Lanthanum optical glasses

New developments have been made in the photographic and optical field with the design of more sophisticated lenses. The lanthanum optical glasses with a high index of refraction and low dispersion have been an outgrowth of the post war period. 

Rare-earth compounds containing lanthanum are extensively used in carbon lighting applications, especially by the motion picture industry for studio lighting and projection. This application consumes about 25 percent of the rare-earth compounds produced. La203 improves the alkali resistance of glass, and is used in making special optical glasses. Small amounts of lanthanum, as an additive, can be used to produce nodular cast iron. 

This soft, silver white metal reacts with air and water. The oxide is applied in optical glasses with high refractive indices (special lenses for powerful cameras and telescopes). Used for special effects in optoelectronics and electronics. Lanthanum exhibits catalytic properties. It is a component of flint and battery electrodes. Lanthanum boride (LaB6) is the superior electron-emitter for electron microscopes. Lanthanum is the first of the series of 14 lanthanides, also called the "rare-earth" metals, whose inner N shells are filled with electrons. They do not belong on the "red list" of endangered species they are neither rare nor threatened with depletion. China is particularly rich in lanthanide ores. 

Highly pure lanthanum oxide is used to make optical glass of high refractive index for camera lenses. It also is used to make glass fibers. The oxide also is used to improve thermal and electrical properties of barium and strontium titanates. Other applications are in glass polishes carbon arc electrodes fluorescent type phosphors and as a diluent for nuclear fuels. In such apph-cations, lanthinum oxide is usually combined with other rare earth oxides. 

In the application of lanthanum oxide in glass use is made of the high index of refraction and the lack of color of this oxide. So today optical glasses with up to 40 % lanthanum oxide are made vhich are corrosion resistant. 

Lanthanum has also found modest uses. Its oxide is an additive in high-quality optical glasses to which it imparts a high refractive index (sparkle) and has been suggested for a variety of catalytic uses. Mischmetal , an unseparated mixture of lanthanide metals containing about 25% La, is used in making lighter flints, and more importantly in the production of alloy steels, (p. 1232). 

Dilanthanum oxide Dllanthanum trIoxide EINECS 215-200-5 Lanthana Lanthania (La203> Lanthanum oxide Lanthanum sesquioxide Lanthanum trioxide Lanthanum(3- ) oxide. Used in oaloium lights, optical glass, technical ceramics, cores for carbon-anc electrodes, fluorescent phosphors, refractories. Solid mp = 2315° bp = 4200° d = 6.5100. Atomergic Chemetals Cerac Rhdne-Poulenc Seimi Chem. 

Lanthanum(III) oxide (Li iOs) is used for making special optical glasses. It improves the optical properties and alkali resistance of the glass (Vinogradova et al. 2004 Royal Society of Chemistry 2015). 

Lanthanum, yttrium, and gadolinium are used in optical glasses with high refractive index and low dispersion. The annual demand for La203 for this purpose in Japan was 502 tons in 2006 none of this glass is recycled (JOGMEC, 2008). 

Jiang et al. (2004) developed a hydrometallurgical process to recover the rare earths from the spent optical glass containing lanthanum, yttrium, and... 

La20a, in proportions of up to 40%, is used in main optical glass (lanthanum heavy crown and heavy flint). The presence of this oxide endows the glass with a high transparency and improves its structural properties [5]. 

Lanthanum Oxide. La203, m.p. approx. 2200 C sp. gr. 6.51 thermal expansion (25-1000°C) 12 X 1(H. A rare earth sometimes used in special optical glasses. Lanthanum Titanates. Two compounds have been reported LaTi203 and La2Ti209 the former has a perovskite (q.v.) structure and can be synthesized by heating a mixture of La203 and Ti203 at 1200°C in a vacuum. 

Lanthanum oxide is a component in optical glass and imparts an extra high refractive index to it It is also added to electrodes for carbon arcs for lighting in film and photographic studios. Lanthanum gives the arc hght an emission spectrum very similar to that of sunlight... 

Rare earth borate glasses of high refractive index (e.g., lanthanum borates) have unusually low dispersions, making them very useful optical glasses. These glasses are much more chemically durable. There are also useful chemically stable aluminum borate optical glasses. 

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