Refining molten non-ferrous metals, such as copper - using a stream of reaction gas surrounded by combustion gas which is blown onto melt

摘要

Reaction gas and combustion gas are blown onto the surface of a melt for the simultaneous optimum transfer of substances and heat. A single lance head is used with a central nozzle supplying reaction gas; and located concentrically around the nozzle are several nozzles (I) supplying gas combustion at a different pressure and conc. Combustion gas streams diverge from reaction stream without any mixing, but due to the angle of the nozzles, (I), the gas streams flow in two layers into a common impact zone on the surface of the melt. The angle of nozzles (I) is pref. 1.5-2.5 times the free spreading of reaction gas, esp. using angles in two planes parallel with the lance axis. Central nozzle is pref. a Laval nozzle. Method is e.g. for the redn. of molten copper contg. oxygen; or the refining of Cu or Zn to remove volatile impurities such as Pb or Bi.