Abstract: Process and system for recovery of energy from geothermal brines and other hot water sources, which comprises direct contact heat exchange between the brine or hot water, and a hydrocarbon working fluid, e.g. n-butane, in a heat transfer column, the heat transfer column being operated at or above the critical pressure of the working fluid, and the hot brine or hot water feed being at a temperature at or above the critical temperature of the working fluid. The heated working fluid exiting the top of the heat transfer column is expanded through an expander to produce work. The discharge from the expander is cooled to condense working fluid which is separated in an accumulator, from condensed water vapor present in the working fluid, and the condensed working fluid is pressurized and fed back to the heat transfer column. Water from the accumulator can be fed to an H.sub.2 S removal system where good quality water can be recovered.

Abstract: Phosphoric acid and ammonia are reacted together with additions of water when necessary in a reaction vessel to form a molten entrained stream reaction mixture to which a water quench is added to produce an ammonium polyphosphate liquid fertilizer.

Abstract: A method is disclosed for the separation of oil shale from run of mine (ROM) oil shale containing particles of oil shale and refuse, which comprises conditioning the ROM oil shale with a coupling agent capable of selectively coating the kerogen hydrocarbons in the particulate oil shale to the substantial exclusion of coating the non-hydrocarbonaceous refuse, which coupling agent is one or more compounds selected from the group consisting of an alcohol, at least one carboxylic acid, preferably containing from about 5 to about 28 carbon atoms and a ketone. Combined with said coupling agent is a fluorescent dye in a quantity to make the coated particles of oil shale fluoresce upon excitation to a degree sufficient to distinguish the coated oil shale particles from the substantially non-coated refuse. Exciting (e.g.

Abstract: A process for separating limestone ore particles from gangue particles comprises the steps of (1) conditioning the mixed particles with an agent comprising a compound having both a surface-selective functional group and a fluorescent moiety, to selectively coat either the ore particles or the gangue particles, to the substantial exclusion of the other; (2) irradiating the mixture to cause fluorescence in the coated particles; and (3) separating the fluorescing, coated particles from the substantially uncoated particles. The process may be used to separate by coating either the ore particles or the gangue particles.

Abstract: A process, for removing solid impurities from impure phosphoric acid containing solids, comprising:(a) passing said acid at an elevated temperature through a filter cake of a phosphoric acid-resistant filter aid supported on a porous medium, thereby to cause at least a portion of said solid impurities of said acid to be filtered therefrom and to be retained by said filter cake;(b) contacting at least a portion of said filter cake with a displacing liquid, maintained at a temperature and in an amount sufficient to cause at least a portion of the acid which remains in said filter cake to pass through said filter cake without fracturing said filter cake;(c) collecting said filtered acid which passes through said filter cake; and(d) removing an impurity-containing portion of said filter cake after contact with said acid and displacing liquid, thereby to present a fresh surface for subsequent filtration.

Abstract: Hydrofluoric acid and/or other fluorine compounds are recovered by reacting fluosilicic acid with a sodium-containing compound to form an alkaline aqueous slurry comprising precipitated amorphous silica and dissolved sodium fluoride. The precipitated amorphous silica is separated from the alkaline aqueous slurry leaving an aqueous solution of sodium fluoride. The sodium fluoride solution can be used as such or reacted with other substances (such as alumina, to form synthetic cryolite). Sodium fluoride is recovered from the aqueous solution (as by evaporation or extraction) and used per se or reacted with sulfuric acid to produce hydrogen fluoride.

Abstract: Hydrofluoric acid is recovered from fluosilicic acid by reacting fluosilicic acid with sodium sulfate to form sodium fluosilicate. The sodium fluosilicate is reacted with a sodium-containing compound to form an alkaline aqueous slurry comprising silica and dissolved sodium fluoride. The reaction occurs under such conditions that the slurry contains precipitated amorphous silica. The precipitated amorphous silica is separated from the alkaline aqueous slurry leaving an aqueous solution of sodium fluoride. Sodium fluoride is recovered from the aqueous solution and reacted with sulfuric acid to produce hydrogen fluoride.

Abstract: High quality phosphoric acid is produced from phosphate rock and high alumina pebble which is a byproduct of phosphate rock mining operations. The rock or pebble with or without comminution is digested in phosphoric and sulfuric acid and the resultant phosphoric acid contains the metallic ions normally present in the treated rock and pebble. The metallic ions are then extracted from the acid by ion exchange with a water-immiscible organic sulphonic acid compound (preferably in the presence of an organophosphate or phosphonate). After phase separation the organic phase containing the extracted metallic ions can be regenerated. The process is especially useful when the digestion is done at a P.sub.2 O.sub.5 concentration and temperature which produces calcium sulfate hemihydrate.

Abstract: Process and system for recovery of energy from geothermal brines and other hot water sources by direct contact heat exchange between the brine or hot water, and a working fluid exiting the top of the heat transfer column is expanded through an expander to produce work. The discharge from the expander is cooled to condense working fluid which is separated in an accumulator from condensed water vapor present in the working fluid, and the condensed working fluid is pressurized and fed back to the heat transfer column. Uncondensible gas together with working fluid losses are vented from the accumulator. In order to decrease the amount of uncondensible vent gas from the accumulator, and the loss of working fluid therein, the hot water or brine feed to the heat transfer column is initially degassed as by flashing, the extent of degassing being controlled based on the concentration of uncondensibles in such hot water or brine feed.

Abstract: Phosphoric acid is prepared from phosphate rock and sulfuric acid by using a reaction train comprising a dissolving slurry and a crystallization slurry maintained at different sulfate levels. Both inter and intra vessel circulation are used at high rates to minimize reagent concentration gradients and temperature gradients and provide a suitable crystallization environment. Preferably, the intra vessel circulation is substantially in plug flow, as through a draft tube.

Abstract: Process and system for recovery of energy from geothermal brines and other hot water sources, by direct contact heat exchange between the brine or hot water, and an immiscible working fluid, e.g. a hydrocarbon such as isobutane, in a heat exchange column, the brine or hot water therein flowing countercurrent to the flow of the working fluid. The column can be operated at subcritical, critical or above the critical pressure of the working fluid. Preferably, the column is provided with a plurality of sieve plates, and the heat exchange process and column, e.g.

Abstract: In a multi-stage, multi-vessel phosphoric acid production system where a first reaction vessel contains a first slurry comprising calcium sulfate hemihydrate, monocalcium phosphate and phosphoric acid and a second reaction vessel contains a second slurry comprising calcium sulfate hemihydrate, sulfuric acid and phosphoric acid, in which the reaction slurry undergoes intra- and inter-vessel circulation, preferably through a draft tube, an improved start-up procedure involves filling the system with heated phosphoric acid having a P.sub.2 O.sub.5 analysis in the range of about 28 to about 38% (e.g. 31%), then feeding phosphate rock to the system, preferably in a separate reaction vessel, while phosphoric acid is recycled from a fourth, filter feed vessel, until the solids content in said slurry is in the range of 25-35% (e.g. about 30%) while the sulfate content in the first vessel is maintained at a negative level (e.g. excess calcium ion) and at a positive level in the second, crystallizer vessel.

Abstract: In a process for purifying an aqueous phosphoric acid containing up to about 55% P.sub.2 O.sub.5 by weight and dissolved magnesium, iron and aluminum ions, wherein (a) said phosphoric acid is contacted with an organic extractant containing a water immiscible organic sulfonic acid to form: a loaded organic extractant phase containing the organic sulfonic acid, extracted ionic metallic impurities and extracted P.sub.2 O.sub.5 values, and a purified aqueous phosphoric acid; (b) the purified aqueous phosphoric acid phase is separated from the loaded organic extractant phase; (c) the separated loaded organic extractant phase is contacted with a solution phase containing calcium ions (e.g., calcium nitrate), under conditions whereby at least some of said extracted ionic metallic impurities (e.g., Mg.sup.+2, Al.sup.+3, Fe.sup.

Abstract: A process for transfer by extraction, of at least one species from a fluid phase to a first liquid phase receptive to such species, comprises intimately contacting the fluid phase with an emulsion of the first liquid phase in a second liquid phase which is permeable with respect to such species and substantially immiscible in the first liquid phase. The emulsion is stabilized by the second liquid phase containing at least one substantially insoluble particulate solid which is substantially non-reactive to constituents contained in each of such phases in an amount sufficient to form a stable emulsion. Transfer of the species is from the fluid phase through the second solids--containing liquid phase to the first liquid phase.In one embodiment, the first liquid phase is lean with respect to the species to be extracted. In another embodiment, mass action is utilized to maintain a driving force by counter-transport of a different ion.

Abstract: A fluosilicate material is added to a suspension of lime in water heated to a temperature at or near its boiling point to form a solid calcium fluoride product in which the silicon present in the fluosilicate material is in chemical combination with calcium. The amount of calcium in the suspension is in excess of stoichiometric for conversion of CaF.sub.2 of all of the fluorine in the fluosilicate and is sufficient to form chemical compounds of calcium and silicon from silicon in the fluosilicate.

Abstract: The invention comprises a multi-vessel reaction apparatus useful for reacting phosphate rock and sulfuric acid in which the reaction slurry undergoes intra- and inter- vessel circulation (preferably through a draft tube). The solution portion of the slurry in a first vessel or set of vessels (the "dissolver") is preferably maintained at at lower sulfate ion concentration and the solution portion of the slurry in the second vessel or system of vessels (the "crystallizer") is preferably maintained at a positive sulfate ion concentration. Also preferred are means for maintaining the second vessel or set of vessels at a reduced pressure. Most preferred is that means be included in at least one said vessel for incorporating a crystal modifier (e.g. a sulfonic acid, a sulfonic acid salt, tall oil fatty acids or alkoxylated or esterified tall oil fatty acids) in the crystallizer. The system can be used in the anhydrite, hemihydrate or gypsum types of processes.

Abstract: A system for the preparation of phosphoric acid from phosphate rock and sulfuric acid, includes in combination a first reaction vessel containing a first slurry comprising calcium sulfate hemihydrate, monocalcium phosphate and phosphoric acid, a second reaction vessel containing a second slurry comprising calcium sulfate hemihydrate, circulation means including a draft tube disposed centrally in each of said vessels and an agitator positioned axially in each of said vessels within said draft tube, a first conduit interconnecting said first and second reaction vessels for conducting said first slurry from said first reaction vessel to said second reaction vessel, a second conduit interconnecting said vessels for conducting said second slurry from said second reaction vessel to said first reaction vessel, an inlet pipe for introducing phosphate rock and phosphoric acid to said first reaction vessel, and wherein a vent is connected to said inlet pipe to permit escape of gases and, thus, increasing the rate of fl

Abstract: A system for the preparation of phosphoric acid from phosphate rock and sulfuric acid, includes in combination a first reaction vessel containing a first slurry comprising calcium sulfate hemihydrate, monocalcium phosphate and phosphoric acid, a second reaction vessel containing a second slurry comprising calcium sulfate hemihydrate, circulation means including a draft tube disposed centrally in each of said vessels and an agitator positioned axially in each of said vessels within said draft tube, a first conduit interconnecting said first and second reaction vessels for conducting said first slurry from said first reaction vessel to said second reaction vessel, a second conduit interconnecting said vessels for conducting said second slurry from said second reaction vessel to said first reaction vessel, an inlet pipe for introducing phosphate rock and phosphoric acid to said first reaction vessel, said inlet pipe connected with the interior of said draft tube in said first vessel and wherein a vent is connect

Abstract: In a process for purifying an aqueous phosphoric acid containing up to about 55% P.sub.2 O.sub.5 by weight and dissolved magnesium, iron and aluminum ions, wherein (a) said phosphoric acid is contacted with an organic extractant containing a water immiscible organic sulfonic acid to form: an organic extractant phase containing the organic sulfonic acid, extracted ionic metallic impurities and extracted P.sub.2 O.sub.5 values, and a purified aqueous phosphoric acid; and (b) the purified aqueous phosphoric acid phase is separated from the organic extractant phase; the improvement comprising (i) contacting said separated organic extractant phase with a solution phase containing calcium ions (e.g., calcium nitrate), under conditions whereby at least some of said extracted ionic metallic impurities (e.g., Mg.sup.+2, Al.sup.+3, Fe.sup.+3) are replaced by calcium and are transferred to said solutions phase; and (ii) separating said solution phase from the contacted extractant phase.

Abstract: A contactor for liquids with gases, solids or liquids which can also serve as an entrainment separator for separating liquids from gases and solids from gases, includes a housing providing an inlet at one end and an outlet at the opposed end, means to introduce a mist or spray of liquid and positioned between said inlet and an adjustable surface (preferably planar) providing a face facing the inlet and the means for introducing said liquid, and an opposed face, an annular deflector beneath the planar surface attached to the housing and extending inward of the housing and positioned relative to the planar surface to provide an opening between the planar surface and annular deflector, means to adjust the position of the planar surface relative to the annular deflector, a tube attached to the opposed face of the planar surface and extending downward of the inlet, a funnel providing a downward extending spout positioned below the tube, means providing flow of liquid in the funnel past the tube and to the spout, a