Selenium recovery

Deposits. Selenium forms natural compounds with 16 other elements. It is a main constituent of 39 mineral species and a minor component of 37 others, chiefly sulfides. The minerals are finely disseminated and do not form a selenium ore. Because there are no deposits that can be worked for selenium recovery alone, there are no mine reserves. Nevertheless, the 1995 world reserves, chiefly in nonferrous metals sulfide deposits, are ca 70,000 metric tons and total resources are ca 130,000 t (24). The principal resources of the world are in the base metal sulfide deposits that are mined primarily for copper, zinc, nickel, and silver, and to a lesser extent, lead and mercury, where selenium recovery is secondary. 

Purifying Selenium and Tellurium. Selenium recovery processes generally yield a metal product which contains some tellurium, and, correspondingly, recovered tellurium generally contains some small amount of selenium (37,41). 

Selenium recovery from electronic, xerographic, or other scrap for sale on the open market remains small. This was less than 100 t/yr in 1995. The xerographic industry recovers essentially all of the selenium it uses in photoreceptor dmms by extremely efficient recycling programs (see... 

Fujimura and A. Katai, Selenium Recovery from Copper Electrolysis Slimes at Mitsubishi Osaka Refinery, paper no. 82-12, TMS, Warrendale, Pa. 

Primary selenium recovery occurs at a single site that does not discharge to the environment. Consequently, this subcategory is not discussed further in this chapter. 

Acid roasting technology, selenium recovery via, 22 81-83 Acids... 

Alkali-metal salts, 24 145 Alkali-metal tellurides, 24 417 Alkali-metal thermal electric conversion (AMTEC), 22 773-774 Alkali-metal titanates, 25 43 44 Alkaline autoclaving, selenium recovery via, 22 81... 

Ferrous castings industry, 21 414 Ferrous chromite, 5 602 Ferrous dititanate, 25 46 Ferrous foundries, types of, 21 412 Ferrous iron salts, in selenium recovery, 22 79-81... 

Outlier detection, in chemometrics, 6 56-57 Outokumpu flash smelting, 16 146 Outokumpu lead smelting process, 14 745 Outokumpu Oy process, selenium recovery via, 22 83... 

Selenium-containing donors, synthesis and manufacture of, 22 212 Selenium dichloride, 22 75t Selenium diethyldithiocarbamate, 22 73t Selenium dioxide, 22 73t, 75t, 88 toxicify of, 22 95 Selenium disulfide, 22 73t Selenium hexafluoride, 22 75t, 87 toxicify of, 22 96 Selenium hypofluorite, 22 75t Selenium iodides, 22 87 Selenium monobromide, 22 75t, 88 Selenium monochloride, 22 75t, 87 in selenium recovery, 22 85 Selenium monoxide, 22 88 Selenium oxidation, selenium recovery via, 22 81-83... 

The selenium recovery is usually about 80%. The authors (22) had good precision in their results. Selenium concentrations in the 86 coals ranged from 0.5 to 11 ppm but usually were from 1 to 5 ppm the median was 2.8 ppm. 

Fractionation of serum proteins was achieved by affinity chromatography three main selenium fractions corresponded to SeP, albumin and GPx. Mass balance performed under different experimental conditions showed quantitative selenium recovery. The distribution of selenium between plasma GPx ( 20%), SeP ( 55%) and albumin ( 20%) was similar in both populations... 

People may also be exposed to selenium from industrial sources. Humans are normally not exposed to large amounts of selenium in the air, unless selenium dust or volatile selenium compounds are formed in their workplace. Occupations in which humans may be exposed to selenium in the air are the metal industries, selenium-recovery processes, paint manufacturing, and special trades. Selenium dioxide and elemental selenium can be released into the air during the burning of coal and oil. In addition, irrigation runoff may cause high levels of selenium in fresh water and can lead to high concentrations in some of the fish and birds that live there. 

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