Calculation of the Specific Surface of a Powder

The advantage of expressing the fineness of a powder by means of the specific surface is the facility with which this factor may be correlated with external factors in an investigation on the production or use of fine powders. A method of calculating the specific surface of a powder has been devised, which can be applied to practically all powders irrespective of the material from which they are produced.

The dimension of a single particle having the same shape and density as the particles constituting a powder, and having the same specific surface as the average for the powder, can be calculated from the grading analysis. The shape of an irregular particle can be defined numerically by two parameters. These shape factors are combined with the above dimensional factor and the density of the material to obtain an expression from which the specific surface of the powder can be calculated.