1. An increase in the concentration of aluminum powder leads to a decrease in the ignition time and an increase in the burning time of the particles. 2. The increased burning time is due to a deterioration in the gas composition of the oxidizing medium (a decrease in the parameterak) and to agglomeration, which leads to the enlargement of the burning particles. 3. The agglomeration of the aluminum depends both on the properties and composition of the condensed mixture (dispersity and concentration of the aluminum powder, fractional composition of the ammonium perchlorate, the type of fuel and the method of preparing the samples) and on the specimen burning conditions (pressure, rate of flow of combustion products over the burning surface). 4. The agglomerates have a complex composition and, in addition to aluminum, contain a considerable quantity of the products of partial decomposition of the fuel and possibly ammonium perchlorate. 5. The burning time of the agglomerates is not determined by their apparent size, but depends on the amount of aluminum they contain.