Mineral wool and process for producing same

Claim 1

A process for producing mineral wool wherein a molten slag substantially free of metallic iron and suitable for fiberizing into mineral wool is formed in a cyclone-type furnace having a combustion zone, a collecting zone and an exhaust gases-combustion air heat exchanger, the process comprising: (a) feeding (i) a first particulate material containing organic combustibles and inorganic non-combustibles and characterized by a composition comprised of between: about 49-62 weight percent silica, about 21-27 weight percent alumina, about 1.0-3.0 weight percent lime, about 0.5-3.0 weight percent magnesia, about 2.5-19 weight percent iron oxides, about 0.3-4.0 weight percent sulfur, a size consist of 100 weight percent -200 mesh and at least about 70 weight percent -325 mesh, and a heating value of about 10 mega J per kilogram of molten slag produced, and (ii) a second particulate material containing fluxstone and characterized by a size consist of 100 weight percent -200 mesh and at least about 30 weight percent -325 mesh, and (iii) preheated air into the combustion zone of the cyclone-like furnace, (b) substantially instantaneously burning the organic combustibles and melting and reacting the inorganic non-combustibles and fluxstone to form a molten slag on the walls of the collecting zone, (c) collecting the molten slag in the bottom of the collecting zone, (d) passing waste combustion gases formed in the furnace through a heat exchanger to thereby heat incoming combustion air used in the process, (e) discharging the molten slag from the collecting zone, and (f) fiberizing the molten slag to form mineral wool.