Abstract: The present invention relates to a catalyst for purifying an exhaust gas, and in particular provides a catalyst for purifying an exhaust gas using a complex oxide, which is not deteriorated in its purifying performance even in a lean atmosphere containing sulfur dioxide SO.sub.2 at temperatures as high as at least 1,000.degree. C., comprising at least one of the noble metals and one or at least two elements selected from the group consisting of alkaline earth metals and Group IIIA elements, and at least one member selected from the group consisting of iron, nickel and cobalt is supported in the surface portion of the catalyst, the catalyst further comprising, as a constituent element of the complex oxide, at least one element selected from the group consisting of iron, nickel and cobalt.

Abstract: A process for abating NF.sub.3 by contacting it with a metal oxalate or carbonate.

Abstract: An aqueous system for the production of metal chalcogenide nanocrystalline salts such as zinc selenide, from a hydrolyzable chalcogen carbonyl compound, such as selenourea, by simple hydrolysis thereof under alkaline conditions in the presence of water soluble metal hydroxide, such as zinc hydroxide in the form of the zincate ion, i.e., Zn(OH).sub.4.sup.-2. Selenourea contains selenium in the correct oxidation state, is inexpensive, commercially-available and readily hydrolyzable under aqueous basic conditions in the presence of the zincate ion to form zinc selenide. The zinc selenide is insoluble in the alkaline aqueous vehicle and precipitates over time in the form of nanocrystallites or quantum dots of the zinc selenide.

Abstract: Continuous process for the manufacture of solid particles of alkali metal persalts by reaction of an aqueous hydrogen peroxide solution with an aqueous solution of an alkali metal salt and crystallization of the persalt formed in a crystallizer-classifier comprising a stirred formation and growth region for the persalt crystals, a nonstirred clarifying region for the solution and a classification region for the particles obtained by elutriation in a liquid stream withdrawn in the clarifying region.Plant for manufacturing the said particles.

Abstract: The invention relates to a process for the removal of ammonia from gasification gas by selective oxidation in the presence of a solid catalyst. The oxidant used may be a mixture of oxygen and one or more oxides of nitrogen, e.g. nitrogen monoxide NO, whereupon gaseous nitrogen, water and possibly hydrogen are obtained as the result of the oxidation reaction. According to the invention, the catalyst used is aluminum oxide, which catalyzes the reaction within a temperature range of approx. 400.degree. C. 700.degree. C. The catalyst, made up of small particles, may be in the form of a solid or fluidized bed (12) in a separate oxidation reactor (11) subsequent to the gasifier (1).

Abstract: A process is disclosed for the separation and removal of hydrogen, alone or together with carbon monoxide, from a mixture of these gases with olefinic hydrocarbons by contacting the mixture with oxygen over a catalyst at conditions sufficient to oxidize the hydrogen to form water while suppressing reaction of the reactive, unsaturated hydrocarbons. The catalyst contains at least one metal or metal oxide from Groups Ib, IIb, IIIa, IVa and Va of the Periodic Table, and the temperature of the reaction may range from about 40.degree. C. to 300.degree. C. and a pressure of about 14.7 psig to 1,000 psig, and the flow rate of the entering feed ranges from about 1 GHSV to about 50,000 GHSV. The process can be conducted using one, two or three reaction zones.

Abstract: A method of treatment of a fleon gas consisting only of carbon and fluorine is provided, wherein the fleon gas is exposed to a plasma to decompose and chemically activate the fleon gas. The fleon gas having been chemically activated is then made into contact with a reactant to form a reaction product.

Abstract: This invention relates to the preparation of novel titanium silicate molecular sieves with modified properties such as adsorption, ion-exchange and catalytic behavior by selective extraction of framework titanium atoms after synthesis of the sieves.

Abstract: There are herein disclosed a raw material for a complex perovskite ceramic composition which is intended to uniformly disperse a trace amount of an addition component (manganese) therein, and a process for preparing the ceramic composition.A manganese-containing composite oxide is represented by the general formula (Mn.sub.a MeI.sub.1-a)MeII.sub.b O.sub.c wherein a is a value in the range of 0<a.ltoreq.0.3; MeI is at least one of Mg, Ni and Zn; MeII is one of Nb, Ta and W; when MeII is Nb or Ta, b is 2 and c is 6, or when MeII is W, b is 1 and c is 4. By the use of a raw material containing this manganese-containing complex oxide, there can be prepared an Mn-containing complex perovskite compound composition which contains Mn and at least one of complex perovskite compounds represented by the general formula Pb(BIBII)O.sub.3 wherein BI is one of Mg, Ni and Zn; and BII is one of Nb, Ta and W.

Abstract: A method for the removal and rapid decomposition of halogenated fumigation agents is described. A fumigation agent, such as methyl bromide, contained in the gas stream exiting a fumigation chamber or structure is captured on activated carbon or other retentive substrate and rapidly decomposed using thiosulfate and water. The method provides an inexpensive, safe, and on-site executable way to remove and detoxify methyl bromide from fumigation discharge gases, thereby reducing or eliminating methyl bromide emissions into the atmosphere.

Abstract: A catalyst system and a process for converting a hydrocarbon stream such as, for example, a C.sub.9 +aromatic compound to C.sub.6 to C.sub.8 aromatic hydrocarbons such as xylenes are disclosed. The catalyst system comprises a first catalyst composition and a second catalyst composition wherein said catalyst system is not a physical mixture of said first catalyst composition and said second catalyst composition, said first catalyst is a metal-promoted, alumina- or silica-bound beta zeolite, and said second catalyst composition is a ZSM-5 zeolite having incorporated therein an activity promoter selected from the group consisting of silicon, phosphorus, sulfur, and combinations of two or more thereof. The process comprises contacting a hydrocarbon stream with the catalyst system under a condition sufficient to effect the conversion of a the hydrocarbon to a C.sub.6 to C.sub.8 aromatic hydrocarbon.

Abstract: The instant invention provides a process for reducing chloride content from by-products generated during production of methylchlorosilanes, comprising, (a) hydrolyzing the by-products by combining the by-products with an aqueous medium, the aqueous medium optionally comprising a surfactant, at a pH of at least about 7 and at a temperature above about 0.degree. C. to yield a first phase comprising essentially solids and a second phase comprising an aqueous phase; (b) separating the first and second phase; and (c) oxidizing the solids from the first phase at a temperature of at least about 300.degree. C. for up to about 24 hours to yield a residue comprising less than about 1% by weight of chloride. The solids from the first phase may alternatively be reduced under a hydrogen flow, at a temperature of at least about 500.degree. C. for up to about 24 hours.

Abstract: A method for producing hydrogen and sulfur from a first gaseous mixture containing hydrogen sulfide and ammonia by separating ammonia from the first gaseous mixture to produce a second gaseous mixture containing hydrogen sulfide; combusting a portion of the hydrogen sulfide in the second gaseous mixture to produce a third gaseous mixture containing hydrogen sulfide and sulfur dioxide; heating the ammonia to a temperature of at least 1800.degree. F. to produce a fourth gaseous mixture containing nitrogen and hydrogen; and, combining the third gaseous mixture and the fourth gaseous mixture and passing the combined gaseous mixture to a sulfur recovery process wherein the hydrogen sulfide and sulfur dioxide are recovered as sulfur.The ammonia may be partially oxidized by the use of substoichiometric amounts of oxygen or thermally dissociated.

Abstract: A wet flue gas desulfurization process wherein sulfur dioxide present in flue gas is absorbed into a slurry containing a calcium compound, the slurry having sulfur dioxide absorbed therein is oxidized to form a gypsum slurry, and gypsum is separated and recovered from the gypsum slurry, which comprises the steps of dipping a part of a circulating filtering surface of a suction filter into the gypsum slurry so as to cause gypsum to adhere the filtering surface, carrying the gypsum-bearing filtering surface above the surface of the gypsum slurry, sucking out the liquid phase through the filtering surface to form a dehydrated gypsum layer thereon, and removing the gypsum layer from the filtering surface, as well as an apparatus for carrying out this process.

Abstract: A catalytic combustion process for at least one fuel comprises the use of a plurality of successive catalytic zones, the process being characterized in that at least one of the first catalytic zones includes a catalyst comprising a monolithic substrate, a porous support based on a refractory inorganic oxide and an active phase constituted by cerium, iron and optionally zirconium, also at least one metal selected from the group formed by palladium and platinum; and in that at least one of the subsequent catalytic zones includes an active phase comprising: an oxide of at least one element A with valency X selected from the group formed by barium, strontium and rare-earths; at least one element B with valency Y selected from the group formed by Mn, Co and Fe; and at least one element C selected from the group formed by Mg and Zn, and aluminium; the oxide may have formula A.sub.1-x B.sub.y C.sub.z Al.sub.12-y-z O.sub.19-.delta., x being 0 to 0.25, y being 0.5 to 3; and z being 0.

Abstract: The present invention relates to a cultivation substrate and to a method of preparing the same. The cultivation substrate of the invention contains comminuted plants selected from among knot grass, C.sub.4 plants and plants of the cannabis and Dicksonia genuses, and is suited as a peat substitute.

Abstract: An oxidation and/or combustion catalyst comprising at least one metal or oxide thereof chosen from the group consisting of palladium, platinum, nickel, cobalt and iron which is in combination with zinc metal or zinc metal oxide so as to result in a catalyst having said metal or oxide thereof to zinc metal or zinc metal oxide in a molar ratio of 1:2 and the catalyst is in the form of a close admixture or alloy, the catalyst further comprising a rare earth metal oxide.

Abstract: A process for the recovery of sulfur from a hydrogen sulfide containing gas, comprising oxidizing hydrogen sulfide with oxygen, and then reacting the product gas of this oxidation further by using at least two catalytic stages. The H.sub.2 S concentration in the gas leaving the last catalytic stage is controlled to have a value ranging between 0.8 and 3% by volume by reducing the quantity of combustion or oxidation air passed to the oxidation stage and/or causing a portion of the hydrogen sulfide-containing feedstock gas to bypass the oxidation stage and to be added to the gas flowing to a catalytic stage. The gas leaving the last catalytic stage is introduced into a heat exchanger having a wall temperature below the solidification point of sulfur and above the dew point of water, wherein the sulfur deposits on the heat exchanger wall and is removed with the aid of gravity.

Abstract: A process for treating contaminated waste to stabilize environmentally harmful heavy metal. The contaminated waste is contacted with a mixture of (i) inorganic sulfide, (ii) calcium phosphate to prevent oxidation of the sulfide and (iii) calcium carbonate, the last acting as a base. Water is added to enhance mass transfer during the mixing. The calcium carbonate may be mixed with calcium oxide, to provide an additional base.

Abstract: This invention is drawn to a process for isomerizing a non-equilibrium mixture of xylenes and ethylbenzene using a silicoaluminophosphate molecular sieve which is enriched in framework silicon at the surface, resulting in a greater yield of para-xylene compared to prior-art processes.