Abstract: Alumina-containing acid adsorbents and process for producing same. The adsorbents comprise activated alumina and an amorphous alkali (preferably sodium) aluminum silicate. The ratio of Si:Al in the amorphous material is preferably 0.25-100:1 by weight. A process for producing such adsorbents comprises treating activated alumina with a solution of an alkali metal silicate followed by an alkali metal aluminate, and forming agglomerates of the treated alumina at a temperature below about 90.degree. C., aging the agglomerates at a temperature in the range of 20.degree.-90.degree. C., and calcining the aged agglomerates at a temperature in the range of 200.degree.-500.degree. C. The adsorbent can be used to remove acidic materials from gases and liquids during industrial processes.

Abstract: The surfaces of articles of manufacture fabricated from aluminum or other metals which are not permanently hydrophilic are made permanently hydrophilic by coating the surfaces with a continuous film containing particles of activated alumina. The coated articles are not only hydrophilic, but also have good corrosion resistance and exhibit low abrasiveness, resulting in decreased wear on manufacturing tools, such as dies.

Abstract: A process for the recovery of rare earth elements from Bayer Process red mud includes the following steps: (a) digesting red mud containing rare earth elements with a dilute acid solution, e.g. sulphur dioxide dissolved in water, to selectively dissolve the rare earth elements while leaving iron in the red mud substantially undissolved; (b) separating the solution obtained from the solid residue and (c) recovering the rare earth elements from the solution.

Abstract: A process is described for the recovery of rare earth elements from a sulphurous acid solution containing them. The rare earth elements can be successfully separated and recovered by solvent extraction from the sulphurous acid solution, being an organo-phosphorus compound as extraction agent. Di-2-ethylhexyl phosphoric acid or 2-ethylhexyl phosphonic acid mono-ethylhexyl ester is preferred as extraction agent.

Abstract: Fluoride-containing wastes, arising in the aluminium industry, particularly spent cell linings from reduction cells, are digested with caustic soda for conversion of sodium cryolite to NaF.By use of very strong caustic soda NaF may be left in the solid residues after removal of the residual liquor and recovered from such residues by water leaching.As an alternative weaker caustic soda may be used in the digestion stage and subsequently be crystallised out from the residual liquor, after separation from the solid residues, by evaporating and/or cooling the liquor. The precipitated NaF is then conventiently redissolved in water.The NaF solution prepared by either route is then preferably subjected to electrodialysis to recover a solution of HF from it. Such HF is conveniently converted to AlF.sub.3 by reaction with alumina.

Abstract: Disclosed are food smoker for household or restaurant use and method for food smoking with the smoker. The food smoker comprises a container containing a liquid wood or pellet(s) onto which the liquid wood is adsorbed, which is installed in the bottom part of the smoker body, a means for heating the container, and a means for holding a material (such as food) to be smoked in the inside of the smoker body. The food smoker is preferably provided with a means capable of radiating far infrared rays by the heat of the heating means at least around the holding means. The liquid wood can be recovered by distillation or solvent extraction of wood chips. For food smoking, the liquid wood or pellet(s) onto which the liquid wood is adsorbed is(are) heated in a container of the smoker body containing the food to be smoked, whereupon the volatilization rate of the liquid wood is controlled by the choice of the heating temperature and the total amount of the liquid wood.

Abstract: Sodium oxalate in supersaturated solution in Bayer spent liquor stabilized by the presence of humic material is precipitated by the treatment with cationic sequestrants which interact with the humic material to give an insoluble product, thus removing it from solution and destabilizing the solution with respect to precipitation of sodium oxalate. Preferred cationic sequestrants are quaternary nitrogen compounds including medium or long chain alkyl groups. Precipitation of sodium oxalate can be expidited by addition of seed crystals and/or addition of sodium oxalate solution which is supersaturated at a temperature higher than that of the spent liquor.