摘要:
This invention relates to a method of treating titania slag to increase the leachability of impurities from the slag consisting of the steps of sizing the titania slag to a particle size from 75 to 850 &mgr;m; oxidizing the sized slag particles at a temperature from about 700° C. to below about 900° C. causing the iron present in the slag to concentrate at the exposed surfaces of the slag particles and/or causing an anatase phase to stabilize in the slag, causing a major portion of the iron in the Fe(II) state to convert to the Fe(III) state, and causing the titanium in the Ti(III) state to be converted to the Ti(IV) state; and reducing the oxidized slag in a reducing atmosphere from about 700° C. to about 950° C. to convert a major portion of the iron in the Fe(III) state to the Fe(II) state. The invention also relates to a method of beneficiating titania slag to increase the TiO2 content thereof wherein the above treated slag is leached with acid.
摘要:
A process and apparatus for regeneration of acid and metal from spent acid liquors includes the steps of, optionally, concentrating (110) the liquor to a concentrated liquor or solid, pyrohydrolysing (114) to regenerate the acid and form metal oxide pellets, and reducing the oxide to metal in a two stage reduction reactor (116, 118) using a partially combusted fuel as reducing agent. Also disclosed is a two-stage reduction process and reactor for production of direct reduced iron (DRI) from iron oxide ores or wastes, including a first stage (416) in which the oxide feed is contacted with a fuel and a sub-stoichiometric amount of an oxygen source to produce a lower oxidation state oxide, and a second stage (418) in which the lower oxidation stage oxide is contacted with off-gases from the first stage to produce iron metal.