(116t) An Experimental Optimization of Ball Milling

During drug manufacturing pharmaceutical companies must ensure that drug batches contain identical compositions of active compounds and possess identical physicochemical attributes. However, granular materials, the main components of drug tablets, are notorious for size segregation, making it difficult to successfully reproduce batches of drugs with identical properties. Therefore our research has focused on efficiently creating reproducible batches with identical particle size distributions. To achieve these goals, experiments were performed by crushing silica sand with steel grinding media in a ball mill, aiming to maximize the amount of material in a certain size range. The dependence of the particle size distribution on operating parameters was determined through three sets of experiments ? varying speed with high J (J = volume % of grinding media in the mill), varying number of grinding media at a single speed, and varying speed with low J. After distinguishing how each operating parameter influenced the particle size distribution, policies optimizing milling time were created. The results showed that the optimum amount of a certain size range can be obtained by milling at a slow speed with a low J for a long amount of time. A more time efficient approach is to initially run at a faster speed and then a slower speed. Multiple optimal policies are possible differing in how long each run operates at the higher speed. However, a longer run at high speed sacrifices the maximum amount of desired product and is not energy efficient. Changing milling speeds partway can improve the efficiency of drug manufacturing by reducing the amount of time spent milling the granular particles.