Calamine brass slowly phased out as zinc smelting techniques were developed in Europe, which produced metallic zinc more suitable for brass production than calamine. However, the conversion away from calamine brass manufacture was slow; a British patent was awarded to William Champion in 1738, but the alloying of metallic zinc and copper to produce brass was not patented until 1781 (by James Emerson), and calamine brass mills persisted in South Wales until as late as 1858. The slow diffusion of this technology was probably the result of economic factors. Calamine brass Calamine brass is brass produced by a particular alloying technique using
Group 5 element magnesium. 230,000 metric tons of niobium ore are produced yearly, with Brazil producing metric 210,000 tons, Canada producing 10000 metric tons, and Australia producing 1000 metric tons. 60000 metric tons of pure niobium are produced each year. 70000 metric tons of tantalum ore are produced yearly. Brazil produces 90% of tantalum ore, with Canada, Australia, China, and Rwanda also producing the element. The demand for tantalum is around 1200 metric tons per year. Dubnium is produced synthetically by bombarding actinides with lighter elements. Vanadium's main application is in alloys, such as vanadium steel. Vanadium alloys are used in springs, tools,