Abstract: Agglomerating agent and method for use in heap leaching of mineral bearing ores. Cationic polymers alone or in combination with cement or lime are highly effective agglomerating agents in acidic or alkaline leaching operations. The cationic polymers are preferably graft copolymers, block copolymers or linear copolymers of acrylamide and diallyl dimethyl ammonium chloride.

Abstract: Heavy metals are removed from paint chips by leaching with an aqueous acid. Heavy metals are also efficiently removed from contaminated soil by a process which comprises leaching or washing the soil with a mild leachant solution comprised of an aqueous solution of an acid and a salt. The heavy metals are recovered from the leachant by cementation.

Abstract: A process for recovering gold from a refractory auriferous ore containing sulfide sulfur. An aqueous slurry of refractory auriferous ore is subjected to pressure oxidation in an autoclave while the distribution of oxygen to the various compartments of the autoclave is controlled in order to achieve increased oxygen utilization.

Abstract: A method of producing a water soluble copper silicate by reacting a copper salt with an alkali silicate in an acidic solvent to produce an aqueous solution of acidified copper silicate capable of being used as a fungicide or pesticide.

Abstract: An agglomerating agent for use in the heap leaching of mineral bearing ores is disclosed. The agglomerating agent is a polyvinyl alcohol of moderate to high molecular weight which is partially or fully hydrolyzed. The polyvinyl alcohol agglomerating agent can be used alone or in combination with cement or lime in acidic or alkaline heap leaching operations.

Abstract: The present invention is a method for cleaning and preparing photographic manufacturing equipment surfaces. An aqueous solution of potassium iodide and ferric ethylenediamine tetraacetate is prepared. The solution is flushed over the surfaces of the photographic manufacturing equipment removing deposited silver halide and silver. A high purity water flush is then performed.

Abstract: Process for biolixiviating minerals from copper sulfides and also from their flotation concentrates, characterized by the use of biolixiviation through indirect contact as well as separation and improvement of the chemical and biological steps of the biolixiviation process. In the chemical step, a low concentration of ferric sulfate is used as the lixiviating agent. In the biological step, bacterial films of Thiobacillus ferrooxidans attached to an inert solid are used to regenerate the lixiviating agent by converting the ferrous ion into ferric ion through oxidation. The regenerated agent is then recycled to the lixiviation reactor. The biolixiviation process permits complete extraction of the copper contained in the ore and results in a lixiviation liquor which contains all the copper charge and a low concentration of ferric sulfate similar to the low concentration of ferric sulfate used initially.

Abstract: A process is provided for recovering gold from refractory sulfide ores. Preferred feed materials have multiple different sulfide mineralogies, with gold being primarily contained within one or more, but not all, of the sulfide mineralogies. Sulfide mineralogies with the highest gold values are preferentially oxidized, while those sulfide mineralogies with relatively little gold remain largely unoxidized. In one embodiment, dissolved arsenic following pressure oxidation is precipitated as ferric arsenate through the control of pH during neutralization. In another embodiment, the oxidized slurry following pressure oxidation is contacted with an oxidizing agent to convert at least a portion of ferrous iron to ferric iron. Following, pressure oxidation, the slurry can be subjected to cyanidation recovery of gold, and liquid from the tailings stream can be recycled upstream of the pressure oxidation step in a substantially untreated form.

Abstract: A method for recovering precious metals from carbonaceous ore comprising leaching the ore with a lixiviant solution and then preg-robbingly concentrating the precious metal-lixiviant complexes in solution on to the native carbonaceous component of the ore for subsequent recovery. The preg-robbing capacity of the native carbonaceous component of the ore can be augmented by adding recycled carbonaceous matter or finely ground carbon to the ore-lixiviant mixture. Furthermore, after the carbonaceous component of the ore is separated from the gangue, the gangue material can be treated in a hot CIL process to further increase the recovery of the precious metal.

Abstract: Oceanographic mining uses a flexible cover draped over a submarine ore-bearing stratum. The cover serves as a blanket-like structure for application of a leaching substance and isolation of the leachate and stratum from the surrounding water. The leachate infiltrates the stratum and becomes pregnant with intended materials. The leaching solution is subsequently pumped to the surface. The ores are separated from the pregnant leaching solution, enabling the solution to be used again. The cover supports and arranges anchor and sealing tubes and leachate and pregnant liquor tubes. Pumps are mounted on a platform connected to the cover. The cover is deployed by sinking parallel coils and filling peripheral tubes to uncoil and anchor the cover on a sea bed. One cover is spread by tube and is sunk in a controlled manner.

Abstract: A hydrometallurgical process is described for recovery of precious metals from ores refractory to treatment by lixiviating agents by crushing the ore to no finer than a nominal 1/4 inch size, treating the ore with about 100% to about 300% of the stoichiometric amount of nitric acid required to react with the ore, maintaining the reaction mixture until the reaction is substantially complete, placing the treated ore in a permeable ore bed, washing the permeable ore bed to remove nitric acid, placing the washed ore in a heap permeable ore bed and passing a lixiviate solution for precious metals through the bed and recovering the dissolved precious metal from the lixiviate solution. All NOx gases generated during the reaction of nitric acid with the ore are recovered for conversion into nitric acid which is recycled for treating ore.

Abstract: A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture.

Abstract: A chemical process for treating pit waste contaminated with chromated copper arsenate (i.e. CCA). CCA is recovered for recycling, and remaining solids are decontaminated for safe disposal. Pit wastes are pulverized and reacted with concentrate sulfuric or phosphoric acid. Wood particles are partially decomposed and approximately 60% to 70% of the CCA is leached out. The acid-treated mixture is centrifuged or filtered to separate liquids from solids. Liquids are recycled for reuse in the CCA process. CCA-bearing solids enter a heated digester equipped with an air or water cooled condenser. Concentrated nitric and sulfuric acids are inputted into the digester and the ratio of nitric acid to sulfuric acid to solids is approximately six to two to one by volume. Nitric acid completely oxidizes all organic matter in the solids. Sulfuric acid serves as a dehydrating agent and liquid media for CCA. The initial oxidation is carried out at a temperature greater than 70.degree. C. and less than 100.degree. C.

Abstract: A process for recovering zinc and iron from zinc- and iron-containing sulphidic material, which also contains lead and silver, in which the sulphidic material is leached under oxidizing conditions in a two stage countercurrent pressure leach to produce a zinc-containing solution from which zinc can be recovered by conventional means such as electrowinning, followed by a reducing leach to produce a lead- and silver-bearing product containing substantially all of the lead and a substantial portion of the silver present in the zinc-containing sulphidic materials, and a high strength iron bearing solution having the iron in the ferrous state from which substantially pure, saleable or environmentally acceptable iron residue in the form of hematite which contains the majority of the soluble iron present in the zinc-containing sulphidic materials is produced.

Abstract: A variety of processes for recovering gold from gold ore are disclosed. Briefly, the methods include culturing at least one microorganism species capable of producing cyanide ion under conditions wherein the microorganism produces cyanide ion, thus forming a cyanide ion-containing culture; contacting the cyanide ion-containing culture with gold ore, causing production of gold ion-cyanide ion complexes and biosorption of said complexes to said cultures; and recovering gold from the culture. The invention may be practiced with a variety of microorganisms, including Chromobacterium violaceum and Chlorella vulgaris.

Abstract: A method of solubilizing metal salts such as metal sulfides in a geothermal sludge using mutant Thiobacilli selected for their ability to metabolize metal salts at high temperature is disclosed, The method includes the introduction of mutated Thiobacillus ferrooxidans and Thiobacillus thiooxidans to a geothermal sludge or brine. The microorganisms catalyze the solubilization of metal salts, For instance, in the case of metal sulfides, the microorganisms catalyze the solubilization to form soluble metal sulfates.

Abstract: A method for recovering precious metals from carbonaceous ore comprising leaching the ore with a lixiviant solution and then preg-robbingly concentrating the precious metal-lixiviant complexes in solution on to the native carbonaceous component of the ore for subsequent recovery. The preg-robbing capacity of the native carbonaceous component of the ore can be augmented by adding recycled carbonaceous matter or finely ground carbon to the ore-lixiviant mixture. Furthermore, after the carbonaceous component of the ore is separated from the gangue, the gangue material can be treated in a hot CIL process to further increase the recovery of the precious metal.

Abstract: A process for recovering at least one precious metal from an ore containing carbonaceous material is disclosed. The process involves the use of certain plant derived ortho-quinone containing components, in particular, certain lignin and/or tannin derived components containing ortho-quinone functionality.Preferred compositions comprise at least one ligno sulfonate component containing ortho-quinone functionality. In the process, the use of at least one additional oxidant capable of maintaining the ortho-quinone containing functionality in the desired oxidation state provides for integrated process synergy.

Abstract: There is proposed a process for recovering lead, comprising the steps of: feeding molten caustic soda, lead-containing feed and an oxygen-containing gas into a reaction some having a temperature of 600.degree. to 700.degree. C. as a result of which there are obtained lead metal withdrawn from the process and a melt containing sodium sulphate, zinc and copper sulphides, and gangue. The melt is discharged from the reaction zone of subjected to a first leaching operation to obtain, as a result, a slurry representing a mixture of solid particles of sodium sulphate, zinc and copper sulphides, gangue and an aqueous solution containing essentially caustic soda. Further on, the slurry is filtered to produce a concentrated aqueous solution containing essentially caustic soda and a solid residue. The concentrated caustic soda solution is subjected to thickening by evaporation and the resulting caustic soda melt is fed into the reaction zone.

Abstract: Apparatus and process for extracting simultaneously metal values from foundry sands, said apparatus comprising a thermostated column which is in flow communication with a controlled air supply source and with a heating system arranged to keep said column at a predetermined temperature; said column is adapted to receive the necessary components to form an aqueous pulp from which the metal values are to be extracted, and has a device for finely dividing the airflow coming from the supply source in order to obtain a suitable suspension and homogenization of said pulp.

Abstract: A process is disclosed for recovering zinc, lead, copper and precious metals from zinc plant residue, said process comprising leaching the residue with return zinc spent electrolyte, neutralizing residual acid and reducing ferric iron in the solution by addition of zinc sulphide concentrate in the presence of a limited quantity of oxygen, flotation of the resulting slurry to separate unreacted zinc sulphide, treatment of flotation tailings with sulphur dioxide and elemental sulphur to further leach iron, zinc and impurity elements and precipitate copper, flotation of the resulting slurry to separate a copper sulphide concentrate, thickening, filtering and washing of the flotation tailings followed by addition of lime and sodium sulphide to activate lead sulphate and flotation of a lead concentrate from the residue.

Abstract: A process is disclosed for separating and recovering nickel and copper values from a nickel-copper matte which may contain iron and arsenic. Finely divided nickel-copper matte is leached in aqueous sulphuric acid solution under oxidizing conditions at atmospheric pressure and at a minimum temperature of about 80.degree. C. to selectively leach nickel from the matte to produce a nickel sulphate solution having a final pH in the range of about 4.0 to 6.5, preferably about 6.5, and to produce a copper-rich sulphide residue. The copper-rich sulphide residue is separated from the nickel sulphate solution and leached in a closed reaction vessel at a minimum temperature of about 120.degree. C. under a non-oxidizing atmosphere in a sulphuric acid solution containing an effective amount of copper and sulphuric acid to provide a terminal concentration of at least about 2 g/L Cu.sup.

Abstract: A process for recovering at least one precious metal from an ore containing metal sulfide material is disclosed. The process involves the use of promoting amounts of certain plant derived ortho-quinone containing components, in particular, certain lignin and/or tannin derived components containing ortho-quinone functionality. Preferred compositions comprise at least one ligno sulfonate component containing ortho-quinone functionality. In the process, the use of at least one additional oxidant capable of maintaining the ortho-quinone containing functionality in the desired oxidation state provides for integrated process synergy.

Abstract: The present invention relates to the decontamination of soil and the like and, in particular, soils which are contaminated with metal as a result of the activities of human beings. The invention provides a physical and a chemical means for treating soil aggregate so as to obtain a product aggregate having a relatively low metal content. The physical means is characterized by the classification of a soil aggregate into portions of differing size and metal content. The chemical means is characterized by contacting a soil aggregate with an aqueous lixiviant comprising an organic acid component to lift metal from the aggregate. The physical and chemical means may be used in a combined process for decontaminating soil aggregate.

Abstract: A hydrometallurgical process for the recovery of one or more metal values from a metal ore material in the presence of clays and/or fines material, said ore material being comprised of one or more metal values and a matrix material having a sulfur content wherein the sulfur is present in an oxidation-reduction state of zero or less. The process comprises forming particulates from particles of said ore material, particles comprising said clays and/or fines material, an acid-resistant polymeric agglomeration aid and an inoculate comprising bacteria capable of at least partially oxidizing the sulfur content; forming a heap of said particulates; biooxidizing the sulfur content and recovering those one or more metal values.

Abstract: Platinum group metals, gold and silver are extracted from complex ores, automobile scrap, refractory ores and as naturally occurring by leaching the precious metal containing materials with a solution containing halogen salts such as potassium or sodium iodide and bromide in the presence of ammonium ions and oxygen. The precious metal containing materials and reactants are charged into a reaction zone held at high temperatures and pressures to form a slurry containing a precious metal ion solution. The precious metal ion solution is separated from the slurry and subjected to recovering techniques to recover the precious metals.

Abstract: Increased efficiency of extraction of silver and gold from ore materials thereof containing active carbonaceous material is obtained by conducting the extraction in two stages. In a first stage a portion of the silver and of the gold when present is extracted in a cyanide leach solution. The leached solids residue is contacted with activated carbon so that the silver and the gold when present are adsorbed on the activated carbon at elevated temperature (most preferably at about 35.degree. C. to about 100.degree. C.). In a modification, a slurry of the ore material is treated with cyanide and the precious metal adsorbed directly from the cyanided slurry with activated carbon at elevated temperature up to about 70.degree. C.

Abstract: A method is described for providing a body of first material and a body of second material in a chemical environment wherein the first material contains first constituents having a lower and higher oxidation state and wherein the second material contains constituents having an oxidation state of energy greater than lower oxidation state of the first constituent. The environment is further provided with first cations energetically disposed for receiving electrons from the first constituents but not energetically disposed for receiving electrons from the second constituents. Electrons transfer from the first constituents to the first cations which are transformed thereby into second cations of lower oxidation state resulting in first body releasing into the environment third cations which are cations of the first (lower) oxidation state of the first constituent.

Abstract: A composition of zirconyl hydroxy chloride and aluminum chlorhydroxide in stable solid form having improved antiperspirant efficacy when dissolved in water is made by heating a 2-20% by weight aqueous solution containing at least the aluminum chlorhydroxide component of the composition at a temperature of at least 50.degree. C. until the ratio of the height of peak 4 at Kd=0.7 to that of peak 3 at Kd=0.5 as measured by gel permeation chromatography on cross-linked dextran is at least 2:1, then subjecting the solution to rapid drying to solid form.

Abstract: A method is provided for recovering at least one platinum group metal from an ore containing the same. The method comprises reducing the particle size of the ore to provide the platinum group metal in a leachable condition following which the ore is subjected to leaching with a sulfuric acid solution maintained at a pH of less than 1 during leaching. The solution contains an amount of a soluble bromide compound at least sufficient to complex the platinum group metal while maintaining an amount of an oxidizing agent dissolved in the solutions at least sufficient to maintain the platinum group metal in an ionic form conducive to forming a soluble bromide complex, thereby dissolving substantial amounts of the platinum group metal.

Abstract: A novel composition for use in reducing and recovering metals, such as silver, and for use in stripping adhesive polymer layers from various polymer bases, such as polyester, and processes for using same are provided. The composition and variations thereof can be useful in separating an adhesive polymeric layer from the film for recovery of either. The composition comprises a reducing sugar/alkaline solution that is particularly useful for recovering silver from polyester photographic film where a silver halide light-sensitive emulsion layer is adhered to the polyester film by a polymeric adhesive resin, such as resins containing copolymers of polyvinylidene chloride and polyvinyl chloride. Processes for separation and recovery are also disclosed and claimed.

Abstract: A method for the continuous treatment of air pollution control residues from various resource recovery systems whereby the air pollution control residue is treated with a dilute salt extracting solution at a pH chosen to maximize the recovery of lead, for a reaction time chosen to maximize the recovery of lead, and for a number of recycles chosen to maximize the recovery of lead from the particular residue being treated. Other metals and dissolved salts can also be recovered from the extracting solution. Thus by monitoring these three variables for each batch of residue, and adjusting the extracting solution accordingly, residue from various sources and of varying composition can be treated efficiently and continuously to remove hazardous metals and dissolved salts from the residue. Bottom residue fines, alone or admixed with air pollution control residues, can also be treated in accordance with the process of the invention.

Abstract: A process for recovering at least one precious metal from an ore containing carbonaceous material is disclosed. The process involves the use of promoting amounts of certain metal redox couples and/or metal components, in particular, certain metal complexes with ligands.Preferred metal compositions comprise at least one of (1) redox cyclable vanadium (5+) ligand complex, (2) redox cyclable iron (3+) ligand complex, and (3) redox cyclable manganese (3+) ligand complex. In the process, the use of at least one regenerable component capable of maintaining the complexed metal in the desired oxidation state provides for integrated process synergy.

Abstract: A process for recovering at least one precious metal from an ore containing carbonaceous material is disclosed. The process involves the use of promoting amounts of certain metal redox couples and/or metal components, in particular, certain metal complexes with ligands.Preferred metal compositions comprise at least one of (1) redox cyclable vanadium (5+) ligand complex, (2) redox cyclable iron (3+) ligand complex, and (3) redox cyclable manganese (3+) ligand complex. In the process, the use of at least one regenerable component capable of maintaining the complexed metal in the desired oxidation state provides for integrated process synergy.

Abstract: A quaternary ammonium trihalide, a novel compound, represented by the formula:[A--R'].sup.+ .multidot.X.sub.3.sup.-(wherein A stands for a trialkyl-amino radical or a pyridyl radical, R' for an alkyl radical of 6 to 22 carbon atoms, and X for a halogen atom) and a method for the dissolution of a metal with a liquid consisting essentially of an organic solvent and the quaternary ammonium trihalide.

Abstract: Method for recognition of noble metals otherwise not recognizable in base material clusters includes using an electron beam furnace in which base material clusters are vaporized by means of an electron beam gun, and the vaporized materials are condensed as free atoms or are alloyed with other components of the base materials, and are able to be recovered by conventional recovery techniques once they are recognized. The base material includes the products of smelting processes, pellets of compacted raw material, like anode-mud or waste material, and the base materials are remelted utilizing the heat from electron beam guns for the remelting.

Abstract: A process for the hydrometallurgical recovery of gold from gold-bearing material comprising the step of treating gold-bearing material with an acidic lixiviant solution containing thiourea and ferric ions, characterized in that the said solution also includes a complexing agent for ferric ions, whereby consumption of thiourea is significantly reduced. The complexing agent may be selected from the group consisting of di- and tri-carboxylic acids, phosphoric acid and phosphate salts, thiocyanates, fluorides, fluosilicic acid and fluosilicate salts, EDTA and EDTA salts, and mixtures thereof.

Abstract: A process and apparatus for leaching metal values from a particulate mineral ore containing metal values employs a fluidized bed of the particles; a leaching agent solution containing dissolved oxygen flows upwardly of the bed in a lower leaching zone, to an upper clarification zone; a velocity profile is maintained to promote settling of particles so that the particulate solids remain in the leaching zone and a clarified leachant-containing liquid low in suspended solids rises and collects in the clarification zone; the process is carried out with a minimum of undissolved gas and avoids the need for mechanical agitation, but the kinetics of the chemical leaching reaction is improved and heat loss via escaping gases is avoided.

Abstract: A process for biooxidation of sulfides in a heap of mineral ores by freeing precious metals dispersed or occluded within said ores as pyritic or arsenopyritic sulfides and the like; the process comprises forming particulates from ore particles with an inoculate comprising bacteria capable of attacking, by biooxidation, sulfides and/or elemental sulfur in said ore particles; from these particulates a heap is constructed; and the biooxidation takes place in such heap by adding to or dispersing within the heap a leaching solution, circulating the leaching solution within the heap and recovering the precious metal values from the heap; recovery may be accomplished with a cyanide, thiourea, or a thiosulfate lixiviant.

Abstract: Disclosed is a process for recovering precious metals using a combination of smelting and an effective utilization of molten salt chlorination. More specifically, disclosed is a process including the steps of (i) contacting, for example, a matte with a chloride salt containing at least one of potassium, cesium or rubidium, but not sodium or lithium to form a matte/salt solids mixture, (ii) introducing the solids mixture into a chloride melt having a temperature ranging from 300.degree. C. to 650.degree. C., said melt containing at least one of potassium, cesium, rubidium, sodium or lithium, (iii) introducing a chlorine containing gas into the melt, and (iv) maintaining the salt ratio in the matte/salt mixture at a stoichiometrically equivalent amount with the precious metals and base metals contained in the matte.

Abstract: Methods are disclosed for treating smelter flue dust and other smelter by-products so as to recover non-ferrous metals therefrom and convert arsenic and sulfur in the flue dust into non-leachable compounds. The methods allow the flue dust and other smelter by-products such as smelter sludges to be disposed of in a natural environment without subsequent leaching of heavy metals, sulfur, and arsenic. The smelter by-products are mixed with hydrated lie, formed into agglomerates, and roasted at an optimal temperature of about 650.degree. C. to form oxidized arsenic and sulfur which react with the lime in the agglomerates to form non-leachable compounds. The roasted agglomerates are contacted with a basic lixiviant comprising dissolved ammonia and an ammonium salt to dissolve non-ferrous metals such as copper from the roasted agglomerates. Used lixiviant can be boiled to precipitate the non-ferrous metals dissolved therein and vaporize the ammonia, thereby regenerating the lixiviant.

Abstract: A process for separating precious metals from an MnO.sub.2, sulfidic or carbonaceous refractory ore or refractory feed such as tailings is provided. The process includes the step of leaching a feed with a leach liquor that includes an acid selected from the group of HCl and H.sub.2 SO.sub.4 in the presence of MnO.sub.2 and a reductant. A source of chloride ion is added to the leach sufficient to dissolve at least about 50% of the precious metals present in the ore. A portion of the leach is removed and precious metals are recovered from the removed portion. A portion of the chloride carrier is recycled to the leach to carry chloride values to the leach. In one embodiment, HCl is regenerated by pyrohydrolysis, which minimizes harmful waste products. The present process can advantageously avoid the use of noxious reagents.

Abstract: A process for the extraction of copper from a copper ore or concentrate comprises first subjecting the ore or concentrate to agitation leaching at an elevated temperature and pressure in the presence of oxygen and water to obtain a resulting acidic leach liquor which contains dissolved copper. The acidity of the resulting acidic leach liquor is then reduced by affecting percolation leaching of a bed of low grade copper ore or waste rock with the resulting acidic leach liquor, whereby the pH of the leach liquor is raised, for example to a value of about 1.5 to 2. In a preferred embodiment the bed of low grade ore or waste rock is in the form of a heap and the percolation leaching comprises heap leaching.

Abstract: Disclosed is an efficient biological process for recovering heavy metals from refractory manganiferous ore, and a process for removing heavy metal contaminants from the soil. The process utilizes manganese reducing Bacillus sp. Specifically exemplified is a novel microbe designated Bacillus MBX 69, or mutants thereof, and the known microbe Bacillus polymyxa, which is disclosed in U.S. Pat. No. 5,055,130. Further, gene(s) encoding the enzyme(s) obtainable from the said bacteria can be used by placing such gene(s) on a suitable vector and transforming a competent host. The transformed host then can be used in the same manner as the native microbe. Also, the enzyme(s) themselves can be used in the above-described processes.

Abstract: Agglomerating agent and method for use in heap leaching of mineral bearing ores. A moderate to high molecular weight anionic polymer preferably in combination with lime provides a highly effective agglomerating agent. The anionic polymer is preferably a copolymer of acrylamide and acrylic acid. The polymer preferably has a molecular weight of from about 1 to 8 million or higher.

Abstract: Improved methods of heap leaching of copper ore with aqueous sulfuric acid solutions comprising a fluoroaliphatic surfactant are disclosed. The fluoroaliphatic surfactant increases the amount of copper values leached and recovered.

Abstract: A process for recovering gold from refractory gold-bearing ores uses sulfurous acid as the leaching agent to form a gold-sulfite complex. The ore is ground, slurried blended with a chelating agent and then subjected to a simultaneous dissolved SO.sub.2 leaching and anion exchange resin adsorption step in the presence of dissolved oxygen. The gold transfers to the resin which is later separated from the resin by chemical stripping.

Abstract: A process for recovering gold from gold-bearing ores includes the steps of forming a slurry of ground ore and treating the ore with an oxidizing and complexing agent such as hydrogen sulfide or a sulfide salt. A chelating agent, SO.sub.2, air, and an anion exchange resin are added to the slurry to subject the ore to a simultaneous sulfurous acid leaching and anion exchange resin adsorption step in the presence of dissolved oxygen. The gold transfers to the resin which is then removed from the slurry. The gold is then separted from the resin by chemical stripping. Alternately, the ground ore is blended with an oxidizing agent such as calcium hypochlorite and then with a gold-complexing agent. The ore blend is slurried in water, with the addition of a chelating agent, SO.sub.2, air and an anion exchange resin to effect the leaching and adsorption of gold values.

Abstract: From an ore containing gold and silver, the gold and silver are extracted by a method which comprises pulverizing the ore and bringing the pulverized ore into contact with an elemental halogen, a halogenated salt, and an organic solvent thereby converting the gold and silver into polyhalogeno anionic complexes and consequently dissolving them in the organic solvent.

Abstract: The invention provides a method of forming copper arsenate. Copper and arsenic are leached into a treatment solution maintained at a pH level of about 2 to 5 in the presence of at least one impurity. An oxidant is added to the treatment solution to oxidize the copper and arsenic. A copper arsenate compound is precipitated from the solution as copper arsenate. Preferably, the copper arsenate is then releached in a purification solution. The molar ratio of copper to arsenic is adjusted to a level of at least 2. The pH of the purification solution is then increased to precipitate copper arsenate having a decreased concentration of said at least one impurity. Impure copper arsenate may be suspended and reacted in a recrystallization solution preferably having cupric ion. The pH of recrystallization solution is adjusted to a valve between about 1 and 4.5.