Abstract: Methods and systems for control and adjustment of the feed rate of mercury reemission control additives (MECA) to a wet flue gas desulfurization system. Predetermined sulfite concentration values are compared to actual sulfite concentrations measured in the scrubber liquid. The MECA feed to the recirculating scrubber liquor is then adjusted and regulated as a result of such comparisons.

Abstract: A process for manufacturing reduced iron agglomerates which comprises introducing starting agglomerates that comprise both an iron oxide-containing material and a carbonaceous reducing agent onto the hearth of a moving-bed heating furnace, and heating the agglomerates to reduce the iron oxide contained in the agglomerates, wherein the iron oxide-containing material contained in the starting agglomerates has a mean particle diameter of 4 to 23 ?m and contains at least 18% of particles having diameters of 10 ?m or less. By the use of such starting agglomerates, the process attains: an improvement in the yield of reduced iron agglomerates having large particle diameters; a reduction in the manufacturing time, said reduction leading to an enhancement in the productivity; and a remarkable reduction in the content of impurities such as sulfur in the reduced-iron agglomerates.

Abstract: Methods for recovering gold from gold-bearing materials are provided. The methods rely upon on the self-assembly of KAuBr4 and ?-cyclodextrin (?-CD) in aqueous solution to form a co-precipitate, a 1:2 complex, KAuBr4•(?-CD)2 (“?•Br”), either alone or in an extended {[K(OH2)6][AuBr4]?(?-CD)2}n chain superstructure (FIG. 1). The co-precipitation of ?•Br is selective for gold, even in the presence of other metals, including other square-planar noble metals. The method enables one to isolate gold from gold-bearing materials from diverse sources, as further described.

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 method for reducing mercury emission and/or re-emission in cleaned flue gas through control of sulfite concentration within a wet flue gas desulfurization (WFGD) system is disclosed. One method for reducing mercury emission and/or re-emission through control of sulfite concentration is to measure the sulfite concentration of an aqueous alkaline slurry used in a WFGD system and comparing the same to a predetermined sulfite concentration value. If the comparison reveals the measured sulfite concentration is above the predetermined values, the amount of oxidation air supplied to the system is increased. If the comparison reveals the measured sulfite concentration is below the predetermined values, the amount of oxidation air supplied to the system is decreased.

Abstract: A method of removing lead sulfide contained in refined molybdenite powder concentrates (major component; MoS2) is provided. More specifically, in order to solve the problems associated with a leaching method using a leaching agent that is employed for conventional hydrometallurgical process, oxygen-free inert gas is circulated in a furnace for pyrometallurgical treatment to evaporate lead sulfide at high temperature, followed by condensing process to recover lead sulfide at low temperature. The method is characterized in that, it can reduce environmental contamination and can easily recover sulfides of valuable metals such as lead, indium, zinc and the like.

Abstract: An improved method and apparatus for recovering metal values from Electric Arc Furnace dust, particularly zinc and iron values, by mixing EAF dust and carbonaceous fines to form a particulate mixture; heating the mixture at a sufficient temperature and for a sufficient time to reduce and release volatile metals and alkali metals in a flue gas; collecting the released metals, and removing the metal values from the process as product.

Abstract: A method of processing flue dust, where the flue dust contains one or more compounds from a first group of zinc, lead and cadmium compounds, and contains one or more compounds from a second group of iron, silicon, calcium, magnesium and aluminum compounds, includes mixing the flue dust with a carbonaceous material, heating the flue dust/carbonaceous material mixture under non-turbulent conditions to cause a substantial portion of the compounds from the first group to become gas-borne while retaining a substantial portion of the compounds of the second group in a non-gas-borne condition, and separating the gas-borne compounds from the non-gas-borne compounds.

Abstract: Finely divided material, such as flue dust from a steel making furnace, is processed to reclaim constituents. The material in hopper (11) is pelletized. The pellets are dried in a dryer (16) and fed to a first rotary kiln (21) where they are sintered to provide very hard pellets, during which process volatile constituents are driven off and collected. The sintered pellets are screened to remove finely divided material and fed with reductant, such as finely divided washed anthracite (35), to a second rotary kiln (31). Reduction of the pellets causes a second constituent to be driven off and the second constituent is then oxidized in the kiln and collected as finely divided oxide. The original pellets retain their integrity and become essentially sponge iron.

Abstract: A method for extracting metals from metal-containing materials, especially waste, by pyrohydrolysis. The metal-containing materials which contain at least one or more of the metals from the group consisting of Zn, Cd, Pb, Hg, Cu, Sn (as Sn(0) and Sn(II)), As, Sb, Au, Ag and Bi, are made to react at 700-1100.degree. C., advantageously 800-900.degree. C., with a gas composition which at least comprises 25-45% by volume of water vapor, 0-12% by volume of carbon dioxide, 2-20% by volume of hydrogen chloride, 0-15% by volume of carbon monoxide, the remainder being nitrogen and possibly oxygen. The metals from the above-mentioned group are extracted in the form of volatile metal chlorides.

Abstract: Mercury-contaminated substances are fed through a shredder to a loader that loads a rotary tubular kiln, in which a mercury content is evaporated by a primary burner. A temperature of an unlined rotary kiln is monitored from an outside at various points over an entire length, by infrared sensors. The thus acquired data are supplied to a regulating unit that regulates fuel supply and primary air supply through various control lines. Burned gas is supplied through a duct to a cyclone separator in which solids are separated and returned to the process. The gaseous substances are fed through a postcombustion chamber of a quench to a washer in which mercury is removed. The residual gas reaches a chimney through an active coal filter. This process is particularly easy to control, economical and allows a particularly low residual mercury content to be reached, for example less than 0.1 ppm, in a residual combustion product.

Abstract: A method for separation and recovery of metals and metal oxides from industrial minerals and waste materials containing zinc, lead, cadmium, arsenic, iron, mercury and selenium. The metals and metal oxides in dust form are mixed with a reducing agent and additives, agglomerated, heated above 800.degree. C., and contacted with a flow of inert, reducing or slightly oxidizing gases to volatilize the metals and metal oxides for recovering separate from solid residual product.

Abstract: The present invention relates to a method of removing a metal from a stream of hot gas, wherein a particulate material comprising calcium and aluminum-silicate is contacted in the hot gas to absorb metal present in the hot gas. According to the invention, a meta-kaolin-containing substance is introduced in the hot gas, said meta-kaolin-containing substance being formed by thermally converting a material chosen from the group of I) waste paper, and ii) residue from the paper industry. The invention may be used to remove metals before, during or after the combustion or gasification of fossil fuels, biomass and organic waste.

Abstract: A method for the recovery of iron products, specifically direct reduced iron and iron oxide suitable for use as the feedstock for steel mills, from industrial waste streams containing iron, by treating the waste streams with an ammonium chloride leaching solution, separating the undissolved precipitates comprising iron compounds from the leachant solution, and further treating the undissolved precipitants by elevated temperature roasting, resulting in the iron feedstocks.

Abstract: A method for the separation and recovery of metals selected from the group consisting of iron, cadmium, zinc, and lead, from raw material comprising a mixture of metals, which comprises the steps of heating the raw material to a temperature sufficient to substantially vaporize cadmium, zinc, and lead, and insufficient to substantially vaporize iron; separating secondary dust and vapors produced during the first step from the residual sinter mass, which mass comprises iron; slurrying the secondary dust in an aqueous solution of ammonia ammonium carbonate to dissolve zinc and cadmium; separating a zinc/cadmium bearing leach liquor from substantially insoluble lead containing particles by filtration; treating the zinc/cadmium bearing leach liquor to recover cadmium by adding metallic zinc to the leachate to produce a cadmium containing cement; separating the cement from the leach liquor; and removing ammonia from the leach liquor to precipitate basic zinc carbonate.

Abstract: A method for the separation and recovery of metals selected from the group consisting of iron, cadmium, zinc, and lead, from raw material comprising a mixture of metals, which comprises the steps of heating the raw material to a temperature sufficient to substantially vaporize cadmium, zinc, and lead, and insufficient to substantially vaporize iron; separating secondary dust and vapors produced during the first step from the residual sinter mass, which mass comprises iron; slurrying the secondary dust in an aqueous solution of ammonia ammonium carbonate to dissolve zinc and cadmium; separating a zinc/cadmium bearing leach liquor from substantially insoluble lead containing particles by filtration; treating the zinc/cadmium bearing leach liquor to recover cadmium by adding metallic zinc to the leachate to produce a cadmium containing cement; separating the cement from the leach liquor; and removing ammonia from the leach liquor to precipitate basic zinc carbonate.

Abstract: Residual metallurgical materials which contain zinc and lead are reprocessed by a thermal treatment in a circulating fluidized bed. The required heat is generated in that solid carbon is combusted in the fluidized bed reactor of the circulating fluidized bed. A solid carbon content of 5 to 30% is maintained in the lower part of the fluidized bed. Oxygen-containing gases are supplied to the upper part of the fluidized bed reactor, and CO.sub.2 is formed only in such an amount that zinc metal will not be reoxidized. Substantially all solids are removed from the discharged suspension in a recycle cyclone and are recycled. The gas is cooled to a temperature at which zinc metal is oxidized to ZnO. The dustlike compounds of zinc and lead are separated from the gas.

Abstract: A process is disclosed for recovering zinc, lead, copper and precious metals from zinc plant residue, said process comprising leaching the residue with return zinc spent electrolyte, neutralizing residual acid and reducing ferric iron in the solution by addition of zinc sulphide concentrate in the presence of a limited quantity of oxygen, flotation of the resulting slurry to separate unreacted zinc sulphide, treatment of flotation tailings with sulphur dioxide and elemental sulphur to further leach iron, zinc and impurity elements and precipitate copper, flotation of the resulting slurry to separate a copper sulphide concentrate, thickening, filtering and washing of the flotation tailings followed by addition of lime and sodium sulphide to activate lead sulphate and flotation of a lead concentrate from the residue.

Abstract: A process for recovering valuable metals from an iron dust using a shaft furnace is disclosed. The iron dust is agglomerated and supplied into a the shaft furnace together with a lump coke and a flux. Valuable metal oxides contained in the iron dust are reduced in this shaft furnace. Volatile metals containing zinc and lead among the valuable metals thus reduced are volatilized within the shaft furnace and reoxidized, and then discharged from the shaft furnace together with an exhaust gas so as to be recovered as a crude zinc oxide. The reduced metal iron and slag are accumulated on a bottom portion of the shaft furnace in their molten states, and then separated and recovered.

Abstract: A pyrometallurgical refining process for obtaining one or both of zinc and lead from a sulfide concentrate, in which an iron-silicate slag or iron-silicate slag containing lime is formed and the sulfide concentrate, incombustible materials, and flux, together with at least one of industrial oxygen, oxygen-enriched air, or air, are blown into the slag to cause a reaction; as a result of the reaction, the major part of the zinc and part of the lead in the sulfide concentrate and the incombustible materials are dissolved in the slag, to arrange the slag and a matte and/or metal from one part of the lead in the raw material. A reducing agent such as heavy oil, pulverized coal, powdered coke, or the like is blown through the resulting slag, and the zinc and the lead in the slag are volatilized then condensed to obtain molten zinc and molten lead.

Abstract: A zinc- and lead-containing residue from a metallurgical plant is reprocessed by a thermal treatment in a circulating fluidized bed system. A major part of the heat demand is satisfied by a combustion of solid carbonaceous material in the fluidized bed reactor of the circulating fluidized bed system. A reducing fluidizing gas, which is virtually free of free oxygen, is fed to the lower part of the fluidized bed reactor. A solid carbon content of from 5 to 30% is adjusted in the fluidized bed in the lower portion of the fluidized bed reactor, which is supplied in its upper portion with oxygen-containing gases and in which CO.sub.2 is formed only at such a rate that zinc metal is not reoxidized. Substantially all solids are removed in a recycling cyclone from the suspension discharged from the reactor and the removed solids are recycled. The gas is cooled to a temperature at which zinc metal is oxidized to ZnO. The dust-like zinc compounds and lead compounds are removed from the gas.

Abstract: A process for the econimic recovery of metallic fractions generated during operation of a cupola furnace comprises the steps of the separating filter dust containing metal fractions from an off-gas stream and recirculating the metal fraction back to the cupola furnace for combustion with additional feedstock so as to enrich the metallic concentration of the filter dust to a level where economic recovery of the metallic fraction can occur.

Abstract: This invention relates to the metallurgy of iron and particularly to the separation and recovery of metals from electric arc furnace (EAF) dusts. While the invention discloses a process for the separation and recovery applicable to zinc, lead, cadmium and antimony contained in such EAF dusts, the invention is particularly applicable to the separation and recovery of zinc. This invention describes a method for reducing the zinc contained in an EAF dust, volatilizing the metallic zinc so produced from the mass of the dust, and reoxidizing the metallic zinc to zinc oxide along with the simultaneous regeneration of hydrogen which can be recycled to treat additional EAF dust.

Abstract: A process for treating electric furnace dust comprising mixing electric furnace dust and a reducing agent with a material for reducing the slag melting point, preheating the mixture, adding the preheated mixture to molten slag which is being subjected to bubbling using oxygen-containing gas, heating the whole mixture, collecting volatilized material, and cooling the remainder.

Abstract: Metallic constituents, especially heavy metal constituents are removed from dust electrostatically separated from a gas mixture consisting substantially of carbon monoxide and phosphorus in vapor form obtained during the electrothermal production of yellow phosphorus. To this end, the dust is initially calcined with continuous agitation under oxidizing conditions at temperatures of 300.degree. to 800.degree. C.; next, the resulting calcined matter is mixed with carbon and the mixture is treated at temperatures of 950.degree. to 1200.degree. C. under reducing conditions with volatilization of the metallic constituents; and the volatized metallic constituents are ultimately condensed and separated.

Abstract: According to the instant invention fine and very fine granular zinc- and lead-containing oxidic byproducts are mixed with thermally inert additives and are hot briquetted with caking coal as a binder at a temperature of 490.degree..+-.40.degree. C. using sufficient carbon to reduce all of the metallic components in the byproducts. Then this mixture is briquetted and heated to more than 700.degree. C. and is maintained at this high temperature for a predetermined time to reduce, that is deoxidize, most of the oxidic components of the briquets, especially zinc, lead, and iron oxides. When the byproducts are not dry, which is standard with a wet scrubbing system for cleaning stack gases, the resultant slurry must be dried before it can be treated according to this invention. The carbon according to the invention is added as fine-granular caking coal in portions of at least 20% by weight. Preferably the portion is between 25% and 35% and up to 40%.

Abstract: In a method for recovering zinc and lead from a dust containing ferric oxide, zinc oxide and lead oxide discharged from a metal refining metallurgical furnace, the dust is charged into the entry of a rotary kiln together with a granular carbonaceous reducing agent. The atmosphere of the interior of the kiln comprises a reducing atmosphere zone accounting for a major portion of the interior including the entry section of the kiln and an oxidizing atmosphere zone accounting for a minor portion of the interior including at least a part of the exit section of the kiln. The temperature of the interior of the kiln is increased by the combustion of a fuel from at least one burner installed at the exit section of the kiln directed toward the interior of the kiln. The dust is reduced in the reducing atmosphere zone to vaporized zinc and lead, and also to reduce the ferric oxide into ferrous oxide.

Abstract: This invention relates to refining platinum group metal concentrates and the separation therefrom of silver and of the majority of base metals with which they naturally occur. In more detail the process comprises the steps of:(a) contacting a solid particulate mixture of base, silver and precious metal components, any of which components may be in metallic or chemically combined form, with a halogen-containing gas at a temperature which is sufficiently high for the base metal and silver components to form their halides and for the said halides substantially to volatilize from the said solid mixture, and(b) removing the said volatilized halides from the solid precious metal-containing component which remains.

Abstract: This invention relates to refining platinum group metal concentrates and the separation therefrom of silver and of the majority of base metals which are present with them. In more detail, the process comprises reacting together gaseous hydrogen and chlorine so as to produce a flame and passing into the reaction zone of the said flame the said mineral concentrate in finely divided particulate form.The specification also describes an apparatus for carrying out the above process comprising a tubular burner having a hydrogen-chlorine flame discharging into an inner heat resistant tube and means for maintaining the inner tube at an elevated temperature up to at least 2500.degree. C.