Showing papers on "Activated alumina published in 1980"

Process for preparing alumina particulates, at least a fraction of which being ultrafine boehmite

Abstract: Aqueous suspensions of alumina particulates, at least a portion of which comprising ultrafine boehmite, are prepared by maintaining a pH<9 aqueous formulation of poorly crystallized and/or amorphous activated alumina powder for such period of time as to effect the at least partial transformation of such alumina powder into ultrafine boehmite.

Production of monoliht catalyst carrier

Abstract: PURPOSE: To form an alumina layer of a platy crystal form on the surface, and obtain a catalyst of high activity and a long life despite the decrease in carrier metals by covering a monolith carrier with activated alumina powder slurry and aging the same in hot water then drying and firing the same. CONSTITUTION: At the time of producing a monolith catalyst carrier for purification treatment of the waste gases of internal combustion engines or the like, first activated alumina powder slurry is coated on a monolith carrier, and after it is aged in hot water, it is dried and fired. Then, an alumina layer of platy crystal structure is formed on the surface of the monolith carrier, and therefore the catalyst having good activity and durability despite reduction of the metal to be deposited to a half is obtained. COPYRIGHT: (C)1982,JPO&Japio

Catalyst for production of ethylene from ethanol

Abstract: An activated alumina catalyst containing alkali metal, sulfur, iron and silicon in an amount of 0.05 wt. % or less respectively, calculated as Na2 O, SO3, Fe2 O3 and SiO2 and having a purity of 99.6 wt. % or more exhibits superior activity and selectivity when used in the dehydration reaction of ethanol to ethylene. By adding to the above mentioned high purity activated alumina catalyst a phosphate of one member selected from the metals of Group IIa, Group IIb, Group IIIa and Group IVb of the Periodic Table in an amount of from 0.05 to 5 wt. % of said catalyst there can be obtained a catalyst having more improved activity and selectivity as well as more increased mechanical strength.

Treating gases by pressure swing adsorption - with two superimposed layers of different adsorbent materials

Abstract: A pressure swing method for selectively adsorbing and removing one or more target components from a gas mixt. with alternating regeneration of the adsorbens is performed in two stages, using two layers of different adsorbent materials. The first stage adsorbs the target component at high concn. and reduces the co-adsorption of other components. The residual target component is adsorbed by a second material having lower adsorbing capacity than the first material both for that component and for the other components. Esp. for removing CO2 and water vapour from air, with zeolite as the first material and activated alumina as the second material, forming 25-80 (50) vol.% of the combined total layers. High efficiency is obtd. with a reduced quantity of adsorbent material and a small unit size.

Vapour phase prepn. of methyl-mercaptan - from methanol and hydrogen sulphide using activated alumina catalyst

Abstract: The parent patent described the prepn. of methylmercaptan which comprised reacting in the vapour phase methanol and H2S at a temp. throughout the reaction medium of 280-450 deg.C and a pressure of 7.5-25 bars in the presence of a catalyst based on activated alumina. The reaction was effected by passing the reactants on at least three successive catalyst beds, with the total amt. of H2S being introduced into the first bed and a fraction of the total MeOH being introduced into each bed, the overall molar ratio of H2S to MeOH being 1.1-2.5. In the parent of addition the mixt. obtd. from the reaction is subjected to a sepn. between the prods. contg. sulphur and those not contg. it. Process results in high selectivity in methylmercaptan and reduced formation of waste waters. The temp. of the reaction medium is pref. 320-370 deg.C and pressure 7-12 bars.

Method of producing an activated alumina Claus catalyst

Abstract: An improved Claus catalyst is provided in the form of activated alumina in which sodium oxide concentration, LOI and surface area of the catalyst are carefully controlled to achieve increased sulfur conversion. Sulfur recovery is enhanced by choosing an alumina catalyst having properties which minimize chemisorption of sulfur dioxide on the catalyst at reaction conditions. Sodium oxide may be present in an amount of 0.1 to 2.5 wt % of the catalyst (1100° C. calcined basis). The catalyst desirably has a surface area greater than 100 m 2 /g (BET) and an LOI (hydroxyl content as determined by heating from 400° to 1100° C.) between 2.0 and 6.0 wt %. A method of producing the catalyst and a method of using the catalyst are also provided.

Manufacture of activated alumina molding with low density

Abstract: PURPOSE: To manufacture activated alumina moldings with low bulk density, large macropore volume and high strength by specifying the particle size of alumina powder and the quarter deviation of the particle size distribution after which the powder is molded, rehydrated, and calcined. CONSTITUTION: Partially rehydratable alumina powder or alumina-contg. matter having about 1W35μm average particle size and ≤about 1.5 quarter deviation of the particle size distribution is used as alumina powder for forming moldings. The alumina powder is mixed with water, molded by granulation, and held in a wet atmosphere. The moldings thus rehydrated are dried, heat treated, and calcined to obtain activated alumina moldings with low density, large macropore volume such as ≥about 0.03cc/g volume of pores having ≥1,000Å pore radius and superior wear resistance. COPYRIGHT: (C)1981,JPO&Japio

Treatment of heavy metallcontaining waste material

Abstract: PURPOSE:To solidify a heavy metal-containing waste material by adding a specific activated aluminum compound such as alumina hydrate or the like to a mixture of a heavy metal-containing waste material, a converter slag, gypsum, etc to promote the hydration reaction of the above described mixture CONSTITUTION:To a mixture comprising a heavy metal-containing powdery or sludge like waste material, a converter slag and gypsum, one or more of an activated aluminum compound such as alumina hydrate, aluminate, and aluminosilicate is added and, by promoting the hydration reaction of the above described mixture, solidification treatment is carried out As gypsum, gypsum hemihydrate or anhydrous gypsum baked at about 300 degC or less is pref used As an activated alumina hydrate, sodium aluminate, ''KANUMA'' soil, gibbsite, etc are designated and, calcium aliminate or the like as an activated aluminate As an activated aluminosilicate, nepheline, mica or kaolinate or the like are designated

Purifying body for waste gas

Abstract: PURPOSE: A waste gas purifying body of high pruification efficiency obtained by constituted it of an agitating layer having porous three-dimensional network structure and a reaction layer in which activated alumina and noble metal catalysts are carried on the surfaces of similar porous ceramics. CONSTITUTION: A purifying body 9 which purifies the waste gas contg. malodor and CO produced at the igniting and putting out of a petroleum heater or the like is constituted of a reaction layer 1 and an agitating layer 2 of a disc shape. The reaction layer 1 is a ceramic porous grating 3 provided with an α-alumina active layer 4 of 0.25W0.6 bulk density obtained by sticking ceramic magma such as α- alumina on soft polyurethane foam of 1W7mm maximum cell diameters, sintering this at 1,000W1,800°C and removing the foam by carbonizing. An activated alumina layer of 3W30wt% based on the weight of the porous body is coated on the grating surface of this porous body and catalysts 5 such as platinum are carried thereon. The agitating layer 2 is constituted of the similar ceramic porous body. The malodorous gas is passed through the agitating layer and is thereby agitated, after which it is passed through the reaction layer 1, whereby the malodor and CO components are purified and removed at high rate of removal. COPYRIGHT: (C)1981,JPO&Japio

Production of exhaust gas cleaning catalyst

Abstract: PURPOSE:To obtain the title catalyst uniformly supporting platinum fine powder and having high activity in a low temp. zone by dissolving dinitrodiaminoplatinum powder in an aq. nitric acid soln. under specified conditions; aging the soln.; impregnating an activated alumina carrier with the aged soln.; and resucing the impregnated carrier. CONSTITUTION:(NH3)2(NO2)2Pt powder is added to a 250-450g/l aq. nitric acid soln. and dissolved by heating to 60-100 deg.C to prepare a soln. contg. 250- 450g/l of Pt. By aging the soln. at 60-100 deg.C for an adequate time the color of the soln. is turned dark reddish brown. An activated alumina carrier is dipped in the aged soln. to well impregnate the carrier with the platinum cpd., and the impregnated carrier is reduced to obtain a catalyst with platinum fine powder uniformly dispersed. This catalyst is suitable for use in oxidation of CO gas in exhaust gas from an internal combustion engine, etc.

Removing method for carbonic acid gas in gas by pressure variation type adsorption method

Abstract: PURPOSE:To remove carbonic acid gas in gas to a high degree by a method wherein synthetic zeolite is used in a high concentration region and an adsorbent, such as activated alumina, etc. in a low concentration region when removing carbonic acid gas in gas by means of a pressure variation type adsorption method. CONSTITUTION:In a method which carbonic acid gas in gas is removed by changing pressure in case of adsorption and pressure in case of desorption, an adsorption column is used which the two layers of activated alumina gel or activated silica gel and synthetic zeolite are filled as adsorbents. Raw material gas is passed from the synthetic zeolite layer side and regenerated gas from the layer side of the activated alumina gel, etc. Thus, carbonic acid gas in gas can be removed up to a high degree of approximate several ppm.

Nitrogen oxide adsorbing material

Abstract: PURPOSE:To increase NOx adsorbing capacity and not to be in danger of sticking on the surface, by containing adsorbent having NOx adsorbing activity, such as activated alumina, molecular sieve etc., in the synthetic resin material. CONSTITUTION:On occasion of containing the NOx adsorbent 2, such as activated alumina or molecular sieve etc., in the synethic resin material 1 having NH radical or NH2 radical, such as nylon, PU etc., powder of the adsorbent 2 is mixed with the synthetic resin molding material and is blended. The above blended material is molded and the adsorbent 2 is mixed with the material 1 or the adsorbent 2 is formed on the surface of inner face side of the material 1. In the former case, NOx is adsorbed on the material 1 and is diffused and then, is adsorbed on the adsorbent 2 firmly. In the latter case, adsorbing effect is high and adsorbing velocity is quick, because NOx in the atmosphere is adsorbed by the adsorbent 2 formed on the surface of the material directly. Also, adsorbing effect is improved, because the moisture etc. in the open air is not adsorbed by the adsorbent 2.

Catalyst for reducing nitrogen oxide

Abstract: PURPOSE:To obtain a catalyst of which the conversion efficiency of nitrogen oxides is not lowered even when used for a long period at high temperature by including activated alumina, oxides of platinum and barium or the like in the active layer of the catalyst for reducing nitrogen oxides. CONSTITUTION:In the preparation of a catalyst which reduces and decomposes harmful nitrogen oxides within exhaust gas to harmless gas, an activated alumina or a silica containing activated alumina is deposited on the surface of a carrier, and thereafter an aqueous solution of platinum and barium oxides is impregnated and dispersed in the alumina layer. The catalyst obtained by this method does not lose the conversion efficiency which converts nitrogen oxides and reductive gas to harmless gas even when used for a long period at high temperatures.

Removal of silicic acid in water

Abstract: PURPOSE:To remove silicic acid in water, which has been recognized as very hard to work, easily and with high efficiency by bringing a silicic acid-containing water into contact with activated alumina particles in the presence of a metal ion CONSTITUTION:The water containing silicic acid is regulated its alkalinity by the addition of an alkali if its alkalinity is deficient, and also its hyrolyzable metal ion content is controlled, if it is deficient, by the addition of a hydrolyzable metal ion, eg, aluminium ion, magnesium ion, iron ion, etc Under these conditions, the silicic acid-containing water is brought into contact with activated alumina particles The alkalis used include caustic soda, caustic potash, aqueous ammonia, alkali aluminates, etc

Fixed bed trapping for gaseous fluoride effluent control

Abstract: To comply with future air quality standards for gaseous fluoride emissions at the PGDP, studies are being made to evaluate the most feasible and efficient method of trapping fluorides from the effluents of the different processes. Although this work is in direct support of environmental projects, its results are applicable in other areas. Throughout the diffusion plants there are several areas where fluorides, either single or multiple species, are controlled and/or processed. The solid sorbent studies represent new, promising technology which could have significant impact on the gaseous diffusion plants. Scoping studies of solid sorbents and reaction conditions have been conducted. In a series of statistically designed experiments, the effects of total gas flow, temperature, and fluoride gas flow were studied for eight dry chemicals in a 1-in. diameter fixed bed designed to remove three separate fluoride gas species (hydrogen fluoride (HF), fluorine (F/sub 2/), and chlorine trifluoride (ClF/sub 3/)) from an air stream. The trapping materials selected for the test include two brands of four different material types: soda lime, oolitic calcium carbonate (CaCO/sub 3/), calcium oxide (CaO), and activated alumina (Al/sub 2/O/sub 3/). Additionally, loading factors and material utilization were determined to allow an economic comparison to bemore » made between bed materials.« less

Catalyst carrier made of woven fabric of metal fiber

Abstract: PURPOSE:To obtain a catalyst for automoble exhaust gas which has a high heat- resisting property, by dipping a metal fiber woven fabric of stainless steel or the like in an alumina-sol containing colloidal alumina and by drying the fabric and treating it with heat. CONSTITUTION:Metal fibers, which are made of ferrite or austenite stainless steel or heat-resisting steel and normally have a diameter of 40mu or less, are dipped in an alumina sol containing colloidal alumina. The metal fibers are then dried by a drier and treated with heat in a heating furnace. This results in providing a catalyst in which activated alumina coating layers are carried between the fibers of a metal fiber woven fabric and on its surface. The catalyst has a small weight and a high heat-resisting property and is used to change the harmful constituents of automobile exhaust gas into unharmful ones.