Determination of the mean particle diameter, particle density, and fraction voids of Ottawa sand

Fluidization is one of the most recent developments in the field of unit operations. It occurs when particles of solids are maintained in a dense turbulent state by means of a moving fluid. The literature pertaining to fluidization covers only limited operating conditions, and the physical variables in fluidization are the characteristics of the retaining vessel, fluidizing medium, and the particles to be fluidized.

The properties of the fluidized solid which are of importance are the size, shape, density, surface tension, and electrostatic charge of the solids, but they have not been fully developed.

The purpose of this investigation was to determine the mean particle diameter, particle density, and the fraction voids of Ottawa sand (20-to 30, 30-to 50, and 50-to 70-mesh) to be used in extended studies on fluidization.

In the above investigation, the mean particle diameters determined by screen analyses for 20-to 30, 30-to 50, and 50-to 70-mesh Ottawa sand were 0.02530, 0.01691, and 0.00981 inches, respectively. The average particle diameters determined by magnified photographs for 20-to 30, 30-to 50, 50-to 70-mesh Ottawa sand were 0.0278, 0.0191, and 0.0108 inches, respectively. The absolute density of the Ottawa sand was 166.6 pounds per cubic foot. The fraction voids for the 20-to 30, 30-to 50, and 50-to 70-mesh Ottawa sand in the 2-inch diameter tube were 37.1, 38.7, and 41.3 per cent and in the 4-inch diameter tube 38.2, 40.7, and 42.7 per cent, respectively.