Method for separating zirconium and hafnium. Specifically, zirconium compounds in acidic aqueous solution as raw materials, using diisobutyl keto (DIBK) or DIBK and neutral phosphorus extractant or DIBK and acidic phosphorus extractant synergism to extract hafnium in the feed liquid into the organic phase, and then the organic phase through washing, back extraction to produce hafnium rich liquid, zirconium and hafnium separation. Atomic grade zirconia and hafnium oxide were obtained after washing and roasting of the precipitates by ammonia water respectively. The process method of the invention gives priority to the extraction of hafnium with less content of zirconium and hafnium, with simple process and high extraction efficiency. The extraction system used in the invention has the same performance of separation of zirconium and hafnium as MIBK, but compared with MIBK, its water solubility is small, boiling flash and flash point is high, and toxicity is small, so as to solve the problems of MIBK in the extraction process such as large solvent loss, easy fire, environmental pollution and so on.
Zirconium in the earth's crust zirconium separation stone mainly exists in the form of plagioclase zircon (ZrO2) and zircon (ZrSiO4), while hafnium has no separate mineral, always symbiotic with zirconium in nature, no separate hafnium ore exists. The hafnium content in natural zirconium is generally 2 ~ 3wt%, and the hafnium content in zirconium products is generally 2 ~ 3wt%. Zirconium has a small thermal neutron absorption cross section, only (0.18±0.02) B (lb= 10_28m2/ atom), which is widely used as nuclear reactor cladding and structural material. In contrast, hafnium has a large thermal neutron absorption cross section (115X IO-28Hi2/ atom) and is an important material for controlling thermonuclear reactions. Zirconium used in nuclear reactors requires less than 0.01 % hafnium. Zirconium and hafnium have very similar chemical properties and are often referred to as "chemical isotopes". They are difficult to separate from each other and are considered to be among the most difficult elements on the periodic table to separate. In industry, solvent extraction of zirconium and hafnium is mainly used in trialkyl (mixed) amine (N235) extraction separation method, tributyl phosphate (TBP) extraction separation method, methyl isobutyl ketone (MIBK) extraction separation method. The separation of zirconium and hafnium by solvent extraction is an important method for the preparation of atomic grade zirconia and hafnium oxide.
Purpose is to provide a solvent extraction from the acidic aqueous solution containing zirconium and hafnium separation of zirconium and hafnium process method, the process approach is focused on solving MIBK extraction separation of zirconium and hafnium MIBK water-soluble, flash point and boiling point in the technological process, toxicity, solvent loss is big, easy to fire, the problem such as poor working conditions, easy to pollute the environment.
