Zone Refining of Rhenium

Zone Refining of Rhenium

About Rhenium

Classified as a refractory metal due to its extremely high melting point of 3180º C, rhenium’s melting point is exceeded only by tungsten. And it is a very dense metal, having a density of 21.04 g/cc which is exceeded only by iridium, osmium and platinum. Unique among refractory metals, rhenium does not have a ductile-to-brittle transition temperature as it remains ductile from absolute zero up to its melting point of 3180º C. And thanks to its high re-crystallization temperature & high modulus of elasticity, parts produced from rhenium offer very good stability & rigidity and can withstand wide swings in temperature without being damaged.

Pure rhenium metal is offered in two grades, commercially pure (minimum purity of 99.95% or greater) and zone-refined (99.99% minimum purity) for applications that demand the highest purity of rhenium metal available. 

What is “Zone Refining”?

Zone refining is a highly technological method for ultra-purification of metals. The principle of zone refining is that the impurities in an ingot of metal are more soluble in the melt state than they are in the corresponding solid state. In the zone refining process, the impurities are concentrated at one end of the ingot of metal so that the rest of the ingot is ultra-purified. It is an effective and easy method for ultra-purifying high-purity metals. 

Zone Refining Process

In the zone refining process, a circular mobile heating element is fixed at one end of the metal ingot to be purified. As the circular mobile heating element is moved slowly across the metal rod, the metallic impurities melt at the temporary position of the heating element. As the heating element moves forward, the concentration of the impurities in the melt area increases. This is due to the fact that the metallic impurities are more soluble in their melt state than in their solid state. The melt containing the metallic impurities moves forward along with the heating element through the entire length of the metal ingot and the pure metal is left to solidify as the heating element moves forward along the ingot. The melting process is repeated many times in the same direction. Finally, the metallic impurities have accumulated at one end of the metal ingot. The end of the ingot containing the accumulated impurities is then cut off, leaving behind an ultra-pure metal ingot.

Zone-Refined Rhenium Ribbon

Rembar offers custom-produced zone-refined rhenium ribbon for use in mass spectrometers & other electronics applications requiring ultra-pure rhenium ribbon. To request a quote on the specific size & length of the zone-refined rhenium ribbon you require, use our “Fast-Quote” form or “Contact Us” form on our website, or for fastest service call us at (914) 693-2620 & speak with one of our knowledgeable sales engineers.

About Rembar

Rembar has been supplying industry with refractory metals since its founding in 1950. In addition to having one of the largest distributor inventories of refractory metal mill products in the U.S., Rembar has a fully equipped machine shop ready to serve you. And with some of the shortest lead-times in the industry for machined & fabricated parts, we can quickly machine & form refractory metals according to customer-supplied specifications and drawings.