Abstract: Method and apparatus for determination of portion of pure metal in dross from a dross source, whereby the metal portion in the dross is determined by measuring the dross density and calculating the metal portion in accordance with the formula m%=k??+a, where m% is percentage pure metal, ? is the dross density and k and a are empirical constants. In accordance with the invention, the apparatus comprises a closed container (1) for dross provided with temperature gauge (9), pressure gauge (8) and an outlet pipe (18) having a valve (12) for removal of gas from the dross container (1), a closed container (2) for gas provided with a valve (14) for supplying gas from a gas source (16) to the gas container (2), whereby the dross container (1) and the gas container (2) are in a flow connection via a pipe (20).

Abstract: Device for adding a fluid to a liquid, for example of gas and/or particles to liquid metal. A rotor is rotated immersed in the liquid, comprising a hollow rotational body 10 with a first inner annular wall 16 with at least one radial opening 18 from a central, cylindrical chamber 19 and with an opening directed downwards. The rotational body is carried by a generally vertical shaft 12 which is connected to a powering unit and which may be arranged to lift the rotational body out of, respectively lower it into the liquid. Outside the central annular wall 16 of the rotational body 10 a further annular wall 14 which forms an annular chamber 17 is arranged, which communicates with the central chamber through the one or more radial openings 18. Advantages are achieved by that the one or more of the radial openings 18 are arranged in the lower part of the inner annular wall 16 of the rotational body, in a area which projects down under the surrounding additional annular wall 14.

Abstract: Method for heating a fluid, in particular a fluid which is not electrical conductive, where a rotor body (10) which is arranged in a chamber for absorption of the fluid, is rotated with a generally vertical shaft (11). A voltage is applied to a rod shaped electrode (16) which is arranged centrally in a rotor chamber (12) and to an electrode at the bottom (13) of the rotor chamber, for creation of a flame arc, so that a flow of the fluid passing the flame arc is created. The length (L) of the flame arc is held generally stable, preferably constant by controlling the position of the rod shaped electrode (16). The fluid is made enter the rotor chamber (12) so that it is kept outside the flame arc, and that the fluid is provided to flow through the rotor chamber (12).