Abstract: A process for recovering zinc from a zinc containing material, the process including the steps of: leaching the zinc containing material with an alkaline lixiviant comprising an aqueous mixture of NH3 and NH4Cl, or ionic equivalent, having a NH4Cl concentration of between about 10 g/L and about 150 g/L H2O and a NH3 concentration of between 20 g/l H2O and 250 g/L H2O, to produce a zinc containing leachate; stripping ammonia from the leachate to produce a stripped liquor which includes a zinc containing precipitate, the stripped liquor having a NH3 concentration of between 7 and 30 g/L H2O; and recovering the zinc from the stripped liquor.

Abstract: A method of production of activated carbon for removal of mercury gas which provides activated carbon impregnated with both sulfur and iodine which gives a higher mercury gas adsorption performance compared with a conventional activated carbon adsorbent and also enables the prime cost of manufacture to be kept down, that is, a method of production provided with a sulfur impregnation step which adds sulfur to activated carbon and heats the mixture to obtain sulfur-impregnated activated carbon comprised of activated carbon to 100 parts by weight of which sulfur is impregnated in 5 to 20 parts by weight and, after the sulfur impregnation step, an iodine substance impregnation step which adds an aqueous solution containing iodine and an iodine salt to the sulfur-impregnated activated carbon.

Abstract: This invention relates to a method for the selective recovery of manganese and zinc from geothermal brines that includes the steps of removing silica and iron from the brine, oxidizing the manganese and zinc to form precipitates thereof, recovering the manganese and zinc precipitates, solubilizing the manganese and zinc precipitates, purifying the manganese and zinc, and forming a manganese precipitate, and recovering the zinc by electrochemical means.

Abstract: An activated catalyst capable of selectively growing single-walled carbon nanotubes when reacted with carbonaceous gas is provided. The activated catalyst is formed by reducing a catalyst that comprises a complex oxide. The complex oxide may be of formula Ax-wFwBy-vGvOz wherein x/y?2; z/y?4; 0?w?0.3x; 0?v?0.3y; A is a Group VIII element; F is an element that is different from A but has, in said composition, the same valence state as A; B is an element different from A and F, and is an element whose simple oxide, in which B is at the same valence state as in the complex oxide, is not reducible in the presence of hydrogen gas at a temperature less than about 900° C.; G is an element different from A, B and F, and is an element whose simple oxide, in which G is at the same valence state as in the complex oxide, is not reducible in the presence of hydrogen gas at a temperature less than about 900° C.; and O is oxygen. The complex oxide is reduced at a temperature less that 950° C.

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: The invention relates to a method for removing chloride from zinc sulphate solution in conjunction with zinc production. According to the method, the chloride is removed from solution by means of monovalent copper, which is produced in a separate copper(I) oxide formation stage, in which the pH is regulated to the region of 4.5-5.

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: A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

Abstract: The present invention relates to a method for removing halides, in particular chlorides and fluorides, from starting secondary zinc oxides, for example Waelz or Primus oxides, comprising the steps (1) for washing the secondary zinc oxides with sodium carbonate and separating the solid residue from the basic liquid, (2) leaching at least one portion of the solid residue of step 1 by means of H2SO4, preferably up to a pH between 2.5 and 4, and separating the solid residue from the acid liquid, and (3) treating the liquid from step 2 by adding Al3+ and PO43? ions and a neutralizing agent in order to remove the residual fluoride, preferably at a pH<4, and separating the liquid from the solid residue containing fluorides.

Abstract: Cd-112 isotope is recycled from a Cd-112 chemical separated solution or a remainder of an electroplating solution having a Cd-112 target. The present invention recycles Cd-112 isotope with a low cost, a high purity and a high recycle rate. The recycled Cd-112 isotope can be easily stored. And, the Cd-112 isotope can be used as an imaging agent in nuclear medicine.

Abstract: Cd-112 isotope is recycled from a Cd-112 chemical separated solution or a remainder of an electroplating solution having a Cd-112 target. The present invention recycles Cd-112 isotope with a low cost, a high purity and a high recycle rate. The recycled Cd-112 isotope can be easily stored. And, the Cd-112 isotope can be used as an imaging agent in nuclear medicine.

Abstract: Method for producing hydrometallurgical zinc oxide powder having characteristics equivalent to that derived from a French process, comprising formation of an aqueous pulp from a starting zinc oxide having particles of nodular structure, wet milling of this aqueous pulp, separation in this milled pulp between a liquid phase and a solid phase containing the zinc oxide, and drying of said solid phase, coupled with a mechanical deagglomeration of the particles during drying, to obtain a dry zinc oxide powder with particles of nodular structure having a particle size distribution where the particles have an average size (d50) between 0.02 and 20 ?m.

Abstract: A process for reclaiming spent selenium filter mass containing an inert material. The spent mass is treated with a hydrogen peroxide solution for leaching out selenium content from unspent active substance present in the filter mass to form selenious acid. The filter mass is treated with aqua regia solution to dissolve mercury selenide present in the mass. The aqua regia solution is separated from the mass and isolated. Suitably, the filter mass, which now contains inert carrier material, is transferred with the isolated selenious acid, to production of new selenium filter mass. After partial neutralization of the aqua regia solution, mercury is precipitated out for disposal. Before this, elemental selenium can be separated from the aqua regia solution by adjusting the pH level and used advantageously for production of new filter mass. Thusly, reclaimed selenium content and inert carrier material can be advantageously used for production of new selenium filters.

Abstract: Mercury emissions in an exhaust gas are mitigated. Mercury dichloride is formed upon a surface from a substantial portion of the mercury in the exhaust gas. The mercury dichloride sublimes from the surface, and the sublimed mercury dichloride is subsequently removed from the exhaust stream.

Abstract: The invention relates to a method for the removal of mercury from gas containing sulphur dioxide and oxygen and from the sulphuric acid vapour contained in the gas. According to the method, the gas is washed with a water solution that contains selenium ions, whereby metallic selenium is formed in the presence of oxygen, which precipitates the mercury in the gas and vapour either as a selenide or in a chlorine-containing environment, as a dichloride of mercury and selenium. Gas washing occurs at a low temperature, below 50° C.

Abstract: Process for the production of ZnCl2 from a Zn bearing primary and/or secondary material comprising the steps of reacting the Zn bearing material with a chlorinating agent such as Cl2 to convert metals into chlorides and vaporising the volatile components of the reaction product at a temperature between the melting point of said reaction product and the boiling point of ZnCl2, thereby recovering a Zn rich chlorinated melt, and thereafter distilling ZnCl2 from this Zn rich chlorinated melt, thereby recovering purified ZnCl2 and a Zn-depleted chlorinated melt.

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 K061) 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: A new process for producing calcium chloride and other metal halides from the carbonates, bicarbonates, oxides of these metals. The process utilizes the discovery that hydrogen halides, when used in a true or conventional fluidizing medium in shallow beds of the aforementioned solids at moderately elevated temperatures in a continuous counter current process results in the conversion of the metal carbonates, bicarbonates, and oxides, into metal halides and carbon dioxide gas and/or water vapor. The process is carried out in a series of true or conventional fluidized beds preferable but not necessarily arranged in a vertical configuration so that the solids flow downward due to the fluidized process and the hydrogen halides flow counter currently in an upward direction producing metal halides at the bottom and pure carbon dioxide gas and/or water vapor at the top.

Abstract: An apparatus and a process for producing zinc oxide from a zinc-bearing material are provided. The process comprises the steps of leaching the complex sulfide material with hydrochloric acid, ferric chloride, and oxygen; precipitating iron from the leach solution using lime and oxygen; removing copper, silver, cadmium, cobalt and lead from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using lime; and regenerating HCl from a calcium chloride leach filtrate solution to regenerate hydrochloric acid and precipitate gypsum. Related processes for recovering copper, silver, lead, and iron from complex sulfide materials and for recovering lead from residue by solubilizing lead chloride and precipitating it with lime are also provided.

Abstract: The invention is directed to a process for oxidizing gaseous pollutants in a flue gas stream composed of flue gases, water vapour and one or more gaseous pollutants selected from the group consisting of SO2, NO, NO2, H2S, and mercury vapour, the oxidized form of the pollutants being more readily removable from the flue gas stream by water absorption than the non-oxidized form thereof, comprising: (a) injecting sufficient chlorine in a gaseous form, a liquid form, or as a chlorine water solution, into the flue gas stream while the flue gas stream is at a temperature greater than 100° C.

Abstract: A method for producing zinc bromide from zinc hydroxide contaminated with iron and manganese compounds. The method comprises the step of mixing zinc hydroxide feedstock containing metal impurities with a hydrobromic acid comprising elemental bromine in the presence of a reducing agent to produce an impure zinc bromide solution. The metal impurities are removed from the zinc bromide solution in a two-stage process: the first stage comprises the steps of precipitating iron by maintaining the pH within a range of from about 3.6 to 4.15 and filtering out the insoluble iron compounds. The second stage comprises the steps of acidifying the zinc hydroxide solution and adjusting the pH to a range of 3.8 to 4.3 with a alkalinity source from metal oxide, hydroxide or carbonate to precipitate the manganese compounds. The resulting mixture is filtered and concentrated to form a solution comprising zinc bromide essentially free of iron and manganese compounds.

Abstract: The invention provides a process for the removal and recovery of zinc from an aqueous process stream. In particular, the process of the invention is useful in the removal and recovery of zinc compounds such as zinc chloride from an aqueous effluent stream produced in various manufacturing processes such as the manufacture of sorbic acid.

Abstract: A cloud or dispersion of a particulate flux is formed in a combustion zone for the purpose of capturing metallic vapor from the combustion gas by formation of a eutectic of the metal and the flux, as a melt on at least the surfaces of the dispersed flux particles. The flux particles are heated within the combustion zone to a temperature sufficient to form the eutectic melt. The preferred flux particles utilized in the invention include conventional metallurgical fluxes, e.g. calcium carbonate, sodium carbonate and magnesium carbonate.

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: This is a method for the complete leaching of the valuable metals in a metal sulphide material which contains copper, zinc, lead, silver and iron by the use of a solution which essentially contains cupric chloride/sulphates. After the valuable metals have been recovered, the solution is regenerated whereby ferrous chloride and cuprous chloride/sulphate is oxidized to a ferric hydroxide solid and a cupric chloride solution respectively. The regenerated solution is split into two part-solutions and returned to the process.One part-solution goes to a metathesis stage where the fresh metal sulphide material is added in large excess with respect to the part-solutions's content of copper. The result is that only the valuable metals like zinc, lead and silver are leached while copper and iron remain in the residue.The other part-solution goes to a leach stage where the residue from the metathesis stage is added.

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: The process for production of lead from lead sulphide ores involves leaching the ores with a ferric chloride solution, at a temperature from about 70.degree. C. to 105.degree. C., at a pH of from about 4.0 to 0.5, recovering the lead by cementation with metallic zinc, recovering the resultant zinc chloride by solvent extraction, and electrowinning zinc metal from the zinc chloride solution. Chlorine is also electrolytically produced for regenerating ferric chloride for the leaching step.

Abstract: A process for the purification of flue gas generated during the combustion of waste materials has a first embodiment wherein soluble heavy metals are precipitated and recovered in a compact form and wherein the soluble heavy metal-free extraction residue is returned to the combustion system where noxious organic substances are pyrolyzed. In another embodiment, substantially all of the heavy metals from the flue gas are collected in a single solid residue, which residue may be thermally treated to recover mercury and the treated residues subsequently returned to the combustion system wherein noxious organic substances are pyrolyzed or combined in a hazardous waste stabilizing substance.

Abstract: A process is provided for hydrometallurgical processing of steel plant dusts containing cadmium, lead, zinc, and iron values, along with impurities such as chloride and fluoride salts of sodium, potassium, magnesium, etc. The first step in the process involves leaching the dust in a mixed sulfate-chloride medium that dissolves most of the zinc and cadmium. Any iron and aluminum dissolved in this step is precipitated by oxidation and neutralization. Zinc is recovered from the resulting solution by solvent extraction which provides a raffinate which is recycled to the leaching step with a bleed stream also provided for recovery of cadmium and removal of other impurities from the circuit. The lead sulfate residue from the leaching step is leached with caustic soda, and zinc dust is used to cement the lead out from the caustic solution, which then joins the main solution for zinc recovery.

Abstract: A process for the treatment of a spent hydrochloric acid solution containing dissolved iron, zinc, and minor amounts of heavy metals to remove such dissolved metals from the solution, which process comprises contacting said solution with metallic iron in a first stage, whereby trivalent iron present in the solution is reduced to divalent iron and certain of said heavy metals may be reduced to elemental form, next, in a second stage, contacting said solution with metallic zinc, whereby any remaining heavy metals are reduced to elemental form, and then extracting zinc, as zinc chloride, from the resulting aqueous phase with an organic liquid containing a complexing agent for zinc chloride.

Abstract: The invention is concerned with a method for the selective dissolution of lead in relation to zinc that is present as a sulphurized compound.The method comprises treating said compound to lixiviation with a solution containing ferrous chloride, while bubbling a gas that contains oxygen through the lixiviating solution.

Abstract: A process for separating inorganic substances involving their abstraction from a mixture with near-supercritical inorganic fluids. One or more inorganic substances are abstracted and then separatively recovered by retrograde condensations. The process particularly is applicable with mixtures obtained from the chlorination of metalliferous ores and may be conjoined to many ancillary metal abstraction processes such as volatilizations, distillations or electrolyses.

Abstract: A pigment for a color-changing heat indicator comprising a product obtained by interaction of an aqueous solution containing ions of copper and mercury with an aqueous solution of a nitrogen-containing organic compound: an amide of carbonic acid, an amide of thiocarbonic acid, a tertiary amine to give a reaction mixture which is reacted with an aqueous solution containing ions of iodine at an atomic ratio of copper:mercury:iodine equal to 2:1.5:3-5 and an amount of the nitrogen-containing organic compound equal to 0.8-8% of the total content of copper and mercury; the pigment has its critical temperature of from 38.degree. to 70.degree. C. and a heat-resistance of from 160.degree. to 180.degree. C.

Abstract: A hydrometallurgical process is provided for separative treatment of zinc-bearing metallurgical flue dust containing significant amounts of lead, chlorine, and iron. The process is especially suited for extraction of zinc sulfate from blast furnace white dust resulting in the smelting of secondary copper. According to the process, the flue dust is leached in sulfuric acid solution for substantially complete dissolution of soluble constituents, notably zinc, leaving insoluble residue consisting principally of lead oxide. At completion of leaching, pH is selectively adjusted corresponding to the desired extent of subsequent chloride removal. Second, the loaded leach solution is treated for chloride removal wherein chloride ion concentration is substantially and selectively reduced by precipitation of cuprous chloride, cuprous ions being provided by pH regulated reduction of cupric ions.

Abstract: The mercury content of electrolysis cell brine sludge is reduced by sequentially: (1) acidifying the sludge to a pH below 2.5 and (2) leaching the sludge with aqueous hypochlorite solvent. The mercury content removed from the sludge may optionally be isolated from the solvent and reused as mercury cathode for brine electrolysis.

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: A process for removing chlorine from a solution of zinc sulfate, in which the pH of the solution is reduced to below 2.6 with sulfuric acid. Cupric ions are established in the solution in an amount such that after removal of the chlorine by precipitation as cuprous chloride, there remains an excess of cupric copper in the solution which is greater than 0.5 g/l. The cupric ions can be added by adding cupric sulphate and zinc powder, or cupric salt and metallic copper, or cupric copper followed by cuprous oxide. The cuprous chloride precipitate is collected and washed and treated with sodium hydroxide in an amount to raise the pH to more than 7, thereby to precipitate cuprous oxide which is separated by filtration.

Abstract: An improved process for the recovery of mercury from exhausted mercury-containing catalyst by heating the inactive catalyst at 270.degree.-600.degree.C. while passing a carrier gas therethrough, which comprises pretreating the exhausted catalyst with chlorine.