Abstract: A method for desulfurizing fluid materials, comprising reacting sulfur to be removed with a rare earth compound, thereby forming rare earth sulfides, oxysulfides or mixtures thereof. The reaction is conducted under conditions of low oxygen potential. Rare earth sulfides and oxysulfides can be reacted with oxygen to restore a capacity for desulfurization.

Abstract: A high shear mixer is used to prepare sulfur particles for soil application. In one embodiment, molten sulfur is added to an aqueous medium being subjected to agitation by a high shear mixer, producing a suspension containing substantial amounts of sulfur with a particle size of less than 200 mesh.

Abstract: Thallium(III) is produced in solution using a photoelectrochemical cell which has an externally electrically interconnected semiconductor photoelectrode and counter electrode. A conductive solution containing thallium(I) is placed in the cell and a flow of current generated by exposing the photoelectrode to actinic radiation, thereby oxidizing the thallium.In another embodiment, a thallium(III) solution is produced by mixing a solution containing thallium(I) with a particulate semiconductor, introducing an oxygen-containing gas into the mixture, and exposing the mixture to actinic radiation.The produced thallium(III) can be reacted with organic compounds, for example with compounds containing at least one carbon-carbon double bond to form epoxides, concurrently reducing thallium. Continuous production can be obtained by recycling the reduced thallium by photoelectrochemical oxidation to thallium(III).

Abstract: A process for separating ore particles from gangue particles comprises the steps of (1) conditioning the particles with an agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively coat either the ore particles or the gangue particles, to the substantial exclusion of the other; (2) detecting the coated particles; and (3) separating the detected, coated particles from the substantially uncoated particles. In one embodiment, the detectable moiety is fluorescent and detecting is performed under ultraviolet radiation.

Abstract: Particulate, easy to handle, inexpensive combination soil amendments and micronutrient sources are disclosed along with methods for their manufacture and use. These compositions comprise highly porous sulfur particles having substantial internal surface area with the micronutrient source dispersed either throughout the sulfur matrix or over the interior surfaces. Major plant nutrients including nitrogen, phosphorus and potassium can also be added but are not essential. These methods allow the use of inexpensive, abundant starting materials, afford slow release sulfur and micronutrient solubility and mobility, reduced micronutrient loss by elution, and minimum ground water pollution and plant toxicity problems associated with heavy metal contamination.

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: 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: 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: 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: 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: 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.