Bastnasite yttrium

Rare Earths are produced primarily from three ores, monazite, xenotime, and bastnasite. Monazite is a phosphate mineral of essentially the cerium subgroup metals and thorium -(light rare Earths, Th) P04. The composition of monazite is reasonably constant throughout the world, with almost 50% of its rare Earth content as cerium and most of the remaining 50% as the other members of the cerium subgroup. Xenotime, like monazite, is a rare Earth orthophosphate but contains up to 63% yttrium oxide and also a markedly higher propor-... 

The ores from which rare-earth elements are extracted are monazite, bastnasite, and oxides of yttrium and related fluorocarbonate minerals. These ores are found in South Africa, Australia, South America, India, and in the United States in Cahfomia, Florida, and the Carolinas. Several of the rare-earth elements are also produced as fission by-products during the decay of the radioactive elements uranium and plutonium. The elements of the lanthanide series that have an even atomic number are much more abundant than are those of the series that have an odd atomic number. 

The element was discovered in 1794 by the Swedish chemist Gadolin. He named it after the small town Ytterby in Sweden where the mineral containing yttria was found. Mosander in 1843 determined that the yttria consisted of three oxides yttria, erbia, and terbia. Yttrium occurs in all rare earths. It is recovered commercially from monazite sand, which contains about 3% yttrium. It also is found in bastnasite in smaller amounts of about 0.2%. Abundance of yttrium in earth s crust is estimated to be 33 mg/kg. The metal has been detected in moon rocks. 

Bastnasite (Y,Ce)(C03)F A fluoro carbonate of cerium/yttrium—concentrates contain 60% REO raised to 70% REO by acid leaching and 85% by leaching and calcining Y2O3 low (0.1-0.3%)... 

HDEP has been found useful for the commercial production of Eu from bastnasite and for the purification of yttrium. 

In general, Y and the heavier lanthanides, Gd to Lu, are less abundant than the lighter lanthanides. La to Eu. However, there are two further complicating factors one is that the elements with even atomic number are more abundant than those of odd atomic number, reflecting the greater stability of such nuclei. Secondly, some ores (e.g. bastnasite, monazite) are richer in the lighter metals while others (e.g. xenotime) have more of the heavier metals. The abundance of yttrium in the Earth s crust is 31 ppm while the total abundance of the lanthanides is some 180 ppm cerium is the most abundant (66 ppm), while thulium and lutetium are the rarest (0.5 and 0.8 ppm, respectively). 

Yttrium By-product from bastnasite REE production Phosphorus... 

Source Monazite, bastnasite, and related fluocarbo-nate minerals as well as minerals of the yttrium group. These ores contain varying percentages of rare-earth oxides, which are often loosely called rare earths. Rare earth elements also occur as fission products of uranium and plutonium. 

Main yttrium minerals are bastnasite, kainosite, xerosime, and zinn-waldite. It is estimated that the upper continental crust contains yttrium at a concentration of 20.7 milligrams (0.00073 ounces) per kilogram and seawater contains a total amount of 1,569,000,000 kilograms (1,730,000 tons). 

Yttrium is found together with other rare earth oxides inmonazite sands (Ce, La, etc.) PO4] and in bastnasite [(Ce, La, etc.)(C03)F] (see Section 1.7.1). Yttrium is extracted together with other rare earth elements in a concentrated solution of sodium hydroxide at 140-150 °C after cooling, the hydroxides of the rare earth elements are separated by filtration. Alternatively, bastnasite may be calcined to drive off CO2 and fluorine, and then leached with hydrochloric acid to dissolve the trivalent rare earth elements. The rare earth hydroxides and chlorides obtained in this way are further processed to produce individual rare earth metal compounds... 

Production The most important base minerals are xenotime, monazite, and bastnasite. The first two are orthophosphate minerals LaP04 and the third is a fluoride carbonate LaCOsF. Lanthanoids with even atomic numbers are more common. Monazite also contains thorium and yttrium which makes handling difficult since thorium and its decomposition products are radioactive. 

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