オキシアルキルアミンを共存させた水酸化第1鉄の湿式酸化法による板状ゲータイト粒子の合成 Synthesis of Plate-like Goethite Particle through Oxidation of Fe(OH)_2 with Oxyalkyl-amine
The plate-like goethite particles were synthesized from a ferrous hydroxide solution with oxyalkylamine (OAA) in the course of oxidation. The ratio of the crystallite sizes of (010) and (110) direction, D<SUB>010</SUB>/D<SUB>110</SUB>, were determined and its correlation with particle morphology was discussed. The value of D<SUB>010</SUB>.D<SUB>110</SUB> was 1.3 times higher than the value calculated from a<SUB>0</SUB> and b<SUB>0</SUB> using Gibbs' equation. It shows growth of the (100) plane was restricted due to adsorption of OAA. Titration of ferrous sulfate with NaOH in the presence of acicular or plate-like goethite particles show that formation of plate-like goethite particles is attributed to the prevention of crystal growth along c-axis. Synthesis of plate-like goethite is related to the preferred adsorption site of alcoholic part of OAA, since plate-like goethite particles have never been synthesized from ammonium. Adsorption of OAA on (100) and (001) decreases the rate of crystal growth of (100) and (001), especially when free OAA concentration exceeds 0.4mol/dm<SUP>3</SUP>.
粉体および粉末冶金 46(4), 342-347, 1999-04-15
Japan Society of Powder and Powder Metallurgy