Abstract: A process for recovering a metal chloride or mixed metal chloride from a solid waste material comprising recoverable metal containing constituents produced by lead, copper or zinc smelting and refining processes, said process comprising the steps of: (i) heating the solid waste material; (ii) treating the heated material of step (i) with a gaseous chloride to form a gaseous metal chloride containing product; and (iii) treating the gaseous metal chloride containing product of step (ii) to recover the metal chloride or mixed metal chloride. The metal chloride may be further treated to extract the metal itself.

Abstract: The present invention relates to methods for recovering precious metals including silver and gold, rare metals including indium and gallium, base metals including copper, lead and zinc or a combination of precious, rare and base metals from complex oxide ores, sulfide ores or oxide and sulphide ores using an acid chloride oxidizing leach.

Abstract: A process for leaching a value metal from a base metal sulfide ore, comprising the step of leaching the ore with a lixiviant comprising a chloride, an oxidant and hydrochloric acid is disclosed. The leaching is controlled, by use of low concentrations of hydrochloric acid and a redox potential, to effect formation of hydrogen sulfide from the base metal sulfide ore. The hydrogen sulfide is stripped from the leach solution, thereby reducing the amount of sulfate generated in the leach to very low levels. The leaching may also be conducted to limit the co-dissolution of platinum group metals and gold with the base value metals. The leach forms a value metal-rich leachate and a solids residue. The solids residue may be subsequently leached to recover the platinum group metals and gold. The value metal-rich leachate can be oxidized and neutralized to recover the value base metals. In an embodiment, the chloride is magnesium chloride and lixiviant solution is regenerated.

Abstract: A hydrometallurgical process for the treatment of complex silver-bearing sulfide ores and concentrates that recovers substantially all silver, lead, antimony, zinc, copper and sulfur, along with the chemical reagents utilized during the process. Finely ground ores and concentrates are leached under heat and pressure with water, sulfuric acid, nitric acid, oxygen, and a catalyst, and are further treated to recover silver in the form of silver chloride; iron in the form of iron hydroxide; copper and all traces of soluble toxic metals as sulfides; zinc as zinc ammonium sulfate and specifically nitric acid, sulfuric acid, oxygen, ammonia, and ammonium compounds as valuable fertilizer products.

Abstract: The invention relates to a method for recovering gold in connection with the hydrometallurgical production of copper from a waste or intermediate product containing sulphur and iron that is generated in the leaching of the copper raw material. The recovery of both copper and gold occurs in a chloride environment. The gold contained in the waste or intermediate is leached by means of divalent copper, oxygen and alkali bromide in a solution of copper (II) chloride and alkali chloride, in conditions where the oxygen-reduction potential is a maximum of 650 mV and the pH a minimum of 0.5. The bromide accelerates the dissolution of the gold.

Abstract: Methods and systems for removing copper minerals from a molybdenite concentrate. One embodiment provides leaching copper from the molybdenite concentrate with a leaching solution comprising ferric chloride, removing molybdenite from the leaching solution, introducing an acid into the leaching solution and introducing O2, O3, or a combination of both, into the leaching solution. A method for regenerating ferric chloride in a leaching solution is also provided. One embodiment provides adding a leaching solution comprising Fe(II) ions, Fe(III) ions, or a combination of both, to a mixture of mineral sulfides, introducing an acid into the leaching solution, and introducing O2, O3, or a combination of both, into the leaching solution.

Abstract: A process for leaching a value metal from a base metal sulfide ore, comprising the step of leaching the ore with a lixiviant comprising a chloride, an oxidant and hydrochloric acid is disclosed. The leaching is controlled, by use of low concentrations of hydrochloric acid and a redox potential, to effect formation of hydrogen sulfide from the base metal sulfide ore. The hydrogen sulfide is stripped from the leach solution, thereby reducing the amount of sulfate generated in the leach to very low levels. The leaching may also be conducted to limit the co-dissolution of platinum group metals and gold with the base value metals. The leach forms a value metal-rich leachate and a solids residue. The solids residue may be subsequently leached to recover the platinum group metals and gold. The value metal-rich leachate can be is oxidized and neutralized to recover the value base metals. In an embodiment, the chloride is magnesium chloride and lixiviant solution is regenerated.

Abstract: A chemical process to leach copper concentrates in the presence of a concentrated solution of sulfates and chlorides. The process includes forming a high reactivity chemical paste containing a high concentration of ions in the liquid phase of the paste which react with copper ores and forms a series of soluble salts. The salts are extracted by a simple wash. Mixing equipment for handling high viscosity liquids is used. The total mixing time is about 5 minutes, after which the paste is poured into a rectangular mold, of several hundred meters per side, and is left to settle and breathe. During settling, water and sulfuric acid are added at intervals to replace that consumed by the reactions taking place during the aeration, until the reactions have virtually end. This treatment results in a dry, very resistant mass, containing the copper extracted in form of chlorine salts, and sulfate.

Abstract: A method for dissolving base metals and noble metals from ores having base metals and noble metals which comprises adding the ore to a solution of a non-acid oxidizing agent, then adding an aqueous solution of an acid forming halide and then adjusting the H+ concentration of the combined solutions to a minimum H+ concentration of 1 mol/l.

Abstract: Precious metal values, e.g., platinum, palladium and rhodium, and, optionally, other valuable elements, e.g., one or more rare earths and cerium in particular, are recovered from a wide variety of compositions of matter and articles of manufacture, for example waste or spent catalysts such as vehicular postcombustion catalysts, by (i) optionally comminuting such composition/article into a finely divided state, (ii) intimately admixing the composition/article with sulfuric acid, (iii) calcining the resulting admixture at a temperature ranging from 150° to 450° C., and (iv) leaching the calcined admixture in an aqueous medium, whether simultaneously or separately, with H+ ions and chloride ions, whereby obtaining (1) a solid residue substantially depleted of such precious metal values and, optionally, of such other elements, and (2) at least one liquid solution comprising such precious metal values and, optionally, such other elements.

Abstract: A method for dissolving noble metals out of segregated ores containing noble metals, comprising: reducing noble metal oxides present to the individual metals in finely divided form; oxidating the segregated ores and/or the noble metals with HCl and chlorate to yield a solution or suspension having a concentration of H+ ions of at least 1 mol/l, a concentration of Cl− ions of at least 1 mol/l and a temperature of at least 50° C.

Abstract: A method of separating copper from chalcopyrite, including heating a mixture containing chalcopyrite particles containing copper components and hydrochloric acid at a temperature of at least 110.degree. C. for a period of time sufficient to convert the copper components into a water-soluble state. The heated mixture is then mixed with water to leach out the water-soluble copper components from the particles into water.

Abstract: An efficient method is proposed for the recovery of gold value from a waste material containing scrap gold by utilizing a principle that metallic gold can be dissolved at elevated temperatures and specifically precipitated at low temperatures with good reversibility in and out of a specific unique liquid medium which is an organic solvent, e.g., acetonitrile, containing an ionic compound of a first halogen, e.g., quaternary ammonium halides, and an elementary form of a second halogen each in a specified concentration, of which at least either one of the first and second halogens is iodine. Namely, a gold-containing waste material is contacted at a high temperature with the liquid medium to have the gold value dissolved therein and the gold-containing solution is then cooled to a low temperature so that the gold value can be recovered in the form of precipitates in a high purity.

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: 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: The present invention is a process to recover precious metals from sulfide ores. It involves chlorinating a mixture of an ore concentrate and salt to form a liquid melt. The salt preferably contains potassium chloride. This chlorination is carried out at a temperature between 300.degree. and 600.degree. C. while stirring. The process converts precious metals in the elemental and sulfide forms into precious metal chlorides which are recovered by subsequent processing steps.

Abstract: A method of treating a gold-bearing ore to render the gold component of the ore more amenable to standard cyanidation treatment in a reduced amount of time is disclosed. An aqueous slurry of the gold-bearing ore is introduced into at least one vessel. An oxidizing agent, such as chlorine gas, an alkali metal hypochlorite and an alkaline earth metal hypochlorite, is rapidly introduced into the vessel so that it intimately contacts the aqueous slurry. While the oxidizing agent is being introduced into the vessel, the slurry is agitated with agitating means including a plurality of impeller blades that provide high shear agitation and a large interfacial surface area between the oxidizing agent and the liquid phase of the slurry to enhance the mass transfer of the oxidizing agent so that it becomes substantially completely adsorbed by the aqueous slurry in about 5 to about 15 minutes.

Abstract: A process for the hydrometallurgical recovery of metal value, particularly copper, from copper-containing sulphide materials in which the material is conventionally ground and reacted with a solution containing less than 3 moles per liter of chloride ion, and optionally as little as 15 g/liter, together with sulphate ions with continuous oxygen injection and vigerous agitation. The reacting may be carried out at a pH in the range of 0.5-4, at moderate pressure as low as atmospheric pressure and at a moderate temperature below the boiling point of the solution such as 85.degree. C.

Abstract: Metal values are extracted from aqueous solutions of metal salts containing halide or pseudo halide ions by pyridine derivatives containing the substituent --(COX).sub.A where X is the group --OR.sub.1 or --NH.sub.2 R.sub.3 and n is 1, 2 or 3. R.sub.1 is a hydrocarbyl group containing from 5 to 36 carbon atoms and R.sub.2 and R.sub.3 are hydrogen or a hydrocarbyl group wherein R.sub.2 and R.sub.3 together contain from 5 to 36 carbon atoms. The process is especially useful for the recovery of metals from leach solutions derived from sulphur-containing ores such as chalcopyrite.

Abstract: A method for removing and recovering toxic heavy metal contaminants from an iron-bearing sludge is provided. The method comprises one or more cycles of a two step, controlled chloride leach comprising a first non-acidic chloride leaching solution and a second acidic chloride leaching solution, wherein said toxic heavy metals are separated from said sludge and said iron-bearing sludge is a substantially non-hazardous material.

Abstract: Disclosed are processes and an apparatus for refining gold. One of the processes comprises dissolving unrefined gold by use of iodine and/or an iodide compound to form a solution containing an iodide compound of gold, removing insoluble substances in the solution, reducing the ions containing the gold by use of an alkali to precipitate the gold of high purity. In this process, the iodine may be obtained by electrolyzing the iodide compound. The other process and the apparatus further comprise circulating the solution having been separated from the precipitated gold for reuse, and the alkali simultaneously produced by the above electrolysis is economically employed therein.

Abstract: Nickel is separated from copper contained in predominantly nickel- and copper-bearing sulphidic matte and alloys by chlorine leaching in an autoclave at over-atmospheric pressure. The leaching is conducted in an acidic solution at a redox potential range which favors the dissolution of nickel over copper. The obtained leach solution is purified in a cementation step carried out at atmospheric or over-atmospheric pressure by adding more sulphidic matte or alloy particles. The separated purified solution is treated for nickel recovery. Any cobalt present in the sulphidic matte or alloy reports with the nickel. Copper is recovered from the separated residue, which will also retain precious metals, if present.

Abstract: A hydrometallurgical process for enrichment of gold, platinum and palladium from copper electrolysis anode sludge, and simultaneously recovery of selenium, in which the sludge is treated with Cl.sub.2 /HCl to transform the selenium of a hexavelent state and precipitate out silver chloride. The filtrate is then subjected to selective reduction of precipitate the noble metals and the resulting filtrate is chlorinated and a further reduction is effected to precipitate the metallic selenium.

Abstract: Silver is recovered from photographic emulsion by a process comprising oxidizing whereby the emulsion is oxidized with an acid solution of 10-26 percent ferric chloride at a pH of up to about 2.

Abstract: An improved process for recovering gold from gold-containing materials by iodide/iodine leaching is provided wherein the pregnant lixiviant containing solubilized gold and iodine is treated in an electrolytic cell to reduce gold in solution to elemental gold for recovery and reduce iodine to iodide at the cathode, so as to prevent iodine from interfering with subsequent gold recovery processes, and at the same time reoxidize iodide present at the anode to elemental iodine to regenerate the leach solution to the desired iodide:iodine weight ratio, e.g. about 2:1 to about 10:1. Gold is precipitated in the cathode compartment, and if desired, the cathode effluent may be treated for further removal of traces of gold before being passed to the anode compartment. A method for preventing iron contamination of the cathode is also provided comprising buffering the lixiviant solution to a pH of about 5.

Abstract: Gold sand resulting from the nitric acid treatment of silver refinery slimes is purified by washing with hydrochloric acid under controlled operating conditions. Platinum and other precious metals and impurities are selectively separated from the gold sand leaving a gold sand which is more efficiently refined.

Abstract: A hydrometallurgical process for recovering pure silver from sludge formed at the anode in copper electrolysis and other sources comprises suspending the sludge, after removing Pb, Ni, and Cu, in hydrochloric acid, subsequently adding an alkali metal hypochlorite, preferably NaOCl, to the resulting suspension to convert the silver present to AgCl, filtering to separate the AgCl containing solid residue from the filtrate containing the other metallic elements, and finally working up the AgCl containing residue to obtain high purity silver. Preferably the high purity silver is obtained from the AgCl containing residue by leaching with an alkaline ammoniacal solution to dissolve the silver as the soluble silver diamine chloride, and subsequently reducing the silver diamine chloride to silver metal. The reducing agent for the silver diamine chloride is preferably either a Cu.sup.+ containing compound such as CuCl or a metal powder such as copper or bronze powder.

Abstract: This invention provides processes for selectively recovering silver and gold values from feed materials containing both precious metals, and comprises leaching the feed material with a hot ferric chloride-acid brine leach solution for a time sufficient to dissolve the silver, but wherein the gold is not dissolved and remains with the solid residue. The silver-containing ferric chloride-acid brine leachate is separated from the solid residue containing the gold. The leach solution is then cooled to precipitate the silver as silver chloride. The solid residue containing the gold is then leached with hypochlorous acid to dissolve the gold, and after separating the solids form the gold-containing hypochlorous acid leach solution, the gold is precipitated by contacting the solution with sulfur dioxide. The silver chloride may be further processed in a fused salt electrolysis step at or above the melting point of silver to produce a substantially pure silver and chlorine gas.

Abstract: Metal values are separated from arsenic sulfide ores in a hydrometallurgical oxidation process using a balanced reactant slurry. The molar concentration of As and Sb in the reactant slurry is controlled with respect to the molar concentration of Cu, Pb, and Zn in the slurry so that, upon reacting, soluble arsenic compounds or toxic arsenic vapors are not formed.

Abstract: A process for the hydrometallurgical recovery of gold from materials containing gold comprising leaching the materials with a lixiviant containing iodine. To a solution concentrated with natural salts is added elemental iodine until saturated, whereupon mineral sulfides in the ore zone charged with this solution react with the iodine to form iodide. Additional elemental iodine is then added to this iodide-bearing solution until the desired concentration of total iodine and ratio of iodine to iodide are achieved for optimum leaching. The lixiviant is then circulated through the ore zone until all the gold is dissolved. Gold is subsequently recovered on activated charcoal. The excess iodide formed during the process is reoxidized to iodine electrochemically in a special diaphragm cell to regenerate the lixiviant.

Abstract: A process for selectively leaching lead and silver chlorides from a sulfide ore residue in a rapid time which comprises brine leaching the residue under pressure at a temperature above the normal boiling point of the solution, preferably above 100.degree. C.Modifications are leaching at the agglomeration temperature of sulfur when present in the residue to agglomerate the sulfur for ease of recovery, and flashing from leach temperature to ambient as a lead chloride crystallization recovery step to produce a large crop of lead chloride crystals per pass.

Abstract: Metal values, such as copper, lead and zinc, are recovered from complex sulfides, e.g., ores or smelter flue dusts, by means of aqueous leaching in the presence of oxygen and CaCl.sub.2 or BaCl.sub.2 at elevated temperature.

Abstract: Gold is recovered from a material including gold and molybdenum or tungsten by contacting the material with an aqueous solution of hydrogen iodide and iodine to solubilize the gold without solubilizing the molybdenum or tungsten and recovering the gold from the solution.

Abstract: A process is disclosed for producing cuprous chloride from chalcopyrite by means of a cupric chloride leach utilizing particular processing conditions in order to obtain relatively high cuprous chloride concentrations. The processing conditions are maintained so as to conduct the leach in accordance with the general reaction:(3X+12Y)Cu.sup.++ +CuFeS.sub.2 +8YH.sub.2 O.fwdarw.(4X+12Y)Cu.sup.++ +XFe.sup.++ +(2X-2Y)S.degree.+2YSO.sub.4 =+16YH.sup.+ +(1-X)CuFeS.sub.2under reaction conditions such that "X" is maintained from about 0.35 to about 0.9, "Y" is maintained from about 0.075 to about 0.35 and the sum of 3X+12Y is initially greater than 3.

Abstract: A process for the production of a sulphidic copper concentrate from a complex sulphidic concentrate containing as its main constituents copper, iron and at least one non-ferrous metal selected from the group consisting of zinc, lead, nickel and cobalt, comprising mixing the complex sulphidic concentrate with a copper-containing predominantly chloridic solution thereby to form a suspension, and treating the suspension thus obtained at elevated temperature and pressure at a pH-value of below 3, thereby to form a sulphidic copper concentrate, thereby the non-ferrous metals being extracted from the concentrate without formation of significant amount of acid. Precious metals may also be present. Advantageously the ratio by weight of the complex concentrate added to the copper-containing predominantly chloridic solution to the copper content of the solution is such that the predominantly chloridic solution after being at least partly freed from copper by an exchange reaction has a potential at 60.degree. C.

Abstract: An improvement in hydrometallurgical recovery of metals, i.e. copper, zinc, cadmium, germanium, indium, lead, silver, gold, antimony and bismuth from materials such as flue dust containing arsenic in which the metals are selectively separated in successive process steps for final recovery, the improvement comprising precipitating arsenic as an insoluble ferric-arsenic compound in the first processing step, carrying the insoluble arsenic compound through subsequent processing steps in which it is insoluble until the other metals have been recovered leaving the ferric-arsenic compound as the final residue which can be disposed of without violating pollution requirements or converted to soluble sodium arsenate and recovered from solution by crystallization.

Abstract: An improvement in the hydrometallurgical recovery of metals, such as, lead, silver, gold, antimony, and bismuth from materials such as flue dust in the presence of arsenic, comprising precipitating arsenic as an insoluble ferric-arsenic compound in the first processing step, carrying the insoluble arsenic compound through a chloride leach step, in which it is insoluble, to recover the metals, and disposing of the residue in which the arsenic has been fixed with ferric ions to render it non-polluting, or alternatively, recovering the arsenic by caustic leach and crystallization.

Abstract: The process of leaching manganiferous ocean nodule ores with HCl whereby the manganese and other metals present, such as iron, zinc, cobalt, nickel, copper, and like are converted from oxides, silicates or other insoluble forms to water soluble chlorides, and are thereafter separated, purified, and the manganese recovered as MnO.sub.2 by oxidation with chlorine to provide a material suitable for use in metallurgical applications, may be improved by controlling the chlorine pressure and the pH of the leaching reaction in order to first leach out the metals other than manganese; as chloride, and thereafter recovering the manganese in the form of its silicate, aluminate, oxide, or the like.

Abstract: Aqueous lead solutions obtained by hot chloride leaching of residues containing lead and silver ore are subjected to selective precipitation of the silver as silver sulphide, with e.g. hydrogen sulphide. The silver can then be recovered in a known manner. Lead can be precipitated from the remaining solution as a basic salt also in a known manner. If the initial residue contains copper, it is also precipitated as sulphide. The copper sulphide can be separated from the precipitate by selectively dissolving the copper with sulphuric acid under an elevated oxygen pressure. Elemental sulphur is formed and the silver sulphide can be separated from the elemental sulphur in a known manner.

Abstract: A process for extracting non-ferrous metal values from an oxide ore. The process comprises leaching the ore with a solution containing at least one alkali metal chloride or alkaline earth chloride salt in the presence of an oxygen-containing gas at a temperature and pressure sufficient to solubilize the non-ferrous metal values into the solution of the metal chloride salt.

Abstract: Copper, iron, and lead impurities are removed from molybdenum flotation concentrates by mixing the feed concentrates with a nonvolatile chloride salt, heating the mixture to a temperature of from about 200.degree. to 350.degree. C for a time sufficient to activate the lead impurities in the concentrates so that they can be leached therefrom during the subsequent leach step, and leaching copper, iron, and lead impurities from the heat-treated concentrates with a mildly oxidizing leach solution containing chloride ions and having a pH of no more than 4. Preferably, the mixing of the chloride salt and the feed concentrates is achieved by thoroughly mixing an aqueous solution of the salt with the feed concentrates.

Abstract: A process for the re-utilization of the sulphate residues from the electrolytic treatment of zinc.The residues are digested hot with concentrated HCl in the presence of CaCl.sub.2. PbCl.sub.2 crystallizes on cooling. FeCl.sub.3 is extracted with TBP circulating in the direction of a series of columns and FeCl.sub.3 is extracted in a first column, washed in a second column and re-extracted a third column. The solution which issues is treated with NH.sub.3, resulting in precipitation of the majority of the hydroxides of the metals contained therein, which are subsequently separated, while Ag, Zn and Cu are complexed. Ag is precipitated with (NH.sub.4).sub.2 S.NH.sub.3 is recovered by means of lime. CaCl.sub.2 is re-cycled to the start of the process and Cu and Zn are leached together with the mineral.Application of the process to the recovery of the metals contained in the residues from the digestion of blends.

Abstract: An improvement in conventional processes for recovering metal values from sulfide ores containing lead, zinc and silver sulfides in which process the metal sulfides are converted to chlorides by chlorination followed by solubilization of the chlorides with a sodium chloride leach and subsequent recovery of the metals from their chlorides in accordance with a conventional flow sheet including crystallization, cementation, precipitation, fused salt electrolysis, etc., with chlorine being recovered for reuse by electrolysis of the sodium chloride leach solution substantially depleted of lead, silver and zinc, the improvement being a pollution-free process which comprises:1. recycling the sodium chloride solution depleted of a major percentage of lead and silver to the sodium chloride or brine leaching step; and2.

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: Complex sulfide ores or concentrates are decomposed by treatment with a combination of chlorine and oxygen, the amount of chlorine being limited to that necessary to convert sulfides of the desired metals, such as zinc, lead, copper, cadmium, silver, nickel and cobalt to chlorides.

Abstract: A method is disclosed for oxidation of finely-divided sulphide ores or mattes containing iron, with one or more of the elements nickel, copper, cobalt, zinc and lead as constituents, in the presence of iron chloride in an oxygen-containing atmosphere at a temperature of 220.degree.-400.degree. C, to convert the mixture of iron chlorides and sulphides to water-insoluble iron oxide, the nickel, copper, cobalt and zinc being converted to water-soluble chlorides and sulphates, and the lead to a sulphate which may be leached away from the residual iron oxide by special solvents for lead sulphate. The initial iron chloride is preferably obtained by adding aqueous hydrochloric acid to the concentrate, if iron sulphide is present in a susceptible form, to drive off a portion of the sulphide sulphur as hydrogen sulphide gas, and to convert the corresponding iron sulphide to iron chloride. Temperatures may rise as high as 450.degree. C during the roasting phase if special conditions are observed while cooling.

Abstract: A process is disclosed for separating cuprous chloride from a solution comprising cuprous chloride and at least one metal chloride compatible with the solubility of cuprous chloride, the process comprising crystallizing the cuprous chloride from the solution in the presence of cupric chloride in an amount such that the cupric chloride to compatible metal chloride mole ratio is at least about 0.1.

Abstract: The raw material contains 80% by weight of an alloy of two at least of the metals of the group Fe, Ni, Cr, Cu, Co (and possibly sulphur), in the form of ingots, scrap-metal or mats, in pieces less than 200 mm in size. The alloys are firstly subjected to a chlorination operation at a temperature comprised between 600.degree.C and 1350.degree.C and then to the recovery operation for the chlorides formed. An enclosure, called a chlorination enclosure, is charged with (a) the alloy, (b) a gaseous mixture containing chlorine and HCl, (c) oxygen, and (d) at least one agent for regulating the temperature of the enclosure. The composition of the gaseous mixture, when it is constituted at the same time of Cl.sub.2 and of HCl, responds to the following conditions:5 % < the proportion of Cl.sub.2 < 90 %1 % < the proportion of HCl < 75 %1 % < the proportion of O.sub.2 < 35 %the partial pressures satisfying on their part the following conditions:2P.sub.Cl.sbsb.2 + P.sub.HCl > 0.2 atmosphere, andP.sub.