固相诱导沉淀法制备单分散NiO微粒

将草酸以固体粉末形式添加到镍氨配合溶液中,沉淀出均一分散的草酸镍铵复合盐(类)球形颗粒,经热分解后可得到单分散NiO微粒。草酸以粉末形式加入,其固液界面对草酸镍铵沉淀微粒的形貌具有显著的诱导效应。实验研究表明,当配合溶液的氨镍摩尔浓度比等于5︰1(其中镍离子浓度设定为0.5mol·dm-3),反应温度为40℃,加入草酸后混合溶液pH值为8.8,反应时间为10min时,得到平均粒度为1.1μm的沉淀颗粒,450℃下热分解后粒子体积发生收缩,形成平均粒度为0.8μm的NiO微粒。该方法易于得到均一的单分散微粒,并可显著减小沉淀母液的体积量。

Preparation of Monodisperse NiO Particles by Solid Phase Induced Precipitation

The dispersed spherical particles of complex nickel and ammonia oxalate with uniform size were precipitated by adding solid oxalic acid powder into the complex solution of nickel chloride and ammonia, and the monedisperse NiO particles were obtained by thermal decomposition of the spherical particles. Because of adding oxalic acid in the form of powder, the shape and morphology of the precipitate particles are significantly changed ascribed to the induction effect of the solid-solution interface. The experimental study shows that when the molar concentration ratio of ammonia to nickel ion is 5 ： l in the complex solution （the reaction solution contains 0.5 mol·dm^-3 NiCl2）, and the mixed solution is at pH 8.8 after adding oxalic acid and aged at 40 ℃ for 10 minutes, the average size of the uniform precipitate particles is 1.1 μm, and 0.8μm for NiO particles obtaiend after calcination at 450 ℃. The morphological change of the precipitate particles can be significantly induced by this method. It is beneficial to preparing the monodisperse particles, and also the volume quantity of mother sohtion for precipitation by this method can be obviously decreased by almost half of volume comparing with the traditional precipitation process in which beth reagents were usually fed in the form of liquid.