Method for production of silicon carbide granularity sand special for recrystallized silicon carbide

[0019] Embodiment one

[0020] like figure 1 As shown, the production method of silicon carbide grain size sand special for recrystallized silicon carbide products includes steps:

[0021] Shaping The silicon carbide particle size sand with a median diameter of 100um is subjected to centrifugal circulation shaping for 5 hours.

[0022] Classification: Classify the grain size sand after shaping treatment, remove the fine powder and coarse powder, and take the silicon carbide grain size sand with a particle size of 80um-150um;

[0023] Purification The separated silicon carbide particle size sand is purified by acid washing and alkali washing respectively with a large amount of sulfuric acid and sodium hydroxide;

[0024] Washing with water, adjust the pH value to 5-6;

[0025] Dehydration, drying After dehydration, drying, drying temperature 120 ℃, time 18 hours, to obtain silicon carbide particle size sand specially used for recrystallized silicon carbide products with smooth surface, silicon carbide particle size sand particle size 80um-150um, average particle size 100±2um Silicon carbide particle size sand, tap density 2.0g/cm 3 , the silicon carbide content is greater than 99wt%.

[0026] Embodiment two

[0027] like figure 1 As shown, the production method of silicon carbide grain size sand special for recrystallized silicon carbide products includes steps:

[0028] Shaping The silicon carbide particle size sand with a median diameter of 80-100um will be shaped by the centrifugal circulation of the shaping machine for 8 hours.

[0029] Classification: Separating the grain size sand after shaping treatment, removing the fine powder and coarse powder, and taking the silicon carbide grain size sand with a particle size of 63um-150um and an average particle size of 100±5um;

[0030] Purification: Purify the separated silicon carbide particle size sand through pickling and alkali washing with excess sulfuric acid and sodium hydroxide respectively;

[0031] Washing with water, adjust the pH value to 5-6;

[0032] Dehydration and drying After dehydration, dry at 140°C for 12 hours to obtain silicon carbide particle size sand specially used for recrystallized silicon carbide products with a smooth surface. The particle size of silicon carbide particle size sand is 63um-150um, and the average diameter is 100±5um. , tap density 1.9g/cm 3 , silicon carbide content of 99.3wt%.

[0033] Centrifugal circulation shaping machine can be used as figure 2 As shown, it includes a shaping mill 1 driven by a power device. The shaping mill 1 includes a grinding cylinder body 11 and a grinding disc, and the grinding disc is rotatably installed in the grinding cylinder body 11; the grinding disc includes a grinding disc body 2 and a stirring block 21 arranged on the grinding disc body 2 , the stirring blocks 21 are arranged in an annular array on the upper surface of the grinding disc body 2 . The upper part of the grinding cylinder body 11 is provided with a negative pressure pipeline 4, which is connected to a separation device such as a grading screen through the negative pressure pipeline. The grain size sand moves, and the silicon carbide grain size sand rubs against each other, passivating the edges and corners of the surface, making the surface smooth, and the smooth surface of the silicon carbide grain size sand is in use, and the mechanical properties are greatly improved. The reshaping method can be carried out by collecting the materials after each reshaping and then reshaping to form a cyclic shaping mode. After the shaping is completed, under the action of the induced air flow, the silicon carbide particle size sand after shaping is transported from the negative pressure pipeline 4 to the The separation device classifies the sieve, after separation, the silicon carbide particle size sand with a particle size of 63um-150um and an average diameter of 100±5um is taken, and the silicon carbide particle size sand coarse powder with a particle size greater than 150um is passed through a conveying device such as a screw conveying device from the return pipe 3. Transport it into the grinding cylinder body 11 to continue shaping, and the silicon carbide particle size sand fine powder with a particle size less than 60um is recycled for other purposes.