Abstract: A process for the recovery of copper and zinc values from copper and zinc containing sulphidic ore includes subjecting ground ore to a flotation operation. An initial copper concentrate is floated in a first flotation step, and the initial copper concentrate is fed to a second flotation step to float a relatively zinc free copper concentrate. Remaining ore from the first flotation step is fed to a third flotation step to float an initial zinc concentrate, and remaining ore from the third flotation step is fed to a fourth flotation step to float a copper and zinc containing material. An intermediate concentrate containing from about 5 to about 25% copper and from about 2 to about 25% zinc, with a total of at least about 12% copper and zinc, is produced by selecting at least the remaining ore from the second flotation step, and a zinc concentrate containing at least about 20% zinc is produced by at least selecting a portion of the initial zinc concentrate.

Abstract: Anode slimes from an electrorefining operation are fed, together with sulfuric acid, into a heated pelletizer wherein a sulfation reaction occurs, simultaneously with pellet formation, to solubilize copper, nickel and tellurium contained in the slimes.

Abstract: Metal sulphide ore is leached by water under a low pressure and oxidizing atmosphere to dissolve zinc and copper, hydrolyze iron to hematite, and leave lead and precious metals as insoluble sulphates. The residue is leached by sodium chloride and calcium chloride to dissolve lead and the precious metals.

Abstract: A process for treating sulfide ores to reduce the sulfur content or recover the metal content therefrom comprises the use of enzymatic action to solubilize the sulfur and metal content.A nutrient, such as a saccharide, is used along with yeast spores which feed on the sugar and produce enzymes which act on sulfur in the sulfide ore to cause the sulfur to go into solution and to dissolve those metals which are soluble in strongly acidic solution. Sulfuric acid can be formed from the sulfide ores or from free sulfur by reaction with water, with evolution of hydrogen sulfide gas. Oxidation of at least a portion of the hydrogen sulfide can be achieved to regenerate sulfuric acid.

Abstract: A process for extracting copper from a compact mass, such as bulk metallic copper and/or copper highly contaminated with insoluble substances, in which the mass of metallic copper is leached with a liquor containing Cu.sup.2+ ions and SO.sub.4.sup.2- ions, the liquor being oxidized separately from the leaching stage, e.g. with oxidizing agents including oxygen-containing gases such as air. At least part of the oxidized liquor is recycled to the leaching stage for the metallic copper. The copper sulfate solution which thus results is recovered.

Abstract: A multi-step process for recovering metal values from lead smelter matte. The matte is mixed with sulfuric acid and manganese oxide and leaching is effected at atmospheric pressure to form an aqueous solution including dissolved metal sulfates and a residue containing sulfur and lead sulfate. The sulfur is removable by conventional means and the lead sulfate may be returned to the smelter. The pH of the aqueous sulfate solution is adjusted to 3.5 to 4.5 to precipitate ferric iron and arsenic and pH is readjusted to about 3.0 to redissolve coprecipitated copper. After separation from the precipitate, the aqueous solution is mixed with a sulfiding agent, such as sodium sulfide at a pH of not more than 3 to selectively precipitate copper sulfide. After separating the copper sulfide, the aqueous solution is mixed with further sulfiding agent at a pH of 3 to 4.5 to form a cobalt-nickel sulfide precipitate in which the weight ratio of copper-nickel to sulfur is 1.8.

Abstract: A process for separating molybdenum values from sea nodules which includes sulfation of the sea nodules, volatilization of the molybdenum values from the sea nodules and collection of the volatile molybdenum values.

Abstract: The specification discloses a method for recovering non-ferrous metals such as zinc or copper from their concentrates, ores or any other metal containing materials into a solution containing these non-ferrous metals as sulphates and a minimal amount of dissolved iron. The resultant solution is suited without or with minimum pre-purification treatment for conventional electrowinning processes to recover such non-ferrous metals with less difficulties than the previous methods involving complex iron-removal processing. There is disclosed a method for recovering at least one non-ferrous metal soluble in sulphuric acid from a strong sulphuric acid solution containing said metal and iron as sulphates, said method comprising the following consecutive steps:subjecting said solution in a sub-divided form to thermal decomposition in a fluidized bed reactor at a temperature of from 600.degree. to 750.degree. C.

Abstract: Process for extraction and separation of metals utilizing the advantages of liquid-liquid extraction with cation exchangers without requiring the equivalent addition of alkali. The process is based on a combination of leaching the metal-containing raw materials with an organic acid (cation exchanger) and a subsequent use of the formed metal cationic complex in a liquid-liquid extraction process. In the said extraction process, the organic solution of metal complexes is used to recover and separate metal ions from an aqueous solution of metal salts.

Abstract: The process of the invention is for the separate recovery of elemental sulfur and residual sulfides and metal salt solution from reaction slurries obtained from leaching of metal sulfides in ores and concentrates.

Abstract: Sulfidic minerals containing metal values such as copper, silver, nickel, cobalt, molybdenum, zinc, iron, or mixtures thereof are leached in two stages. In the second stage, preleached minerals are oxidized with nitrogen dioxide to enable the metal values to be solubilized in the aqueous acidic leach liquor in that stage. During the reaction, the nitrogen dioxide is reduced to nitric oxide. The nitric oxide is oxidized to nitrogen dioxide by oxygen. The acidic metal bearing liquor from the second stage flows to a first stage where it preleaches fresh minerals. The metal bearing liquor is delivered from the first stage to metal recovery while preleached minerals are delivered to the second stage.

Abstract: A process for the dissolution of precious metal values in a concentrate thereof wherein the concentrate is caused to alloy with aluminum and the alloy is then leached in at least two steps, the first of which is to remove base metals and in the second of which the precious metals are dissolved using hydrochloric acid and chlorine gas or nitric acid as an oxidant.

Abstract: A copper-containing sulfidic material is dead-roasted at a temperature of at least 750.degree. C. and the resulting calcine is leached in a sulfuric acid solution to dissolve most of the copper in preference to any iron, nickel and cobalt in the material.

Abstract: A hydrometallurgical process for treating copper refinery anode slimes containing selenium, lead and precious metals in which a selenium product of better than 99.7% purity can be produced and the final residue is suitable for smelting to produce anodes for silver refining.

Abstract: A method for treating nonferrous metal hydroxide sludge waste to separate and recover the nonferrous metals therein wherein the waste is first mixed with an alkali hydroxide or carbonate, dried, and then roasted and the water-insoluble residue in the roasted material is treated with sulfuric acid to produce an acid-insoluble residue and a sulfuric acid solution containing copper, aluminum and chromium and thereafter, separating the copper from this solution by liquid-liquid extraction and thereafter, separating the aluminium, chromium, zinc and nickel from the remaining solution by separate liquid-liquid extraction steps.

Abstract: A process for treating thermally activated metal sulfides containing copper, iron and zinc for separate recovery of zinc as zinc sulfide in which the metal sulfides are subjected to a two-stage countercurrent acid leach for the formation of copper sulfide containing acid leach residue and ferrous sulfate solution. The second-stage acid leach is performed in two steps; the first step is operated at a relatively high pulp density and high acid concentration for iron and zinc extraction, the resulting slurry diluted, and the second step is operated at a relatively low pulp density and low acid concentration for dissolution of precipitated ferrous sulfate and precipitation of any dissolved copper values by H.sub.2 S. The diluent solution for the slurry from the second-stage first step preferably is generated sulfuric acid solution from a jarosite precipitation and iron and zinc-containing solution from a subsequent activation leach.

Abstract: A process for improving overall recovery of copper from an integrated mining and metallurgical processing operation by utilizing iron-containing copper ore materials as mined, such as low-grade copper ores and mine wastes, and crushed or granulated copper-containing slag obtained by smelting the higher-grade portions of such ore materials, involves the minign of such ore materials, the smelting of higher grade portions thereof, and the leaching of copper values from lower grade portions thereof with an aqueous, weakly acidic lixiviant to produce an acidic, ferric, effluent solution. The smelter slag is leached with the such effluent solution and copper values are recovered from the resulting pregnant solution. If desired, the barren solution may be recycled to the initial ore leaching step. By maintaining the pH of the acidic, ferric effluent solution from the initial leach within its normal range of about 1.9 to 3.

Abstract: An integrated process for the recovery of copper from impure copper bearing materials is provided by leaching the copper bearing material with sulfuric acid to convert the copper value to the soluble copper sulfate, selectively extracting the copper value from the leach liquor by contacting the liquor with an organic extractant stripping the copper from the organic copper extractant by contacting with liquor of enhanced acid content resulting from a subsequent reduction step, thus regenerating the organic extractant, contacting and thus reacting the acidified copper containing solution with an organic solution of amine extractant to reduce its acid concentration to a desired level, and recovering the copper metal by reacting the copper containing solution of lowered acid content with sulfur dioxide.

Abstract: Highly toxic metallurgical waste materials from copper smelting and/or refining operations are processed on a cyclic basis for recovering copper values therefrom while protecting the environment from contamination. The waste materials, usually smelter flue dust and/or refinery sludge containing copper values and principally arsenic, bismuth, lead, antimony, and cadmium, as toxic values, with or without added sulfuric acid, are reacted in an autoclave at an overpressure atmosphere of O.sub.2. The resulting solution, pregnant with copper and still containing a significant amount of arsenic, i.e. from about 0.5 to about 2.0 grams per liter, is subjected to copper cementation on metallic iron to recover copper and to provide iron values in the solution while substantially eliminating residual toxic constituents, surprisingly without the evolution of arsine gas. The copper-barren but iron-containing solution is then recycled to the leaching step.

Abstract: A sulfide containing copper and one or more of iron, nickel and cobalt, is dead-roasted at a temperature of 750.degree. C or above, then subjected to a pressure leach under reducing conditions to produce elemental copper and an aqueous solution of the other metals.

Abstract: Sulfidic minerals containing metal values such as copper, silver, nickel, cobalt, molybdenum, zinc, iron, or mixtures thereof are oxidized with nitrogen dioxide to enable the metal values to be solubilized in an aqueous acidic leach liquor. In practicing the invention, the minerals are added to an aqueous acidic leach liquor and a nitrogen dioxide containing gas is sparged through the slurry to oxidize the metal values. During the reaction, the nitrogen dioxide is reduced to nitric oxide. The nitric oxide is oxidized to nitrogen dioxide by oxygen, either in-situ, or in a separate off-gas oxidizer.

Abstract: Undigested matte particles in autoclave leach residues containing iron oxide are separated from iron oxide by subjecting an aqueous slurry thereof to flotation without the use of a flotation reagent by bubbling air therethrough to form a froth containing said undigested matte particles which is recycled for further leaching and provide an iron oxide-containing tails which is removed and discarded.

Abstract: The improvement in the method of recovering copper from low grade ore containing oxidized copper ore which comprises establishing a dump of such ore in fragmented form, substantially completely wetting the ore in the dump with strong aqueous sulfuric acid containing at least about 100 g/l H.sub.2 SO.sub.4, allowing the acid wetted ore to age for a period of at least about three days, thereafter washing the aged ore with dilute aqueous sulfuric acid containing about 5 to 40 g/l H.sub.2 SO.sub.4, collecting such washings, and recovering copper therefrom.

Abstract: Copper is processed via solutions of copper salts, both cupric and cuprous, in acidified aqueous solutions containing organic nitriles. Methods of producting solutions of cuprous salts include reduction of cupric salts and oxidation of copper and copper sulphides. Solutions of cuprous salts are thermally or electrochemically disproportionated to produce copper and solutions of cupric salts.

Abstract: Process for quantitatively converting non-ferrous metals chosen from the group consisting of copper, nickel, cobalt, vanadium, and manganese in an ore concentrate to soluble sulfates and simultaneously convert the ferrous values in the ore to insoluble oxides. The process comprises roasting finely divided ore particles at a temperature in excess of 650.degree. C. in the presence of a roaster gas comprising at least a stoichiometric amount of oxygen and at least 1% SO.sub.2. The roasting is performed in the presence of a sufficient amount of a mixture of salts to allow the formation of a liquid coating on the ore particles. In a preferred embodiment, the mixed salt which forms the liquid coating comprises Na.sub.2 SO.sub.4 and K.sub.2 SO.sub.4 with the ratio of sodium to potassium being between 1.0 and 2.0.

Abstract: A method is provided for leaching comminuted nickeliferous sulfide matte containing by weight about 20 to 75% nickel, about 5 to 50% copper, non-stoichiometric sulfur in the range of over 4 to about 24%, over 0.5 to about 20% iron, the sum of the nickel, copper and sulfur contents being at least about 80% of the matte composition, with the balance gangue or slag and incidental impurities.Nickel is selectively leached from the comminuted matte using sulfuric acid or spent copper electrolyte solution at substantially atmospheric pressure while vigorously aerating the solution, wherein the pH is raised sufficiently to produce a nickel solution with an iron content of less than about 10 ppm and a copper content of over 5 ppm, the copper being thereafter selectively removed from the nickel solution by passing the solution through an ion-exchange resin selective to the absorption of copper.

Abstract: Nickel is selectively leached efficiently and rapidly from Ni-Cu-Fe-S matte under oxidizing conditions at ordinary pressure by controlling in combination the following variables: (1) the acid-to-copper mole ratio in the leaching solution, (2) the temperature, and (3) the sulfur content of the matte, whereby an enriched nickel solution is obtained low in copper and iron.

Abstract: Copper is recovered from ores containing sulfidic copper minerals by forming the ore into a dump leach heap, and substantially saturating (i.e. thoroughly wetting) the ore in the heap with an aqueous strong acid solution containing 100 to 400 g/l H.sub.2 SO.sub.4 and 5 to 50 g/l ferric ion. The ore thus saturated is cured in contact with the strong acid solution for a curing period of at least 2 days, and generally from 5 days to 6 months or even longer, depending on the character of the ore and its permeability by the acid solution. The ore in the heap may be run of mine size, or may be coarsely crushed, again depending on permeability to the strong acid solution. After the curing period, the ore in the heap is washed by percolating through it a weak acid solution containing up to 50 g/l H.sub.2 SO.sub.4 and 5 to 50 g/l ferric ion. The wash solutions are collected and treated for copper recovery. Washing is continued until the copper content of the heap has been largely extracted.

Abstract: Pressure leaching metal bearing mineral material such as silver and copper bearing mineral material, e.g. sulfide and/or oxide, with an aqueous liquid containing sulfuric acid and very low concentration nitric acid under oxygen pressure, to dissolve out the corresponding desired metal values from such mineral material with nitric acid regeneration;Acid pretreatment of such metal bearing mineral material by preliminary leaching with an aqueous liquid containing sulfuric acid and very low concentration nitric acid under normal ambient pressure, to dissolve substantially attendant acid soluble metal carbonate values, e.g.

Abstract: After separating brine from the slime and drying the same with solids therein, dried solids are subjected to roasting in an oxydizing temperature of 350.degree. to 400.degree. C, and then leaching the roasted material with predetermined acid and withdrawing sulfur oxides from waste gases generated during the roasting step.

Abstract: This invention relates to a process for leaching broken or fragmented ore or metal-value containing bodies with a reagent-carrying foam. The foam is generated by adding a surfactant to a leaching solution and passing air or other gas through the solution to generate relatively stable foam bubbles which are propelled through the fragmented mass by gas pressure. The foam can be injected in cycles, allowing drain time, or can be injected continuously with the leachant drainage taking place at the periphery of the ore mass and removed continuously.

Abstract: A method and apparatus are described for continuously leaching ore, including the continuous addition of crushed ore to the top of a cylindrical columnar container. The ore passes downwardly through the container and is removed from the bottom of the container through a centrally disposed conduit by airlifting. A plurality of grids are spaced along the column and deflect, accelerate and turbulate the ore as it passes each of the grids. A washing liquid such as water is fed to the bottom of the column to displace leaching solutions from the ore prior to its removal from the column. Leaching reagents are continuously added through channels provided in the grids while the pregnant solution formed by the reaction of the leaching solutions to the ore is monitored through sampling intakes mounted on the grids. A deflection cone is positioned near the bottom of the column to cause the descent of the crushed ore in the column to be uniform across the width of the column.

Abstract: Cuprous sulphate solutions, suitable for thermal or electrochemical disproportionation to yield copper, are obtained by dissolving copper sulphites, such as Chevreul's salt or cuprous ammonium sulphite, in acetonitrile-water or 2 hydroxycyanoethane-water mixtures, preferably in the presence of cupric sulphate. This discovery is capable of a number of applications, one of which is the recovery of copper from chalcopyrite by the following five steps. An oxidizing roast of chalcopyrite such as to produce either cupric sulphate and/or copper oxide, leaching of cupric sulphate from the calcine, precipitation of Chevreul's salt and/or other copper sulphites with a soluble salt of sulphurous acid, including bisulphites, dissolution of the copper sulphite as cuprous sulphate, using cupric sulphate in an acetonitrile-water solution as oxidant; precipitation of pure copper by thermal disproportionation of the cuprous sulphate solution. Acetonitrile and acidic cupric sulphate solution may be recycled.

Abstract: A process which enables cumulative recovery of nonferrous metal values from manganiferous sea nodules and a limonitic ore comprises treating the limonitic ore in an aqueous acidic medium under reducing conditions to extract nonferrous metals and iron from the ore and form a solution containing ferrous iron and then leaching the sea nodules with such solution to extract nonferrous metals from the sea nodules and precipitate a predominant amount of the iron as hydrated ferric oxide.

Abstract: A process for recovery of zinc values contained in thermally activated iron containing copper and zinc sulfides in which said activated sulfides have been subjected to an acid leach in aqueous sulfuric acid to produce a solution of ferrous sulfate and a solids residue containing copper and zinc values. The solids residue containing copper and zinc values is reacted with an acidic copper sulfate solution to precipitate copper values as a simple copper sulfide with concurrent dissolution of iron and zinc values to form a solution of ferrous sulfate containing said dissolved zinc values and said solution of ferrous sulfate is separated from the simple copper sulfides and reacted with H.sub.2 S for precipitation of zinc values therefrom as zinc sulfide. Any nickel and cobalt values present in said activated sulfides is dissolved in said solution of ferrous sulfate and reacted with the H.sub.2 S at elevated temperature for selective precipitaton.

Abstract: A process for extracting metal values from manganiferous sea nodules is provided in which nickel, copper, and cobalt values are selectively leached in a sulfuric acid medium in two stages, the first stage being effected at a temperature up to about 100.degree. C and to a final pH of not less than about 1.5 and the second stage being effected at a temperature of about 160.degree. C to about 260.degree. C and at an initial pH of not less than about 1.5.

Abstract: A counter current decantation system for the fluid separation of liquids or solids having different densities or absorptive capacities wherein the material to be separated is placed in an inclined separator having a series of decantation pipes, each of which is connected at the bottom thereof to a pump for pumping a fluid mixture upstream at varying pressures. The separation fluid enters the separator at the bottom with sufficient force to form a mixture with and agitate the material to be separated. Lighter material is caused to rise toward the fluid surface and the heavier material is caused to settle to the separator floor by gravity. The force supplied is sufficient to cause the fluid mixture to pass forwardly through the length of the separator and thus the fluid mixture has a tendency to flow downstream toward the bottom end of the separator.

Abstract: A process for the recovery of metals from copper reverberatory slag containing iron in the form of silicates comprising roasting said slag in an oxidizing atmosphere at a temperature of at least about 550.degree. C in the presence of sulfur trioxide for a time sufficient to effect decomposition of substantially all of said iron present in the slag to iron oxide and the other metals therein to water-soluble salts and metal oxides, and separating the water-soluble metal salts and metal oxides from the iron oxide and silica residue.

Abstract: This invention provides a novel and an improved hydrometallurgical method for recovering copper values from copper concentrates. The method essentially comprises the following steps:A. forming an aqueous leach solution containing chloride or bromide ions in a predetermined concentration;B. dispersing copper concentrates in such leach solution to form a slurry;C. carrying out the leaching operation of the slurry at an elevated temperature and under an overpressure of oxygen so as to transform a major proportion of the copper values present in the concentrates into a solid basic copper sulphate;D. separating the resulting leach residue containing the basic copper sulphate from the leach solution; andE. recovering the copper values from the obtained leach residue.The process is simple and efficient and can be carried out either batchwise or continuously.

Abstract: The ore is subjected to nitric acid leaching and the leach solution is heated to a temperature at which one of the additional sulfur and iron values is selectively insolubilized with respect to the solution, while the other is maintained in solution for subsequent separation from the liquor after the insolubles have been removed and the liquor has been neutralized. In addition, in one embodiment of the invention the heating and acid neutralization steps are controlled within certain prescribed limits to make it possible to remove the metals from the liquor by solvent extraction without the problem of lasting precipitates forming in the liquor and fouling the extraction process. Where there is a sizable amount of dissolved iron in the liquor, the liquor may be subjected to autoclaving at a temperature above about 149.degree. C (300.degree. F) to precipitate the iron as the oxide thereof. This effect is possible even where the liquor is high in sulfate concentration.

Abstract: A process for the leaching and recovery of copper values from copper-containing material which comprises vat leaching a sulfidic copper-containing material with an aqueous acidic ferric sulfate leach solution initially containing at least 10 gpl ferric ion to form a copper pregnant leach solution containing substantially less than 10 gpl ferric ion and a corresponding increase in ferrous ion concentration, extracting said leach solution with an extractant selective to copper and non-selective to iron to strip the copper values from said leach solution, adjusting the acid content of the stripped leach solution to between about 10 to 20 gpl to form an acidic leach solution, passing said acidic stripped leach solution through at least one mineral dump containing oxidized copper for a time sufficient to cause reoxidation of ferrous ion to restore the concentration of ferric ion to at least about 10 gpl, adding sufficient sulfuric acid to the dump off-solution to cause said solution to have an acid concentration o

Abstract: The method comprises the steps of crushing of the ore, neutralization by a mixture of water and sulphuric acid, introduction of a controlled quantity of sulphur dioxide gas at a pH value between 1.5 and 4 for promoting dissolution of nickel, copper and a desired quantity of manganese, leaching of the ore with sulphuric acid at a pH value between 1 and 3 for selectively dissolving the nickel and copper, separation of the solid and liquid phases, and separation of the metals contained in the liquid phase.

Abstract: A technique is provided for leaching particulate ores for recovering metal values. Ore is crushed to less than about one inch with at least 25% being greater than 4 mesh. The crushed ore is mixed with a small amount of acid and the moistened mixture is kept in a curling pile for about two days for dehydration and induration of the ore. The induration is sufficient that the ore can sustain the weight of a thin layer of about one-half to one meter thick without appreciable compacting. The indurated ore is spread on a permeable substrate in a thin layer about one-half to one meter thick. A leaching solution is then percolated through this thin layer to remove the metal values. The initial effluent leach liquor has high metal values and low acid content and is passed to a solvent extraction system where the metal values are recovered. The solvent extraction raffinate, which is high in acid, is recirculated as a leach liquid.

Abstract: This invention provides a method for treating manganese oxide ores in an aqueous medium, with hydrogen halide or sulfuric acid, and a hydrogen sulfide or a metal sulfide, e.g. an ore. A leach liquor containing the desirable metal halides is then separated from the solid, insoluble residue. Any iron value in either the manganese oxide ore or in any metal sulfide ore present is not dissolved or is converted to an insoluble iron oxide. Elemental sulfur is also obtained.The metal values in the leach liquor are recovered by crystallization of the manganese halide and liquid ion exchange extraction of the other metal values present.

Abstract: According to the process described, non-ferrous metal values, particularly nickel, copper and/or cobalt, are extracted from metallurgical intermediates, such as matte and speiss, by reacting the material under oxidizing conditions at a pH of about 4.5 to 6.5 with an ammonia free aqueous solution containing ammonium sulphate, sodium sulphate and/or nickel sulphate. The reaction-products of this operation are then mixed with sulphuric acid under ambient conditions to decrease the pH to about 3-4.5 and to dissolve the non-ferrous metals in the solution which is then separated from the undissolved residue. The process is particularly useful in treating intermediates containing precious metals in that the precious metals are substantially completely recovered in concentrated form in the undissolved residue.

Abstract: In the oxidative leaching of copper ores with a silver catalyst initially dissolved in the leaching liquor, all or a portion of the silver precipitates and is recovered with the tailings. Elemental sulfur is extracted from the tailings, and the tailings are treated with concentrated sulfuric acid in the presence of oxygen to recover silver values for recycle to the leaching.

Abstract: The ore is subjected to nitric acid leaching and the leach solution is heated to a temperature at which one of the additional sulfur and iron values is selectively insolubilized with respect to the solution, while the other is maintained in solution for subsequent separation from the liquor after the insolubles have been removed and the liquor has been neutralized. In addition, in one embodiment of the invention the heating and acid neutralization steps are controlled within certain prescribed limits to make it possible to remove the metals from the liquor by solvent extraction without the problem of lasting precipitates forming in the liquor and fouling the extraction process. Where there is a sizable amount of dissolved iron in the liquor, the liquor may be subjected to autoclaving at a temperature above about 149.degree.C (300.degree.F) to precipitate the iron as the oxide thereof. This effect is possible even where the liquor is high in sulfate concentration.

Abstract: A method is described for the oxidation-leaching of chalcopyrite concentrates at high temperatures and pressures for the extraction of copper values as copper sulfate in which temperatures are maintained between about 425.degree. and 450.degree.F, oxygen partial pressures of between about 50 and 200 psi are provided, and levels of acidity are permitted to increase above about 50 grams of H.sub.2 SO.sub.4 per liter in order to obtain maximum rates of extraction of virtually all of the copper. Thereafter, while maintaining the temperature and pressure at elevated levels, the acidity of the slurry is reduced to between about 10 and 40 grams of H.sub.2 SO.sub.4 per liter in order to obtain reduction of dissolved iron to optimal levels. The resulting slurry is then cooled and further processed for the production of a very pure copper sulfate solution.

Abstract: Method of preparing cuprous sulfate and bisulfate solutions from materials containing copper and impurities by a leaching process are disclosed. The leaching composition contains sulfuric acid, cupric ions, water and an organic nitrile. The leaching composition may be used with copper sulfide ores in particulate form. The cuprous solutions resulting from the leaching can be treated by disproportionation methods to recover pure copper.

Abstract: A hydrometallurgical method of recovering zinc, copper and cadmium from their ferrites so that the ferrites are treated under atmospheric conditions in sulphuric acid bearing solution in the presence of potassium-, sodium- or ammonium-ions, is disclosed, in which the treatment takes place in one stage under such conditions that the non-ferrous metals, zinc, copper and cadmium, contained in the ferrites are transferred as sulphates to the solution and the iron is converted in the same stage to a solid basic iron salt by adjusting the sulphuric acid or ferric sulphate addition to be equivalent with regard to the ferrite amount fed into this stage and by adjusting the temperature to 80.degree. - 105.degree.C, preferably to 95.degree. - 105.degree.