| 摘要 |
PURPOSE:To uniformly coat a precipitated oxide of a metal or other compds. on fine particles by dissolving the salt of the above-mentioned metal and urea in the aq. suspension of the above-mentioned fine particles of an acicular iron oxyhydroxide, etc., and heating the suspension to increase pH by the thermal decomposition of urea and to obtain the precipitated oxide. CONSTITUTION:The salt of a metal or the compd. soluble in the water or aq. soln. at <10 pH and precipitating as iron oxide or other compds. in the water or aq. soln. at pH higher than above-mentioned pH and lower than 10 and urea are dissolved in an aq. suspension of the fine particles of acicular iron oxyhydroxide or iron oxide. One or more kinds among the salts of Cu, Ag, Ca, Sr, etc., can be used as the salt of the metal or other compds. The aq. suspension is heated at >=60 deg.C at which urea is thermally decomposed, or especially at 80-95 deg.C, to increase the pH. By this method, the hydroxides of the above-mentioned metals or other compds. are uniformly deposited and coated on the fine particles.
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