Spiral air jet mills are widely used for grinding particles to a product size of 5-10 microns. The mill comprises a short cylindrical geometry with tangential air jets. Material is continuously fed to the mill and exits from a central opening. The grinding is done by high speed jets (larger than 100 m/s), and the mill has no moving parts. Further, the centrifugal motion in the mill results in simultaneous grinding and classification, with fine particles flowing out of the system once they become smaller than the cut size. This prevents over-grinding and improves the grinding efficiency of the mill. Spiral jet mills are finding increasing usage in the pharmaceutical industry for the manufacture of drugs for pulmonary inhalation drug delivery deep in the lung, micronization of APIs with poor water solubility to improve dissolution rates, and highly potent and cytotoxic APIs since the mills are easy to isolate in containment boxes. The worldwide market for spiral mills in the pharmaceutical industry is growing rapidly because they are easy to sterilize and have no mechanical seals or grinding media. Unlike other industries, where the energy efficiency is of prime importance, in the pharmaceutical industry control of the size distribution, determined by the efficiency of classification, is paramount, given the small volume and high cost of APIs. Issues such as amorphization and introduction of surface defects due to high speed impacts are also important in some cases. Based on our previous work, and currently on-going work, we have developed new insights into the mechanisms of grinding and classification. The goal of the present project is to carry out experimental and computational studies, using these insights, to optimize the geometrical design and the operating parameters of the mill for application in the pharmaceutical industry. The work will be done in collaboration with Gansons (established 1947), a leading pharma equipment manufacturer, who are interested in commercializing the jet mill.