YTTRIUM

Description

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.
Yttrium alloys have many applications. The metal doped with rare earths such as europium is used as phosphor for color television receivers. When added to iron, chromium, vanadium, niobium, and other metals it enhances resistance of these metals and their alloys to high temperature oxidation and recrystallization. It is a deoxidizer for vanadium and other nonferrous metals. Yttrium-aluminum garnets are used in lasers and in jewelery gemstones. Yttrium-iron garnets are used as transmitters and as transducers of acoustic energy.

Uses

Yttrium has the highest thermo-dynamic affinity for oxygen of any element, this characteristic is the basis for many of its applications. While not part of the rare earth series, it resembles the heavy rare earths which are sometimes referred to as the Yttrics for this reason. Another unique characteristic derives from its ability to form crystals with useful properties. Some of the many applications of Yttrium include in ceramics for crucibles for molten reactive metals, in florescent lighting phosphors, computer displays and automotive fuel consumption sensors. Yttria stabilized Zirconium Oxide are used in high temperature applications, such as in thermal plasma sprays to protect aerospace high temperature surfaces.
Yttrium is also used for producing a variety of synthetic garnets with different applications such as microwave filters, acoustic energy transmitters and transducers. Yttrium can be used to produce powerful pulsed lasers and superconductors. In biomedical field, yttrium is used in cancer treatment drugs, rheumatoid arthritis medicines and surgical supplies.
Yttrium Metal is widely applied in making speciality alloys, it increase the strengths of alloys of metals such as Chromium, Aluminium, and Magnesium. Yttrium is one of the elements used to make the red color in CRT televisions. As a metal, it is used on the electrodes of some high-performance spark plugs. Yttrium is also used in the manufacturing of gas mantles for propane lanterns as a replacement for Thorium. It is also used to increase the strength of Aluminium and Magnesium alloys. The addition of Yttrium to alloys generally improves workability, adds resistance to high-temperature recrystallization and significantly enhances resistance to high-temperature oxidation. Yttrium Metal can be further processed to various shapes of ingots, pieces, wires, foils, slabs, rods, discs and powder.

Preparation

Yttrium is recovered commercially from its two principal sources, xenotime and monazite. Ore is opened by digestion with hot sulfuric acid. Insoluble residues are filtered out and leachate solution containing yttrium and other rare-earths is loaded onto cation exchange resin beds for separation. Fractions are eluted with ethylenediamine tetraacetic acid (EDTA) buffered with ammonia at varying temperatures. Also, many other chelates are highly effective in eluting rare earths. Such temperature adjustments of resin beds enhance separation efficiency, particularly for separating yttrium. Separated rate earths including yttrium are converted into insoluble oxalates that precipitate when treated with oxalic acid or sodium oxalate.
Yttrium oxalate is then ignited to its oxide, Y2O3. The oxide is heated at 750°C in a stream of anhydrous hydrogen fluoride to yield yttrium fluoride, YF3. Alternatively, the oxide is mixed with ammonium hydrogen fluoride NH4HF2 and heated at 400°C in a stream of dry air or helium. Yttrium metal may be produced from its fluoride either by metallothermic reduction or electrolysis. The more common metallothermic reduction involves reducing the fluoride with redistilled calcium in 10% excess over the stoichiometric amounts at elevated temperatures:
2YF3 + 3Ca → 2Y + 3CaF2
In the electrolytic process, a fused bath of yttrium fluoride and lithium fluoride is heated to nearly 1,700°C and electrolyzed. The electrolysis is done in a graphite crucible using molybdenum cathodes at which yttrium is produced as molten metal.
Yttrium is purified by distillation at high temperatures under vacuum.

Chemical Properties

Yttrium is a silvery-white to dark-gray, or black solid or gray powder. Odorless. An element in Group III-B of the Periodic Table. It is very similar to the rare earth metals.

Chemical Properties

Dark-gray metal. Soluble in dilute acids and potassium hydroxide solution; decomposeswater. Known only in the tripositive state. Low neutron capture cross section.

Physical properties

Yttrium is always found with the rare-earth elements, and in some ways it resembles them.Although it is sometimes classified as a rare-earth element, it is listed in the periodic table asthe first element in the second row (period 5) of the transition metals. It is thus also classifiedas the lightest in atomic weight of all the rare-earths. (Note: Yttrium is located in the periodictable just above the element lanthanum (group 3), which begins the lanthanide rare-earthseries.Yttrium dissolves in weak acids and also dissolves in strong alkalis such as potassiumhydroxide. It will also decompose in water.Yttrium’s melting point is 1,522°C, its boiling point is 5,338°C, and its density is 4.469g/cm³.

Isotopes

There are 50 isotopes of Yttrium. Only one is stable (Y-89), and it constitutes100% of the element’s natural existence on Earth. The other isotopes range from Y-77to Y-108 and are all produced artificially in nuclear reactions. The radioactive isotopeshave half-lives ranging from 105 nanoseconds to 106.65 days.

Origin of Name

Yttrium was originally found with other elements in a mineral called gadolinite that was discovered in a mine near the Swedish the town of Ytterby.

Occurrence

Yttrium is the 27th most abundant element found on Earth, so it is not exactly correct tothink of it as “rare”—rather just difficult to find and extract from all the other similar elementsfound in its minerals.The mineral gadolinite that was discovered in a quarry near Ytterby, Sweden, was analyzedas (Ce,La,Nd,Y)2FeBe₂Si₂O₁₀. Today most yttrium is recovered from the ores of the mineralmonazite, which is a dark, sandy mixture of elements [(Ce,La,Th,Nd,Y)PO₄] and containsabout 50% rare-earths, including about 3% yttrium. The yttrium is separated from the otherrare-earths first by magnetic and flotation processes, which are followed by an iron-exchangedisplacement process. Yttrium’s ions are combined with fluorine ions that are then reduced byusing calcium metal that yields yttrium metal (3Ca + 2YF₃ → 2Y + 3CaF₂). This reductionprocess produces high-purity yttrium that can be formed into ingots, crystals, sponge, powder,and wires.

History

Yttria, which is an earth containing yttrium, was discovered by Gadolin in 1794. Ytterby is the site of a quarry which yielded many unusually minerals containing rare earths and other elements. This small town, near Stockholm, bears the honor of giving names to erbium, terbium, and ytterbium as well as yttrium. In 1843 Mosander showed that yttria could be resolved into the oxides (or earths) of three elements. The name yttria was reserved for the most basic one; the others were named erbia and terbia. Yttrium occurs in nearly all of the rare-earth minerals. Analysis of lunar rock samples obtained during the Apollo missions show a relatively high yttrium content. It is recovered commercially from monazite sand, which contains about 3%, and from bastnasite, which contains about 0.2%. Wohler obtained the impure element in 1828 by reduction of the anhydrous chloride with potassium. The metal is now produced commercially by reduction of the fluoride with calcium metal. It can also be prepared by other techniques. Yttrium has a silver-metallic luster and is relatively stable in air. Turnings of the metal, however, ignite in air if their temperature exceeds 400°C, and finely divided yttrium is very unstable in air. Yttrium oxide is one of the most important compounds of yttrium and accounts for the largest use. It is widely used in making YVO4 europium, and Y2O3 europium phosphors to give the red color in color television tubes. Many hundreds of thousands of pounds are now used in this application. Yttrium oxide also is used to produce yttrium iron garnets, which are very effective microwave filters. Yttrium iron, aluminum, and gadolinium garnets, with formulas such as Y3Fe5O12 and Y3Al5O12, have interesting magnetic properties. Yttrium iron garnet is also exceptionally efficient as both a transmitter and transducer of acoustic energy. Yttrium aluminum garnet, with a hardness of 8.5, is also finding use as a gemstone (simulated diamond). Small amounts of yttrium (0.1 to 0.2%) can be used to reduce the grain size in chromium, molybdenum, zirconium, and titanium, and to increase strength of aluminum and magnesium alloys. Alloys with other useful properties can be obtained by using yttrium as an additive. The metal can be used as a deoxidizer for vanadium and other nonferrous metals. The metal has a low cross section for nuclear capture. Y, one of the isotopes of yttrium, exists in equilibrium with its parent Sr, a product of atomic explosions. Yttrium has been considered for use as a nodulizer for producing nodular cast iron, in which the graphite forms compact nodules instead of the usual flakes. Such iron has increased ductility. Yttrium is also finding application in laser systems and as a catalyst for ethylene polymerization. It also has potential use in ceramic and glass formulas, as the oxide has a high melting point and imparts shock resistance and low expansion characteristics to glass. Natural yttrium contains but one isotope, Y. Forty-three other unstable isotopes and isomers have been characterized. Yttrium metal of 99.9% purity is commercially available at a cost of about $5/g.

Characteristics

Yttrium (₃₉Y) is often confused with another element of the lanthanide series of rareEarths—Ytterbium (₇₀Yb). Also confusing is the fact that the rare-earth elements terbiumand erbium were found in the same minerals in the same quarry in Sweden. Yttrium rankssecond in abundance of all 16 rare-earth, and Ytterbium ranks 10th. Yttrium is a dark silverygray lightweight metal that, in the form of powder or shavings, will ignite spontaneously.Therefore, it is considered a moderately active rare-earth metal.

Uses

Although yttrium metal by itself is not very useful, it has many unusual applicationswhen combined as an alloy or as a compound with other elements. For example, whencombined with iron, it is known as garnet (Y₃Fe₅O₁₂), which is used as a “filter” in microwave communication systems. When garnets are made with aluminum instead of iron,they form semiprecious garnet gemstones (Y₃Al₅O₁₂) that resemble diamonds. Aluminumgarnets are referred to as “YAG” solid-state lasers because they are capable of intensifyingand strengthening a single frequency of light energy that is focused through a crystal ofgarnet. This produces a very powerful narrow band of light waves of a single color (microwave frequency). YAG-type lasers have found uses in the medical industry and as a cuttingtool for metals.When combined with oxygen and europium, yttrium produces the red phosphor used asa coating in color television screens to produce the bright red color. Yttrium is also used asan alloy metal and as a high-temperature coating on iron and steel alloys. It is used as a substance to deoxidize (remove the oxygen) during the production of nonferrous metals such asvanadium. Yttrium has the ability to “capture” neutrons, making it useful in the nuclear powerindustry. It is also used in the production of several types of semiconductors.

Uses

Yttrium, plasma standard solution is used as a standard solution in analytical chemistry and atomic absorption spectroscopy. It is also used as a single-element standard solution for plasma emission spectrometry.

Uses

Yttrium is mixed with rare earths as phosphors for color television receivers; oxide for mantles in gas and acetylene lights; in ceramics; in superconductors.

Definition

yttrium: Symbol Y. A silvery-greymetallic element belonging to group3 (formerly IIIA) of the periodic table;a.n. 39; r.a.m. 88.905; r.d. 4.469(20°C); m.p. 1522°C; b.p. 3338°C. Itoccurs in uranium ores and in lanthanoidores, from which it can beextracted by an ion exchangeprocess. The natural isotope is yttrium–89, and there are 14 known artificialisotopes. The metal is used insuperconducting alloys and in alloysfor strong permanent magnets (inboth cases, with cobalt). The oxide(Y₂O₃) is used in colour-televisionphosphors, neodymium-doped lasers,and microwave components. Chemicallyit resembles the lanthanoids,forming ionic compounds containingY3+ ions. The metal is stable in airbelow 400°C. It was discovered in1828 by Friedrich W?hler.

Definition

A silvery metallic element belonging to the second transition series. It is found in almost every lanthanoid mineral, particularly monazite. Yttrium is used in various alloys, in yttrium–aluminum garnets used in the electronics industry and as gemstones, as a catalyst, and in superconductors. A mixture of yttrium and europium oxides is widely used as the red phosphor on television screens. Symbol: Y; m.p. 1522°C; b.p. 3338°C; r.d. 4.469 (20°C); p.n. 39; r.a.m. 88.90585.

General Description

Soft silvery-white metal in bulk. Dark-gray to black odorless powder. Mp: 1509°C; bp 2927°C. Density: 4.47 g cm-3 at 20°C. May irritate the respiratory tract if inhaled as a powder. May irritate the digestive tract if swallowed. Vapors may cause dizziness or suffocation.

Reactivity Profile

YTTRIUM in bulk is stable in air due to the formation of oxide films. Powder or dust is light-sensitive and air-sensitive and flammable in the air and (Hazardous Chemicals Desk Reference, p. 861(1987)). Reacts with water to form gaseous hydrogen (H2). Reacts with strong oxidizing agents, strong acids, strong bases, and halogens. The products of these reactions are irritating and toxic.

Hazard

As a powder or in fine particles, yttrium is flammable and may spontaneously ignite inmoist air. Some of its compounds, particularly those used in the semiconductor and electricalindustries, are very toxic if inhaled or ingested and should only be used under proper conditions.

Health Hazard

Yttrium compounds cause pulmonary irritation in animals. No effects in humans have been reported.

Flammability and Explosibility

Flammable

Safety Profile

It may have an anticoagulant effect on the blood. Flammable in the form of dust when reacted with air, halogens.

Potential Exposure

Yttrium is used in iron and other alloys, in incandescent gas mantles, and as a deoxidizer for metals. Yttrium metal has a low cross section for neutron capture and is very stable at high temperatures. Further, it is very inert toward liquid uranium and many liquid uranium alloys. Thus, it may well have applications in nuclear power generation. The metal is usually prepared by reduction of the halide with an active metal, such as calcium. To identify and analyze this element, X-ray fluorescence spectroscopy is commonly employed.

Shipping

UN3089 Metal powders, flammable, n.o.s., Hazard Class: 4.1; Labels: 4.1-Flammable solid. UN3178 Flammable solids, inorganic, n.o.s., Hazard Class: 4.1; Labels: 4.1-Flammable solid.

Incompatibilities

Flammable in the form of dust; may form explosive mixture with air. A strong reducing agent; reacts violently with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, halogens. Yttrium nitrate is a combustible material.

Waste Disposal

Recovery is indicated wherever possible. Specifically, processes are available for yttrium oxysulfide recovery from color television tube manufacture.