The content of zirconium in the crust is 0.025%, ranking 20th. There are more than a dozen zro2-containing mineral deposits, but only two zircons (ZrSiO4) and zircon (ZrO2) have been selected for industrial use. Zircon is symbiotic with ilmenite, rutile and monazite, and can also be found in beach sand. All zircons contain hafnium oxide (HfO2) and radioactive materials, usually on the order of 1×10-7 millicurie/g, with high levels of HfO2.
Zircon, zircon is the primary source of zirconium, zircon to participate in the right amount of petroleum coke, at 1000 ° c, can be obtained (ZrCl4), its vapor with the molten metal magnesium touch, that is, is restored to. High purity can be obtained by thermal differentiation of iodide.
ZrCl4 was solid at room temperature and increased at 437℃. Therefore, the ZrCl4 obtained in the condenser is formed by condensation of the gas phase. After controlling the heat transfer rate and other conditions, products with high density and fine density can be obtained. ZrCl4 can be recovered to obtain ZrCl3 and ZrCl2, which are the first components of molten salt in electrolytic preparation. If make general industry zirconium, need not leave hafnium, can improve purify method to become refined ZrCl4, with magnesium recovery to make sponge zirconium.
Zirconium is mainly used as the cladding material of nuclear reactor fuel element, so zirconium is separated from hafnium in the smelting process. The most commonly used separation method in industry is nh4cns-mibk solvent extraction with methyl isobutyl ketone (MIBK) as the extractant. The disadvantages of this method are as follows: (1) low separation coefficient, demand series; (2) NH4CNS simple differentiation of CN-, make the waste water toxic, need to be treated in the factory. The world's zirconium reserves mainly occur in the coastal placer deposits, but only a small part of them occur in eluvial placer and primary ore, which has little industrial value. The main minerals in zirconium resources are zirconite and oblique zirconium ore, which are more symbiotic with ilmenite, monazite, rutile, phosphorus yttrium, cassiterite and other minerals. Australia zirconium resources and production are ranked first, followed by the United States, South Africa and other countries.
