Abstract: A process is described for restoring and maintaining the total ion exchange capacity of the resin used for uranium recovery in in situ uranium leaching. The used resin of lowered exchange capacity is treated with a solution containing Na.sub.2 CO.sub.3 or NaHCO.sub.3, or admixtures thereof. The process preferably is used in conjunction with acid elution of the uranium from the resin.

Abstract: A process is described for improving yield and leaching rates of mineral values in uranium-bearing formations associated with high brine aquifers by using high pressure CO.sub.2 /oxidant in the leaching solution. The high pressure CO.sub.2 overcomes the inhibiting effect of NaCl on the rate of leaching. Uranium is recovered at the well head by ion exchange at a pH of about 4.5 to about 5.0 either under pressure to keep the CO.sub.2 in solution or with provision for CO.sub.2 recovery and recycle.

Abstract: A two-stage in situ uranium leaching process is described wherein H.sub.2 SO.sub.4 /oxidant is used as the principal leaching solution. Prior to leaching, the formation is treated with a dilute solution of hydrochloric acid, carbonic acid, or other acid (without oxidant) capable of removing the most accessible portions of CaCO.sub.3. The pretreatment improves the permeability of the formation and precludes plugging with CaSO.sub.4. The invention is particularly advantageous when applied to ores which cannot readily be leached with alkaline solutions.

Abstract: Method and apparatus for mixing a gaseous oxidant (e.g., oxygen) and a lixiviant (e.g., an aqueous carbonate solution) at a downhole location in a well before the oxygen-saturated lixiviant is injected into a formation to be leached. The invention involves establishing a mixing zone in the well by positioning an orifice plate in the well at the downhole location. Lixiviant as it is flowed down the well passes through a restrictive opening in the plate causing a substantial increase in the flow velocity of the lixiviant. At the same time, gaseous oxidant is supplied to a point adjacent the opening in the plate and due to the increased velocity of the lixiviant flowing through the orifice, the oxidant is trapped to form a gas pocket below the orifice. Lixiviant flows through the gas pocket and becomes saturated with the gaseous oxidant.

Abstract: A process is described for maintaining a relatively high and constant concentration in the leachate of an in situ leaching operation as the mineral value in the formation is depleted, and without reducing the daily production, by adjusting the pumping rate of lixiviant proportionally to the depletion of the mineral value. A method for achieving this result by increasing the residence time of the leach solution in the formation is also disclosed.

Abstract: A process is described for improving yields and leaching rates of mineral values in highly reducing uranium-bearing formations, while minimizing deleterious environmental impact, by injecting an oxidant such as gaseous air or O.sub.2 into the formation prior to leaching. The preoxidation may be enhanced by the presence of CO.sub.2 gas in the pre-leaching oxidant. The process is particularly suitable for systems employing a CO.sub.2 /O.sub.2 lixiviant. The presence of sulfate ion further improves the leaching rate of such a system.

Abstract: Process for the in-situ leaching of uranium from a subterranean ore deposit comprising introducing into the deposit an aqueous lixiviant formulated from a dilute sulfuric acid solution which also contains carbon dioxide. The lixiviant has a pH within the range of 1.0-2.5. The lixiviant may also contain an alkali metal sulfate such as sodium sulfate. The process is particularly applicable to subterranean deposits containing uranium associated with carbonaceous material.

Abstract: Process for the in-situ leaching of uranium from a subterranean ore deposit employing a lixiviant containing an oxidizing agent, sulfuric acid, and carbon dioxide. Prior to the injection of the lixiviant, an aqueous solution of sulfuric acid and oxidizing agent is injected into the deposit in an amount of at least 1 pore volume. The initially injected acid solution is substantially free of carbon dioxide. The process is particularly applicable to subterranean deposits containing uranium associated with carbonaceous material.

Abstract: Ion exchange process for the recovery of uranium from a pregnant carbonate lixiviant employed in uranium leaching operations in which the lixiviant is passed over a precipitation inducing anionic ion exchange resin under conditions to load the resin predominantly with non-exchangeable uranium. Non-exchangeable uranium is then recovered from the resin by eluting the resin with an aqueous acid solution having a pH no greater than 2. The process is useful in those applications in which the lixiviant contains chloride ions which inhibit the adsorption of uranyl ions.

Abstract: An improved method of restoring a subterranean clay-containing formation having ammonium ions absorbed on the clay, wherein the formation is flushed with a halogenated restoration fluid having a halogen therein which reacts with the ammonium ion in the formation to decompose the ammonium ions is disclosed. The barren ammonia-containing restoration fluid, after it passes through the formation, is withdrawn, reconstituted and recycled as fresh restoration fluid back into the formation. The barren fluid is treated with an appropriate base to raise the pH to a highly alkaline level, the treated highly alkaline barren fluid is passed through an airstripping tower to strip substantially all the ammonia from the fluid, chlorine gas is added to the fluid from which the ammonia has been stripped, while controlling the amount of chlorine to produce a reconstituted restoration fluid of a predetermined pH level. Finally, the reconstituted restoration fluid is recycled back into the formation.

Abstract: A method for recovering uranium and/or related values which include means for protecting ion-exchange resins in the recovery operation from oxidative degradation due to contact with hydrogen peroxide. A guard chamber is positioned in the elution circuit so that barren eluant, after it is stripped of its uranium and/or related values by treatment with hydrogen peroxide, will flow through the chamber. The guard chamber contains catalytic material, e.g. activated carbon, which decomposes hydrogen peroxide upon contact into water and oxygen. The barren eluant, after it passes through the catalytic material, is used to make up fresh eluant for reuse in the recovery method without the risk of the fresh eluant causing oxidative degradation of the resins.

Abstract: A method for protecting an ion-exchange resin in a uranium and/or related values recovery operation from poisoning by polythionates contained in the leach solution. A guard chamber containing a catalytic material is positioned in the leaching circuit upstream of the resin so the leach solution will pass through the catalytic material before it contacts the resin. The catalytic material, e.g. activated carbon, converts the polythionates to non-poisoning thiosulfates, sulfites, and water which offer no poisoning threat to the resins. An oxidant, e.g. oxygen, is added to the leach solution before it passes through the catalytic material to speed up the catalytic reaction.

Abstract: Process for the recovery of uranium from a pregnant lixiviant employed in uranium leaching operations in which the uranium is concentrated by ion exchange resin. The ion exchange resin is eluted with an eluant containing 0.05-0.5 molar ammonium carbonate. The eluant also contains a base such as ammonium hydroxide in an amount sufficient to increase the pH to a value within the range of 9.0-11.0, thus increasing the carbonate/bicarbonate ratio. This enables the use of a relatively small quantity of ammonium carbonate to provide the desired carbonate ion concentration during the elution step.

Abstract: Process for the stabilization of formation clays by the use of aluminum in the in-situ leaching of uranium or the restoration of contaminated formations. The aluminum is added to a lixiviant having a pH in the range of 6-10 or to a restoration fluid having a pH of at least 6 in an amount effective for the stabilization of clays.

Abstract: An ion exchange process for the recovery of uranium from a pregnant lixiviant employed in uranium leaching operations in which the lixiviant contains chloride ions inhibiting the adsorption of uranyl ions. The ion exchange resin employed to adsorb uranium from the lixiviant has cationic adsorption sites provided by quaternary ammonium groups having a hydroxyalkyl group as a quaternizing substituent. Through the use of a resin of this type, the resin loading in the presence of chloride ions is materially increased.

Abstract: An improved solvent refining process for hydrocarbon oils such as asphalt-free lube fractions and diesel fuels is provided by recycling an inert gas such as nitrogen through the contact zone of the extraction tower.

Abstract: A method for restoring a formation which has undergone an in situ leaching operation wherein minerals oxidized during the leach operation pose a contamination threat to the formation water. In the present invention, the formation is flushed with a restoration fluid which contains a reducing agent capable of reducing the oxidized minerals to their reduced, insoluble state so that they are redeposited into the formation. Examples of suitable reducing agents are hydrogen gas, hydrogen sulfide, sulfur dioxide, carbon monoxide, and ferrous iron solutions.

Abstract: This invention provides a method for solubilizing scrap rubber, or coal and scrap rubber mixtures, in a highly aromatic refinery petroleum solvent to produce homogeneous compositions which have a physical state ranging from flowable pitch-like consistency to asphaltic hardness at ambient temperatures. The products of the present invention are high quality rubberized pitch and asphalt compositions which have utility in applications as caulk, mastic, adhesive, sealant and road paving compositions.

Abstract: This invention provides a novel asphalt composition suitable for use as a binder for carbon electrodes which consists essentially of a homogeneous blend of three organic materials comprising (1) a highly aromatic hydrocarbon solvent having a specific combination of physical properties and chemical constituency, (2) a benzene-soluble fraction of solvent-refined coal and/or solvent-refined wood, and (3) a benzene-insoluble fraction of solvent-refined coal and/or solvent-refined wood. The novel asphaltic compositions is characterized by low sulfur content and high binding strength, which are desirable properties for application as a carbon electrode binder.

Abstract: This invention provides novel electrode formulations which consist of solid carbonaceous filler, binder pitch, and an additive selected from phosphorus-containing and boron-containing compounds such as phosphorous pentoxide and boric acid.