In industry, high purity metals have been expected for many reasons. Tantalum, a metal of higher purity, is particularly needed because it can be used as a sputtering target and in electronic components such as capacitors. In this way, impurities in tantalum have an adverse effect on the properties of tantalum products.
When tantalum is processed, tantalum is derived from ore and then broken, and an acid solution is used to separate tantalum from the broken ore, and then an acid solution containing tantalum is densified from an acid solution containing niobium and other impurities. The acid solution containing tantalum is then crystallized to a salt and the salt containing tantalum is reacted with pure sodium in a vessel with a stirring usually made of a nickel-alloy material of which tungsten or molybdenum is a component. The vessel is usually double-walled and has an inner surface of pure nickel. The salt is then dissolved in water to obtain tantalum powder. In this treatment, however, the tantalum powder is contaminated by various surfaces in contact with it, such as surfaces containing tungsten and/or molybdenum. Many pollutants can be volatilized during subsequent smelting, with the exception of soluble refractory metals such as niobium, molybdenum and tungsten. These impurities are extremely difficult or impossible to remove, thus impeding the availability of extra-high purity tantalum products.
Relates to an alloy or mixture containing tantalum in which tantalum in the alloy or mixture has a purity of at least 99.995% and preferably at least 99.999%. The alloy or mixture (if at least tantalum is present in the alloy or mixture) is similarly preferred to have a fine grain structure and/or uniform texture.
Tantalum metal with a purity of at least 99.995%. The tantalum metal is preferably 99.999% pure and its purity can range from approximately 99.995% to approximately 99.999% or higher. Other ranges include approximately 99.998% to approximately 99.999%, approximately 99.999% to approximately 99.9992% and approximately 99.999% to approximately 99.9995%. The invention also relates to metal alloys containing high purity tantalum metal, such as tantalum base alloys or other alloys containing high purity tantalum as one of the components.
