Abstract: In a device and a process for purifying water which is contaminated with sulphate ions and heavy metal ions, the water is collected in a water reservoir and a substance having basic activity in water is fed to the water reservoir in such a manner that a precipitant having heavy metal ions is precipitated from the water, wherein at least a subquantity of water is taken off from the water reservoir and is separated into pure water which is substantially freed from sulphate ions and heavy metal ions and dirty water which is enriched with sulphate ions and heavy metal ions. The dirty water is at least in part recirculated to the water reservoir, as a result of which a concentration of sulphate ions in the water reservoir is achieved such that a precipitant having sulphate ions is precipitated from the water.

Abstract: A process is provided for stabilizing a sulfate and/or sulfide-rich waste material, comprising metal sulfide minerals, and sequestering CO2 comprises exposing the material to a CO2-enriched gas mixture, reacting the CO2-enriched gas mixture with the metal sulfide minerals and forming a CO2-depleted gas mixture and a carbon-containing compound and at least one product selected from the group consisting of a purified metal or a metal-rich compound suitable for smelting or refining, sulfuric acid, sulfur and sulfurous acid, and system and apparatus therefor.

Abstract: A process is disclosed for separation and recovery of vanadium, molybdenum, iron, tungsten, cobalt and nickel from alumina-based materials, mattes, ores, manufacturing by-products and waste. These elements are oxidized. The oxides are reacted with gaseous HCl to form volatile chloride-bearing compounds that subsequently sublimate. The volatile compounds are condensed in a downward-stepped thermal gradient that allows collection of moderate to high purity compounds of individual elements with exception of a nickel-cobalt co-condensate. Nickel is separated from cobalt by precipitation of nickel chloride from concentrated HCl pressurized with gaseous HCl.

Abstract: The invention provides a process for producing purified synthesis gas from synthesis gas comprising sulphur contaminants in the ppmv range, the process comprising the step of: (a) contacting the synthesis gas comprising sulphur contaminants with solid sorbent comprising a metal organic framework, thereby separating sulphur contaminants from the synthesis gas to obtain purified synthesis gas.

Abstract: The method of dissolving the solids formed in the apparatus and pipework of a nuclear plant, in which the solids are brought into contact with an aqueous dissolving solution chosen from aqueous solutions of carbonate ions having a concentration of greater than or equal to 0.3M, aqueous solutions of bicarbonate ions, and solutions of a mixture of nitric acid and of a polycarboxylic acid chosen from oxalic acid and triacids.

Abstract: Provided is a roasting method capable of reducing both C and S components in minerals down to 0.5% or less, respectively, and securing a yield ratio of 90% or more for the Mo component. In a rotary kiln 7, a V, Mo and Ni containing material containing C and S components is subjected to oxidizing roasting to remove the C and S components from the material before reducing the material by means of a reducing agent in order to recover valuable metals composed of V, Mo and Ni. The rotary kiln is equipped with a burner 11 disposed on a material charge side 8a of the roasting furnace 8 to which the material is charged. In the roasting furnace, a direction along which the material moves and a flow of oxygen-containing gas introduced into the roasting furnace 8 are set to be parallel with each other.

Abstract: Method for preparing material containing amorphous iron oxide hydroxide, the method including: mixing an aqueous ferrous salt solution and hydroxide solution or solid hydroxides at the temperature of below 70° C., filtering the reaction solution, washing the filter cake, preparing suspension solution of the filter cake, blowing an oxygen-containing gas into the suspension solution to oxidize the ferrous iron, and then filtering and drying. The material after being used as desulfurization agent can be repeatedly regenerated through oxidation in an oxygen-containing gas. A desulfurization agent, and methods for preparation and repeated regeneration thereof. The desulfurization agent contains the material and organic binders, and may also include a small amount of additives. The organic binders are selected from sodium carboxymethyl cellulose, sesbania powder, and cellulose powder, and the additives are selected from sawdust, rice husk power, and bran.

Abstract: The invention relates to an effective and environmentally safe process for the microbial leaching of sulfidic materials, particularly of sulfide ores such as pyrite, marcasite, chalcopyrite, bornite, or covelline, which process is characterized in that the aqueous leaching fluid is added with sulfur-containing amino acids or derivatives thereof. The invention is also directed to the use of sulfur-containing amino acids or derivatives thereof in the microbial leaching of sulfidic materials, particularly in pyrite leaching.

Abstract: A method of treating metal-contaminated spent foundry sand, or other industrial waste, by combining the sand with a sulfite to produce insoluble metal sulfur oxide complexes that do not leach from the sand. The treated waste may also be processed to reducing “clumping,” thereby rendering the treated waste appropriate for use in another industrial process.

Abstract: A method of treating metal-contaminated spent foundry sand, or other industrial waste, by combining the sand with a sulfite to produce insoluble metal sulfur oxide complexes that do not leach from the sand. The treated waste may also be processed to reduce “clumping,” thereby rendering the treated waste appropriate for use in another industrial process.

Abstract: The present invention provides a process for treating a particulate material, in which particles of the material to be treated interact with non-static particles of a second material, the process comprising the steps of: (i) providing a processing chamber (1) having an inlet (7) and an outlet (10) spaced downstream therefrom, the base (15) of said chamber comprising a plurality of outwardly radiating inclined vanes (20, 25), (ii) providing a host bed of particles (30) which include inert particles, alumina, limestone and activated carbon in the chamber (1) and generating a flow of fluid through the vanes (20, 25) at the base (15) of the processing chamber such that the bed of host particles (30) circulates about an axis of the chamber in a compact band, (iii) injecting particles of the material to be treated including sulphide ore, kaolin, gypsum and talc through an inlet (5) of the chamber (1) to contact with the circulating bed of the host particles (30), wherein the relative terminal velocity of the partic

Abstract: An iron based product having at least a sufficient total ferrous content by weight to render the product commercially feasible wherein the product is derived by a process comprising the beneficiation of kish slag waste material having a relatively low ferrous material content before beneficiation. The resulting iron based product has a total ferrous content of substantially 90% by weight thereby making it both practical and economical for the reintroduction into iron and/or steel making processes utilizing an injection method or by briquetting at at least a portion of the resulting product. The beneficiation process involves the heating of the waste material to an extent at least sufficient for drying, separating the high sulphur slag from a remainder of the waste material and subsequently classifying the remainder of the waste material, once separated from the high sulphur slag by particle size.

Abstract: A process for treating sulphate- and metal-containing waste water, includes subjecting, in a reaction stage, the sulphate- and metal-containing waste water to biological sulphate reduction in which sulphates in the waste water are converted to sulphides, with metals present in the waste water precipitating out and treated waste water being obtained. The precipitated metals are withdrawn from the reaction stage, while treated waste water is withdrawn from the reaction stage. The treated waste water is subjected to polishing and/or to nutrient removal.

Abstract: An improved process for the beneficiation of mixtures of mineral particles (such as kaolin clays) containing minerals which chelate with hydroxamates. The use of a silicon-containing compound in combination with a hydroxamate results in a more effective separation of minerals which chelate with the hydroxamate.

Abstract: A method of treating a mined material which includes a sulphide mineral and iron or a concentrate of the mined material to improve the recovery of a valuable metal from the sulphide mineral is disclosed. The method comprises: (i) oxidising the sulphide mineral in the presence of ferric ions to make the valuable metal in the sulphide mineral more accessible to extraction; and (ii) oxidising ferrous ions generated in step (i) or derived from iron in the mined material with a mixture of sulphur dioxide and oxygen to produce ferric ions for step (i).

Abstract: Pyritic ores are heated with microwave energy in a fluidized bed to a temperature in the range of approximately 573 degrees Kelvin to 823 degrees Kelvin with a controlled amount of oxygen to promote the oxidation of the pyritic ores according to the reaction: 2FeS.sub.2 +3/2 O.sub.2 .fwdarw.Fe.sub.2 O.sub.3 +4S, thereby preventing the production of sulphur dioxide.

Abstract: The ore which contains gold and/or silver and as accompanying metal at least iron is calcined at temperatures in the range from 500.degree. to 900.degree. C. with the addition of oxygen-containing gas. There is obtained a metal-oxide-containing solids mixture and a SO.sub.2 -containing exhaust gas. The solids mixture from the calcination is cooled, the temperature being reduced by at least 50.degree. C. The cooled solids mixture is added to a fluidized-bed reactor, and SO.sub.2 -containing exhaust gas is introduced into the fluidized-bed reactor. In the reactor, metal sulfate is produced in the solids mixture, so that at least 10% of the sulfur content are bound in the exhaust gas. Solids mixture containing metal sulfate is withdrawn from the fluidized-bed reactor, is stirred up with an aqueous acid solution, thereby dissolving metal sulfate. The remaining solids are supplied to a recovery of gold and/or silver.

Abstract: Methods are disclosed for treating smelter flue dust and other smelter by-products so as to recover non-ferrous metals therefrom and convert arsenic and sulfur in the flue dust into non-leachable compounds. The methods allow the flue dust and other smelter by-products such as smelter sludges to be disposed of in a natural environment without subsequent leaching of heavy metals, sulfur, and arsenic. The smelter by-products are mixed with hydrated lie, formed into agglomerates, and roasted at an optimal temperature of about 650.degree. C. to form oxidized arsenic and sulfur which react with the lime in the agglomerates to form non-leachable compounds. The roasted agglomerates are contacted with a basic lixiviant comprising dissolved ammonia and an ammonium salt to dissolve non-ferrous metals such as copper from the roasted agglomerates. Used lixiviant can be boiled to precipitate the non-ferrous metals dissolved therein and vaporize the ammonia, thereby regenerating the lixiviant.

Abstract: A method of carrying out a chemical reaction in a fluidized bed reactor is provided wherein the reactants include at least one finely sub-divided reactant having a particle size substantially smaller than that of the particles constituting the fluidized bed. The reactor includes a downcomer compartment and a riser compartment operated such that the fluidized bed particles circulate by moving down the downcomer compartment and up the riser compartment. The finely divided solid reactant is introduced, either as such, or in an agglomerated form, into the central or upper region of the fluidized bed in the downcomer compartment such that it becomes entrained in the downwardly moving fluidized bed in the downcomer compartment and moves countercurrent to the fluidizing gas towards the lower end of the riser compartment. The reaction products which may be, or include, fine divided solids are carried out of the top of the reactor from the riser compartment.

Abstract: In accordance with the invention, gases containing sulfur dioxide are passed through a solution rich in ferric iron and containing barium chloride or calcium chloride. Sulfur dioxide is oxidized by the ferric ion to sulfur trioxide when then forms sulfuric acid in the water. The sulfuric acid reacts with the barium ion to form barium sulfate, while the ferric ion is reduced to the ferrous state. The barium sulfate is separated from the mother liquor by filtration and is then reduced to barium sulfide with a carbonaceous material or any reducing gas. Then, the barium sulfide is reacted with another portion of solution rich in ferric iron to form elemental sulfur, while the barium ion or calcium ion combines with the chloride ion to regenerate barium chloride or calcium chloride as the case may be. The resulting solution, after the sulfur has been removed, is now rich in ferrous iron.

Abstract: Iron-containing zinc sulfide concentrate is processed to recover zinc values therefrom. The concentrate is roasted to convert zinc sulfide and iron sulfide to their oxides while adequate sulfide-sulfur is retained to maintain the iron values in the ferrous state and thereby avoid ferrite formation. Zinc oxide and iron oxide values are recovered from the roast, simultaneously or sequentially, and residual zinc sulfide may be recycled to the roasting step.

Abstract: A process is described for the controlled oxidation roasting of zinc bearing sulphidic ores and concentrates by adjusting the furnace temperature and residence time together with the oxygen availability to the sulphide retention requirements in the calcine. The obtained calcine is subsequently subjected to various physical and chemical process steps to separate the unreacted sulphides which are then dead roasted and treated for zinc recovery, according to one embodiment of the process. In another embodiment the separated, unreacted sulphides are returned to the controlled oxidation roasting step.The chemical separation process steps include sulphur dioxide leaching. In one embodiment zinc is preferentially dissolved as sulphite and the solution obtained is further treated for zinc recovery. In other embodiments sulphuric acid, or ammonical ammonium carbonate or similar leaching reagents are used for the preferential dissolution of the zinc oxide present in the calcine.

Abstract: A process comprises leaching zinc oxide either separately or in conjunction with iron oxides from a partially desulfurized zinc bearing sulfide ore of concentrate. The ore is pretreated to eliminate in a controlled manner sulfur-sulfur-sulfide in the ore yet leaving sufficient residual sulfur-sulfide in the material such that iron values are maintained substantially wholly in the ferrous state, while converting zinc sulfide to zinc oxide without formation of FeO-ZnO complexes. The partially desulfurized material may be selectively leached with a sulfuric acid containing solution under neutral leach conditions to dissolve thereby preferentially the zinc oxide over the iron oxide. Alternatively the material may be leached with a higher concentration of sulfuric acid containing solution to dissolve preferentially zinc oxide and iron oxide simultaneously. The leach liquor may be subsequently treated to electrolytically remove zinc.

Abstract: Production of elementary sulphur from an iron sulphide mineral, which comprises oxidizing acid lixiviation of the pulverized mineral, for extraction of the sulfur. The pulp obtained from the lixiviation is treated in the hot with an organic solvent for sulphur, the solvent having a density higher than 1, to separate this pulp into an aqueous phase containing in solution the non-ferrous metals, the sulphates of which are water soluble, and into a suspension of the solid of the pulp in an organic phase consisting of a solution of sulphur in the solvent separated by decantation and, after separation of the solid in suspension in the organic phase, the sulphur is recovered by crystallization after cooling of the organic phase.

Abstract: Waste containing sulfur and nickel sulfide is heated to volatilize sulfur and reacted with hydrogen chloride to form nickel chloride.

Abstract: In a process for making ferrous sulphate in granule form, ferrous sulphate heptahydrate is mixed with fine-grain brown coal or lignite having a low water content, in such an amount that the resulting mixture is pourable.

Abstract: A process for removing sulfur from sulfide-bearing ores by reacting water vapor with the sulfide-bearing ore forming hydrogen sulfide while simultaneously regenerating water vapor by reacting the hydrogen sulfide with lime. Advantageously, the process occurs in the absence of a net consumption or production of gaseous species so that the process can be carried out in a closed system with respect to the gaseous species. Sulfide-bearing ores which can be treated using the process of this invention include sulfide-bearing ores of molybdenum, zinc, iron, mercury, and copper. Advantageously, the molybdenum oxide so produced from the sulfide-bearing ore of molybdenum can be reacted further with lime and water producing calcium molybdate and hydrogen. The chalcopyrite form of the sulfide-bearing ore of copper produces bornite and magnetite.

Abstract: Finely-divided iron ores and concentrates which contain non-ferrous metals are roasted and chlorinated in order to vaporize the non-ferrous metals as metal chloride compounds, whereby the finely-divided raw material is oxidized at an elevated temperature to produce an oxide melt, with which a chlorinating reagent and air are mixed in order to vaporize non-ferrous metal chlorides from the iron oxide melt.

Abstract: This invention relates to method and apparatus for treating a sulfur containing material having at least one principal sulfide either in the form of a sulfide or in a form that is transformable into a sulfide and at least one auxiliary sulfide more volatile than the principal sulfide or transformable into another sulfide more volatile than the principal sulfide, wherein the sulfurous material is heated in one furnace zone, having a non-oxidizing atmosphere in the gas phase, to a temperature between that required for volatilization of the principal sulfide and that required for volatilization of the auxiliary sulfide to volatilize the auxiliary sulfide and labile sulfur, without volatilizing or substantially oxidizing the principal sulfide; and heating the sulfurous material in another furnace zone, having an oxidizing atmosphere in the gas phase, to a temperature lower than that required for substantial oxidization of the principal sulfide, to oxidize the volatilized labile sulfur and auxiliary sulfide, witho

Abstract: Nickeliferous sulfidic materials containing at least one other metal selected from the group consisting of cobalt, copper and iron are leached with an at least 3 N hydrochloric acid solution to produce a pregnant nickel chloride solution. The pregnant nickel chloride solution is treated with a liquid organic extractant to extract the other metals. The nickel chloride raffinate is concentrated with respect to nickel chloride, and the concentrated nickel chloride solution is heated to at least about 750.degree. C. to hydrolyze the nickel chloride to a refined nickel oxide product and a hydrogen chloride-containing gaseous effluent which is recycled to the concentration step and then through water to regenerate the leaching solution.

Abstract: This disclosure describes a process for the preparation of iron-bearing and calcium-bearing sorbent solids for use in the desulfurization of gases. The process involves mechanical procedures for generating porous agglomerated solids that are high in surface area and uniquely suitable in both particle size and mechanical properties for processing in gas-solids contacting equipment of conventional design. The process also involves the use of water in the agglomeration procedures in quantities controlled to react both chemically and mechanically with solid components of the feed materials and to generate adhesive cement between finely divided solids in porous agglomerated particles of the sorbent product.

Abstract: The invention provides a cyclic process for recovering copper from sulfide ores containing copper and iron which comprises reacting the sulfide ore with sulfur dioxide gas at a temperature of at least about 500.degree. C. to form elemental sulfur, removing the elemental sulfur, reacting the residual solids with concentrated sulfuric acid at a temperature of about 180.degree. to 500.degree. C. to form copper sulfate and sulfur dioxide gas, recycling the sulfur dioxide gas for reaction with additional ore, roasting the remaining solids at a temperature of about 400.degree. C. to 900.degree. C., leaching the roasted solids with an aqueous solution to solubilize the copper sulfate and recovering copper from the solubilized copper sulfate. In another embodiment of the invention, the roasting step is eliminated by removing magnetite from the solids remaining after removal of the elemental sulfur.

Abstract: The sulfides of nickel and cobalt prepared by sulfiding nickel and cobalt-enriched ammoniacal solutions oxidize rapidly (and often pyrophorically) when exposed to normal atmospheric conditions. The oxidized sulfides then react with water present in the atmosphere in a hydration reaction. This oxidation and hydration may increase the weight of the sulfides by as much as 150% or more, depending upon such factors as the type of sulfides involved and the duration of the exposure. However, when nickel sulfide, cobalt sulfide, or mixtures thereof are dried, dehydrated, heated at temperatures of about 1000.degree.F. or higher in a substantially inert atmosphere, and then cooled in a substantially inert atmosphere, the sulfides can surprisingly be exposed to normal atmospheric conditions for prolonged periods of time without undergoing significant oxidation or hydration. Consequently, only minimal weight increases are observed with the treated sulfides.