Production of Complex Fine Powders Using Solvent Extraction and Evaluation of the Powders

溶剂萃取反萃段可用于生产金属盐、金属氧化物、金属粉末和复杂金属粉末。这被称为结晶剥离。结晶溶出法以较低的成本制备了复杂的金属微粉和金属氧化物微粉。将含有不同金属离子的两种或三种有机相混合在一起，并对有机相进行结晶反萃，可制得复杂的金属和金属氧化物微粉。研究了以草酸和D2EHPA为萃取剂对Co、Ag、Ni、Cu、Zn、Fe和Sm的萃取，并以草酸和二氧化碳为结晶剂测定了这些金属离子的结晶反萃性能。由于草酸盐的低溶解度，这些金属的结晶在5分钟内定量发生。当含有两种金属离子的有机相用于结晶时--sr…倾斜越多，结晶按与萃取剂亲和力较小的金属离子的顺序发生。如果使用与有机相中金属浓度相对应的草酸量，所有金属离子都以络合金属草酸盐的形式从有机相中析出。在这种情况下，每种金属草酸盐，如铜、镍和锌的草酸盐的颗粒大小是不同的。例如，铜、镍和锌的粒度分别为0.5微米、2.5微米和5微米。在水溶液中的沉降速度取决于颗粒的大小。由于粒度差异，无法得到混合状态较好的复杂金属草酸盐。这些金属草酸盐的热分解发生在300400ﾟC的温度范围内。在空气中热分解得到金属氧化物粉末，而在氢气中分解得到还原的金属粉末。对含银、镍的有机相用二氧化碳结晶反萃，可得到混合态良好的复合金属碳酸盐。较少

The stripping stage of solvent extraction can be applied for the production of metal salts, metal oxide, metal powders and complex metal powders. It is called the crystallization-stripping. In the crystallization-stripping, the complex fine metal and metal oxide powders are prepared less costly in the simple process. If two or three kinds of organic phases containing different metal ions are mixed together and the crystallization-stripping is applied to the organic phase, we can make complex fine metal and metal oxide powders.Extraction of Co, Ag, Ni, Cu, Zn, Fe and Sm were investigated using Versatic Acid and D2EHPA as extractants, and then the properties of crystallization-stripping of these metal ions were measured using oxalic acid and carbon dioxide as crystallization agents.The crystallization of these metals takes place quantitatively within 5 min.due to the low solubility of metal oxalates. When the organic phase containing two kinds of metal ions is used for crystallization-sr … More tipping, the crystallization happens in the order of metal ions which have less strong affinity with the extractant. If the amount of oxalic acid corres-ponding to metal concentration in the organic phase is used, all of metal ions are precipitated as copmlex metal oxalates from the organic phase. In this case, the particle size of each metal oxalate, such as copper, nickel and zinc oxalates is different from one to other oxalates. For example, the particle size of copper, nickel and zinc oxalates is found to be 0.5,2.5 and 5mum, respectively. The sedimentation speed in aqueous solution depends on the particle size. The complex metal oxalate with good mixed state cannot be produced by the reason of particle size difference. The thermal decomposition of these metal oxalates takes place in the temperature range, 300-400ﾟC.The thermal decomposition in air gives the metal oxide powders, while the decomposition in hydrogen results in reduced metal powder. When the crystallization-stripping with carbon dioxide is applied to the organic phase containing silver and nickel, the complex metal carbonate with good mixed state can be obtained. Less