Hydrogen inhibition effect of chitosan and sodium phosphate on ZK60 waste dust in a wet dust removal system:A feasible way to control hydrogen explosion

Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avoiding hydrogen explosion risks,we try to use a combination of chitosan(CS)and sodium phosphate(SP)to inhibit the hydrogen evolution reaction between magnesium alloy waste dust and water.The hydrogen evolution curves and chemical kinetics modeling for ten different mixing ratios demonstrate that 0.4wt%CS+0.1wt%SP yields the best inhibition efficiency with hydrogen generation rate of almost zero.SEM and EDS analyses indicate that this composite inhibitor can create a uniform,smooth,tight protective film over the surface of the alloy dust particles.FTIR and XRD analysis of the chemical composition of the surface film show that this protective film contains CS and SP chemically adsorbed on the surface of ZK60 but no detectable Mg(OH)_(2),suggesting that magnesium-water reaction was totally blocked.Our new method offers a thorough solution to hydrogen explosion by inhibiting the hydrogen generation of magnesium alloy waste dust in a wet dust removal system.

Study on the force chain characteristics with coal dust layer and the three-body contact stiffness

To explore the influence of the meso-mechanical behaviors of the wet coal dust layers on the contact stiffness of mechanical bonding surfaces,a three-body contact model incorporating an interface with wet coal dust was constructed based on breakage theory.The model considered the mechanical surface morphology and contact characteristics of the wet coal dust.The force chain evolution laws of the wet coal dust layer were elucidated under the effects of gap filling and the cover layer,and the bearing characteristics of the three-body contact bonding surfaces were revealed by quantitative analyses of the number,length,collimation coefficient,and coordination number of the force chains within the wet coal dust layer.Finally,the three-body normal contact stiffness under various preload forces was computed and experimentally validated.The results demonstrate that the external load transfer path of the three-body contact bonding surfaces was from mechanical surface(macroscopic stress)to wet coal dust layer(mesoscopic force chains)and then to mechanical surface(peaks and valleys).The interactions among these three elements contributed to transforming the distributions of the macroscopic stresses and mesoscopic force chains to the locations at the peaks and valleys of the mechanical surface.Among them,the proportion of short force chains in the wet coal dust layer increased from approximately 0.8%–91%,while the proportion of long force chains exhibited an opposite changing trend.The force chain collimation coefficient initially increased and subsequently stabilized,reaching a maximum value of 0.93.A large number of broken,small particles in the wet coal dust layer mainly served to fill the gaps among large particles.The maximum relative error between the experimental and simulated values on the three-body contact stiffness is 7.26%,indicating that the simulation results can be an approximate substitute for the experimental results with a certain degree of accuracy and practicality.The research results are of great significance for understanding the contact characteristics of mechanical surfaces containing particulate media.