| 摘要 |
PURPOSE:To manufacture magnetite particles with superior settleability by adding an alkali soln. to a ferrous salt soln. and blowing an oxidizing gas while adjusting the concn. of the ferrous salt, the amount of the alkali added and the ozone concn. of the oxidizing gas to specified values. CONSTITUTION:An aqueous soln. of an alkali such as NaOH is added to an aqueous soln. of a ferrous salt such as FeCl2 and agitated to deposit Fe(OH)3 particles. By blowing air contg. a highly oxidizing gas such as ozone the Fe(OH)3 particles are oxidized to form magnetite (Fe3O4) powder. The concn. of the FeCl2 as starting material in the soln. is adjusted to 0.65-9.1wt% as Fe, and the NaOH soln. added is 0.98-1.4 times as much as the Fe contained by chemical equivalent. In addition, by adjusting the ozone content of the air used in the oxidizing process to 2-20g/Nm<3> Fe3O4 with superior settleability is obtd. in a very short time. |
