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: A method for preparing cadmium sulfide nanocrystals emitting light at multiple wavelengths. The method comprises the steps of (a) mixing a cadmium precursor and a dispersant in a solvent that weakly coordinates to the cadmium precursor, and heating the mixture to obtain a cadmium precursor solution, (b) dissolving a sulfur precursor in a solvent that weakly coordinates to the sulfur precursor to obtain a sulfur precursor solution, and (c) feeding the sulfur precursor solution to the heated cadmium precursor solution maintained at a high temperature to prepare cadmium sulfide crystals, and growing the cadmium sulfide crystals. Further, cadmium sulfide nanocrystals prepared by the method. The cadmium sulfide nanocrystals have uniform size and shape and can emit light close to white light simultaneously at different wavelengths upon excitation. Due to these characteristics, the cadmium sulfide nanocrystals can be applied to white light-emitting diode devices.

Abstract: A process for the recovery of zinc metal from a zinc mineral includes the steps of leaching the zinc mineral in a solution including a halide species formed from two or more different halides, to leach the zinc into the solution. The zinc-bearing solution is then electrolyzed to yield zinc metal and to generate the halide species. The electrolyzed solution including the halide species is then returned to the leaching step. A portion of the electrolyzed solution can be removed as a bleed stream from a cathode compartment of an electrolytic cell of the electrolysis process and processed to remove manganese as manganese dioxide precipitate by adding thereto limestone, and the halide species from an anode compartment of the electrolysis process. In this regard, the pH and Eh of the solution can regulated in a manner that favors the formation of the manganese dioxide precipitate over the formation of a precipitate of zinc.

Abstract: The present invention is a method of recovering valuable metals from a quantity of furnace dust consisting the following steps. A first leaching step wherein the furnace dust is leached at atmospheric pressure in a first leaching solution to produce a first leach liquor and a first leach residue, the first leaching solution consisting of an aqueous mineral acid solution. The first leach liquor is then separated from the first leach residue. A second leaching step is then performed wherein the first leach residue is atmospherically leached in a second leaching solution to form a second leach liquor and a second leach residue, the second leaching solution comprising a solution of aqueous HCl with a reductant. The second leach liquor is then separated from the second leach residue.

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: The present invention discloses a process for producing nano-powders and powders of nano-particle loose aggregate, which includes: (a) providing at least two reactant solutions A and B capable of rapidly reacting to form deposits; (b) supplying the at least two reactant solutions A and B at least at the reaction temperature into a mixing and reaction precipitator respectively, in which mixing reaction and precipitation are continuously carried out in sequence, the mixing and reaction precipitator being selected from at least one of a tubular ejection mixing reactor, a tubular static mixing reactor and an atomization mixing reactor; and (c) treating the deposit-containing slurry continuously discharged from the mixing reaction precipitator.

Abstract: A method of flotation processing ores and other mineral materials containing soluble nonferrous base metal and sulfide minerals involves dissolving the soluble nonferrous base metal and precipitating the soluble nonferrous base metal in the form of a floatable precipitate that is collected as part of a sulfide concentrate. The use of an oxygen-deficient flotation gas, such as nitrogen gas, promotes the precipitation of the floatable precipitate. A method for removing dissolved nonferrous base metal from solution involves contacting the solution with a particulate containing sulfide minerals under conditions promoting precipitation of the nonferrous base metal onto the sulfide mineral.

Abstract: The present invention discloses a process for producing nanometer powders, comprising the following steps: (a) providing reactant solution A and reactant solution B that can rapidly react to form precipitate; (b) continuously adding said solution A and solution B into a mixing and reacting precipitator with a stator and a rotor in operation, respectively; and (c) post-treating the precipitate-containing slurry discharged continuously from the mixing and reacting precipitator. The present process could produce nanometer powders with adjustable particle size, good homogeneity in size and good dispersity. The method also has the characteristics of high production yield, simplicity in process and low consumption of energy. It could be applied to produce various nanometer powders of metals, oxides, hydroxides, salts, phosphides and sulfides as well as organic compounds.

Abstract: The oxide materials are of the class of ternary mesoporous mixed oxide materials including lanthanum, a metal M selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu and Zn, and zirconium or cerium such a mesoporous La—Co—Zr mixed oxide material designated as Meso LCZ[x] where x is the atomic ratio (La+Co)/La+Co+Zr. They are useful as catalysts since they show high activities for hydrocarbon oxidation and good resistance against poisoning agents. These highly ordered mesoporous mixed oxides are synthesized by: preparing an amorphous solution of a La-M precursor and adding a salt of zirconium or cerium thereto; acidifying the amorphous solution in the presence of a surfactant under conditions to obtain a clear homogeneous solution; adjusting pH of the solution under conditions to form a solid precipitate; separating the solution and surfactant from the precipitate; and calcinating the precipitate.

Abstract: A method of sulfidation removal of zinc using hydrogen sulfide is provided, desirably at a temperature at 60° C. or lower, wherein in a container that is pressurized at 0.1 MPa or less with respect to atmospheric pressure, by making the pH of the solution 1.5 to 4.0, and the concentration of hydrogen sulfide in gas 2 volume % or greater in equilibrium with the hydrogen sulfide dissolved in the solution, the zinc in solution is removed by sulfidation to 1 mg/liter or less.

Abstract: The present invention is directed to a process and apparatus for removing and stabilizing mercury from mercury-containing gas streams. A gas stream containing vapor phase elemental and/or speciated mercury is contacted with reagent, such as an oxygen-containing oxidant, in a liquid environment to form a mercury-containing precipitate. The mercury-containing precipitate is kept or placed in solution and reacts with one or more additional reagents to form a solid, stable mercury-containing compound.

Abstract: A method for extraction of zinc values from an aqueous alkaline solution of zinc, especially a solution obtained by the stripping of a galvanized coating from a ferrous metal product e.g. steel, or from electric arc furnace dust. The method comprises subjecting the aqueous alkaline solution to solvent extraction using an organic solution of an oxine i.e. an organic extractant containing an 8-hydroxyquinoline group, and separating the organic solution from aqueous alkaline solution. Zinc values are recovered from the organic solution e.g. by stripping with acid and subjecting the resultant aqueous solution containing zinc values for recovery of zinc e.g. to electrowinning or to precipitation of zinc carbonate. The method may be used in the preparation of galvanized steel for recycle to a steel manufacturing plant, with recovery of zinc and for recovery of zinc values from electric arc furnace dust.

Abstract: The invention relates to a process involving the following steps: a) performing leaching of the raw material with an acid aqueous solution to dissolve the zinc if said raw material is a solid; b) optionally performing solid-liquid separation; c) neutralizing the aqueous solution once the zinc-containing raw material is in liquid form; d) performing solid-liquid separation of the solution rich in zinc from the solids precipitated during the neutralization step; e) extracting the zinc using an acid organic solvent; f) purifying the organic solvent from the extraction step; g) re-extracting zinc from the organic solvent using an acid aqueous solution; h) recovering the zinc by electrolysis and/or crystallization and/or precipitation.

Abstract: Aqueous mineralizer solutions having retrograde solubility for ZnO contain a mineral acid in which ZnO is soluble and at least one compound of a coordinating ligand for Zn2+ ions wherein the coordinating ligand compound is present in an amount that is effective to inhibit Zn(OH)+ ion formation as ZnO is dissolved in the solution. Reduced temperature methods using the mineralizer solutions to grow pure or doped ZnO crystals, pure or doped ZnO thick or thin films, and pure or doped ZnO crystalline powders are also disclosed. Cation doped ZnOs prepared by the inventive methods are also disclosed.

Abstract: A nanoporous reactive adsorbent incorporates a relatively small number of relatively larger reactant, e.g., metal, enzyme, etc., particles (10) forming a discontinuous or continuous phase interspersed among and surrounded by a continuous phase of smaller adsorbent particles (12) and connected interstitial pores (14) therebetween. The reactive adsorbent can effectively remove inorganic or organic impurities in a liquid by causing the liquid to flow through the adsorbent. For example, silver ions may be adsorbed by the adsorbent particles (12) and reduced to metallic silver by reducing metal, such as ions, as the reactant particles (10). The column can be regenerated by backwashing with the liquid effluent containing, for example, acetic acid.

Abstract: Nickel and lead ions are eliminated from an acidic concentrated iron(II) salt solution by adding an alkali sulfide and precipitating nickel and lead sulphides.

Abstract: A method for the recovery of high purity zinc oxide products, and optionally iron-carbon feedstocks, from industrial waste streams containing zinc oxide and/or iron. The waste streams preliminary can be treated by adding carbon and an ammonium chloride solution, separating any undissolved components from the solution, displacing undesired metal ions from the solution using zinc metal, treating the solution to remove therefrom zinc compounds, and further treating the zinc compounds and the undissolved components, as necessary, resulting in the zinc products and the optional iron-carbon feedbacks. Once the zinc oxide has been recovered, the purification process is used to further purify the zinc oxide to obtain zinc oxide which is at least 99.8% pure and which has predeterminable purity and particle characteristics. Various zinc compounds may then be quickly, easily, and economically produced from this recovered zinc oxide.

Abstract: The present invention relates to an apparatus and a process for producing zinc oxide from an acid soluble zinc-bearing material. The process according to the present invention comprises the steps of leaching the zinc oxide material with sulphuric acid; precipitating iron and silica from the leach solution using calcium oxide; removing copper, cadmium and cobalt from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using calcium oxide; and upgrading zinc content in zinc oxide precipitates by separating zinc oxide from gypsum using a flotation or granulometric sizing technique.

Abstract: The invention relates to a concentration device using magnetic particles and a method therefor aimed at performing concentration of a large volume of liquid efficiently and reliably with a simple structure and on a small device scale. The construction involves having: a liquid suction passage in which liquid can pass through only in a suction direction; a liquid discharge passage in which liquid can pass through only in a discharge direction; a magnetic force device which can exert a magnetic field from outside of the liquid passage on at least one liquid passage thereof or remove the magnetic field, and which can separate magnetic particles having directly or indirectly captured a target substance suspended in the liquid by having the magnetic particles adhere to the inner wall of the liquid passage; a storage section communicated with each liquid passage, for storing the sucked liquid; and a pressure adjustment device for sucking and discharging the liquid by adjusting the pressure in the storage section.

Abstract: A method for the preparation of nano size zinc oxide particles having an average primary particle diameter of less than or equal to 15 nm, which are redispersible in organic solvents and/or water, by basic hydrolysis of at least one zinc compound in alcohol or an alcohol/water mixture. The hydrolysis is carried out with substoichiometric amounts of base, based on the zinc compound. The precipitate which originally forms during hydrolysis is left to mature until the zinc oxide has completely flocculated. This precipitate is then thickened to give a gel and separated off from the supernatant phase.

Abstract: A method for the recovery of high purity zinc oxide products, and optionally iron-carbon feedstocks, from industrial waste streams containing zinc oxide and/or iron. The waste streams preliminary can be treated by adding carbon and an ammonium chloride solution, separating any undissolved components from the solution, displacing undesired metal ions from the solution using zinc metal, treating the solution to remove therefrom zinc compounds, and further treating the zinc compounds and the undissolved components, as necessary, resulting in the zinc products and the optional iron-carbon feedbacks. Once the zinc oxide has been recovered, the purification process is used to further purify the zinc oxide to obtain zinc oxide which is at least 99.8% pure and which has predeterminable purity and particle characteristics. Various zinc compounds may then be quickly, easily, and economically produced from this recovered zinc oxide.

Abstract: The present invention relates to an apparatus and a process for producing zinc oxide from an acid soluble zinc-bearing material. The process according to the present invention comprises the steps of leaching the zinc oxide material with sulphuric acid; precipitating iron and silica from the leach solution using calcium oxide; removing copper, cadmium and cobalt from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using calcium oxide; and upgrading zinc content in zinc oxide precipitates by separating zinc oxide from gypsum using a flotation or granulometric sizing technique.

Abstract: An industrial waste stream recycling method for recovery of high purity zinc oxide products and other chemical and metal values from industrial waste streams containing zinc compounds by leaching the waste stream with a solution of 30% or greater by weight ammonium chloride, resulting in a first product solution and undissolved materials; adding zinc metal to the first product solution, whereby zinc-displaceable metal ions contained in the first product solution are displaced by the zinc metal and precipitate out of the first product solution as metals, leaving a second product solution; and diluting the second product solution with water, resulting in the precipitation of zinc oxide.

Abstract: A process for producing potassium nitrate and other metal nitrates from the chlorides, sulfates, oxides of these metals. The process uses nitrogen dioxide as a true fluidizing medium in shallow beds of the aforementioned solids at moderately elevated temperatures in a continuous counter current process to convert the metal chlorides, sulfates, and oxides, into metal nitrates and effluent gas and water vapor. The process may be carried out in a series of true fluidized beds arranged in a vertical configuration so that the solids flow downward due to the fluidized process and the nitrogen dioxide gas flows counter currently in an upward direction producing pure metal nitrates at the bottom and nitrosyl chloride gas and/or water vapor at the top.

Abstract: A method and apparatus for removing metal contaminants from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents may be added to precipitate the metal oxide and/or the metal as either metal oxide, metal hydroxide, or as a salt. The precipitated materials are filtered, dried and packaged for disposal as waste or can be immobilized as ceramic pellets. More than about 90% of the metals and mineral residues (ashes) present are removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be spray-dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 1.0 ppm of contaminants.

Abstract: A method for reducing the formation of Zn(NH4)4Cl2 from ZnO/NH4Cl solutions formed during an industrial waste stream recycling method useful for the recovery of high purity zinc oxide products and other chemical and metal values from industrial waste streams.

Abstract: A technique is presented for the sequential extraction of nearly pure metal sulfides from solutions containing a mixture of metals, such as acid mine drainage. The technique is based on analysis of naturally occurring biofilms that selectively concentrate zinc, in zinc-sulfide, from a complex natural groundwater solution associated with a subsurface metal-sulfide mine. It was predicted and shown experimentally that release of sulfide ions, due to the activity of sulfate reducing bacteria, leads to sequential precipitation of pure metal sulfide phases from a solution of mixed metal ions, so long as the rate of production of sulfide ions does not exceed the rate of supply of the metal ions. This observation makes possible the design of biochemical processes to harness sulfate-reducing bacteria to separate and recover metals from mixed-metal waste streams.

Abstract: The present invention is directed to a system and method for converting hazardous speciated and elemental mercury-containing wastes to environmentally acceptable wastes by mixing the wastes in the presence of a polysulfide, water, and an mercury-reactive material, such as elemental sulfur.

Abstract: The present invention relates to an apparatus and a process for producing zinc oxide from a zinc-bearing material. The process according to the present invention comprises the steps of leaching the complex sulfide material with hydrochloric acid and oxygen; precipitating iron from the leach solution using magnesium oxide 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 magnesium oxide; and spray roasting the remaining magnesium chloride leach solution to regenerate hydrochloric acid and magnesium oxide. The present invention further relates to processes for recovering copper, silver, lead, and iron from complex sulfide materials.

Abstract: A process for preparing a nanocrystalline material comprising at least a first ion and at least a second ion different from the first ion, and wherein at least the first ion is a metal ion, is described. The process comprises contacting a metal complex comprising the first ion and the second ion with a dispersing medium suitable to form the nanocrystalline material and wherein the dispersing medium is at a temperature to allow formation by pyrolysis of the nanocrystalline material when contacted with the metal complex.

Abstract: We recover chlorine-free zinc solids in substantially 100% yield from a solution of base metals extracted from electric arc flue dust (EAFD) by reacting a zinc chloride solution formed after leaching metals from the EAFD with a calcium reactant at an elevated temperature and pressure under an inert atmosphere to produce the chlorine-free zinc precipitate and a calcium chloride solution for recycle to the EAFD reactor. We generally use about 90-110% of the theoretical stoichiometric amount of calcium hydroxide (hydrate of lime) to reduce the amount of calcium in the solid zinc. The metastasis process at the elevated temperature and pressure at which we perform it produces both ZnO and Zn(OH)2, so that the recovered solid has a Zn composition of at least about 55-65 wt. % with less than 1.0 wt. % Cl.

Abstract: The present invention provides both reagents and a process for removing heavy metals from a caustic fluid stream by the addition of reagents which are not corrosive or deleterious. Specifically, the present invention is directed to removing heavy metals from a Bayer liquor in an aluminum processing plant. The reagents, dithiocarbamate and dithocarbonate groups, are added individually or in combination thereof to the Bayer liquor for the removal of heavy metals, such as zinc. The reagents form a complex with the heavy metal for the precipitation of the metal from the fluid stream. Once a complex is formed, the Bayer liquor is held in a quiescent state for a period of time sufficient for settling out of solution the precipitate. After settling out of solution, the precipitate is separated and removed and the Bayer liquor is then further processed into alumina.

Abstract: The invention relates to a method for recovering non-ferrous metals, particularly nickel, cobalt, copper, zinc, manganese and magnesium, from materials containing said metals by converting said non-ferrous metals into sulphates by means of melt and melt coating sulphation, i.e. by a thermal treatment under oxidizing conditions within a temperature range of 400 to 800° C., during which a reaction mixture is formed containing at least one said non-ferrous metal, iron(III)sulphate and alkali metal sulphate, and appropriate reaction conditions are selected to substantially prevent iron(III)sulphate from thermally decomposing to hematite, and finally, said non-ferrous metals are recovered as metallic compounds. In the method of the invention, a process is formed around the melt and melt coating sulphation, which comprises nine steps.

Abstract: A method is disclosed for recovering and separating precious and non-precious metals from waste streams, which removes, separates, and recovers such metals in a cost effective manner with more than 95% removal from waste streams and with minimal amounts of unprocessed solids and sludge remaining in the environment. Metals such as chromium, manganese, cobalt, nickel, copper, zinc, silver, gold, platinum, vanadium, sodium, potassium, beryllium, magnesium, calcium, barium, lead, aluminum, tin; and the like are removed and recovered from the waste streams with at least 95% removal and other metals and compounds, such as antimony, sulfur, and selenium are removed and recovered from waste streams with at least 50% removal. The method employs a unique complexing agent comprising a carbamate compound and an alkali metal hydroxide which facilitates the formation of the metals into ionic metal particles enabling them to be readily separated, removed and recovered.

Abstract: An industrial waste stream recycling method for recovery of high purity zinc oxide products and other chemical and metal values from industrial waste streams containing zinc compounds by leaching the waste stream with a solution of 30% or greater by weight ammonium chloride, resulting in a first product solution and undissolved materials; adding zinc metal to the first product solution, whereby zinc-displaceable metal ions contained in the first product solution are displaced by the zinc metal and precipitate out of the first product solution as metals, leaving a second product solution; and diluting the second product solution with water, resulting in the precipitation of zinc oxide.

Abstract: A method for reducing the formation of Zn(NH4)4Cl2 from ZnO/NH4Cl solutions formed during an industrial waste stream recycling method useful for the recovery of high purity zinc oxide products and other chemical and metal values from industrial waste streams.

Abstract: A process for preparing a nanocrystalline material comprising at least a first ion and at least a second ion different from the first ion, and wherein at least the first ion is a metal ion, is described. The process comprises contacting a metal complex comprising the first ion and the second ion with a dispersing medium suitable to form the nanocrystalline material and wherein the dispersing medium is at a temperature to allow formation by pyrolysis of the nanocrystalline material when contacted with the metal complex.

Abstract: The present invention relates to an apparatus for removing volatile impurities such as mercury and selenium from a weak acid solution resulting from scrubbing gases created in the production of sulfuric acid by roasting of sulfide concentrates. The apparatus comprises a calcine filtering unit for removing calcine from the weak acid solution, a sodium sulfide mixing unit for precipitating mercury from the weak acid solution, a sodium dithionite mixing unit for precipitating selenium from the weak acid solution, and a mercury-selenium filtering unit for filtering the precipitated mercury and selenium from the weak acid solution. The present invention further relates to a treatment plant utilizing such an apparatus, a process for removing volatile impurities from a weak acid solution, and a selenium cake obtained by utilizing the resent invention.

Abstract: Mercury salt-containing discharge effluents such as from B-5 fixatives and PVA fixatives are treated to remove mercury therefrom. The present method contemplates plates the addition of aluminum to the effluent to cause the precipitation of elemental mercury therefrom. The remaining effluent, after precipitation, can be decanted and post treated while recovering precipitated elemental mercury. The decanted effluent, once subjected to post treatment, by first rendering the effluent highly basic, is the neutralized. Neutralization causes the precipitation of sodium chloride. A water conditioner is then added thereto. Subsequently, the so-treated decanted effluent is then filtered through a filtering medium such as filter paper or the like. A second filtration step may then be carried out by passing the so-filtered effluent through a mixed bed or through a filter paper.

Abstract: Provided herein is a method for the removal of soluble metal species consisting of lead, cadmium, zinc and mixtures thereof, present in an aqueous effluent, the method comprising the steps of: a) contacting the aqueous effluent with a organophosphorus salt selected from sodium di-(n-octyl) phosphinate and sodium di-(n-dodecyl) phosphinate or mixtures thereof; b) achieving precipitation of said soluble metal species by reaction with said organophosphorus salts to yield a precipitate; and c) recovering said precipitate by filtration. Preferably, the mole ratio of organophosphorus salt is about 1.5 to 2.5 and most preferably about 2, in relation to the total mole ratio of the said soluble metal species. Preferably, prior to step a), the pH of the aqueous effluent to be treated is adjusted to at least about 3 and most preferably at least about 4.

Abstract: A process for preparing compounds of the formulae I and II ##STR1## where R.sup.1 and R have the meanings indicated in the specification by an addition reaction of a compound of the formula IIIR.sup.1 OH IIIwith an acetylene or allene of the formula IV or V ##STR2## in the gas phase at elevated temperatures in the presence of a heterogeneous catalyst. The catalyst is obtained by impregnating silica with a zinc salt, by a process in which the reaction is carried out at below 200.degree. C. and the catalyst contains, as an active component, an X-ray amorphous zinc silicate or cadmium silicate containing from 1 to 40% by weight, calculated as oxide, of zinc or cadmium, obtainable by applying a salt of zinc or cadmium and an inorganic oxo acid, which salt is decomposable at below 400.degree. C., to amorphous silica and forming the catalyst before the reaction at from 50 to 500.degree. C. or during the reaction in situ at from 50 to 200.degree. C.

Abstract: A process is disclosed which involves removing hydrocarbons, arsenic and mercury from wastewater produced in oil and gas fields. An oxidant, ferric ions, and flocculent are sequentially added to the wastewater to form a removable sludge containing the arsenic, hydrocarbon, and mercury contaminants. The Oxidation-Reduction Potential of the wastewater is controlled by oxidant addition to allow the required arsenic oxidation to occur while maintaining the mercury in elemental form. The process requires relatively short residence times between chemical additions and provides for large wastewater throughputs. The cleaned wastewater is suitable for discharge to the environment.

Abstract: A protective element for an electrochemical accumulator is made of granular varistor material, the mean diameter of the grains of the varistor material being less than 1 .mu.m, in particular less than 250 nm and, for more than 60% of the grains of the varistor material, the grain size deviating by at most 40% from its statistical average. For the preparation of such grains, a dispersion is made up to form biochemical hollow bodies which have an internal diameter in accordance with the above requirements. The dispersion is admixed with salts which dissolve in the dispersion with the formation of intermediate ions of a substance forming an intermediate for a varistor material, the intermediate ion of a substance forming an intermediate for a varistor material being an intermediate ion of an element required for the varistor material or of a corresponding compound.

Abstract: The beneficiation of an electric arc furnace (EAF) dust waste stream comprising zinc compounds by collecting and combining dust from two or more EAF batches with coal fines to form briquettes, adding the briquettes to a final EAF batch with the charge, and collecting the dust from the final EAF batch, so that the zinc in the beneficiated dust is of a greater proportion than in a typical batch of EAF dust. Alternatively, the EAF dust can be split into two dust streams, one of which is returned to the EAF, while the other is treated in a hydrometallurgical process. Either waste stream preliminary can be treated by adding carbon and an ammonium chloride solution, separating any undissolved components from the solution, displacing undesired metal ions from the solution using zinc metal, treating the solution to remove therefrom zinc compounds, and further treating the zinc compounds and the undissolved components resulting in zinc products and an optional iron-carbon feedback.

Abstract: A method for the production of zinc ammonium chloride complex salts for use as galvanizing fluxes by heating waste materials captured from industrial processes containing zinc in a reducing atmosphere, leaching the resultant captured waste materials in an ammonium chloride solution resulting in a first product solution and a first undissolved materials, adding zinc metal to the first product solution resulting in a second product solution and a second undissolved materials, and adding additional ammonium chloride and/or hydrochloric acid to the second product solution resulting in the production of zinc ammonium chloride complex salts for use as galvanizing fluxes.

Abstract: The object of the invention is to provide a zinc antimonate anhydride and a production method thereof. The invention relates to a particle having a ZnO/Sb.sub.2 O.sub.5 molar ratio in a range of from 0.8 to 1.2, a crystal structure of zinc antimonate anhydride (Znsb.sub.2 O.sub.6), and a primary particle size in a range of from 5 to 500 nm. The production method of these particles comprises the steps of mixing a zinc compound with a colloidal antimony oxide at a ZnO/Sb.sub.2 O.sub.5 molar rate in a range of from 0.8 to 1.2, followed by calcining the mixture within a temperature range of from 500.degree. to 1100.degree. C. The particles of this invention are applicable as a flame retardant for plastics, a smoke suppressant, antistatic agent for plastics and glasses, and resistor.

Abstract: A method for the recovery of high purity zinc oxide products, and optionally iron-carbon feedstocks, from industrial waste streams containing zinc oxide and/or iron. The waste streams preliminarily can be treated by adding carbon and an ammonium chloride solution, separating any undissolved components from the solution, displacing undesired metal ions from the solution using zinc metal, treating the solution to remove therefrom zinc compounds, and further treating the zinc compounds and the undissolved components, as necessary, resulting in the zinc products and the optional iron-carbon feedbacks. Once the zinc oxide has been recovered, the purification process is used to further purify the zinc oxide to obtain zinc oxide which is at least 99.8% pure and which hsa predeterminable purity and particle characteristics.

Abstract: Procedure for the simultaneous collection and precipitation of mercury in gases containing it. It consists on passing the mercury gas through a washing tower where hydrogen sulfide (gas) is continuously and intermittently injected at the same time that it is watered with a solution containing a mercury complex (II) stable in semi acid, such as ?I.sub.2 Hg!.sup.2- or ?(SCN).sub.4 Hg!.sup.2-, without requiring the use of an additional oxidant. Both the collection and precipitation of the mercury and the regeneration of the solution containing the mercury complex (II) take place simultaneously in just one stage.

Abstract: The object of the invention is to provide a zinc antimonate anhydride and a production method thereof. The invention relates to a particle having a ZnO/Sb.sub.2 O.sub.5 molar ratio in a range of from 0.8 to 1.2, a crystal structure of zinc antimonate anhydride (Znsb.sub.2 O.sub.6), and a primary particle size in a range of from 5 to 500 nm. The production method of these particles comprises the steps of mixing a zinc compound with a colloidal antimony oxide at a ZnO/Sb.sub.2 O.sub.5 molar rate in a range of from 0.8 to 1.2, followed by calcining the mixture within a temperature range of from 500.degree. to 680.degree. C. The particles of this invention are applicable as a flame retardant for plastics, a smoke suppressant, antistatic agent for plastics and glasses, and resistor.

Abstract: This invention is directed to a novel method for purifying calomel (Hg.sub.2 Cl.sub.2). More particularly, this invention pertains to a novel process for treating impure calomel (Hg.sub.2 Cl.sub.2) to produce a highly purified calomel product that passes American Chemical Society requirements for calomel assay and mercuric chloride contamination. A process for treating impure calomel to produce purified calomel comprising: (a) incorporating impure calomel into an aqueous slurry; (b) oxidizing the aqueous slurry with an oxidizing agent to form soluble mercuric chloride; (c) filtering the aqueous slurry containing soluble mercuric chloride into liquid and solid components; (d) heating the liquid component to greater than 70.degree. C; (e) treating the liquid component with a reducing agent to precipitate purified calomel; and (f) separating the precipitated purified calomel from the filtrate.