Hydrogen inhibition in a wet aluminum dust collection system using dichromate solution

Abstract

Wet dust collection systems are used worldwide for aluminum dust treatment. However, these systems pose a risk of hydrogen fire and explosion because of the reaction between aluminum dust and water produce hydrogen. This study undertakes a field survey of the wet dust collection system in an atomized aluminum powder production enterprise in China. A hydrogen inhibition method (HIM) was proposed to inhibit hydrogen production. Hydrogen production inhibition tests were conducted using specialized equipment developed by the authors. The experimental data showed that the HIM effectively inhibited the reaction between aluminum and water. To study the changes in the aluminum particles before and after application of the HIM, scanning electron microscopy (SEM) was used to characterize the morphological changes in the aluminum powder. Energy-dispersive X-ray spectroscopy (EDS) revealed that Cr was evenly distributed around the aluminum particles, indicating that the inhibition film evenly covered these particles. X-ray photoelectron spectroscopy (XPS) was used to test the valence of Cr in the inhibition film, and X-ray diffraction (XRD) was used to analyze the chemical composition of the film after the HIM treatment. The results showed that Cr(OH)₃ and Al(OH)₃ were widely distributed in the inhibition film, confirming the effectiveness of the HIM. The reaction mechanism between the aluminum dust and dichromate solutions was discussed, and a chemical reaction kinetics model of the hydrogen production inhibition was established. The environmental issues regarding the use of dichromate solutions were discussed. Using HIM achieved the maximum reduction in the cost of the wet dust collection-system-and-in-the-hydrogen-fire-or-explosion-risk.