Reactor for acicular alpha-iron oxide hydrate prepn. - has rigid annular pipe conduit(s) fitted with inlet(s) connected to gas inlet conduit

摘要

Acicular alpha-FeOOH is prepd. from an aq. FeSO4 soln. by oxidative pptn. with an alkali, in a reactor contg. >=1 rigid annular pipe conduit fitted with >=1 inlet connected directly or indirectly to a conduit for introducing the oxidising gas or the non-reactive gas for turning round or conveying the reaction compsn. in starting the reactor. The inlet is formed so as to generate the gas pressure required to bubble the oxidising gas in the liq. and to turn or convey the reaction compsn. alpha-FeOOH is converted to acicular gamma-Fe2O3. Efficiency is 8-20 g/hr.1. ppted., oxidised Fe. Morphological structure of samples and the magnetic properties of the end-prod. can be repeated. On conversion to gamma-Fe2O3, induction coercivity achieved is >340 (390-430) Oe. Reactor construction is simple, requiring no mechanical units for conveying, turning or stirring the reaction mixt. Temp. can be controlled accurately.