Morphology control of goethite acicular particles during aging by nitrogen bubbling and subsequent reactive aeration
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Conditions for synthesizing acicular fine particles of goethite with high aspect ratio were devised by oxidizing mixed slurry comprising ferrous carbonate and hydroxide after neutralizing by alkali carbonate. By bubbling N2 after neutralization into the slurry containing FeCO3 and Fe(OH)2, dissolved CO2 is ejected. As a consequence, the relative concentration of CO 3 2− decreases and that of hydroxide increases. These favor the increase of the aspect ratio of the goethite particles via two factors, i.e., (1) decrease in the critical size of the nuclei and (2) suppression of growth inhibition at the tip of needle-like particles due to CO 3 2− adsorption. We propose a reaction scheme for the entire processing.
KeywordsGoethite Maghemite Ferrous Hydroxide FeCO3 Twin Formation
- 5.Sudakar C, Subbanna GN, Kutty TRN (2004) J Mater Sci 39:4271. doi: https://doi.org/10.1023/B:JMSC.0000033409.26766.62 CrossRefGoogle Scholar