Abstract: A pond for cooling and/or recovering salt from a hot aqueous solution of a salt such as potassium chloride produced by solution mining. The pond comprises a plurality of channels arranged side-by-side, each of the channels being defined by a plurality of sides. An inlet is provided in a side of a channel for receiving the aqueous solution, and an outlet is provided in a side of another one of the channels for discharging the aqueous solution. The pond has at least one dike separating the channels from one another. A gap is formed in each dike to permit the aqueous solution to flow between the channels, the gap having a length which is about 10 to about 40 percent of the length of the sides of the channels. Salt is crystallized and the solution is cooled as it passes through the channels of the pond.

Abstract: In a process for biodegrading under highly alkaline conditions organics in a waste stream derived from a Bayer processing system for producing aluminum oxides,i) the waste stream being typical of oxalate waste streams resulting from alkaline treatment of bauxite, the oxalate waste streams being rich in oxalates, formates, acetates, benzoates and sodium ions and having a pH in excess of 8,ii) treating the highly alkaline waste stream to neutralize and thereby lower pH and to reduce sodium ion concentration prior to introducing the waste stream into a bioreactor,iii) biodegrading the oxalates in the bioreactor by use of Pseudomonas genus microorganisms, andiv) discharging at least a portion of the biodegraded waste stream, the improvement being characterized by:a) introducing the highly alkaline waste stream rich in sodium ions to the bioreactor to avoid the treatment of step ii),b) biodegrading the organics in the waste stream with the Pseudomonas genus microorganisms characterized by ATCC 53883 deposited micr

Abstract: A method of transferring heat between process liquor streams such as streams of caustic liquor in the Bayer process for producing alumina from bauxite, utilizing a heat pipe arrangement for heat exchange. The process streams respectively pass in contact with one surface of a first heat-exchange wall and one surface of a second heat-exchange wall while being isolated from the second surfaces of the two walls; these second walls are exposed to a closed volume (also isolated from both process streams) containing a heat transfer fluid that vaporizes below the temperature of the hotter process stream and condenses above the temperature of the cooler process stream. The heat transfer fluid vaporizes at the exposed surface of the wall contacted by the hotter stream, and condenses at the exposed surface of the wall contacted by the cooler stream, thereby transferring heat (as heat of vaporization) from the former stream to the latter.

Abstract: A process for producing alumina from bauxite by the Bayer process. Bauxite slurry is pressure digested in caustic soda solution to dissolve aluminum hydroxides in the bauxite as sodium aluminate while leaving most of the remaining constituents of the bauxite in solid form as red mud. The red mud is separated from the digested slurry to obtain a caustic-aluminate pregnant liquor, alumina hydrate is precipitated from the pregnant liquor and the alumina hydrate is calcined to obtain the alumina. The separation of the red mud from the digested slurry is carried out at a temperature above the boiling atmospheric temperature of the liquor phase of the slurry.