Allied Corporation

Eugene B Recla

Richard E Eibeck

David Nalewajek

Martin A Robinson

Francis E Evans

Robert A Wiles

Gd.sub.2 O.sub.3 and Ga.sub.2 O.sub.3 are currently used for the fabrication of Gd.sub.3 Ga.sub.5 O.sub.12 (GGG) wafers which are employed as substrates for bubble domain memory devices. In the processing, in the order of 25% of the starting material ends up as process 'saw kerf' contaminated with variable amounts of iron, nickel, magnesium, aluminum, zirconium, iridium and silicon. A process is described whereby the 'saw kerf' can be reprocessed in sufficient purity to be re-used in the process, thereby improving the economics of production of GGG wafers significantly. Gadolinium and gallium oxides are recovered and separated from transition metal impurities introduced during fabrication of GGG wafers. The process 'saw kerf' produced from slicing the crystal boule is dissolved in HCl, treated with H.sub.2 SO.sub.4, and the resulting sulfates separated. Metathesis with (NH.sub.4).sub.2 C.sub.2 O.sub.4 results in conversion of the sulfates to the ammonium oxalates which were calcined at 850.degree. C. to form Ga.sub.2 O.sub.3 and Gd.sub.2 O.sub.3 of purity &gt;99.99%. The process can be extended to include purification and re-use of by-products generated in other grinding and polishing operations which may result in the recycling of the order of 80% of the generated by-products.

Recovery of gadolinium and gallium oxides

A process for the conversion of boron trifluoride dimethyl ether complex to boron trifluoride dialkyl ether complex substantially free of dimethyl ether impurities, which comprises reacting the boron trifluoride-dimethyl ether complex, in the liquid phase, in the presence of dialkyl ether wherein at least one of the alkyl groups contains at least two carbon atoms, in a restricted vapor equilibration region, while simultaneously sweeping the said vapor equilibration region with a substantially inert gas, and heating to distill off the dimethyl ether. High purity of the boron trifluoride dialkyl ether complex is attained with this method, with only minimal traces of the boron trifluoride dimethyl ether complex, dimethyl ether remaining. The preferred product is boron trifluoride diethyl ether.

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Hamburg, NY, United States of America

Eugene B Recla