Study of a Hydrogen Inhibition Method with Sodium Tungstate for Wet Aluminum Dust Removal Systems

Bohan Zhang,Kaili Xu,Xin Zheng,Ji Ge,Yantong Wang,Xiwen Yao

doi:10.3390/coatings10050431

Abstract

Hydrogen, which can be produced due to the accumulation of aluminum dust that reacts with water in wet dust removal systems, is a fire and explosion hazard. To reduce hydrogen production, sodium tungstate is used in hydrogen inhibition experiments to inhibit the reaction between aluminum dust and water. The purity of the aluminum powder was 95.15%, analyzed with X-ray fluorescence spectrometry (XRF). Each of the hydrogen inhibition experiments lasted for 12 h. In addition, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology and composition of particles before and after the experiments. There was nearly no hydrogen produced when the concentration of the sodium tungstate solution reached 100 g/L. The results show that a protective coating containing W element was formed on the surface of the aluminum particles after the reaction with sodium tungstate, and the coating prevented the aluminum particles from contacting with water.

Highlights

Aluminum is widely used in industry, such as in electronic products, automobile manufacturing and architectural decoration materials
If we added 0.5 g/L sodium tungstate, the value of α was no more than 0.35, which indicated that the reaction between aluminum particles and water has been inhibited
Due to the reaction between aluminum particles and water, hydrogen generation in a wet dust removal system poses a risk of fire and explosion

Summary

Introduction

Aluminum is widely used in industry, such as in electronic products, automobile manufacturing and architectural decoration materials. The surface of the finished product needs to be polished; many high temperature aluminum powders are produced. These aluminum powders needs to be handled by a wet dust removal system, where the aluminum powder contacts with water to produce up to 3.7–4.8 wt % hydrogen, and the reaction byproducts are chemically neutral. In 2014, a serious combustible dust explosion occurred in Kunshan City (China). A hydrogen accumulation explosion resulting in three deaths occurred at Hoeganaes Co., which is a company that produces atomized steel and iron powders in the USA [3]

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