Influence of humidifying on charged characteristic in ultrafine pulverization of sulfur.

• The relation of relative humidity and temperature can be expressed as: Q = A 1 - A 2 1 + e d x ζ (a + A e - t b ) + A 2. • The charge-to-mass ratio of sulfur decreased with increases in absolute humidity. • Humidify sulfur better eliminate static electricity than raising absolute humidity. The accumulation of static electricity is a big headache in the industry of sulfur ultrafine pulverization, as the fluidized sulfur powder charged with electricity will change the flow behavior, causing particles aggregation and lowered pulverization efficiency, which will impede the pneumatic transmission and collection system or even trigger the fire blast. In order to effectively reduce the accumulation of static electricity in the dry pulverization process of sulfur, LNI-330A impact mill was utilized to prepare −200-mesh sulfur powder, aiming to explore the influence of absolute humidity and wet basis moisture content on charge-to-mass ratio of the sulfur powder. The results show that the charge-to-mass ratio of sulfur powder decreased with the increase of the absolute humidity, and the formula implying the relation of the charge-to-mass ratio with relative humidity and the temperature was converted: Q = A 1 - A 2 1 + e d x ζ (a + A e - t b ) + A 2. Increased wet basis moisture content could also lower the charge-to-mass ratio, e.g. raising the wet basis moisture content of sulfur powder from 0 to 1.469% could lower the charge-to-mass ratio by 80.91%, and direct humidification of sulfur could better lower the charge-to-mass ratio of sulfur powder than increasing absolute humidity. This study provides a feasible method for reducing of static electricity in the process of the ultrafine pulverization to promote safety and pollution reduction in chemical engineering production. [ABSTRACT FROM AUTHOR]