Patent ID: 8308844
Filing Date: 2012-11-13
Classification: C21B,C22B,Y02P,Y10S

Abstract:
1. A method of reduction treatment of metal oxides, characterized by: using as a feed material a mixed powder of a powder containing both iron oxide and zinc oxide and/or lead oxide and containing alkali metals and halogen elements and a powder containing carbon, wherein an (alkali)/(zinc+lead) ratio is at least 0.1, where (alkali) is total moles of alkali salts and (zinc+lead) is total moles of zinc+lead, mixing said feed material with water sufficient to solubilize alkali salts to produce a slurry, wherein the pH of water forming said slurry is adjusted to within the range from 7 to 11.5 to reduce dissolution of zinc and/or lead compounds, then dehydrating said slurry, thereby providing a dehydrated material enriched in zinc and/or lead, wherein said dehydrated material is optionally shaped, and charging said dehydrated material directly into a rotary hearth type reduction furnace and reducing said dehydrated material in the rotary hearth type reduction furnace, said rotary hearth type reduction furnace provided with an exhaust gas treatment facility having at least one of a waste heat boiler and an air preheater.