials, DeBeers and G. since the 1990s. E. The company uses powder catalysts for the production of high-grade diamonds and monopolizes the international market for high-grade diamonds.
2. Production Status of Domestic Synthetic Diamond and Market Forecast of Diamond Catalyst Powder The market of synthetic diamond materials in the world is increasing at an average annual growth rate of 8%. In China, 70-80% of the diamond production is used in the stone industry. By 2000, the output of stone plates was calculated at 100 million cubic meters, and the annual requirement for high-grade coarse-grain diamond for sheet cutting was 1.3-150 million carats. According to estimates by relevant departments, in recent years, China's imports of high-grade synthetic diamonds are above 10 million carats. China's annual diamond production increased rapidly from 440 million carats in 1997 to 2.5 billion carats in 2003, making China's diamond production account for more than 60% of the world's total diamond production, and diamond exports soared to 900 million carats. China is a world diamond production country, but the variety is single, the grade is in the middle and low grade, about one-third of the presses are forced to stop production. Although the quality of the diamond produced by the two-sided top press is good, due to the high technical requirements, the localization is quite difficult. Since the 1980s, China has introduced two-side press equipment, which cost about RMB 2 billion. This is equivalent to the total investment of the six-face presses currently in China, and no unit has yet entered normal production. For many domestic small and medium-sized enterprises, there is no strength to introduce two-sided presses and technologies. At present, the six-face press is developing in the direction of large-scale and refined technology. The combination of powder catalysts, especially with the advantages of large tonnage presses, will greatly advance the industrialization of high-grade diamonds in China.
Ni-Mn-Co sheet-like catalyst is widely used in China. Because of its high Mn content, the brittleness is large. When the rolling thickness is reduced to 0.4 mm or less, it is often brittle, which limits the further thinning of the catalyst thickness and the long production process. The energy consumption is large and the material utilization rate is not high. The segregation of the flake catalyst component is obvious, which is not conducive to the growth of high quality diamond. [2] Since the end of the 1970s, the use of single-powder mixing, turning powder and water atomized powder has been continuously studied in the powder catalyst synthesis diamond process, but there has not been a major breakthrough. The main problem is that the quality of the powder catalyst is not High, such as the current production of water atomization catalyst alloy powder enterprises, subject to the production process, the oxygen content of up to 2000ppm. The production of water atomized catalyst alloy powder is a systematic project. It contains two aspects of hardware and software. Generally speaking, because diamond manufacturers do not know much about the technology of atomization to produce metal powder, so pay attention to investment. Most of it is in the hardware part, and the result is that it costs a lot of money and the things that are obtained are not ideal.
The catalyst alloy powder is mainly prepared by high-temperature melting, high-pressure water atomization and crushing, and dried by vacuum drying. The diamond crystals synthesized by it are good in color and golden in color. The powder catalyst synthetic diamond test results show that the synthetic yield can be improved, the consumption of cemented carbide and raw materials can be reduced, the production cost of diamond can be reduced, and high-yield abrasive grade diamond can be synthesized, and high-quality coarse particles and high-grade diamond can be synthesized. The diamond single crystal synthesized by the powder catalyst is mainly composed of six to octahedrons, the crystal form integrity rate is high, the crystal is relatively pure, the total amount of inclusions is small, the distribution is fine and dispersed, and the room temperature and high temperature impact strength are good.
The use of powder catalyst technology to synthesize diamond has been recognized by domestic manufacturers. Various companies are increasing their investment in the research and development of powder catalysts. The demand for diamond catalyst powder is in a period of rapid growth. According to statistics, the total number of domestic diamond production enterprises is 248 (excluding many individual enterprises), which are spread all over the country, and there are many large-scale production enterprises in Henan, Anhui, Hunan, Hebei and other provinces. In recent years, the total number of new presses of 6×12MN and above has exceeded 800, and dozens of presses on both sides have been added, plus 4000 sets of original 6×8MN and below, with a total of nearly 5,000. With the large-scale adoption of the powder catalyst process, the annual demand for catalyst alloy powder will be above 3,000 tons. [3] And because most of the foreign diamond production uses powder catalyst, the products can also be exported to foreign exchange. According to the use of diamonds, the British Debeers company has a total of 44 brands, the United States GE has a total of 25 brands; China has only 11 brands, and the most high-end DMD level has no commercial products. The use of powder catalyst can achieve multi-variety, multi-grade and serialization of diamond products, providing an opportunity for SMEs to adjust product structure and improve the production technology level of enterprises. It will promote technological innovation in the diamond industry, enhance the ability of enterprises to participate in international market competition, and promote the diamond industry in China to embark on the road of sustainable development. Some large domestic diamond manufacturers have invested in the construction of catalyst alloy powder production lines because of the considerable use of catalyst alloy powder.
The high-pressure water atomization method on the market now produces catalyst alloy powder, which sells for more than 500,000, and has the following problems:
The oxygen content of the powder is quite high due to the structure of the existing equipment. The following are the main performance indicators provided by a certain equipment supplier:
Oxygen content: <3000ppm, loose density: 3.6g/cm3
Scope of application: Suitable for powder synthesis of high-grade synthetic diamond powder. Number of mesh: -320 mesh, -200 mesh, 200-320 mesh. Two equipment suppliers simply copy other equipment to the user for the production of catalyst alloy powder. And adjustment, no more technical skills for users. Because the production of catalyst alloy powder is not only a problem of crushing a metal liquid, its composition should be adjusted according to the needs of the diamond process. This requires you to be familiar with the metal material and have rich experience in powder production. It's handy.
The three users can't understand more about the overall situation of the device. If you want to improve the device, you don't know where to start. In other words, the price/performance of the services users receive is not high.
According to the inquiry from the household, in addition to these obvious shortcomings, there are other problems, so I will not write more here. If you have any questions, please feel free to contact and communicate with the author.
Third, high-pressure water atomization process for the production of diamond catalyst powder From a broad perspective, the high-pressure water atomization process for the production of diamond catalyst powder is part of the metal powder production process, or only one of the varieties produced Only. The production process is the same as the production of other metal powders by atomization.
First, according to the alloy composition formula of the diamond catalyst powder, the selected materials are melted into a molten metal in the intermediate frequency furnace according to the requirements of the melting process. Then start the high-pressure water pump matched with the atomization device, adjust the water level in the atomization cylinder, and prepare for atomization. After everything is ready, the atomization begins. After the metal liquid is injected into the tundish, it is restricted by the flow restricting nozzle and then enters the atomization chamber. Under the action of the main high pressure water jet from the atomizer, it is rapidly atomized into a very fine Metal droplets, because the specific heat of water is quite large, after heat exchange, the metal droplets solidify into metal powder after a short period of time. The oxidation of the diamond catalyst powder occurs mainly during the short period of time during which the fracture and solidification occur. If the oxidation does not occur too much, the subsequent oxygen content is substantially fixed.
As for the dehydration and drying of the powder in the future, as long as the temperature can be properly controlled, the oxygen content will not be greatly improved. The prepared powder is mixed with water, so the powder after atomization is a mixture of water powder. After being dehydrated after collection, the powder is post-treated, and after the test component is qualified, it can be used as a diamond catalyst powder for diamond production.
The control of alloy impurity content of diamond catalyst powder and the control of alloy composition uniformity are mainly done during smelting and atomization, so producers should pay sufficient attention to this.
4. Chemical composition of diamond catalyst powder Diamond catalyst powder is generally selected from 200-300 mesh powder. The process of graphite pressing into diamond is related to the 3d electronic state of the transition metal element in the catalyst. The diamond synthesis under high temperature and high pressure is basically Transition metal elements are used as catalysts, such as iron-based or nickel-based. From the basic principle of diamond transformation, the iron-based catalyst is more in line with the principle of the structure corresponding to the diamond catalyst design, the orientation of the bond and the soluble carbon. [4] Therefore, considering the process and production cost, the diamond catalyst powder is a large amount of iron-based powder. The following are some examples:
(a) iron 70 nickel 30
Note: 1. The diamond synthesized by the iron 70 nickel 30 powder catalyst process is golden yellow, the crystal form integrity rate is high, mostly the octahedron is in the same product shape, the impurity content is small, and the distribution is regular or fine.
2, the following is a measured example: iron 68.47 nickel 29.59 silicon 0.26 aluminum 0.21 manganese 0.095 copper 0.075 chrome observed by stereomicroscope the alloy powder is light gray, the surface is bright, very few small particles have oxidation color, most of Spherical particles with few irregular particles.
(two) iron 25 nickel 75
(three) nickel 70 manganese 25 cobalt 5
Synthetic diamonds, more or less always have impurities, and these impurity elements directly affect the color of the piano diamond. For example, as the nitrogen content in the diamond increases, the crystal changes from yellow to dark green, and the color tone gradually increases. When the boron content in the diamond crystal increases, the crystal gradually changes from yellow to brownish red, gray, and blue until it turns black. The desired synthetic diamond product can be obtained by adjusting the diamond manufacturing process or the composition of the diamond catalyst powder.
V. Equipment for producing diamond catalyst powder by high-pressure water atomization method A set of equipment for producing diamond catalyst powder with high-pressure water atomization method with annual output of 100 tons is required. The equipment and investment amount required are as follows:
Metal melting furnace and medium frequency power supply 50,000 high-pressure water pump 60,000 pipes, fans 10,000 atomization device (including atomizer, tundish) 50,000 technical service fee 50,000 auxiliary tools 30,000 total investment of about 250,000.
Of course, nitrogen catalyst can also be used to produce diamond catalyst powder. The investment amount of the project from the online inquiry is: a 100 kg class smelting furnace to prepare ingots, three 100 kg class atomization equipments, plus a matching screening, packaging and storage system, with an investment of about 10 million yuan; 1000 square meters, plus supporting water and electricity, gas stations and personnel, etc., about 10 million yuan. Therefore, the total investment is about 20 million yuan. Because the investment in gas atomization is quite large, the general enterprise will not use it. Of course, it can also be done in a frugal manner, and the investment can be greatly reduced.
In foreign countries, in the late 1980s, German Winter Company successfully developed a process of powder catalyst synthesis of coarse-grained high-strength diamond on a double-faced ultra-high pressure device, realizing the breakthrough of powder-catalyst industrial production of high-grade diamond. [1] Since the powder catalyst synthetic diamond has the advantages of high yield, good quality, and low consumption of raw and auxiliary materials, DeBeers and G. since the 1990s. E. The company uses powder catalysts for the production of high-grade diamonds and monopolizes the international market for high-grade diamonds.
2. Production Status of Domestic Synthetic Diamond and Market Forecast of Diamond Catalyst Powder The market of synthetic diamond materials in the world is increasing at an average annual growth rate of 8%. In China, 70-80% of the diamond production is used in the stone industry. By 2000, the output of stone plates was calculated at 100 million cubic meters, and the annual requirement for high-grade coarse-grain diamond for sheet cutting was 1.3-150 million carats. According to estimates by relevant departments, in recent years, China's imports of high-grade synthetic diamonds are above 10 million carats. China's annual diamond production increased rapidly from 440 million carats in 1997 to 2.5 billion carats in 2003, making China's diamond production account for more than 60% of the world's total diamond production, and diamond exports soared to 900 million carats. China is a world diamond production country, but the variety is single, the grade is in the middle and low grade, about one-third of the presses are forced to stop production. Although the quality of the diamond produced by the two-sided top press is good, due to the high technical requirements, the localization is quite difficult. Since the 1980s, China has introduced two-side press equipment, which cost about RMB 2 billion. This is equivalent to the total investment of the six-face presses currently in China, and no unit has yet entered normal production. For many domestic small and medium-sized enterprises, there is no strength to introduce two-sided presses and technologies. At present, the six-face press is developing in the direction of large-scale and refined technology. The combination of powder catalysts, especially with the advantages of large tonnage presses, will greatly advance the industrialization of high-grade diamonds in China.
Ni-Mn-Co sheet-like catalyst is widely used in China. Because of its high Mn content, the brittleness is large. When the rolling thickness is reduced to 0.4 mm or less, it is often brittle, which limits the further thinning of the catalyst thickness and the long production process. The energy consumption is large and the material utilization rate is not high. The segregation of the flake catalyst component is obvious, which is not conducive to the growth of high quality diamond. [2] Since the end of the 1970s, the use of single-powder mixing, turning powder and water atomized powder has been continuously studied in the powder catalyst synthesis diamond process, but there has not been a major breakthrough. The main problem is that the quality of the powder catalyst is not High, such as the current production of water atomization catalyst alloy powder enterprises, subject to the production process, the oxygen content of up to 2000ppm. The production of water atomized catalyst alloy powder is a systematic project. It contains two aspects of hardware and software. Generally speaking, because diamond manufacturers do not know much about the technology of atomization to produce metal powder, so pay attention to investment. Most of it is in the hardware part, and the result is that it costs a lot of money and the things that are obtained are not ideal.
The catalyst alloy powder is mainly prepared by high-temperature melting, high-pressure water atomization and crushing, and dried by vacuum drying. The diamond crystals synthesized by it are good in color and golden in color. The powder catalyst synthetic diamond test results show that the synthetic yield can be improved, the consumption of cemented carbide and raw materials can be reduced, the production cost of diamond can be reduced, and high-yield abrasive grade diamond can be synthesized, and high-quality coarse particles and high-grade diamond can be synthesized. The diamond single crystal synthesized by the powder catalyst is mainly composed of six to octahedrons, the crystal form integrity rate is high, the crystal is relatively pure, the total amount of inclusions is small, the distribution is fine and dispersed, and the room temperature and high temperature impact strength are good.
The use of powder catalyst technology to synthesize diamond has been recognized by domestic manufacturers. Various companies are increasing their investment in the research and development of powder catalysts. The demand for diamond catalyst powder is in a period of rapid growth. According to statistics, the total number of domestic diamond production enterprises is 248 (excluding many individual enterprises), which are spread all over the country, and there are many large-scale production enterprises in Henan, Anhui, Hunan, Hebei and other provinces. In recent years, the total number of new presses of 6×12MN and above has exceeded 800, and dozens of presses on both sides have been added, plus 4000 sets of original 6×8MN and below, with a total of nearly 5,000. With the large-scale adoption of the powder catalyst process, the annual demand for catalyst alloy powder will be above 3,000 tons. [3] And because most of the foreign diamond production uses powder catalyst, the products can also be exported to foreign exchange. According to the use of diamonds, the British Debeers company has a total of 44 brands, the United States GE has a total of 25 brands; China has only 11 brands, and the most high-end DMD level has no commercial products. The use of powder catalyst can achieve multi-variety, multi-grade and serialization of diamond products, providing an opportunity for SMEs to adjust product structure and improve the production technology level of enterprises. It will promote technological innovation in the diamond industry, enhance the ability of enterprises to participate in international market competition, and promote the diamond industry in China to embark on the road of sustainable development. Some large domestic diamond manufacturers have invested in the construction of catalyst alloy powder production lines because of the considerable use of catalyst alloy powder.
The high-pressure water atomization method on the market now produces catalyst alloy powder, which sells for more than 500,000, and has the following problems:
The oxygen content of the powder is quite high due to the structure of the existing equipment. The following are the main performance indicators provided by a certain equipment supplier:
Oxygen content: <3000ppm, loose density: 3.6g/cm3
Scope of application: Suitable for powder synthesis of high-grade synthetic diamond powder. Number of mesh: -320 mesh, -200 mesh, 200-320 mesh. Two equipment suppliers simply copy other equipment to the user for the production of catalyst alloy powder. And adjustment, no more technical skills for users. Because the production of catalyst alloy powder is not only a problem of crushing a metal liquid, its composition should be adjusted according to the needs of the diamond process. This requires you to be familiar with the metal material and have rich experience in powder production. It's handy.
The three users can't understand more about the overall situation of the device. If you want to improve the device, you don't know where to start. In other words, the price/performance of the services users receive is not high.
According to the inquiry from the household, in addition to these obvious shortcomings, there are other problems, so I will not write more here. If you have any questions, please feel free to contact and communicate with the author.
Third, high-pressure water atomization process for the production of diamond catalyst powder From a broad perspective, the high-pressure water atomization process for the production of diamond catalyst powder is part of the metal powder production process, or only one of the varieties produced Only. The production process is the same as the production of other metal powders by atomization.
First, according to the alloy composition formula of the diamond catalyst powder, the selected materials are melted into a molten metal in the intermediate frequency furnace according to the requirements of the melting process. Then start the high-pressure water pump matched with the atomization device, adjust the water level in the atomization cylinder, and prepare for atomization. After everything is ready, the atomization begins. After the metal liquid is injected into the tundish, it is restricted by the flow restricting nozzle and then enters the atomization chamber. Under the action of the main high pressure water jet from the atomizer, it is rapidly atomized into a very fine Metal droplets, because the specific heat of water is quite large, after heat exchange, the metal droplets solidify into metal powder after a short period of time. The oxidation of the diamond catalyst powder occurs mainly during the short period of time during which the fracture and solidification occur. If the oxidation does not occur too much, the subsequent oxygen content is substantially fixed.
As for the dehydration and drying of the powder in the future, as long as the temperature can be properly controlled, the oxygen content will not be greatly improved. The prepared powder is mixed with water, so the powder after atomization is a mixture of water powder. After being dehydrated after collection, the powder is post-treated, and after the test component is qualified, it can be used as a diamond catalyst powder for diamond production.
The control of alloy impurity content of diamond catalyst powder and the control of alloy composition uniformity are mainly done during smelting and atomization, so producers should pay sufficient attention to this.
4. Chemical composition of diamond catalyst powder Diamond catalyst powder is generally selected from 200-300 mesh powder. The process of graphite pressing into diamond is related to the 3d electronic state of the transition metal element in the catalyst. The diamond synthesis under high temperature and high pressure is basically Transition metal elements are used as catalysts, such as iron-based or nickel-based. From the basic principle of diamond transformation, the iron-based catalyst is more in line with the principle of the structure corresponding to the diamond catalyst design, the orientation of the bond and the soluble carbon. [4] Therefore, considering the process and production cost, the diamond catalyst powder is a large amount of iron-based powder. The following are some examples:
(a) iron 70 nickel 30
Note: 1. The diamond synthesized by the iron 70 nickel 30 powder catalyst process is golden yellow, the crystal form integrity rate is high, mostly the octahedron is in the same product shape, the impurity content is small, and the distribution is regular or fine.
2, the following is a measured example: iron 68.47 nickel 29.59 silicon 0.26 aluminum 0.21 manganese 0.095 copper 0.075 chrome observed by stereomicroscope the alloy powder is light gray, the surface is bright, very few small particles have oxidation color, most of Spherical particles with few irregular particles.
(two) iron 25 nickel 75
(three) nickel 70 manganese 25 cobalt 5
Synthetic diamonds, more or less always have impurities, and these impurity elements directly affect the color of the piano diamond. For example, as the nitrogen content in the diamond increases, the crystal changes from yellow to dark green, and the color tone gradually increases. When the boron content in the diamond crystal increases, the crystal gradually changes from yellow to brownish red, gray, and blue until it turns black. The desired synthetic diamond product can be obtained by adjusting the diamond manufacturing process or the composition of the diamond catalyst powder.
V. Equipment for producing diamond catalyst powder by high-pressure water atomization method A set of equipment for producing diamond catalyst powder with high-pressure water atomization method with annual output of 100 tons is required. The equipment and investment amount required are as follows:
Metal melting furnace and medium frequency power supply 50,000 high-pressure water pump 60,000 pipes, fans 10,000 atomization device (including atomizer, tundish) 50,000 technical service fee 50,000 auxiliary tools 30,000 total investment of about 250,000.
Of course, nitrogen catalyst can also be used to produce diamond catalyst powder. The investment amount of the project from the online inquiry is: a 100 kg class smelting furnace to prepare ingots, three 100 kg class atomization equipments, plus a matching screening, packaging and storage system, with an investment of about 10 million yuan; 1000 square meters, plus supporting water and electricity, gas stations and personnel, etc., about 10 million yuan. Therefore, the total investment is about 20 million yuan. Because the investment in gas atomization is quite large, the general enterprise will not use it. Of course, it can also be done in a frugal manner, and the investment can be greatly reduced.
Solar Flood Light,Solar Flood Lights Outdoor,Solar Led Flood Lights,Led Flood Lights Waterproof
Yantai LUHAO Lighting CO.,Ltd , https://www.luhaolight.com