PRODUCTION OF ACICULAR ZINC OXIDE AND ACICULAR ZINC OXIDE AND COMPOSITION CONTAINING THIS ACICULAR ZINC OXIDE

摘要

PURPOSE: To improve the yield of acicular crystals by settling ZnCO₃ from a soln. mixture composed of a specific water-soluble org. solvent contg. Zn ions, ammonium ions, carbonate ions and/or bicarbonate ions and water, then calcining the same. ;CONSTITUTION: Zn compds., such as Zn(OH)₂, (NH₄)₂CO₃, NH₃ water, and Al₂(SO₄)₃, are dissolved into a solvent mixture composed of 5/95 to 70/30 (by volume) composed of a water-soluble org. solvent having ≥12 dielectric constant and water to prepare the soln. contg. 3 to 10mol ammonium ions (hereafter [NH₄]) per 1mol Zn atom, 0.5 to 7mol carbonate ions (hereinafter [CO₃]) and/or bicarbonate ions, and 0.0001 to 0.1mol trivalent to quadrivalent metal atoms. The soln. is then maintained at pH 6.5 to 9.0 and gaseous CO₂ is blown thereto or 0.3 to 5N acid is added thereto to settle the acicular ZnCO₃; thereafter, this ZnCO₃ is separated and dried. The ZnCO₃ is then calcined at 600 to 1000°C in a nonoxidative atmosphere, by which the acicular conductive ZnO contg. ≥50% particles having 1 to 30μm major axis, 0.01 to 3μm minor axis and ≥10 aspect ratio is obtd.;COPYRIGHT: (C)1993,JPO&Japio