Abstract: Gold values are obtained from gold cyanidation tailings or gold bearing ores by treating the same with a flotation collector consisting of 5 to 20% xanthate collector and 80 to 95% fatty acid collector of a pulp pH range from 5 to 8.

Abstract: The invention relates to a process for the recovery of gold from an alkaline aqueous liquid solution containing gold-cyanide ion, and possibly silver and/or copper and/or mercury, which comprises adding a quantity of thiourea to the solution so as to allow formation of a gold complex with thiourea which gold complex is soluble and stable in dilute acid solution, then adjusting the pH of the solution to make the solution mildly acidic, whereby gold and mercury remain in solution in the liquid and silver and/or copper is incorporated in a precipitate containing silver and/or copper cyanide compounds, and then separating the precipitate from the liquid to leave a solution of dissolved gold complex and subsequently recovering the gold from the solution.

Abstract: A process for the extraction of silver and gold from refractory ore is disclosed. The process includes first grinding the refractory ore. This ground refractory ore is subsequently treated with an alkali solution of a stoichiometric excess amount of sulphide in relation to the amount of gold and silver contained in the refractory ore, to thus form a pulp containing a gold and silver sulfide. The pulp and alkaline solution ore are aerated to oxidize the excess sulfide to sulfate and then a mixture of the pulp and cyanide liquor are formed. Finally this mixture is aerated to obtain a final gold and silver product.

Abstract: A method for recovering precious metals from ore is disclosed. Ore is treated in an acidic slurry with an activated oxygen mixture obtained from an ultraviolet light ozone generator. The activated oxygen frees chemically bonded precious metals creating an expanded, hydrated ore so that the metals may be oxidized and leached out using standard leaching techniques. In addition, the activated oxygen aids in the leaching process. Substantial increases in the amount of precious metal recovered from a given amount of ore result.

Abstract: A process for the recovery of silver from a residue essentially free of elemental sulphur obtained by acidic pressure oxidation leaching or iron-containing sulphidic material which comprises forming a slurry of the residue with lime at a temperature of at least about 80.degree. C. to raise the pH of the slurry to at least about 9. The slurry is maintained at this temperature for from about 0.5 to about 4 hours, and the resultant slurry is subjected to silver recovery treatment.

Abstract: Metal is removed from particlized metal bearing refractory ores in an efficient manner utilizing pressure metallurgy with heat recovery. The particlized ore is mixed with a heated liquid, and preferably a flocculant and fibers, to form a slurry. The ore in the slurry is oxidized at superatmospheric pressure, and elevated temperatures (e.g. around 300.degree. F.). The oxidized ore is washed to remove acids, and like products of oxidation, and the washed ore is subsequently subjected to conventional leaching processes to effect an actual metal recovery. Heat recovery is practiced by utilizing spent wash water as part of the slurrying liquid, and using two or more liquid-interconnected vessels in effecting the oxidization.

Abstract: A process for recovering gold from refractory auriferous iron containing sulphidic material which comprises treating an aqueous slurry of the material in a pressure oxidation step at a temperature in the range of from about 135.degree. to about 250.degree. C. under a total pressure of from about 500 to about 5000 kPa to oxidize sulphide sulphur to sulphate form and release gold from a refractory state. The pH of the resultant oxidized slurry is adjusted to a value suitable for cyanidation. The pH adjusted slurry is subjected to a cyanidation step in which gold is dissolved in a cyanide solution. The cyanided slurry is diluted to a pulp density in the range of from about 2 to about 10% solids by weight. The diluted slurry is subjected to a liquid-solids separation step to produce a gold containing solution and a relatively high pulp density gold-containing slurry, and gold from the gold-containing solution and from the high pulp density gold-containing slurry is separately recovered.

Abstract: A process for separately recovering gold and silver from a solution containing dissolved gold and silver by carbon adsorption which comprises passing the solution sequentially through a series of carbon adsorption stages and passing carbon sequentially through the series countercurrent to the solution to cause gold and silver to be loaded onto the carbon. A portion of the loaded carbon is removed partway along the series, and silver is recovered from the removed portion of the loaded carbon. Loaded carbon is removed from the beginning of the series, and gold is recovered from the carbon removed from the beginning of the series. Carbon from which gold and silver have been removed is returned to the end of the series for re-use.

Abstract: Residual hypochlorite contained in chlorinated slurries of either carbonaceous gold-containing ores or mixtures of carbonaceous and oxide gold-containing ores are reduced by reaction with sulfide ion-providing chemical compounds preferably sodium hydrosulfide, sodium sulfide or hydrogen sulfide. The hypochlorite "kill" step enables subsequent cyanide leach operations to be conducted more efficiently.

Abstract: A method of recovering gold and silver efficiently and almost completely from an aqueous solution containing cyanic compounds of gold and silver and which comprises adjusting the pH of the aqueous solution containing cyanic compounds of gold and silver to 6.0 or less, preferably to pH 3.0-5.0, by adding mineral acid, such as sulfuric acid or hydrochloric acid, preferably together with a small amount of active carbon, and subsequently passing the aqueous solution through an active carbon bed, preferably pretreated with mineral acid.

Abstract: Particlized mineral material, such as gold ore, silver ore, or coal, is subjected to a leaching process in a manner to maximize treatment effectiveness even when the particlized mineral material contains small fines. The material is slurried with a flocculating material and fibers, such as cellulosic fibers, fiberglass fibers, or ceramic fibers, and a liquid, and then is passed to the top of a leaching reactor. The slurry is continuously passed downwardly in the reactor while the leaching liquid, such as a cyanide solution, is passed counter-current to the slurry. Leaching liquid is removed from the top of the leaching reactor by a stilling well, and then passed through a carbon adsorber and reintroduced into the reactor. Leached slurry is passed to a continuous washing station, with spent wash liquid from the top of the washing station being utilized as a slurrying liquid for the particlized mineral material.

Abstract: An introduction process and apparatus is described concerning the continuous elution of a value, i.e. a metal value such as gold, from a particulate carrier by a counterflow of stripping liquid through the pressurized vessel in which the loaded particulate carrier is introduced to the vessel as a low velocity plug in a liquid carrier. The extraction process is also used with the continuous elution process in which the particulate material is extracted from the bottom part of a pressure vessel through a discharge pipe extending therefrom and in which a discharge liquid is introduced into the discharge pipe upstream of the discharge end under such pressure as to maintain a head of the discharge liquid upstream of that location and a flow of the liquid downstream from the location to transport the particulate material through the discharge pipe.

Abstract: A process for recovering precious metals from a refractory ore by forming a slurry which is heated to a temperature in excess of about 150.degree. C. at an oxygen partial pressure in excess of about 10 psia for an effective amount of time to form a partially oxidized slurry which is then subjected to carbon-in-leach treatment to separate the precious metals.

Abstract: A solution for simultaneously stripping gold and palladium-containing deposits from substrates carrying them is provided, which is capable of efficient operation under practical and desirable conditions, particularly for recovering the precious metal electroplate and flash coatings from electronic components. The solution contains a thallium compound, in addition to a nitrobenzoate derivative, a soluble cyanide, and certain optional ingredients.

Abstract: The extent of recovery of precious metals, preferably gold and silver, from precious metal ores, concentrates, tailings and wastes which are also sulphide- and arsenic- and/or antimony-bearing, is enhanced by treatment with Caro's acid (H.sub.2 SO.sub.5).

Abstract: Particlized mineral material, such as gold ore, silver ore, or coal, is subjected to a leaching process in a manner to maximize treatment effectiveness even when the particlized mineral material contains small fines. The material is slurried with a flocculating material and fibers, such as cellulosic fibers, fiberglass fibers, or ceramic fibers, and a liquid, and then is passed to the top of a leaching reactor. The slurry is continuously passed downwardly in the reactor while the leaching liquid, such as a cyanide solution, is passed counter-current to the slurry. Leaching liquid is removed from the top of the leaching reactor by a stilling well, and then passed through a carbon adsorber and reintroduced into the reactor. Leached slurry is passed to a continuous washing station being utilized as a slurrying liquid for the particlized mineral material.

Abstract: A process for recovering metallic values by putting the values into solution and separating undesired mineral matter from the solution using countercurrent flotation is provided. The process involves leaching metallic values from host rock, conditioning the resultant ore pulp with the required reagents to achieve selective flotation of mineral matter in the metallic values solution, introducing the conditioned ore pulp into flotation cells, along with counterflow of solution from an immediately subsequent flotation step, wherein simultaneous washing and flotation is achieved, and the mineral matter is removed leaving a solution of the metallic values. The resultant mineral matter froth product is subjected to subsequent stages of flotation and simultaneous washing with counterflow of solution removed from each subsequent stage of flotation, water and/or barren solution being used for washing in the final flotation stage.

Abstract: The present invention relates to a process for the separation of gold and silver from complex sulfide ores and concentrates which, in addition to the primary metals, contain constituents having an adverse effect on the separation of the noble metals, by heating the sulfide ore or concentrate at a temperature of 600.degree.-900.degree. C. and a sulfur pressure of 0.2-1 atm in order to bring the complex metal compounds to a suitable form for subsequent alkalic cyanide leaching, and by separating the gold- and silver-bearing cyanide solution from the undissolved residue.

Abstract: The disclosure relates to desorption of gold or silver from particulate materials and in particular to a composition for use in separating gold or silver from particulate material on which it is adsorbed, which comprises a homogeneous phase mixture of aqueous solvent having dissolved therein at least 20% by volume of polar organic solvent or mixture of polar organic solvents selected from ketones containing up to 5 carbon atoms and, preferably, nitriles containing up to 3 carbon atoms, said solvent mixture containing from 0.1% by weight to saturation of a water soluble inorganic cyanide or thio cyanate salt which produces free cyanide or thio cyanate ions in water.The invention also provides a method of separating gold or silver from particulate materials on which the gold is adsorbed, where the particulate material is eluted with a composition in accordance with the present invention at a temperature in the range from 10.degree. to 50.degree. C.

Abstract: The method for extraction of precious metals from leachable ores and forming a building materials which includes the steps of crushing a quantity of leachable ore into a powder of substantially uniform particle size, mixing with a quantity of a binding material and mixing with a leaching material. The materials are then formed into a masonry building construction article having at least one passage therein. A plurality of the masonry building construction articles are stacked with at least some of the passages disposed therein in generally parallel flow paths and a solvent is passed through the passages of the masonry building construction articles.

Abstract: Cyanic extraction of precious metal from comminuted, refractory precious metal ore as well as refractory precious metal concentrates and tailings from such ore is effected with rapidity and high yield by agitationally treating the refractory material with an aerated, alkaline solution containing a high concentration of water soluble cyanide and a low concentration of chemical oxidizer such as potassium permanganate.

Abstract: This invention relates to environmentally sound hydrometallurgical methods and processes for extraction of cobalt, nickel and silver from complex concentrates. The finely ground minerals are converted during an oxidative caustic leach at elevated pressures and temperatures to insoluble metal hydroxides and are separated from soluble sodium arsenate and sodium sulphate. Cobalt and nickel are extracted from the caustic cake during a two-stage sulphuric acid leach. Solution purification for cobalt and nickel recovery proceeds on the basis that only one waste residue and one liquid effluent are generated which meet strict environmental standards. A small amount of cyanidation residue is generated after silver extraction by cyanidation from the acid leach residue. Metal values extraction reaches +99.0%. Arsenic and sulphur can be recovered in an innovative recycle system as sodium, zinc or copper arsenate chemicals and as anhydrous sodium sulphate.

Abstract: A functionalized silica is prepared by reacting silica with a silane and an aromatic hydroxy aldehyde. The product is useful for removing metals from solution, e.g., Cu from ATK, or in the extraction of U from solutions arising from the processing of its ores.

Abstract: Method for extracting precious metals from their ores in which the ore is particulated and mixed with a binding agent to form a paste. The paste material is discharged into a rotary drum at an extruding station where it is pelletized by forcing it through a perforated sidewall of the drum. The pellets are discharged onto a conveyor belt and are transported to a spray station where they are wetted with a lixiviant solution. The lixiviant coated pellets are then dried by exposure to a heated air stream at a drying station as they are transported to an open air curing stockpile. The cured pellets are heaped in a pile and are then washed with a water spray to yield a pregnant solution of a precious metal salt.

Abstract: Disclosed is a method for above-ground leaching of metal bearing ores comprising (a) providing an ore body to be leached having positioned therein void-creating members, said members being positioned substantially vertical or at an angle to the horizontal plane in order that they are capable of being pulled out of said ore body in a substantially upward direction; (b) partially performing the leaching; (c) removing said members by pulling out in a substantially upward direction, thereby creating internal voids and causing shifting of ore in said ore body; and (d) completing the leaching.

Abstract: The invention concerns the recovery of non-ferrous metals, such as gold, uranium or the like from iron oxide containing calcines which have the non-ferrous metal present in solid solution and/or encapsulated within the iron oxide. The calcine is reacted, while stirring vigorously, with sulphuric acid or another strong inorganic acid to cause the iron to form the ferric salt. The material obtained is mixed with water and the liquid and solid phases are separated from each other. The non-ferrous metal is then obtained from at least one of these phases by leaching, or the like.

Abstract: The recovery of gold from refractory carbonaceous gold-containing ores by cyanidation techniques is improved by subjecting an oxidized slurry of this type of ores to simultaneous cyanidation and countercurrent granular activated carbon adsorption in two or more stages. The gold transfers to the carbon and may be separated from it by conventional methods.

Abstract: An improved leaching method for metal bearing ores, wherein removable, void-forming members are placed near the bottom of the ore body and removed during the leaching process, causing partial internal collapse and shifting of the ore, thus exposing additional ore surfaces to the effect of the leaching solution.

Abstract: This invention relates to a process for treating a liquid containing an Au-CN compound and optionally an Ag-CN compound to decompose the compound(s) and, at the same time, separate gold and optionally silver from the liquid with ease. When containing the Au-CN compound alone, the liquid is heated at a temperature of at least 170.degree. C. in the presence of at least 0.1 mole of a water-soluble metallic hydroxide per gram atom of the gold in the Au-CN compound. When containing the Au-CN compound and the Ag-CN compound, the liquid is heated at a temperature of at least 170.degree. C. in the presence of a water-soluble metallic hydroxide in a total amount of at least 0.1 mole per gram atom of the gold in the Au-CN compound and at least 0.05 mole per gram atom of the silver in the Ag-CN compound. The compound(s) in the liquid are fully decomposable, and at the same time, gold or both gold and silver can be separated out from the liquid singly as such and recovered with a high recovery rate(s).

Abstract: A continuous process for recovery of metals, especially precious metals, from various ores, involves pulverizing the ore to a particle size less than five microns, forming a colloidal suspension of the particles in a liquid, extracting metal from the slurry with a solvent, and separating the solvent from the particles centrifugally. Metals are recovered from the liquid solvent, which is recycled. Contacting of the slurry with fresh solvent is preferably effected in a staged counter-current centrifugal extraction unit.

Abstract: Spent aqueous liquor containing cyanide, as from ore treatment, is passed through a bed of suitable anion-exchange resin to segregate the cyanide, which is subsequently recovered in regeneration of the resin by weak alkaline solution. Both the eluted cyanide and the alkaline regenerant are recycled, if desired, for further ore treatment. A most important benefit of such procedure is nearly complete elimination of cyanide as a component of the treatment effluent. Free cyanide may be separated from complexed cyanides when present by using weak alkaline regenerant to elute the free cyanide from the resin and stronger alkaline regenerant to elute the complexed cyanides.

Abstract: Gold-bearing ore of sedimentary origin containing organic carbonaceous material and gold-bearing sulfides is treated to increase the recovery of the gold content thereof by standard cyanidation practice. An aqueous slurry of the finely ground ore is first subjected to a preliminary oxidation treatment wherein air or oxygen is bubbled through the slurry while maintaining the slurry at a temperature of from 167.degree. to 212.degree. F. for a period of from 8 to 24 hours. The oxygenated slurry is then cooled to a temperature of from 70.degree. to 125.degree. F. and acid is added to bring the pH of the slurry down to 6.0 of lower. Chlorine gas or an alkali metal or alkaline earth metal hypochlorite is then added to the slurry unitl the slurry will no longer absorb or react with these reagents. The thus treated slurry is maintained at a temperature of from 70.degree. to 125.degree. F. for a period of from 6 to 12 hours.

Abstract: Percolation leaching of gold or silver ores, tailings or wastes is accomplished by a process comprising initial agglomeration of fines in the feed by means of a binding agent and water, followed by aging and, subsequently, leaching to recover gold or silver values.

Abstract: A rapid, energy efficient, low cost, nonhazardous method for the selective removal of mercury from mercury-containing metal cyanide solutions, particularly the cyanide solutions resulting from the cyanidation of gold ore and the like, wherein a reactive sulfide is admixed with the solution for a time sufficient to form an insoluble mercuric sulfide precipitate. The mercuric sulfide precipitate is then separated from the metal cyanide solution by filtration or other conventional means.

Abstract: Percolation leaching of gold or silver ores, tailings or wastes is accomplished by a process comprising initial agglomeration of fines in the feed by means of a binding agent and cyanide solution, followed by aging and, subsequently, leaching to recover gold or silver values.

Abstract: Process for recovery of copper, molybdenum, gold and elemental sulfur in tailings from hydrometallurgical processing of copper sulfide ores, particularly chalcopyrite. The tailings are usually discarded, and thus the recovery of valuable elements therefrom makes the environmentally desirable hydrometallurgical processes of FIG. 1 economically feasible.The tailings are concentrated to a small bulk volume by froth flotation to reject barren gangue and the process (FIG.

Abstract: A process for the treatment of incinerated sewage sludge ash containing silicic compounds and metal values including phosphorus and at least one precious metal comprises leaching the ash in an acid solution in a first leach to dissolve phosphorus. The leach solution is separated from the undissolved residue, which is then treated to recover at least one precious metal.

Abstract: Timed or regulated air bursts are employed to agitate and oxygenate leachable ores or other material containing valuable leachable elements in the presence of a leaching solution. The process provides a homogenous mixing of fines within the leaching solution thereby reducing channeling within the ore.

Abstract: When certain sedimentary gold ores containing indigenous organic carbonaceous materials are slurried with an aqueous solution containing an alkali metal cyanide, the aurocyanide complex which is formed is adsorbed by an adsorptive carbon component of the ore. Dissolution of the gold proceeds until chemical equilibrium is attained between the aurocyanide complex in solution and the aurocyanide complex adsorbed by the ore. In the process of the invention, the gold is dissolved from the ore by using (1) much higher strengths of cyanide solution, and (2) much higher temperatures than are normally used in the standard cyanidation process, allowing higher extractions of gold to take place. Because the concentration of aurocyanide in solution is limited by chemical equilibrium, the dissolution of gold must be done in stages.

Abstract: A process for the extraction of gold and silver from their ores in which the ore is reduced to a particle size of 1 mm or less and mixed with a lixiviant, e.g., alkaline sodium or potassium cyanide, in an amount to provide a liquor content of about 8 to 12%, the lixiviant coated particles are allowed to react for a time sufficient for the lixiviant to extract the noble metal and the particles washed with water to obtain a solution of the noble metal salt from which the noble metal is recovered.

Abstract: A method of treating a solution comprising ions of gold and cyanide is disclosed. The method comprises treating the solution with metallic gold to precipitate therefrom metallic silver.

Abstract: A process for the recovery of copper, molybdenum, gold and elemental sulfur in tailings from hydrometallurgical processing of copper sulfide ores, the process comprising concentrating the tailings containing elemental sulfur and copper, gold and molybdenum to a small bulk volume by froth flotation to reject barren gangue including jarosite, if present, and other impurities, separating the liquids and solids in the float concentrate, leaching the resulting residue with a solvent for sulfur followed by liquid-solids separation and recovering elemental sulfur from the liquid, leaching the residue from the sulfur solvent leach with ferric chloride to selectively dissolve copper and iron therein followed by liquid-solids separation and recovering copper from the liquid or sending it back to the hydrometallurgical circuit, leaching the residue from the ferric chloride leach with cyanide to selectively solubilize gold followed by liquid-solids separation and recovering of solubilized gold from the liquid, recovering

Abstract: The recoverability by cyanidation of the gold content of sedimentary gold-bearing ores containing organic carbonaceous material and gold-bearing pyrite, or other gold-bearing sulfides, is greatly increased by heating an aqueous slurry of the ore to about 167.degree. to 212.degree. F. and then introducing air or oxygen into the heated slurry to oxidize and eliminate a substantial portion of the carbonaceous material and oxidizable sulfides in the slurried ore, followed by cooling the slurry to about 70.degree. to 85.degree. F. and then introducing chlorine gas into the slurry to substantially complete the oxidation and chlorination of the carbonaceous content of the slurried ore. The ore is then subjected to conventional cyanidation to recover the gold content thereof.

Abstract: A process for pretreating refractory ores improves the recovery of gold from such ores upon subsequent cyanidation. After comminuting the ore and forming an aqueous slurry, the ore is subjected to pressurized oxidation at an elevated temperature. By adjusting the pH to below about 1.85 and maintaining the pressure and temperature above 300 psig and 160.degree. C., respectively, very high recovery of gold can be achieved. Additionally, by maintaining a preselected soluble iron concentration in the slurry, the oxidation of the ore is promoted and proceeds at a more rapid rate.