Abstract: A nonhygroscopic thermally stable aluminum hydroxide, which is particularly useful for the preparation of thermally stable and fire retardant laminates for printed circuit boards.

Abstract: The present invention provides a subsurface instrument and a system for the collection and transmission of deep ocean data utilizing standard buoy mooring lines. The system includes a moored surface buoy and a submerged data collection instrument both inductively coupled to the buoy cable. The instrument has a transducer responsive to the characteristics of seawater. A slave modem is interconnected to the transducer through an A/D converter allowing analog transducer signals to be converted to standard telephone modem signals. The modem signals are inductively coupled into the mooring cable and received by a master modem located in the buoy. The buoy may contain a satellite transceiver allowing transmission of the signals to a remote location. The subsurface instrument is battery powered and battery life is extended by powering down when the instrument is not in use.

Abstract: A process for the coating of glass microspheres with an aluminium hydroxide, which involves the hydrothermal treatment of a suspension of complexed Al3+-ions with glass microspheres. The aluminium hydroxide coated glass microspheres can be applied in the production of light weight glass-reinforced plastic materials, e.g., for use in mass transportation.

Abstract: A process for the production of an aluminum hydroxide with rounded grain surfaces. An alkaline solution of a specific composition derived from the Bayer process is inoculated and adsorptively precipitated with an aluminum hydroxide with a specific grain distribution. The aluminum hydroxide obtained according to the new process is especially suitable for the flameproof finishing of polyesters.

Abstract: A process for the production of an aluminum hydroxide with rounded grain surfaces. An alkaline solution of a specific composition derived from the Bayer process is inoculated and adsorptively precipitated with an aluminum hydroxide with a specific grain distribution. The aluminum hydroxide obtained according to the new process is especially suitable for the flameproof finishing of polyesters.

Abstract: The present invention provides a process for the production of crystalline boehmite of fine particle size and enhanced specific surface area. Coarse gibbsite particles, obtained from the Bayer Process, are lightly calcined and the non-boehmite-containing material is removed by dissolution in caustic aluminate liquors of appropriate composition.

Abstract: A method for removing sodium oxalate from a caustic aluminate liquor produced using the Bayer process is disclosed which includes the steps of initially washing all the product aluminum trihydroxide obtained from the precipitation circuit to remove any crystalline sodium oxalate, thereby preventing any further sodium oxalate precipitation within the aluminum trihydroxide precipitators. This causes the dissolved sodium oxalate concentration to rise to a level which is conducive to economic removal of sodium oxalate by side-stream crystallization, without requiring a costly evaporation step. The sodium oxalate may be removed in an amount equal to the new sodium oxalate formed during fresh bauxite digestion, thus maintaining a steady dissolved concentration of sodium oxalate during aluminum trihydroxide precipitation. In addition, the aluminum trihydroxide precipitation circuit may further be stabilized in the crystalline oxalate-free condition by the addition of small amounts of an organic polymer.

Abstract: A process for the production of large boehmite crystal aggregates, useful for soft polishing applications is provided herein. A caustic aluminate liquor is contacted with an oxygen-containing gas at elevated temperatures and pressures in the presence of about 1-50 mg/L of copper ions. The liquor is oxidized until a molar ratio of Na.sub.2 O.sub.free to Al.sub.2 O.sub.3 of less than or equal to 1 is achieved, and the oxidized liquor is cooled under quiescent conditions of little or no agitation which causes the crystallization and precipitation or novel large boehmite particles.

Abstract: The present invention provides a process for the production of fine, tabular boehmite crystals substantially within the size range of 0.2-0.8 microns. The crystals are particularly suitable for use as a pigment/filler in paper, paint and ink applications.

Abstract: The present invention is directed to a method for removing organic substances from aluminate liquors of the Bayer process. The method comprises the steps of contacting the liquor with an oxygen containing gas under elevated pressure in the presence of metallic ions acting as a catalyst to oxidize the organic substances, precipitating the metallic ions jointly with aluminum hydroxide, separating the precipitate from the oxidized liquor and recycling the precipitated aluminum hydroxide containing the metallic ions into the oxidation step as a catalyst carrier.