Abstract: Anti-caking agent is thoroughly distributed upon particulate hygroscopic materials, e.g., particulate inorganic salts such as potassium chloride and sodium chloride, by contacting an agitated stream of the particulate material with an aqueous dispersion of anticaking agent and then passing the treated material through a fluid bed of the treated particulate material. The pretreated particulate hygroscopic material is typically warm, i.e., has a temperature above 25.degree. C., and is cooled in the fluid bed which is fluidized with dehumidified, fluidizing gas having a temperature lower than the treated particulate hygroscopic material entering the bed. Cooled particulate hygroscopic material having a coating of anticaking agent distributed substantially uniformly over the surface of the particles and having a water content substantially the same as the pretreated warm particulate material is removed from the fluid bed.

Abstract: Disclosed is a method of increasing and maintaining high concentrations of potassium chloride in a refinery process stream of brine containing potassium chloride, sodium chloride and a minor amount of salt impurities by mixing with a first process stream potassium chloride crystallized from a pond wherein a brine from a second process stream is concentrated by solar evaporation and/or cooled by low ambient air temperatures.

Abstract: Industrially crystallized potassium chloride having a potassium chloride content of at least 95 weight percent and containing a minor contaminating amount of inorganic metal salt impurities, e.g., sodium chloride, is purified by leaching compacted particles of said potassium chloride with an aqueous leaching solution, the solute of which solution is selected from the group consisting of potassium chloride and mixtures of potassium chloride and sodium chloride. The leaching solution is saturated with respect to potassium chloride and substantially unsaturated with respect to sodium chloride. The compacted particles are maintained in contact with the leaching solution for a time sufficient to reduce substantially the sodium chloride content thereof, and potassium chloride particles of reduced sodium chloride content are recovered from the leaching solution. The leached compacted particles are transparent and comprise single and compound euhedral cubic crystals.

Abstract: Disclosed is a method of connecting two or more subterranean cavities in a deposit having a potassium chloride-rich stratum which contains sodium chloride and which is disposed above a potassium chloride-lean, sodium chloride-rich stratum. The method comprises drilling at least two adjacent wells into the sodium chloride-rich stratum, establishing a chimney filled with insulating fluid at the bottom of at least one of the wells, extracting ore from the potassium chloride-lean stratum with solvent, raising the roof of the cavities by incrementally raising the insulating fluid level and allowing the cavities to grow laterally until the cavities connect.

Abstract: Disclosed is a method of solution mining the mineral content of a subterranean cavity containing a rubble pile positioned on the floor thereof and the subterranean cavity communicating with the surface by at least two boreholes, by drilling a liner through a cased borehole into the rubble pile, disconnecting the drill string from the liner, withdrawing the drill string from the borehole, introducing into the borehole a sealing meant to seal the annular space between the liner and the casing, introducing a solvent into the cavity and withdrawing from the cavity a solution enriched in the mineral contained in the rubble.

Abstract: Disclosed is an improved method of producing potassium chloride by concentrating a brine thereof with respect to potassium chloride by multiple stage evaporation conducted at progressively higher temperatures, thereby precipitating other salts and thereafter cooling the brine in multiple stage crystallizers operated at progressively lower temperatures, thereby precipitating potassium chloride crystals. The improvement comprises cooling the brine in hotter crystallizer utilizing streams to or between cooler evaporators whereby in addition heat is provided to the evaporator stream.

Abstract: The invention disclosed herein relates to solution mining soluble ore deposits by creating a cavity substantially entirely filled with a deep bed of rubble. Solvent introduced at the top of the cavity is permitted to percolate downwardly through the rubble and is withdrawn near the bottom of the cavity. More specifically, the invention relates to selective solution mining generally horizontal beds of sylvinite, i.e., a mixture of crystals of halite (NaCl) and sylvite (KCl) wherein water or salt brine is washed down a generally vertical bore hole into the deposits and recovered enriched with dissolved KCl.

Abstract: Disclosed is a method of increasing the solution mining rate of potassium chloride from a cavity in a subterranean ore deposit containing potassium chloride and sodium chloride, in which cavity ore has been rubblized to effect a large contact surface area, by (1) solution mining the ore rubble at a first temperature for a time sufficient to determine the mining rate at that temperature; (2) increasing the temperature of the cavity solution to a temperature determined to be near the highest temperature at which the invariant composition is achievable at the solvent dissolving rate; and (3) solution mining the ore at the higher temperature.

Abstract: Disclosed is an improved method of solution mining a mineral from a subterranean deposit thereof, where an aqueous solvent is introduced into the deposit and a solution enriched in the mineral is withdrawn from the deposit through a conduit which traverses a water bearing formation which overlies the deposit. The improvement comprises establishing through the wall of the conduit communication between the water bearing formation and the conduit to effect dilution of the enriched withdrawn solution thereby avoiding plugging of the conduit caused by crystallization of the mineral.

Abstract: Disclosed is an improved method of concentrating an aqueous solution containing a first salt and a second salt, the solubility of the first salt increasing more with increasing temperature than the solubility of the second salt, by multiple effect evaporation, wherein the multiple effect evaporators are backward fed, wherein the first evaporator effect is the hottest, wherein second salt is precipitated during evaporation, wherein the concentrated mother liquor is forwarded to a zone operated at atmospheric pressure, and wherein mother liquor effluent from the zone operated at atmospheric pressure is forwarded to a zone wherein the first salt is recovered.

Abstract: Disclosed is an improved method of separating a first salt and a second salt from an aqueous solution containing both salts and salt impurities, where the solubility of the first salt increases more with increasing temperatures than the solubility of the second salt, and at least a portion of the salt impurities precipitates as slower settling rate crystals than the settling rate of precipitated second salt. The solution is passed through a series of evaporators in which second salt and salt impurities are precipitated. The bottom of each evaporator communicates with an elutriation leg into which precipitated salts settle, and into which a fluidizing liquid is introduced to carry precipitated salt impurities back to the evaporators and from which second salt slurry is withdrawn.

Abstract: Disclosed is an improved method of concentrating an aqueous solution containing a first salt and a second salt, the solubility of the first salt increasing more greatly with increasing temperatures than the solubility of the second salt, by multiple effect evaporation, wherein the first evaporator effect is the hottest, mother liquor effluent overflow from cooler evaporator effects is forwarded to hotter evaporator effects, mother liquid effluent overflow from the first evaporator effect is forwarded to a zone maintained at atmospheric pressure and mother liquor effluent from the zone maintained at atmospheric pressure is forwarded to a first salt recovery step. In the improved method, the first evaporator effect is operated at super atmospheric pressure and at least 4.degree. C.

Abstract: Disclosed is an improved method of recovering a salt having a solubility which increases with increasing temperatures from a multiple salt aqueous solution also containing a salt having a solubility which increases less with increasing temperatures than the solubility of the salt to be recovered. The solution is subjected to multiple effect evaporation having a plurality of evaporator effects operating at progressively higher temperatures. In the improved method, a means is provided whereby the mother liquor effluent overflow from the hottest evaporator effect is saturated with the salt to be recovered. Additionally, solution being concentrated in other effects having at least one preceding cooler evaporator effect may be allowed to become saturated with respect to the salt to be recovered. A slurry of the salt having a solubility increasing less with temperature is withdrawn from all effects.

Abstract: Disclosed is a method of disposing solid sodium chloride while selectively solution mining potassium chloride from a subterranean deposit containing potassium chloride and sodium chloride. In this novel method an aqueous solvent saturated with respect to sodium chloride, unsaturated with respect to potassium chloride and slurried with solid sodium chloride, is fed into the deposit having a cavity wherein there is face on which rich and lean potassium chloride ore is exposed. Potassium chloride is thereby dissolved while sodium chloride is deposited from the solvent slurry and the resultant solution withdrawn from the cavity enriched in potassium chloride.

Abstract: Disclosed is a bipolar electrolyzer having individual bipolar units. Each of the bipolar units has a steel cathodic member and a valve metal anodic member in back-to-back configuration. The bipolar electrolyzer is characterized in that the cathodic member is spaced from the anodic member defining an electrolyte tight compartment therebetween, and that the bipolar unit further has conduit means extending outwardly from between the anodic member and the cathodic member. Also disclosed is a method of electrolysis in a bipolar electrolyzer which method is characterized by collecting hydrogen between the anodic and cathodic members of the bipolar unit and removing the hydrogen so collected through hydrogen removal means.

Abstract: Disclosed is a method of preferentially solution mining potassium chloride from a stratified subterranean deposit of potassium chloride and sodium chloride where a plurality of strata are present in a single common solution mining cavity. According to an embodiment of the disclosed method, a first aqueous working solution is established in a lower zone of the cavity in contact with lower strata. Thereafter, a second aqueous working solution is established in contact with a higher zone intended to be preferentially mined. The second aqueous working solution is maintained at a lower specific gravity than the first aqueous working solution. Effluent is withdrawn from the second aqueous working solution near the lower boundary thereof and an extracting solution is added to the cavity at a rate sufficient to maintain the second aqueous working solution less dense than the subjacent solution, i.e., the first aqueous working solution.