The influences of preparation conditions on the particle properties of spray dried slurries of the double salt burkeite (Na2CO3 .(Na2SO4)(2)) are examined to define particle size and porosity for maximal uptake of detergent components. Use of X-ray powder diffraction and energy dispersive elemental analysis showed that in the process burkeite was the only salt formed. The structure of the pores within particles, formed by the spaces between the crystals, was characterized by mercury intrusion. Typically, a pore volume of 0.5 mi g(-1) was obtained, in which more than half of the volume was in pores less than 0.5 mu m. The particle porosity was rather insensitive to variation in the size of the atomizing nozzle. However, the rate of drying, which was controlled by changing the air inlet flow rate, was found to be an important parameter. The pore volume was found to increase significantly with reduction in drying rate. The observation is interpreted in terms of established models for the drying of slurry droplets.