Abstract: The disclosure relates to pre-treatment of precious metal-bearing oxide ores, prior to precious metal leaching by thiosulfate. The process comprises mixing oxide ore in oxygenated water in the presence of a carbon-based material (e.g., activated carbon or other type of carbon). The carbon-based material can be separated from the ore slurry, and, the gold is thereafter leached by a thiosulfate lixiviant.

Abstract: Disclosed are various methods for reducing levels of elemental sulfur within gypsum products such as wall board. Gypsum sometimes includes increased levels of elemental sulfur. Such sulfur can be corrosive and otherwise harmful at elevated levels. The disclosure contemplates reacting the elemental sulfur with copper to copper sulfide. This reaction has the benefit of reducing the levels of elemental sulfur present within the final gypsum product. The copper can be added at any of a variety of locations in the manufacturing process. This is a very efficient method for reducing elemental sulfur in the production of gypsum products.

Abstract: A method for manufacturing a multiple oxide includes: a solution preparing step of adding to iron and steel pickling waste liquid, a lithium compound soluble in acidic aqueous solution and an oxoanion raw-material compound to prepare a mixed solution; a roasting step of introducing the mixed solution into a roasting furnace to roast the mixed solution; and a collecting step of collecting the multiple oxide obtained in the roasting step.

Abstract: The invention relates to a method for separating nickel and other valuable metals particularly from material having low nickel content, which contains iron and magnesium in addition to nickel and other valuable metals. The material having low nickel content is subjected to pulping and atmospheric leaching in acidic and oxidizing conditions, in which the majority of the metals in the material dissolve and the iron is partially precipitated. The precipitated iron is separated from the solution, after which nickel and the other dissolved valuable metals are precipitated as sulphides.

Abstract: A method oxidizes ferrous iron to ferric iron. The method includes providing a liquid, which includes the ferrous iron, and a gas, which includes an oxidizing agent, such as oxygen and/or chlorine; providing two separate mixes, with both mixes including the gas and the liquid; and colliding the separate mixes, thereby obtaining the ferric iron.

Abstract: A method of processing waste iron chloride solution including ferrous chloride, ferric chloride or mixtures thereof and optionally free hydrochloric acid, includes concentrating waste iron chloride solution into concentrated liquid having iron chloride concentration of at least 30%-40% by weight; optionally oxidizing ferrous chloride in the concentrated liquid from the concentration step to ferric chloride providing liquid containing ferric chloride; hydrolyzing the liquid containing ferric chloride from the oxidation step at 155-350° C.

Abstract: The invention relates to a method for separating nickel and other valuable metalsparticularly from material having low nickel content, which contains iron and magnesium in addition to nickel and other valuable metals. The material havinglow nickel content is subjected to pulpingand atmospheric leaching in acidic and oxidising conditions, in which the majority of the metals in themate-rialdissolve and the iron is partially precipitated. The precipitated iron is sepa-rated from the solution, after which nickel and the other dissolved valuable metalsare precipitated as sulphides.

Abstract: The invention relates to a method for hydrolyzing hydrolyzable solid metallic salts, wherein the metallic salts are reacted with aqueous saline solutions.

Abstract: Methods for regenerating amorphous iron oxide hydroxide after being used as desulfurizer by (1) grinding a waste mixture into waste powder, wherein the waste mixture results from use of the composition comprising amorphous iron oxide hydroxide as desulfurizer; (2) preparing the waste powder into a suspension and charging the suspension with a gas containing oxygen to obtain a slurry comprising amorphous iron oxide hydroxide and elemental sulfur; and (3) placing the slurry or a solid resulting from filtering the slurry into a container and charging the slurry or the solid with air so that the elemental sulfur floats and the amorphous iron oxide hydroxide precipitates.

Abstract: The invention is a method of separating metals such as zinc, lead and cadmium from iron in secondary feed stocks such as EAF Dust, BOF Sludge, mill scale, iron fines, tire dust and other iron and zinc containing residues and dusts. The method includes the steps of reduction roasting the feed stocks at a volatizing temperature sufficient to volatilize the zinc and other metals into metal fumes but insufficient to volatize iron and then collecting the metal fumes as a metal dust. The metal dust is then leached with a leaching liquid to form a leach liquor and a leach residue. The leach liquor is then purified by zinc dust cementation to form a purified liquor and a zinc dust cement residue. The purified liquor is then separated from the zinc dust cement residue, and a zinc recovery step is then performed on the purified liquor.

Abstract: A process for treating a finely particulate, in particular metal-containing, charge material: The charge material and a treatment gas, in particular a reduction gas, are introduced into a fluidized bed chamber of a fluidized bed reactor to form a fluidized bed. After at least partial reaction in the fluidized bed, the treatment gas is discharged from the fluidized bed and, outside the fluidized bed, is at least partially reprocessed, preferably oxidized, by an exothermic, chemical reaction with a reactant, preferably with a gaseous and/or liquid oxidizing agent. The thermal energy of this reaction is at least partially introduced into the fluidized bed chamber, in particular into the fluidized bed, or being discharged therefrom to affect the temperature of the particulate material above the bed. Also an apparatus for operating such a fluidized bed includes the chamber, lines into and out of the chamber for gas and material and a cyclone at the chamber for the material.

Abstract: A process for the recovery of nickel and/or cobalt from an impure nickel, cobalt or mixed nickel/cobalt material including the steps of: a) providing a nickel, cobalt or mixed nickel/cobalt material; and b) contacting the nickel, cobalt or mixed nickel/cobalt material with a feed ammoniacal ammonium carbonate solution and a reductant in a leach step.

Abstract: A hydrometallurgical process based on pressure leaching at elevated temperature for recovering nickel from nickel oxide ores, characterized by a simplified and efficient process as a whole, realizing a simplified leaching stage, reduced neutralizer consumption and precipitate production in the neutralization stage, and efficient use of recycled water. The hydrometallurgical process of the present invention, comprising a leaching stage which stirs the slurried ore in the presence of sulfuric acid at 220 to 280° C.

Abstract: A process for recovering nickel from a solid feed material containing nickel in the form of millerite is disclosed. The process includes treating a slurry of the solid feed material and a process solution so that all or at least part of the nickel in the millerite forms an acid leachable solid form. The process also includes pressure acid leaching the treated slurry and leaching nickel in solids in the slurry into solution. Finally, the process includes recovering nickel from solution.

Abstract: Acid mine drainage is treated to form a wet meal-containing precipitate. Such wet metal containing precipitate is dried and processed to form a powder which contains one or more metals. The powder (alone or in combination with other metal powders or other additives) is then compressed (e.g., pressed in a die, rolled, extruded) and sintered to form a desired sintered metal article. In some embodiments, the sintered metal article may be subjected to one or more secondary processes (e.g., oil impregnation, resin impregnation, metal infiltration, copper infiltration, heat treating, steam oxidizing, plating and secondary machining) to alter the strength, configuration or other property of the pressed metal article.

Abstract: A reactor 20 has a plurality of tubular downcomers 32, 34, 36, 38, 40 and risers 42, 44, 46, 48, 50, joined by sections 86, 88 in a continuous serpentine path the tubes dimensioned to provide substantially plug flow conditions for solid and liquid reagents fed into a first downcomer 24 with the products extracted from final riser 52. The reactor 20 is designed for a desired residence time by the number, height and diameter of the tubes. The downcomers 24, 32, 34, 36, 38, 40 may include a bend to improve residence time and to thereby reduce the number of tubes required for a desired overall residence time. The reactor 20 can be used in a leaching operation for producing synthetic rutile, where a pre-treated feedstock including ilmenite, leueoxene or titania slag is leached with hot HCl.

Abstract: Improved methods for treating metallurgical compositions involve reacting a metallurgical composition with an aqueous nitric acid solution. The reaction is performed at a pressure of at least about 220 psig and at a temperature of at least 100° C. The metallurgical composition comprises iron and one or more non-ferrous metals. The reaction dissolves the majority of the non-ferrous metal compositions into the solution which is in contact with solid ferric oxide. The reaction can be repeated on the isolated solids to increase the purity of ferric oxide in the solids. Zinc can be removed from the mixed metal solutions obtained from furnace dust by a variety of separation techniques.

Abstract: A process for recovering nickel and cobalt values from nickel- and cobalt-containing laterite ores as an enriched mixed nickel and cobalt sulphide intermediate and for producing nickel and cobalt metal from the nickel and cobalt sulphide intermediate. The laterite ore is leached as a slurry in a pressure acid leach containing an excess of aqueous sulphuric acid at high pressure and temperature, excess free acid in the leach slurry is partially neutralized to a range of 5 to 10 g/L residual free H2SO4 and washed to yield a nickel- and cobalt-containing product liquor, the product liquor is subjected to a reductant to reduce any Cr(VI) in solution to Cr(III), the reduced product liquor is neutralized to precipitate ferric iron and silicon at a pH of about 3.5 to 4.0, and the neutralized and reduced product liquor is contacted with hydrogen sulphide gas to precipitate nickel and cobalt sulphides.

Abstract: Iron oxides are upgraded by calcining at from 700 to 1200° C.

Abstract: Described is a method for the manufacture of iron hydroxide, iron oxide hydrate or iron oxide from filter salts from thin acid recovery, in which the filter salts are dissolved in water, the solution is adjusted to a pH of <1, then a pH of 2 to 4 is established by the addition of a strong base, with stirring, the substances precipitating are separated in a known manner, the remanent solution is adjusted to a pH of 6 to 8 by the addition of a strong base, the precipitating iron hydroxide is separated from the solution, washed, dried, and, if desired, dried and/or calcined to form iron oxide.

Abstract: The invention relates to a method for the hydrolytic precipitation of iron as jarosite from a sulphate-containing solution in connection with zinc recovery from zinc calcine. The recovey contains neutral leach, ferrite leach, zinc electrolysis and iron precipitation stages. The ferrite included in the calcine is leached with return acid of the electrolysis after which the iron present in ferrous form is neutralized and routed to an iron precipitation stage, where the iron is oxidised to the trivalent form using an oxygen-containing gas. Also present in the precipitation stage arc Na, K or NH4 ions and jarosite nuclei.

Abstract: In a method of producing ferrous sulfate heptahydrate, ferrous sulfate monohydrate is converted in a crystallization reactor in the presence of water into ferrous sulfate heptahydrate as crystallized product, and water is subsequently isolated from the ferrous sulfate heptahydrate. Ferrous sulfate monohydrate is obtained from a pickling solution containing ferrous chloride, hydrochloric acid and water and reacted in a precipitating reactor in the presence of excess sulfuric acid to form ferrous sulfate monohydrate and hydrochloric acid. The ferrous sulfate monohydrate is then dehumidified and converted in a crystallization reactor in the presence of excess water into ferrous sulfate heptahydrate.

Abstract: A method of recovering metal and/or oxide thereof from a slurry is described. The method involves magnetically separating at least a portion of any magnetic impurities from the slurry and then leaching or dissolving at least a portion of any remaining magnetic impurities in a slurry. At least one chelating agent can then be added to the slurry and the solids can be recovered from the slurry by various separation techniques. The methods of the present invention are particularly useful in the recovery of tantalum and/or oxide thereof especially tantalum and/or oxide thereof having a very fine size.

Abstract: A treatment for waste pickling solutions containing iron and method of ferric oxide formation, consisting of spent acid with iron content, the addition therein of sodium hydroxide to adjust the pH value, the execution of a chemical reaction in another tank into which sodium hydroxide and air are added while the admixture is exposed to an ultraviolet beam circuit in a photo-oxidation process, and finally magnetic culling to separate ferric oxide in the solution.

Abstract: A hydrometallurgical process utilizing an atmospheric calcium chloride leach to selectively recover from various metal feed stocks (consisting of elemental metals, metal oxides, metal ferrite, metal hydroxide, metal carbonates, metal sulfate/sulfur compounds, and their hydrates, specifically including but not limited to EAF Dust KO61) zinc, lead, cadmium, silver, copper and other valuable metals to the exclusion of iron, magnesium, halogen salts and other unwanted elements. The process solves the problem of iron and magnesium leach solution contamination because iron is unexpectedly converted to magnetite. The heavy metals are cemented out of solution using zinc or other selected dust at a pH of 6 or greater under unique and unexpected conditions, which do not require acid.

Abstract: Fairly pure metallic nickel may be efficiently dissolved in non-oxidizing acid. If the nickel includes individual pieces longer than 0.5 mm in any linear dimension, oxidizing agent is preferably added from the beginning of dissolution, while if the nickel is powdered so that no single piece has a linear dimension longer than 0.35 mm, oxidizing agent is preferably added only after most of the originally supplied nickel has been dissolved. After oxidizing agent is added, most or all of the remaining undissolved nickeliferous solid will then dissolve. The temperature of the reaction mixture of acid liquid and solid nickel preferably is room temperature at the beginning of dissolution but is raised in steps to a final value of at least 65° C. and maintained at that temperature for several hours.

Abstract: A method of recovering precious metals from metal alloys produced aluminothermically from base metal smelter slag, includes treating the metal alloy with aqueous sulphuric acid solution having a pH of not greater than about 2 to cause dissolution of nickel and/or cobalt and iron and to cause formation of hydrogen sulfide which reacts with copper in the metal alloy to form a copper sulfide precipitate containing at least one precious metal, and separating the copper sulphide precipitate containing at least one precious metal from the remaining solution containing cobalt sulphate and/or nickel sulphate and ferrous sulphate.

Abstract: An improved process of hydrometallurgical treatment of laterite ores predominantly of the limonitic type for the recovery of nickel and cobalt using sulphuric acid. In order to obtain high extractions of these metals while treating these ores in their humid state, in reaction times of up to 60 minutes, temperatures of up to 270° C. and corresponding pressures of up to 800 psia are used. In the present invention, a significant portion of the “mother liquor” emanating from the pressure leaching reaction is recycled to the feed preparation stage thereby substituting for all or a major proportion of the water that must be added. Concomitantly with the major savings in water requirements, a significant reduction in new sulphuric acid requirements is effected along with a corresponding saving in limestone and lime required for subsequent neutralizations. The amount of process water released to the environment is significantly reduced or eliminated.

Abstract: The invention relates to a process for the preparation of superazeotropic hydrochloric acid from metal chloride solutions, e.g. spent pickling solutions. The process is characterized in that the metal chloride solutions are thermally decomposed with the formation of a hydrochloric gas, that the hydrochloric gas is processed in a manner known per se into a superazeotropic mixture of hydrogen chloride and water, the superazeotropic gas mixture being condensed to yield a superazeotropic hydrochloric acid. The invention further relates to a process for ore and/or metal processing employing superazeotropic hydrochloric acid prepared according to the invention.

Abstract: Apparatus and method for regenerating spent pickling liquor from the acid pickling of a metal are disclosed. Acid pickling of a metal uses a first acid and forms a spent pickling liquor (SPL). A second acid added to the spent pickling liquor, under specific low temperatures produces a metal salt of the second acid. The metal salt of the second acid is crystallized and removed from a regenerated first acid. In one aspect, hydrochloric acid is regenerated from a pickling process for iron or steel, using sulfuric acid as the second acid, and ferrous sulfate heptahydrate crystals are produced. Regenerated hydrochloric acid is recycled to the acid pickling process.

Abstract: A method for processing red mud to recover iron, aluminum, silicon and titanium metal values therefrom the method comprising the steps of adding the red mud to a digester containing an acid to provide a mixture of acid and red mud and heating the mixture to dissolve soluble compounds of at least one of iron, aluminum, silicon and titanium to provide a digest containing dissolved salts of the soluble compounds and to provide a gas component. Thereafter, the digest is treated with water to dissolve water soluble salts therein to provide a slurry comprised of a liquid containing water and the dissolved soluble salts and a solid component comprised of silica. The solid component is separated from the liquid and the pH of the liquid is adjusted to form an aluminate and an iron-containing precipitate.