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Zirconium Preparation Method

Sep 12, 2017

Zirconium (Zirconium) is a chemical element, its chemical symbol is Zr, its atomic number is 40, is a high melting point metal, was light gray. Density of 6.49 g / cm3. The temperature of 1852 ± 2.001 ° C, the boiling point of 4377 ° C. Valence + 2, + 3 and +4. The first ionization energy is 6.84 electron volts. The surface of zirconium is easy to form a layer of oxide film, with a gloss, so the appearance and steel similar. Corrosion resistance, soluble in hydrofluoric acid and aqua regia, high temperature, with non-metallic elements and many metal elements to produce solid solution compounds.

Basic nature

Zirconium easily absorbs hydrogen, nitrogen and oxygen; zircon has a strong affinity for oxygen, and 1000 ° C of oxygen is dissolved in zirconium to increase its volume significantly. The surface of zirconium is easy to form a layer of oxide film, with a gloss, so the appearance and steel similar. Corrosion resistance, but soluble in hydrofluoric acid and aqua regia. High temperature, with non-metallic elements and many metal elements to generate solid solution. Zirconium plasticity is good, easy to process into a plate, silk and so on. Zirconium in the heating can absorb a lot of oxygen, hydrogen, nitrogen and other gases can be used as hydrogen storage materials. The corrosion resistance of zirconium is better than that of titanium, close to niobium and tantalum. Zirconium and hafnium are similar in chemical properties, but also together with the two metals, and contains radioactive material.

Zirconium silicate

ZrSiO4, high refractive index of 1.93-2.01, chemical stability, is a high-quality, inexpensive opacifier, is widely used in a variety of building ceramics, sanitary ceramics, ceramics for daily use, a ceramic crafts, In the ceramic glaze processing production, the use of a wide range of applications. The reason why zirconium silicate is widely used in ceramic production, but also because of its good chemical stability, which is not affected by the ceramic firing atmosphere, and can significantly improve the ceramic glaze bonding performance, improve the ceramic glaze hardness. Zirconium silicate is also used in the television industry's color picture tube, glass industry, emulsified glass, enamel glaze production has been further applied. Zirconium silicate high melting point: 2500 degrees Celsius, so in refractory materials, glass kiln zirconium ramming material, castable, spray paint is also widely used. [7]

Zirconium index

Zr index, the post-treatment process used to measure the degree of solvent degradation indicators. 95Zr is an important lobes. The degraded solvent has a high selectivity for 95Zr. The greater the zirconium index, the more serious degradation of the solvent. The zirconium index (Z value) was measured by the following steps: the organic phase was washed with sodium hydroxide, water and nitric acid after stripping, and then equilibrated with the tracer amount 95Zr. The organic phase was washed three times with 3 mol / L nitric acid and removed TBP extraction of 95Zr. The amount of zirconium retained in the solvent phase was determined, and the number of moles of Zr95 retained per 109 L of solvent was the Z value of the solvent. As the zirconium in the aqueous solution of complex behavior, with the measurement conditions are different, Z value will be different, and thus commonly used to characterize the stability of the solvent stability: Goldberg - Hoghes box.

Preparation method

1, the calcined zircon calcined into zirconium tetrachloride. Zircon and carbon co-heat, into zirconium carbide, and then chlorinated to zirconium tetrachloride, and then reduced with magnesium can be made of zirconium metal. The preferred method is industrially produced by molten salt electrolysis with ZrCl4 or K2ZrF6 as raw material.

ZrO2 + 3C = ZrC + 2CO ↑

ZrC + 2Cl2 = ZrCl4 + C

ZrCl4 + 2Mg = Zr + 2MgCl2

2, zircon and carbon with the electric furnace can be heated zirconium carbide, followed by carbonyl chloride at 500 ℃ chloride can be crude zirconium tetrachloride. In order to separate the hafnium from it, the crude zirconium tetrachloride was first dissolved in water and the hafnium was separated from the aqueous solution. At present, representative solvent extraction and separation method is based on isohexanone as solvent. With this method, hafnium oxide can be obtained, and hafnium oxide is heated to 900 ° C in the presence of carbon, and then chlorinated to form zirconium tetrachloride, and zirconium tetrachloride is purified by sublimation purification. At about 850 ° C using magnesium reduction, by-product of magnesium chloride at about 900 ° C can be vacuum distillation separation removed, and finally to the sponge-like zirconium. [9] 

ZrSiO4 + 3C = ZrC + SiO2 + 2CO ↑

ZrC + 2Cl2 = ZrCl4 + C

ZrCl4 + 2Mg = Zr + 2MgCl2