Yttrium Mining

Yttrium is one of the Rare Earth Elements (REE) found on earth along lanthanides and scandium. Yttrium is a common element occupied the earth's surface.

Ores:

Yttrium occurs with Rare Earth Element ores such as bastn?site, xenotime and monazite. It also occurs in ion absorption clays, samrskite and fergusonite.

Mining:

Bastn?site is a carbonate fluoride REE ore with an average of 0.1% of yttrium in it. This yttrium comprising ore is mined by open pit surface mining method. The pit is made in the formation of steps for easy extraction of ore and transportation. Bastn?site is mined in 1940 to 1960 at California, USA.

Monazites are ores in the alluvial or placer deposits which are mined by scrappers and excavators. The scrapper removes the dirt of from upper layer of the placer deposits while the excavator digs out the ores. The ore is collected and transported to the nearby processing unit. Monazite has an average of 2% yttrium in it. Monazite is mined in South Africa and Australia.

Xenotime is mined as an accessory ore for gemstones in most of the regions. It is mined by open pit method. Areas which mine xenotime widely are Bayan Oba, China; Arendal and Tvedestrand, Norway; Novo Horizonte, S?o Paulo, Novo Horizonte, Bahia and MinasGerais, Brazil; Madagascar and California, Colorado, Georgia, North Carolina and New Hampshire, United States and North of Mount Funabuse in Gifu Prefecture, Japan.

Processing and extraction:

The separation of yttrium from Bastn?site and xenotime is a complex process. The ores are first leached with sulfuric acid. After leaching, the ore is introduced to ion exchange chromatography by adding oxalic acid to it. The oxalic acid precipitates the yttrium as oxalate salts. The yttrium oxalates are converted into yttrium oxides by reacting with oxygen. Now, yttrium oxide is converted into yttrium fluoride by reacting with hydrogen fluoride. Quaternary ammonium salts are used as extractants in the ion exchange chromatography which holds yttrium in the aqueous phase by separating other lanthanides from it. Thus, 99.9% pure yttrium salts are produced.

In monazite sand ores, the yttrium is separated and extracted by several methods. Te first step is grinding in which the sand is grinded to micrometers. The grinded ore then dissolved in concentrated sulfuric acid and it is leached with water for 12 hours. The leached resultant is employed to filtration in which the undigested ores are filtered. The filtered ore now called as monazite sulfate.

The monazite sulfate is neutralized and filtered in which thorium precipitate is formed and removed. It is again filtered and neutralized in which lanthanides with yttrium precipitate is formed and separated. From those lanthanides yttrium is further separated by ion exchange chromatography.The yttrium producing countries are China, India, Brazil, Australia and United States.

Definition:

Yttrium is a chemical component which has symbol Y. It is a silvery-metallic transition metal chemically similar to the lanthanoids and has historically been classified as a rare earth element. Yttrium is almost always found mutual with the lanthanoids in rare earth minerals and is never found in nature as a free element.

Properties:

Yttrium is a soft, silver-metallic, shiny and highly crystalline transition metal in group 3. As predictable by periodic trends, it is less electronegative than its forerunner in the group, scandium, more electronegative than its successor in the group, lanthanum, and less electronegative than the next member of period 5, zirconium. Yttrium is the first d-block element in the fifth period.
The pure constituent is relatively stable in air in bulk form, due to passivation resulting from the configuration of a protective oxide film on its surface.

Application:

Yttrium is originate in most rare earth minerals, as well as some uranium ores, but is never found in nature as a free element.About 31 ppm of the Earth's crust is yttrium, making it the 28th most rich element there, and 400 times more frequent than silver. Yttrium is available in soil in concentrations between 10 and 150 ppm of and in sea water at 9 ppt.