Abstract: A process for the recovery of zinc from zinc-containing sulphidic material which also contains iron and from zinc oxide containing material, at least one of the materials containing lead and/or silver values. The process includes leaching zinc-containing sulphidic material and zinc oxide containing material under pressurized oxidizing conditions at a temperature in the range of from about 130.degree. to about 170.degree. C. in aqueous sulphuric acid solution with a stoichiometric excess of sulphuric acid relative to the zinc content of the materials of from about 40 to about 100% to produce a residue containing a major proportion of lead and/or silver values and a leach solution containing a major proportion of the zinc and iron. The residue is separated from the leach solution and treated to recover lead and/or silver values.

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 catalyst, such as FeCl.sub.3, useful in the production of chlorinated hydrocarbons such as 1,1-dichloroethane is removed from the effluent of a process reactor and recycled. Hydrochloric acid is removed from the process stream resulting in the catalyst present in the process stream in solution precipitating out of solution. Then it can be removed from the process stream by conventional separation techniques. Alternatively, the catalyst present in the process stream as a solid, without the removal of HCl, is separated from the liquid present by means of a cyclone and recycled. In both cases, the catalyst retains its catalytic activity.

Abstract: A process for recovering cobalt and nickel values from cobalt and nickel containing sulphidic material also containing iron includes roasting the sulphidic material to produce a calcine containing water soluble cobalt and nickel sulphate, and leaching the calcine in aqueous sulphate solution under oxidizing conditions at an oxygen overpressure in the range of from about 50 kPa to about 1500 kPa and at a temperature in the range of from about 100.degree. to about 180.degree. C. to produce an iron-containing residue and a cobalt and nickel containing solution. The residue is separated from the solution, and cobalt and nickel values are recovered from the solution.

Abstract: According to the present invention, processes are provided for recovery of nickel, cobalt and like metal values from laterite ores wherein the ores are separated into high and low magnesium containing fractions, the low magnesium fraction is leached with sulfuric acid at elevated temperatures and pressure to solubilize the metal values. The pregnant liquor resulting from the high pressure which also contains solubilized Fe, Al and acid is then contacted with a low magnesium fraction of the ore in a low pressure leach under conditions such that at least some of the acid is neutralized and substantially all of the solubilized Fe and Al is removed as hematite and alunite precipitate.In one embodiment, the pregnant liquor from the high pressure leach and the high magnesium fraction are contacted at atmospheric pressure and a temperature of about 80.degree. C. prior to low pressure leaching. In other embodiments, various process streams are separated by size and otherwise, and recycled to within the processes.

Abstract: A process wherein nickel in an aqueous stream is recovered as nickel sulfide by precipitation in an autoclave with pressurized hydrogen sulfide in the presence of a large quantity of recycled fine nickel sulfide seed material is improved when operated under continuous conditions by introducing into the autoclave a small, controlled quantity of supplemental seed material designed to maintain the seed surface area within required limits.

Abstract: The selective leaching of metal ions from various iron oxide and manganese oxide containing ores employs intermediary solutions. The leaching processes are based upon a redox acid leach step employing stabilized cuprous ions and, in one instance, a combination thereof with ferrous ions. Leaching is conducted at low temperatures, up to about 90.degree. C. and low pressures, up to about 1.5 MPa and at a pH of about 1.5 to 2.5. Nickel and cobalt recoveries from the ores, employing these processes, will usually equal or exceed 90 percent. The intermediary solutions comprise stabilized acidic cuprous ions Cu.sup.+ L wherein L is a stabilizing ligand selected from the group consisting of CO, XRCN and Cl.sup.-, X being --H or --OH and R being aliphatic having from one to about four carbon atoms. In at least one process, ferrous ions are introduced for a separate leaching step.

Abstract: According to the present invention, Ni- and Co-rich, low Mg fines may be advantageously separated from the coarse fractions of lateritic ores by atmospheric or low pressure leaching. In particular, the process of the present invention comprises contacting a lateritic ore or ore fraction at temperatures from about 20.degree. C. to about 200.degree. C. and pressures from about atmospheric to about 200 psig with an aqueous acid solution to form a leach liquor, a leach residue and a fines fraction. The fines fraction which can be separated from the residue with the leach liquor by conventional means such as cycloning is found to be richer in Ni and Co and lower than the remainder of the residue.

Abstract: According to the present invention, improved dissolution of nickel and cobalt and thus improved recovery of those desired metal values is achieved by modifying the ore recovery processes wherein sulfuric acid leaching at elevated temperatures is used to dissolve the nickel and cobalt. In particular, according to the present invention, processes are provided wherein the sulfuric acid and ore are contacted at substantially ambient temperature prior to subsequent heating to attain the elevated temperatures of the sulfuric acid leach. Practice of the present invention has been found to result in improved metal value recovery.

Abstract: A hydrometallurgical process for the recovery of cobalt from cobaltite-pyrite concentrates containing substantial amounts of cobalt, arsenic, iron and sulphur is disclosed. The hydrometallurgical process comprises pressure leaching of the cobaltite-pyrite concentrates with a sodium chloride or sodium sulphate solution at a temperature in the range of 130.degree.-160.degree. C. and under oxygen partial pressures in the range of 75-200 psi to solubilize at least 90% of the cobalt content, while simultaneously precipitating most of the iron and arsenic as jarosite and ferric arsenate.

Abstract: The scaling of autoclave and leaching-equipment surfaces during the high pressure leaching of nickeliferous oxide and silicate ores is controlled during leaching to favor the formation of scale containing substantial amounts of magnesium sulfate that is more easily removed by chemical dissolution using water or dilute sulfuric acid at temperatures ranging from about 50.degree. C. to 250.degree. C. than scale containing substantial amounts of alunite.

Abstract: An improved process for de-cobaltizing the primary product of an oxo synthesis is disclosed wherein the primary product is contacted with steam introduced into a vessel to which the primary oxo product is introduced but initially maintained in out of contact relationship to such product by a cooling medium whereby heat transfer from the steam to the primary product is initially avoided. The primary product and steam are fed to a cylindrical reactor having a conical base, and after the steam has risen 1/2 to 2/3 of the height of the conical base it comes in contact with the primary product whose liquid level height in the vessel is maintained at one to two times the vessel's diameter. An apparatus for performing such process is also disclosed.

Abstract: A method is provided for inhibiting the formation of silica scale on flash-pot surfaces during the multi-stage flashing of sulfuric acid pressure-leach slurry obtained following the continuous autoclave leaching of nickel lateritic ore at elevated temperature and pressure during which silica is dissolved, wherein the leach slurry is subjected to a high-temperature flash stage such that the slurry at the flash temperature is supersaturated in soluble silica, and wherein the slurry is thereafter subjected to at least one additional flash at an intermediate-temperature flash stage at which silica precipitates and tends to form a scale accompanied by a decrease in said supersaturation.

Abstract: Fine particle size cobalt metal powder is prepared absent tailings by heating an aqueous solution of soluble cobaltic ammine halide to a temperature of at least about 120 degrees centigrade for a sufficient period of time to decompose said cobaltic ammine halide and form a cobalt containing precipitate. The precipitate is separated from the solution and reduced in a reducing atmosphere to produce fine metal cobalt powder.

Abstract: A process for the removal of iron and aluminum values from acidic solutions thereof with zinc chloride wherein the solution is subjected to pressure hydrolysis to precipitate the iron and aluminum as the hydroxides or oxide hydrates, and then the precipitate is removed and washed. Zinc chlorides which are particularly free from iron and aluminum can be rapidly and easily obtained with this process.

Abstract: A process for purifying copper sulfate solution by converting contained hexavalent selenium to tetravalent selenium which is amenable to removal from solution by heating and maintaining the solution at a temperature in the range of about 135.degree. to 220.degree. C. under a non-oxidizing atmosphere in the presence of bivalent iron. The converted selenium is removed from the solution either by co-precipitation with ferrous iron oxidized and hydrolyzed to ferric oxide at a temperature in the range of 135.degree. to 220.degree. C. and under an oxygen pressure of about 140 to 450 kPa or by cementation with a metal powder at a temperature in the range of about 25.degree. to 85.degree. C. at about ambient pressure under a non-oxidizing atmosphere.

Abstract: A process for precipitation of iron as a jarosite compound from sulfate solution in which said solution fed sequentially through a plurality of reaction zones for oxidation and hydrolysis of ferrous sulfate in the presence of alkali-metal or ammonium ions for jarosite precipitation and simultaneous generation of sulfuric acid is subjected to a "reverse temperature profile", i.e., higher temperature in the last reaction zone than in the first reaction zone, by injection of steam to the last reaction zone.

Abstract: Titanium metal values are recovered from a titanium bearing source such as an ilmenite ore by subjecting the source to a reductive roast and leaching the reduced source with a halogen-containing compound. Following this the soluble metal halides are separated from gangue and the pregnant leach liquor if treated with an iron oxide such as ferric oxide to precipitate titanium dioxide. The nucleation of the titanium dioxide may be improved by using a large excess of ferric oxide in the precipitation step. The improvement will thus result in an increased yield of the desired titanium dioxide.

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: A process for separating and recovering metal values and salts from brine, such as brine produced from a subterranean geothermal reservoir, in which the brine is pressurized to above the bubble point pressure and thereafter a precipitating agent, such as a soluble sulfide, is added to the brine to form insoluble metal sulfide precipitates. The precipitates are separated from the brine while maintaining the brine at a pressure above the bubble point pressure, and the hot brine is subsequently utilized to derive energy therefrom. The brine effluent after such energy derivation and the precipitate are optionally processed to primarily recover saleable salts and metal values, respectively.

Abstract: A method for producing metallic oxide compounds having a spinel type structure by reacting the beta form of hydrated iron oxide with a salt of an effective metallic cation.

Abstract: A method for efficiently precipitating nickel sulfide from an acidic nickel sulfate solution having a pH between 1.5 and 4, containing about 1 to 40 gpl nickel, optionally containing cobalt, and containing sufficient inert soluble sulfate salt to buffer the solution during the precipitation of nickel sulfide at relatively low temperature and pressure.

Abstract: A process for treating a residue from the sulfuric acid leaching of roasted zinc blende, comprising(a) leaching the residue in a single stage with sulfuric acid and a metal sulfide supplied in a quantity sufficient for transforming the iron into divalent iron, the temperature being maintained between about 60.degree. C and the boiling point,(b) heating the mass to a temperature above the melting point of sulfur, separating a first fine-grained residue of low zinc and iron contents and high lead content, and separating a coarse-grained residue containing sulfur, compounds of iron and any excess metal sulfide from (a),(c) adjusting the pH of the residual solution to at most about 2, at a temperature between about 80.degree.

Abstract: A process for the production of high purity iron sulfate monohydrate from an iron sulfide mineral feed involving a leaching, purification, crystallization and dehydration procedure to recover a solution of iron sulfate containing iron sulfate polyhydrates and to convert iron sulfate polyhydrates in a series of steps to monohydrate crystals. The process can be also advantageously used with iron sulfide feed materials containing non-ferrous metals with full separation and recovery of the non-ferrous metals in the sulfide residue of the leaching and purification process of this invention. It can also be used for the purification of industrial pickle liquor solutions which can be treated with the iron sulfide mineral feed in this process leach circuit with full recovery of the ferrous and non-ferrous metals content of these solutions.

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 and apparatus for reclaiming nickel values from a nickeliferous alloy in which the nickeliferous alloy is subjected to nitric lixiviation and the nickel values are recovered from the resulting nickel nitrate solution.

Abstract: The pregnant solution obtained from high pressure and high temperature leaching of nickel-cobalt bearing low magnesium oxidic ores is neutralized at high temperature and pressure by coordinating the leaching of the low magnesium ores with the leaching of nickel-cobalt bearing high magnesium ores, the leach slurry from said low magnesium ore being neutralized by mixing it with said high magnesium ore which is simultaneously leached with said solution to produce a final pregnant solution from which metal values are subsequently recovered.

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 process for the treatment of zinc plant residue formed on leaching zinc calcine with sulphuric acid in which the residue is leached in a first leaching step with a sulphuric acid solution at atmospheric pressure, and a temperature above about 60.degree.C, in the presence of excess zinc sulphide reductant whereby ferric iron in the residue is reduced to the ferrous state, thereby forming a zinc sulphate solution containing excess acid, ferrous iron and other dissolved impurities such as germanium, indium, gallium, antimony and arsenic nd a mixture of solids containing undigested zinc residue, lead residue, and unreacted zinc sulphide. Clarified solution is separated, preferably by thickening, from the mixture of solids. The mixture of solids is leached in a second residue leaching step at atmospheric pressure and at a temperature above about 60.degree.

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.