By reacting the molten mixture with chlorine gas the metals are converted to their chlorides while bismuth remains unchanged. Impurities can also be removed by various other methods for example with fluxes and treatments yielding high-purity bismuth metal (over 99% Bi). Price
The price for pure bismuth metal has been relatively stable through most of the 20th century, except for a spike in the 1970s. Bismuth has always been produced mainly as a byproduct of lead refining, and thus the price usually reflected the cost of recovery and the balance between production and demand.Prior to World War II, demand for bismuth was small and mainly pharmaceutical — bismuth compounds were used to treat such conditions as digestive disorders, sexually transmitted diseases and burns. Minor amounts of bismuth metal were consumed in fusible alloys for fire sprinkler systems and fuse wire. During World War II bismuth was considered a strategic material, used for solders, fusible alloys, medications and atomic research. To stabilize the market, the producers set the price at $1.25 per pound ($2.75 /kg) during the war and at $2.25 per pound ($4.96 /kg) from 1950 until 1964.In the early 1970s, the price rose rapidly as a result of increasing demand for bismuth as a metallurgical additive to aluminium, iron and steel. This was followed by a decline owing to increased world production, stabilized consumption, and the recessions of 1980 and 1981–1982. In 1984, the price began to climb as consumption increased worldwide, especially in the United States and Japan.
Bismuth is a chemical element with the symbol Bi and atomic number 83. It is a weakly radioactive post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth may occur naturally, and its sulfide and oxide forms are important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery-white color when freshly produced. Surface oxidation generally gives samples of the metal a somewhat rosy cast. Further oxidation under heat can give bismuth a vividly iridescent appearance due to thin-film interference. Bismuth is both the most diamagnetic element and one of the least thermally conductive metals known. Bismuth was long considered the element with the highest atomic mass whose nuclei do not spontaneously decay. However, in 2003 it was discovered to be extremely weakly radioactive. The metals only primordial isotope, bismuth-209, experiences alpha decay at such a minute rate that its half-life is more than a billion times the estimated age of the observable universe. For all but the most exotic of uses bismuth may be considered stable because of its tremendously long half-life.Bismuth metal has been known since ancient times. Before modern analytical methods bismuths metallurgical similarities to lead and tin often led it to be confused for those metals. The etymology of "bismuth" is uncertain. The name may come from mid-sixteenth century New Latin translations of the German words weiße Masse or Wismuth, meaning white mass, which were rendered as bisemutum or bisemutium.