Abstract: A method and apparatus for accelerating solid particles entrained in a carrier gas so as to maximize the velocity of the particles at the output end of a duct is presented. This maximized or optimal acceleration is achieved by varying the cross section of the duct over at least the last 5 meters upstream from the opening thereof. Preferrably, the cross section of the duct should continuously increase i.e. diverge, towards the opening. This diverging cross section is preferrably in accordance with a nonlinear function of the length.

Abstract: Apparatus for closing the discharge aperture of a metallurgical vessel is presented. This apparatus includes a closure element attached to a pivoted lever in order to prevent undesirable discharge of slag at the beginning and end of the casting process and during refining. The lever pivotally opens and closes the aperture by means of a piston rod and pressure cylinder. The closure element, preferably made from wood, is temporarily attached to the lever by a friction fit and is designed to be used only once.

Abstract: An apparatus and process for rapidly injecting or blowing solid combustible material into a metal pool is presented. In a preferred embodiment, the apparatus essentially comprises at least one nonoxidizing compressed gas source, a circuit which supplies granulated carbonaceous material suspended in a carrier gas, at least one circuit which supplies flushing gas, various means for metering different flow rates of the gas and solid particulate streams and means for separately or jointly connecting the above described circuits to appropriate conduits which terminate in a blowing lance.