Shanghai Luxiangyi’s 10 high-capacity centrifuges have been installed at a synthetic diamond manufacturer!

　　In recent years, with the rapid development of China’s manufacturing industry, many enterprises have been... Centrifuge Demand has begun to steadily increase. In this context, it’s worth noting that Shanghai Luxiangyi Centrifuge Instrument Co., Ltd. (hereinafter referred to as “Shanghai Luxiangyi”), a company specializing in the R&D and production of centrifuges, has also been reporting frequent positive developments; an increasing number of companies from diverse sectors are starting to purchase its products.

　　On April 19, a large blue truck parked in front of the Shanghai Luxiangyi Company. Staff members were carefully loading 10 DL-8M high-capacity refrigerated centrifuges onto the vehicle. “This batch of high-capacity centrifuges is headed to a synthetic diamond manufacturer and will primarily help the company improve its synthetic diamond recovery rate, reduce pollution, and lower costs,” said a company official.

　　The staff are loading the centrifuge onto the truck.

　　 Traditional synthetic diamond purification technologies have numerous shortcomings.

　　It is understood that synthetic diamonds possess several advantageous properties, including extremely high hardness, exceptionally high thermal conductivity, and excellent wear resistance and chemical stability. As a result, they hold broad application prospects in fields such as mechanics, thermodynamics, electronics, and optics. In China, the synthetic diamond industry has been developing rapidly; however, the relatively low level of purification technology is increasingly becoming a major challenge restricting its further growth. Currently, the most widely used purification techniques include strong-acid and strong-base chemical separation methods as well as physical separation methods using jigging tables. In reality, these conventional purification technologies all have numerous significant shortcomings.

　　① Strong acid-strong base chemical separation method

　　In the purification technology for synthetically produced ultra-hard materials, a beneficiation process is employed to achieve rough purification of diamonds based on the density difference between diamonds and graphite. However, due to factors such as water resistance and surface tension of water molecules, the settling velocities of diamond particles and graphite micropowder in water are not significantly different, making it difficult to completely remove the graphite micropowder. Therefore, leveraging the chemical properties of diamonds and graphite, traditional processes utilize high-temperature, high-concentration oxidizing acids—such as nitric-sulfuric acid mixtures or perchloric acid processes—to selectively remove graphite and achieve impurity removal and purification. The primary drawbacks of this approach are: the extensive use of highly concentrated strong acids, which, while removing impurities and purifying the material, also generate large amounts of sulfuric acid fumes and NOx gases, along with acidic wastewater. This severely degrades the production environment and leads to high costs for treating exhaust gases and wastewater.

　　② Physical separation method using a shaking table for mineral processing

　　Chinese patent with publication number CN 103303914A discloses a diamond purification process that involves mixing diamonds with graphite, adding a loosening agent to the mixture, and then subjecting the resulting blend to high-temperature treatment. After cooling, the diamonds are separated from the graphite using a physical method—specifically, a shaking table for mineral separation. The main drawback of this method is that the shaking-table separation technique cannot completely and cleanly separate diamonds from graphite. Moreover, in the intermediate transition zone of the shaking-table separation, there exists a mixed region where diamonds contained in the mixed material fail to be fully incorporated into the final separation product, thus leading to a waste of diamonds.

　　 Using the Lu Xiangyi centrifuge, the purification rate achieved through centrifugal separation exceeds 99.5%.

　　Overall, traditional purification techniques have numerous shortcomings. Therefore, to improve the purification efficiency, Shanghai Luxiangyi has supplied 10 DL-8M high-capacity refrigerated centrifuges to diamond manufacturers, introducing a new centrifugal separation method for distinguishing between synthetic diamonds and graphite. This method can further reduce contamination, lower costs, increase the recovery rate of synthetic diamonds, and prevent the loss of synthetic diamonds.

　　DL-8M High-Capacity Refrigerated Centrifuge

　　It is reported that this separation method leverages the differences in physical properties of the sorting medium to separate graphite from synthetic diamond. The sorting medium, J-10 (supplied by the Institute of Geochemistry, Chinese Academy of Sciences), is non-toxic, odorless, and does not pollute humans or the environment. It is easy to handle, safe and reliable, completely harmless, and can be recycled and reused. The separation efficiency is excellent, enabling the removal of graphite from synthetic diamond in the mixed material, with a recovery rate of synthetic diamond exceeding 99.5%. Although some residual catalyst alloys from electrolysis and metal carbides formed under high pressure remain in the separated diamonds, these substances can be easily purified into pure synthetic metallic stone by treating them with only small amounts of dilute acid and alkali. The cost of this separation process is 1.5 cents per carat.

　　In summary, this method not only boasts high sorting efficiency but also significantly reduces sorting time and labor intensity. During the cleaning process, there is no loss of synthetic diamonds (including fine-grained diamonds). Compared with other methods currently used both domestically and internationally, this approach will substantially lower costs.

　　According to the introduction, the specific details of the centrifugal separation method are as follows:

　　1. Ball-mill the mixture—consisting of synthetic diamond and graphite in the test rod, which has been dissociated by electrolysis or acid leaching (hereinafter referred to as the “mixture”)—for 30 minutes.

　　2. Place the ball-milled mixture and the separation medium J-10 into a centrifuge tube with a volume of 250 milliliters. The ratio is 100 grams of the ball-milled mixture to 200 milligrams of the separation medium. After centrifuging for 5 minutes, stop the machine, stir thoroughly, and then restart the centrifuge for another 10 minutes. As a result, graphite will separate from the diamond and heavier impurities—such as catalyst alloys and metal compounds—due to density differences. The graphite will float to the top, while the diamond and heavier impurities will settle at the bottom of the centrifuge tube.

　　3. Pour the diamonds and the separation medium into a glass sand funnel, or directly into a filter for filtration. The glass sand funnel is mounted on a vacuum flask and connected to a vacuum pump. Start the vacuum pump to evacuate the air from the vacuum flask, thereby reducing the pressure inside the flask. As a result, the separation medium solution is filtered into the flask, achieving both the separation of diamonds from the separation medium and the recovery of the separation medium itself.

　　4. A small amount of sorting medium adhering to the diamond surface can be directly washed off using water on a glass sand funnel. After dehydration, the washed-off sorting medium can be reused.

　　 About Shanghai Luxiangyi Centrifuge Instrument Co., Ltd.

　　Shanghai Luxiangyi boasts a long history and strong technical expertise. Since its establishment, the company has been committed to promoting the innovative development of domestically produced centrifuges. To date, Shanghai Luxiangyi has designed and manufactured centrifuge products suitable for a wide range of applications, which are now widely used in higher education institutions, research organizations, biopharmaceutical companies, healthcare facilities, and the petrochemical industry.

　　In the future, guided by the production philosophy of “quality and credibility first,” Shanghai Luxiangyi will continue to push forward and relentlessly pursue excellence. While striving to provide customers with even better equipment, we will also keep contributing our technology and methodologies to scientific research and industrial production. We are committed to supporting the "Made in China 2025" strategy and the rise of China’s science and technology!