Grinding powders in jet mills makes it possible to obtain materials uncontaminated by wear products of grinding media to prepare pure products in chemical and pharmaceutical industries. It should be noted that for different technologies, the requirements for the granulometric composition of powders vary significantly, and to meet these requirements, specific approaches are often required. Experimental determination of optimal conditions to obtain new powders is often associated with significant costs, which is not always justified from an economic point of view. Mathematical modeling allows us to obtain effective solutions in a shorter time and at lower costs in most cases. Thus, the development of adequate models, methods of calculation and optimization of jet grinding technology is an urgent scientific and practical task. To simulate grinding, a matrix methodology is used to describe technological processes. To identify the model, the results of specially conducted experimental studies are used. During experimental studies, the granulometric compositions of powders after single and multiple grinding in a jet mill have been determined. The results obtained have been used to identify and verify the matrix grinding model. Within the framework of the resulting model, a method for technological calculation of a jet mill operating in an open grinding cycle has been developed. The presented approach allows us to propose the ways to develop and implement new jet grinding technologies to obtain highly pure products in open and closed grinding cycles.