Crystallization process of cimetidine crude product

The invention discloses a crystallization process of cimetidine crude product. The process comprises the following steps: introducing recirculated cooling water into a crystallization tank wall jacket, and controlling the temperature at 0-3 DEG C and the flow rate at 3-4 m/s; subjecting a cimetidine crude product to filter press into a crystallization tank; starting a stirrer for stirring the cimetidine crude product in the crystallization tank at a speed of 50 r/ min; continuing stirring for 20min, and stopping stirring; 30min later, continuing to stir for 20 min, and stopping stirring; repeating the above steps for 3-4 h until no crystal precipitation; and finally, sucking the crystals into a vacuum drier to obtain the cimetidine product. The invention has the following beneficial effects of: (1) increasing the rate of crystallization, and saving energy; (2) improving the production efficiency and output; (3) increasing the bulk density, facilitating packaging, reducing transport and storage volume of products, improving productivity and output of the downstream customers; therefore, the process is more in line with customer demand and production process.