| 摘要 |
<p>PURPOSE:To recover niobium from a waste material containing a small amount of niobium in high concn. and high efficiency, by concentrating a metal chloride- containing hydrochloric acid solution prepared by eluting an inorg. mixture containing a small amount of niobium chloride with an aqueous hydrochloric acid solution with a specific concn. CONSTITUTION:An inorg. powdery mixture in which a small amount of NbCl2 coexists along with chlorides of Ti, Ta and Zr remaining after main metal chloride is extracted from a raw ore by treating the same with chlorine is used as a stock material. This stock material is thrown into a proper amount (about three times the vol. of the stock material) of a 15-25% aqueous hydrochloric acid solution and stirring is performed for about 20hr at a room temp. to eluate soluble metal chloride in the stock material. Subsequently, insolubles are removed by filtering while the obtained metal chloride-containing hydrochloric acid solution being the filtrate is concentrated but, because an aqueous hydrochloric acid solution is subjected to azeotropy at a hydrochloric acid concn. of about 20%, said solution is concentrated until the hydrochloric acid concn. becomes constant at about 20%. Moreover, the solubility of metal chloride to the 20% aqueous hydrochloric acid solution is considerably different for every metal and, because the solubility of NbCl2 is small, it is precipitated as a crystal.</p> |
