Aluminum Company of America

Ajay Sood

Hubert L Fleming

John W Novak, Jr

Robert A Marra

An improved process is disclosed for the purification of an impure aqueous solution containing heavy metal ions which comprises passing the impure solution through a bed of activated alumina adsorbent. The heavy metal ions are removed from the impure aqueous solution by adsorption onto the activated alumina adsorbent. The adsorbent may be regenerated for reuse and the adsorbed metals recovered by subsequently stripping the metal ions from the adsorbent and recycling the metal ions back to the process of origin. The pH of the effluent may be monitored to determine when the capacity of the adsorbent has been reached and regeneration of the adsorbent should be commenced. In a preferred embodiment, a portion of the activated alumina is pretreated with acid before passing the impure solution through the adsorbent to enhance the chromium ion adsorption of the acid-treated activated alumina and a portion of the regenerated activated alumina is again treated with acid after each regeneration cycle.

Process for removal, separation and recovery of heavy metal ions from

An improved process is disclosed for the purification of an impure aqueous solution containing heavy metal ions which comprises passing the impure solution through a bed of activated adsorbent containing at least 20 wt. % activated hydrotalcite formed by reacting activated magnesia with an aqueous solution containing ions of aluminate, carbonate, and hydroxyl. The heavy metal ions are removed from the impure aqueous solution by adsorption onto the activated hydrotalcite-containing adsorbent. The adsorbent may be regenerated for reuse and the adsorbed metals recovered by subsequently stripping the metal ions from the adsorbent and recycling the metal ions back to the process of origin. The pH of the effluent may be monitored to determine when the capacity of the adsorbent has been reached and regeneration of the adsorbent should be commenced.

Process for removing heavy metal ions from solutions using adsorbents

The invention comprises high purity substantially spherical metal oxide particles having one or more predominant particle sizes formed from one or more metal alkoxides. In one embodiment there is disclosed multimodal particle size distributions of such substantially spherical metal hydroxide particles while a second embodiment describes the formation of such particles using more than one metal alkoxide to form either a mixed metal hydroxide particle or a layered particle comprising a core of a first metal hydroxide and at least one layer of an additional metal hydroxide.

Production of tailor-made particle size distributions of substantially

The invention comprises a process for the production of high purity substantially spherical metal oxide particles using seed nuclei without introducing impurities into the desired product which comprises forming a metal alkoxide vapor; reacting the vapor with a non-reactive gas containing sufficient water vapor to hydrolyze a portion of the metal alkoxide vapor to form solid seed nuclei of metal hydroxide; cooling the remaining metal alkoxide vapor containing the metal hydroxide seed nuclei sufficiently to form an aerosol comprising finely divided metal alkoxide liquid condensed on the solid metal hydroxide seed nuclei; hydrolyzing the metal alkoxide aerosol by contact with water vapor to hydrolyze the metal alkoxide liquid to form substantially spherical metal hydroxide particles; and calcining the substantially spherical metal hydroxide particles to form the corresponding metal oxide.

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Ross Township, PA, United States of America

Ajay Sood