Briefly describe the characteristics of extrusion granulation.

Answer: ① The particle size is adjusted by the screen aperture, and the particle shape is cylindrical with narrow particle size distribution; ② Soft granules can be made under low extrusion pressure, which is suitable for tabletting; ③ The granulation process involves many processes such as mixing materials and making soft materials, which is labor-intensive and not suitable for mass and continuous production; ④ When preparing small particle size, the screen life is short.

① The particle size is adjusted by the aperture of the screen, the particle shape is cylindrical, and the particle size distribution is narrow; ② The extrusion pressure is not high, and it can be made into soft granules, which is suitable for tabletting; (3) The granulation process involves mixing and making soft materials, which has many working procedures and high labor intensity, and is not suitable for mass and continuous production; ④ When preparing small particle size, the screen life is short.