Abstract: A method for removing impurities from wet process produced phosphoric acid and recovering phosphate values retained by the impurities is disclosed. The wet process produced phosphoric acid is filtered through a diatomite filter cake in a porous medium at a temperature from about 57.degree. C. to about 77.degree. C. During filtering an impurity-containing upper portion of the filter cake is removed exposing a fresh surface of the filter cake. An aqueous slurry is formed with the removed portion of filter cake. The slurry is filtered to recover a filtrate containing a major portion of the phosphate values retained by the removed portion of the filter cake.

Abstract: A method of separating a mineral component from particulate ore consisting of many components, such as oxides, silicates, carbonates, sulfides etc. is disclosed. The particulate ore is conditioned with a surface-active agent capable of selectively coating one of the components of the ore to the substantial exclusion of coating the other components. A coloring agent having an affinity towards the coating of surface active agent is combined with the surface active agent, providing the coated ore particles with a distinguishable color from the non-coated ore particles. The distinguishable color-coated ore particles are separated from the non-coated ore particles.

Abstract: Anhydrous hydrogen fluoride of high purity can be recovered from metallic fluoride salts containing phosphate values by digesting the metallic salts in an aqueous solution in a humid atmosphere at a sufficiently high temperature to release a gas containing hydrogen fluoride and negligible amount of P.sub.2 O.sub.5. The released gas is rectified in a rectification operation which includes a rectification zone in which the rectification occurs in the presence of sulfuric acid.

Abstract: A monolithic bipolar membrane having elastic properties is immersed in a polar solvent or an electrolyte, such as water. An electric field is used to control the transfer rate of neutral or ionized molecules in solution in the electrolyte through the membrane in response to an applied external electromotive force. By adjusting the external electromotive force the membrane can be controlled to selectively pass one type of molecule while rejecting other molecules in solution. A separation between molecules of two or more materials in solution in the electrolyte can thus be achieved.

Abstract: When sulfate ions and a solution of monocalcium phosphate are reacted under conditions which result in the formation of a slurry comprising calcium sulfate hemihydrate and phosphoric acid of about 35% to about 55% P.sub.2 O.sub.5, filtration is improved when a sulfonic acid, a sulfonic acid salt, tall oil fatty acid or alkoxylated or esterified tall oil fatty acid and mixtures thereof is present in the slurry (preferably at 1-1000 ppm). Preferably a two vessel reaction system is used in which the reaction slurry undergoes intra- and inter- vessel circulation (preferably through a draft tube). The solution portion of the slurry in the first vessel (the "dissolver") is preferably maintained at a negative sulfate concentration (i.e. excess Ca.sup.+2) and the solution in the second vessel (the "crystallizer") is preferably maintained at a positive sulfate ion concentration, most preferably at a reduced pressure, (e.g. to provide evaporative cooling).

Abstract: Particulate glass values contained in the final inorganic fraction from comminuted municipal wastes and having the particle size below 10 mesh, preferably between about 325 to about 20 mesh, are recovered by froth flotation by activating the glass surface with a bi or trivalent metal ion and using as the beneficiation reagent a water compatible sulfonated hydrocarbon.

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 sodium hydroxide to form a first slurry having a pH of from about 11 to about 14, the first slurry containing sodium metasilicate and precipitated sodium fluoride. Sodium fluoride is recovered from the first slurry leaving a first solution which is reacted with sodium fluosilicate or fluosilicic acid or both to form a second slurry comprising silica and dissolved sodium fluoride. The reaction occurs under such conditions that the second slurry contains precipitated amorphous silica. The precipitated amorphous silica is separated from the second slurry leaving a second solution of sodium fluoride. Sodium fluoride is recovered from the second solution. Recovered sodium fluoride is reacted with sulfuric acid to produce hydrogen fluoride.

Abstract: Hydrofluoric acid is recovered from fluosilicic acid by reacting fluosilicic acid with sodium hydroxide to form a first slurry having a pH of from about 11 to about 14, the first slurry containing sodium metasilicate and precipitated sodium fluoride. Sodium fluoride is recovered from the first slurry leaving a first solution which is reacted with sodium fluosilicate or fluosilicic acid or both to form a second slurry comprising silica and dissolved sodium fluoride. The reaction occurs under such conditions that the second slurry contains precipitated amorphous silica. The precipitated amorphous silica is separated from the second slurry leaving a second solution of sodium fluoride. Sodium fluoride is recovered from the second solution. Recovered sodium fluoride is reacted with sulfuric acid to produce hydrogen fluoride.

Abstract: Process and system for recovery of energy from geothermal brines and other water containing or hot water sources, which comprises direct contact heat exchange between the brine or hot water, and a working fluid, e.g. n-butane, in a heat transfer column, the heat transfer column being operated in the subcritical pressure region of the working fluid, preferably close to or approaching the apex of the saturated vapor curve for such working fluid on the Mollier enthalpy-entropy diagram for such 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: Liquid ammonia, a reactant with superphosphoric acid in the process for fertilizer production, is passed through an annular jacket surrounding a tubular reaction zone where reaction occurs to maintain the interior surface of the tubular reactor at a temperature sufficiently low to prevent the formation of scale on interior reactor surfaces.

Abstract: A method for the separation of limestone from a particulate limestone ore containing particles of limestone and gangue which comprises conditioning the limestone ore with at least one coupling agent selected from saturated and unsaturated carboxylic acids containing from about 4 to about 22 carbon atoms, or at least one coupling agent selected from the group consisting of aliphatic amines containing from about 8 to about 22 carbon atoms, and beta amines containing from about 7 to about 21 carbon atoms, to selectively coat the limestone or the gangue in the ore to the substantial exclusion of the other in combination with providing at least one fluorescent dye to said coupling agent; radiating the conditioned ore to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish the coated particles from the non-coated particles and separating the fluorescing, coated particles from the nonfluorescing, non-coated particles.

Abstract: A method is disclosed for the separation of coal from run of mine (ROM) coal containing particles of coal and refuse, which comprises conditioning the ROM coal with a coupling agent capable of selectively coating the particulate coal to the substantial exclusion of coating the refuse, which coupling agent is at least one alcohol containing from about 6 to about 22 carbon atoms. Combined with said coupling agent is a fluorescent dye in a quantity to make the coated particles of coal fluoresce upon excitation to a degree sufficient to distinguish the coated coal particles from the substantially non-coated refuse. Exciting (e.g. as with ultraviolet light) the fluorescent dye coupled to the coal particles induces fluorescence and enables separating the fluorescing, coated coal particles from substantially non-fluorescing, non-coated refuse particles.

Abstract: A method for the separation of magnesite from a particulate ore containing particles relatively rich in magnesite and particles relatively rich in dolomite and/or calcite, which comprises conditioning the ore with at least one coupling agent selected from saturated and unsaturated carboxylic acids containing from about 4 to about 22 carbon atoms, to selectively coat the calcite and/or dolomite in the ore to the substantial exclusion of the magnesite, in combination with providing at least one fluorescent dye to said coupling agent; radiating the conditioned ore to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish the coated particles from the non-coated particles and separating the fluorescing, coated particles from the non-fluorescing, non-coated particles.

Abstract: Phosphate rock and sulfuric acid are reacted under conditions which result in the formation of calcium sulfate hemihydrate and phosphoric acid of about 35% to about 55% P.sub.2 O.sub.5. A two vessel reaction system is used in which the reaction slurry undergoes intra- and inter- vessel circulation (preferably through a draft tube). The solution portion of the slurry in the first vessel (the "dissolver") is preferably maintained at a negative sulfate concentration (i.e. excess Ca.sup.+2) and the solution in the second vessel (the "crystallizer") is preferably maintained at a positive sulfate ion concentration. Also preferred is that the second vessel be maintained at a reduced pressure, (e.g. to provide evaporation cooling). Better filtration rates can thus be obtained due to the favorable shape, dominant size and size distribution of the hemihydrate crystals. Most preferred is that a crystal modifier (e.g.

Abstract: An apparatus for reacting phosphoric acid and ammonia to form a molten reaction mixture, to which water can be added to produce an ammonium polyphosphate product, comprises:(A) fluid reactor means having a plurality of inlet means suitable for administration of reactants and positioned to provide for rapid ammoniation of the phosphoric acid with evolution of heat and aperatures to the other end providing exit means for the reaction mixture, said reactor means being adapted to the expulsion of the reaction mixture by steam generated in situ;(B) means for separating the steam from the liquid product solution and removal of said steam from the apparatus; and(C) columnar vessel means having outlet means at one end and enclosing at the other end the exit means of said fluid reactor means and a plurality of barrier means partially blocking said columnar vessel means in spaced-apart relationship and having aperatures therein for passage of reaction product therethrough and inlet means suitable for introduction of a

Abstract: Anodes for current generating cells having good corrosion resistance, voltage stability and long life, especially in primary current generating cells, are described. The anodes comprise an anode composition having from about 20 to about 90 weight percent of the first constituent selected from the group consisting of iron and silicon and at least about 10 weight percent of a second constituent different from the first constituent and selected from the group consisting of molybdenum, tungsten, vanadium, niobium, titanium, phosphorus, and silicon. Anode compositions containing iron and a second constituent other than silicon may also contain up to about 10 weight percent silicon.

Abstract: Calcium fluoride is produced from pond waters resulting from phosphoric acid processing by treating the pond waters with calcium carbonate and/or calcium oxide in two stages to precipitate out the major part of the fluorine values from the waters as calcium fluoride. After removal of the calcium fluoride the filtrate is treated with calcium oxide to remove a substantial portion of the remaining fluorine values as calcium fluoride. After removal of these calcium fluoride solids, the filtrate is treated with another charge of calcium oxide to produce dicalcium phosphate (dical) which is separated from the aqueous phase. The aqueous phase is treated with an additional charge of calcium oxide to remove a substantial portion of the solids from the aqueous phase leaving waters that can be discharged as waste or recycled as process water.

Abstract: Recovery of energy from geothermal brines and other hot water sources by direct contact heat exchange with a working fluid, such as a hydrocarbon working fluid, e.g. isobutane. The process and system consists of a plurality of stages, each stage including mixing and settling units. In the first stage, hot brine and arm working fluid are intimately mixed and passed into a settler wherein the brine settles to the bottom of the settler and the hot working fluid rises to the top. The hot working fluid is passed to a heat engine or turbine to produce work and the working fluid is then recycled back into the system. The system is comprised of a series of stages each containing a settler and mixer, and wherein the working fluid and the brine flow in a countercurrent manner through the stages to recover the heat from the brine in increments and raise the temperature of the working fluid in increments.

Abstract: An entrainment separator for separating liquids from gases and solids from gases, including a housing providing an inlet at one end and an outlet at the opposed end, an adjustable planar surface providing a face facing the inlet 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, and a gas outlet extending through the side of the housing.

Abstract: Phosphate rock and sulfuric acid are reacted to produce phosphoric acid and calcium sulfate by means of the hemihydrate wet process. In this improved process, the calcium sulfate hemihydrate is crystallized from solution in the presence of an organic sulfonic acid or a derivative thereof. The organic sulfonic acid or its derivative improves the growth of the calcium sulfate hemihydrate crystals and thus improves the filtration rate of the slurry produced in this improved process.