The internal structure of detergent surfactant agglomerates is modified using electromagnetic heating to produce a lower bulk density final product. The agglomerates are heated in a 1.8 KW microwave waveguide heating applicator operating at license-free ISM frequency band of 2450 MHz. The density of the agglomerates reduces significantly when exposed to high power electromagnetic fields. The effect of number of process variables such as input power initial moisture content over bulk density of detergent particles is studied. Three different input power levels (500 W, 1 KW & 1.6 KW) are applied to the agglomerates and it has been observed that higher input powers raise the temperature of the agglomerates very quickly, hence reducing the required residence time of the sample. Agglomerates exposed to the highest input power (1.6 KW) had the lowest bulk density. The temperature profile and residence time of the agglomerates during heating was continuously recorded. Experimental results obtained in the lab-based process will be used to design a full scale continuous mode applicator.