Abstract: Molybdenum is removed from a uranium bearing alkaline carbonate leach solution, by adding a compound which provides lead ion to react with the molybdenum present to form insoluble lead molybdate (PbMoO.sub.4) which precipitates from the solution.

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: A process for the in-situ mining of subterranean uranium ore deposits comprising pretreating the deposits by the steps of injecting an aqueous inorganic chloride solution therein to substantially saturate the deposits and injecting an aqueous alkaline lixiviant solution therein to flush the chloride solution from the deposits. Thereafter, the pretreated deposits may be solution mined in conventional fashion such as by injecting an oxidant-containing aqueous alkaline lixiviant therein and recovering uranium-containing lixiviant solution. The inorganic chloride solution is preferably potassium chloride and the preferred lixiviants are potassium carbonate, sodium carbonate and ammonium carbonate.

Abstract: Alkaline solutions containing sulfate and sodium ions such as uranium leach liquors, are treated with cationic ion exchange resins in the ammonium form to form a solution containing soluble ammonium salts and complexes; the solution is further treated to convert the soluble sulfates into insoluble sulfates and, in the case of uranium, further treating to separate the uranium by heat and/or acidification. The ammonium can be recovered and reused as ammonium carbonate to regenerate the ion exchange resin whereby sodium ions are eluted from the resin in the form of sodium carbonate which is converted to sodium hydroxide and re-cycled for use as leaching solution.

Abstract: In the solution mining of uranium ores using an aqueous ammonium carbonate leaching solution containing hydrogen peroxide and/or molecular oxygen as oxidant, permeability of the ore formation during the leaching operation is maintained or improved by including a small amount of alkali metal silicate dissolved in the leaching solution. The silicate also improves the stability of the oxidant in many instances.

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: A method for controlling calcium, e.g. calcite, build-up in the leach solution of a uranium and/or related values recovery operation wherein the leach solution is flowed through a value bearing ore to dissolve the desired values. A soluble fluoride, e.g. sodium fluoride, is added to the leach solution after it has passed through the ore to thereby precipitate calcium fluoride from the leach solution and lower the calcium content of the leach solution. The soluble fluoride may be added to the leach solution before the leach solution passes through the process equipment which is used to remove the values from the leach solution or the soluble fluoride may be added after the leach solution passes through the process equipment. If added before, it is preferable to also add a carbonate/bicarbonate solution along with the soluble fluoride to prevent coprecipitation of uranyl/desired value fluoride or to redissolve coprecipitated fluoride back into the leach solution.

Abstract: Process for the in-situ leaching of uranium employing an alkaline lixiviant and an alkali metal or alkaline earth metal hypochlorite as an oxidizing agent. The use of the hypochlorite oxidant results in significantly higher uranium recoveries and leaching rates than those attained by the use of conventional oxidants. The invention is particularly suitable for use in subterranean deposits in which the uranium mineral is associated with carbonaceous material which retards access to the uranium by the lixiviant.

Abstract: A cyclic process for the treatment of a uraniferous liquor containing, in addition to the desired metal, sodium carbonate and/or bicarbonate and sodium sulphate, obtained by the alkaline attack of a sulphur-containing uraniferous ore, the said process comprising fixing the uranium over a first strong anion-exchange resin, eluting it with an ammonium carbonate and/or bicarbonate solution in the form of an ammonium uranyl tricarbonate which is subsequently decomplexed, precipitating and calcinating the precipitated uranates and/or diuranates with regeneration of the eluant solution of ammonium carbonate and/or bicarbonate, passing the liquor which is freed from uranium and leaves the first strong anion-exchange resin into a neutralization zone then over a second anion-exchange resin, eliminating the SO.sub.4.sup..dbd. ions which are subsequently precipitated in calcium form, recycling a carbonate and/or bicarbonated liquor which is free from SO.sub.4.sup..dbd.

Abstract: A method of controlling the molybdenum content of uranium yellowcake which is precipitated from an eluate of ammonium carbonate. The pH of the eluate is maintained at a relatively high value, i.e., never less than 9.3, while the eluate is heated to strip off ammonia, carbon dioxide, and water. Ammonia is added to the eluate during heating to keep the pH high and the molybdenum in solution in the eluate. Also, the precipitated uranium yellowcake may be treated by adding aqueous ammonia and heating to form an insoluble uranium salt and a soluble molybdenum salt which can be filtered to produce a uranium yellowcake having a reduced molybdenum content.

Abstract: In a process for the solution mining of a uranium ore formation using an aqueous alkaline carbonate leaching solution containing hydrogen peroxide as oxidant, the solution is passed through the ore formation in the presence of an alkylidene-1,1-diphosphonic acid. Such an acid has been found to be unique in its capability for stabilizing the peroxide against decomposition in the presence of the uranium ore.

Abstract: Uranium is recovered from phosphate ore in a process comprising making phosphoric acid, partially reacting same with NH.sub.3, removing aluminum with dilute sodium carbonate and sodium bicarbonate and extracting the uranium with a concentrated solution of said carbonates.

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: A process for the oxidizing attack at high temperature of ores containing at least one metal belonging to the group formed by uranium, vanadium and molybdenum, by means of an aqueous liquor containing a majority of sodium bicarbonate and a minority of sodium carbonate according to a ratio by weight of sodium bicarbonate to sodium carbonate of at least 1.5, in the presence of free oxygen injected into the reaction medium, this medium being maintained at a temperature of between 160.degree. C. and 300.degree. C. for at most six hours.

Abstract: A method is described for reducing the volume of radioactive waste produced during the solution mining of uranium and for recovering uranium from it. The recovery leach, which contains uranium in solution and is supersaturated with calcium carbonate, is treated with bicarbonate and made basic which precipitates calcium carbonate and some of the uranium. The precipitated calcium carbonate is dissolved with acid and the uranium in the solution is removed by extraction or precipitation. The remaining solution is contacted with sulfate ions and barium or strontium ions to precipitate BaSO.sub.4.RaSO.sub.4 or SrSO.sub.4.RaSO.sub.4, the principal radioactive constituent in the solid waste product.

Abstract: The present invention relates to a method for the renovation of an aquifer subsequent to the solution mining of a mineral from the aquifer. More specifically, the invention relates to the utilization of spent ion exchange resin to remove chloride ions from the aquifer.

Abstract: Improvement in the process for recovering uranium from wet-process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange liquid-liquid solvent extraction circuits in which in the first circuit (a) the uranium is reduced to the uranous form; (b) the uranous uranium is recovered by liquid-liquid solvent extraction using a mixture of mono- and di-(alkyl-phenyl) esters of orthophosphoric acid as the ion exchange agent; and (c) the uranium oxidatively stripped from the agent with phosphoric acid containing an oxidizing agent to convert uranous to uranyl ions, and in the second circuit (d) recovering the uranyl uranium from the strip solution by liquid-liquid solvent extraction using di(2-ethylhexyl)phosphoric acid in the presence of trioctylphosphine oxide as a synergist; (e) scrubbing the uranium loaded agent with water; (f) stripping the loaded agent with ammonium carbonate, and (g) calcining the formed ammonium uranyl carbonate to uranium oxide, the i

Abstract: The invention is an improvement in the process for recovering uranyl uranium from solutions in which the uranyl uranium is recovered with an liquid-liquid solvent extraction agent dissolved in an inert solvent, the loaded agent scrubbed with water, the scrubbed agent stripped with ammonium carbonate solution to form a slurry of ammonium uranyl tricarbonate, the stripped agent returned to the liquid-liquid solvent extraction step, and the ammonium uranyl tricarbonate calcined to a uranium oxide product, the improvement which comprises stripping the uranium from the ion exchange agent with an alkali metal carbonate rather than ammonium carbonate, scrubbing the loaded agent with acidified alkali carbonate strip solution prior to stripping, and regenerating the stripped liquid-liquid solvent extraction agent with a mineral acid before return to the liquid-liquid solvent extraction circuit.

Abstract: Uranium is recovered from alkaline leach liquors of uranium ores by treating the leach liquors with an ion exchange resin in the ammonium form to provide a solution of salts and complexes of uranium and ammonium from which the uranium is separated by treating with heat or an acid.

Abstract: Uranium ore deposits which contain uranium in the relatively insoluble tetravalent state are readily selectively leached in situ to recover relatively pure uranium compounds, by: (a) passing through the ore deposit a relatively dilute aqueous leach solution of ammonium bicarbonate, ferric ammonium ethylenediaminetetraacetic acid (EDTA), and a source of oxygen, the leach solution converting the tetravalent uranium to hexavalent uranium which readily dissolves in the leach solution; (b) withdrawing the reacted leach solution enriched in dissolved uranium from the ore deposit; and (c) stripping the uranium from the withdrawn leach solution. The stripping of the uranium from the leach solution is preferably accomplished by countercurrent flow of the enriched leach solution to a column of base anion exchange material which preferentially extracts the uranium.

Abstract: A process for the recovery of uranium from a saline alkaline lixiviant employed in a uranium leaching operation. An ion exchange resin is employed to adsorb uranium from the lixiviant. Prior to contacting the resin with the lixiviant, the pH of the lixiviant is reduced to a value of less than 7. By this technique, the resin loading in the presence of chloride ion is materially increased. The pH values for optimum resin loading capacity decrease as the salinity of the lixiviant increases. Resin loading is also enhanced by the presence of bicarbonate ion in the lixiviant.

Abstract: A process for the continuous leaching of ores and an apparatus for practicing this continuous leaching process are disclosed. According to this process, a plurality of unit layers composed of a pulverized uranium ore or other ore are continuously laminated while a minimum necessary amount of an acid, alkali or organic solvent (hereinafter referred to as "solvent") is uniformly sprinkled on the flat surfaces of these unit layers. In the state where the concentration of the solvent mixed into the ore is maintained at a high level, the heat generated by exothermic reaction caused by contact among the solvent, ore and water is effectively stored and used for thermally curing the ore. According to this process, the speed of extraction of the intended metal component can be increased, the leaching time shortened and the filtration characteristics improved, whereby a highly concentrated pregnant liquor can be recovered at a high efficiency.

Abstract: The invention relates to a process for the treatment of an uraniferous ore containing sulfur in the form of sulfates or sulfides with one or more alkaline solutions containing sodium carbonate in the presence of an oxidant, for extracting uranium in the form of soluble uranium salt in said solution.It comprises subjecting the ore, in a first step, to the action of a dilute pre-leach solution of sodium carbonate, whose concentration does not substantially exceed, or by very little, that which is required for the solubilization of the major part of the sulfur initially contained in the ore to convert it to sulfate in the presence of the oxidant and, in a second step, to the action of a leach solution, more concentrated in sodium carbonate, enabling the extraction and solubilization in the medium of the major part of the uranium still contained in the ore, not extracted in the pre-leach medium of the first step.

Abstract: The oxidation of uranium is catalyzed with water-soluble copper or zinc chelates. An aqueous solution is prepared containing carbonate or bicarbonate ion, an oxidizer such as hydrogen peroxide or oxygen, and a water-soluble copper or zinc chelate which has at least two amino, carboxylic acid, or thiocarboxylic acid donor groups. The solution is pumped into an underground deposit of uranium. The water-soluble +4 state uranium is oxidized to the water-soluble +6 state which forms a complex with the carbonate ion. The solution is pumped to the surface and is recycled after precipitation of the uranium.

Abstract: Process for the in-situ leaching of uranium from a subterranean ore deposit comprising introducing into the deposit an aqueous lixiviant having a pH of at least 6.0 and containing an alkali metal sulfate leaching agent. The alkali metal sulfate may be employed in combination with an alkali metal carbonate or bicarbonate with the sulfate comprising the predominant leaching agent. The lixiviant may be at a pH of at least 7.5 and contain an alkali metal sulfate leaching agent and a hypochlorite oxidizing agent.

Abstract: Uranium ore deposits which contain certain proportions of other metals and elemental components, such as are present in redox roll front ore deposits, are selectively leached in situ by passing therethrough relatively dilute aqueous leach solutions comprising essentially from about 0.5 to 5 grams per liter of ammonium bicarbonate and from about 0.1 to 3 grams per liter of peroxide, preferably introduced as aqueous H.sub.2 O.sub.2, and sufficient ammonia to bring the solution to a pH of from about 7.4 to 9, and preferably from 7.5 to 8.5, thereafter withdrawing from the ore deposit the aqueous leach solution enriched in uranium which it preferentially extracts along with a generally lower proportion of other metals and elements as compared to their respective ratios in the ore deposit, and contacting the enriched leach solution with a strong base anion exchange material to strip the uranium from the leach solution.

Abstract: The present invention relates to a method for the restoring of an underground reservoir subsequent to the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to the introduction of a sulfate reducing bacteria into a subterranean formation to decrease the total dissolved solids level of the reservoir present therein.

Abstract: Carbon dioxide is admixed with water to form a carbonic acid solution for use as a leaching solution for extraction of uranium by solution mining. An oxidizing agent is also present in the solution.

Abstract: The present invention relates to a process for the solution mining of uranium from a subterranean formation. More specifically, the invention relates to the injection of an alkaline leach solution undersaturated in carbonates into a subterranean formation for the mining of uranium.

Abstract: The present invention relates to an improved method for the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to an improved method which enhances significantly the recovery of a mineral from a subterranean formation via solution mining utilizing an injection and production well. The improvement comprises positioning an injection well in the reduced zone and a production well in the oxidized zone of a formation.

Abstract: Uranium yields, derived from alkaline leaching of a uranium ore, are increased and at the same time the need for fresh water to dissolve a flocculant is eliminated by using sodium polyacrylate as the flocculant, diluted with and dissolved by system water.

Abstract: Improved flocculation efficiency and filtration of carbonate leached uranium ore pulps are obtained by incorporating hydroxyalkyl guars in the filter feed slurry.