Preparation Process for Fine Particles of Finely-Controlled Morphology using Emulsion as a Reaction Field

以乳液为反应场制备形貌精细颗粒的工艺

基本信息

批准号：
09650829
负责人：
HIRAI Takayuki
金额：
$ 1.86万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

W/O/W emulsion (emulsion liquid membrane) system, which has been used for separation and concentration of metal ions, was utilized for preparation of fine particles.1. Preparation of Spherical Fine Particles of Rare Earth OxalateRare earth ions were transported from the external water phase into the internal water phase through the membrane, and well-defined spherical oxalate particles of 200-600 nm in diameter were obtained for almost all rare earths, Ce-Yb and Y. A simulation for rare earth ion transport through the membrane phase revealed that the particle size was controlled by the quantity of oxalic acid in each water droplet and also by the distribution of rare earth ions into the droplets, and this was confirmed experimentally. The control of the particle size was feasible by control of the feed rare earth concentration and size of the internal water droplets.2. Preparation of Calcium Carbonate Fine ParticlesCa ions were transported into the internal water droplets containing ca … More rbonate ions, and calcium carbonate particles were obtained. When the W/O emulsion was demulsified by Freeze-thaw method, micrometer-sized vaterite particles of hollow structure were obtained. Thus, by using W/O/W emulsion system, size, morphology, and also crystal structure could be controlled. In the case where phosphate ions were fed into the internal droplets, calcium hydroxyapatite fine particles were obtained.3. Preparation of Composite Oxalate ParticlesWhen binary metal ions are fed into the external phase, fine structure of the particles is expected to be controlled by controlling the transport of the ions through the membrane phase. As case studies, Sr-Pb oxalate and Co or Ni ferrite particles were prepared. As the former case, Sr oxalate particles containing finely dispersed nanometer-sized Pb oxalate were obtained. As the latter case, acicular Fe oxalate particles containing Co or Ni oxalate located near the particle surface were obtained, and were calcined to give Co ferrite or Ni ferrite acicular particles. Less

采用W/O/W乳液（乳液液膜）系统对金属离子进行分离浓缩，用于制备细颗粒。 1．稀土草酸盐球形细颗粒的制备稀土离子从草酸盐中分离出来。外部水相通过膜进入内部水相，几乎所有稀土、Ce-Yb和稀土都获得了直径200-600 nm的清晰球形草酸盐颗粒。 Y. 稀土离子通过膜相传输的模拟表明，颗粒尺寸是由每个水滴中草酸的量以及稀土离子在液滴中的分布来控制的，并且这已通过实验控制得到证实。通过控制进料稀土浓度和内部水滴的大小，可以实现碳酸钙细颗粒的制备Ca离子被输送到含有碳酸钙的内部水滴中。采用W/O/W乳液体系对W/O乳液进行冻融破乳，得到微米级的中空结构的球霰石颗粒。当磷酸盐离子进入内部液滴时，可以控制晶体结构，得到羟基磷灰石细颗粒。3．二元金属复合草酸盐颗粒的制备。作为案例研究，制备了 Sr-Pb 草酸盐和 Co 或 Ni 铁氧体颗粒。在后者的情况下，得到含有微细分散的纳米级草酸Pb的草酸锶颗粒。对于后者的情况，得到了位于颗粒表面附近的含有草酸Co或Ni的针状草酸铁颗粒。煅烧后得到Co铁氧体或Ni铁氧体针状颗粒。