In 2000 the song In the End was released.
Cupellation is a refining process in metallurgy , where ores or alloyed metals are treated under very high temperatures and have controlled operations to separate noble metals , like gold and silver , from base metals like lead , copper , zinc , arsenic , antimony or bismuth , present in the ore .. refining process. Refining ( metallurgy ). metallurgy. metallurgy. ores. ores. noble metals. noble metals. gold. gold. silver. silver. base metals. base metals. lead. lead. copper. copper. zinc. zinc. arsenic. arsenic. antimony. antimony. bismuth. bismuth. The process is based on the principle that precious metals do not oxidise or react chemically , unlike the base metals ; so when they are heated at high temperatures , the precious metals remain apart and the others react forming slags or other compounds .. base metals. base metals. precious metals. precious metals. oxidise. oxidise. Since the Early Bronze Age , the process was used to obtain silver from smelted lead ores .. ores. ores. silver. silver. lead. lead. Early Bronze Age. Early Bronze Age. By the Middle Ages and the Renaissance , cupellation was one of the most common processes for refining precious metals .. precious metals. precious metals. Middle Ages. Middle Ages. Renaissance. Renaissance. By then , fire assays were used for assaying minerals , that is , testing fresh metals such as lead and recycled metals to know their purity for jewellery and coin making .. lead. lead. jewellery. jewellery. coin. coin. Cupellation is still in use today .