Model and experimental investigations of aluminum oxide slurry transportation and vaporization behavior for nebulization inductively coupled plasma optical emission spectrometry

Abstract

We analyzed aluminum oxide (Al2O3) by slurry introduction inductively coupled plasma (ICP) optical emission spectrometry through modeling and experimentation. We also studied the relationship between the ICP nebulizer gas flow, the spray chamber geometry, and the particle size of Al2O3 in an attempt to minimize the need for correction factors by ensuring an efficient aerosol mass transport. A cut-off point for the particle size was implemented at approximately 7–10μm for the sample introduction system. Based on modeling using a customized computer model and some experimental evidences, the maximum particle size for complete vaporization is approximately 7μm. For a gas flow of 0.8Lmin−1, particles with a diameter of up to 8μm can be evaporated with an efficiency of 68% and particles as large as 5μm can be evaporated completely within the nebulization gas flow region. The Al2O3 sintering block was ground using a self-made alumina mortar combined with a mixer mill device for particle reduction. The sample slurry was prepared by directly dispersing powdered Al2O3 in an aqueous solution with an addition of 0.5wt% poly (acrylate amine) (NH4PAA) as the dispersant. The accuracy of the results was compared with the data obtained through high-pressure digestion with acid and with the value of a certified reference material, NIST SRM 699 alumina.