Showing papers on "Aluminium hydroxide published in 1996"

The bioavailability of 26Al-labelled aluminium citrate and aluminium hydroxide in volunteers.

Abstract: A study was undertaken to determine the fraction of ingested aluminium taken up by two male volunteers, following their ingestion of either aluminium citrate or aluminium hydroxide. In addition, the effects of simultaneous citrate ingestion on the gastrointestinal absorption of aluminium from its hydroxide was studied. Volunteers received three oral doses of 26Al-labelled aluminium compound in water. The doses were administered directly into the stomach using a paediatric feeding tube. Blood samples were collected from the volunteers at 1, 4 and 24 h after administration, and their daily output of urine and faeces was collected for 6 days. These samples were analysed for their 26Al content using either coincidence gamma-counting or accelerator mass spectrometry. The uptake of aluminium was greatest following its administration in the citrate form and was least following intake as the aluminium hydroxide suspension. The co-administration of citrate, with the aluminium hydroxide suspension, was found to enhance the levels of 26Al uptake in both volunteers. Using a urinary excretion factor based on the results of previous studies, the fractional aluminium uptake from each of the species was calculated: aluminium citrate, 5.23 x 10(-3); aluminium hydroxide, 1.04 x 10(-4); aluminium hydroxide with citrate, 1.36 x 10(-3).

Solidifying and hardening accelerator for hydraulic binders

Abstract: The invention concerns novel liquid solidifying and hardening accelerators obtained by a process in which the following components: component a: basic aluminium salts and/or aluminium hydroxide; component b: aluminium sulphate and/or sulphuric acid; component c: organic carboxylic acids or mixtures of at least two of the organic carboxylic acids; component d: aluminium salts of organic carboxylic acids; component e: organic and/or inorganic sulphates and/or hydrogen sulphates and/or carbonates and/or hydrogen carbonates and/or alkaline earth oxides and/or alkaline earth hydroxides, are reacted in water at temperatures of up to 150 °C such that a solution is obtained, wherein: 1. all the components or a selection of the components react with one another such that the molar ratios of aluminium to sulphate in the end product are between 0.83 and 13.3 and the molar ratios of the aluminium to organic carboxylic acid are between 0.67 and 33.3; or 2. all the components apart from component e or a selection of the components apart from component e react with one another such that the molar ratios of aluminium to sulphate in the end product are between 0.83 and 13.3 and the molar ratios of aluminium to organic carboxylic acid in the end product are between 0.67 and 33.3; or 3. component e is subsequently dissolved in the reaction product according to point 2. The compounds can be used in combination with other compounds.

Influence of organic acids on aluminium absorption and storage in rat tissues

Abstract: Six groups of 16 rats each were fed a standard diet for 8 weeks. Aluminium (Al) complexed with organic anions (citrate, lactate, malate or tartrate) was added to the diet of four of the groups and aluminium hydroxide to the diet of one group (control ‘Al +'). Aluminium concentrations in the diets were 1500–2000 mg/kg. The sixth group (control ‘Al ‐ ‘) served as control. Plasma, bone (femur), kidneys, cerebral cortex and cerebellum levels of aluminium were determined at 4 and 8 weeks. All the complexing agents increased tissue accumulations, compared with values in the two control groups, especially citrate in bone and kidneys and lactate in cerebral cortex. There were no significant differences (P < 0.05) in aluminium levels in the tissues considered between the ‘Al +’ and ‘Al ‐ ‘ control groups. Our results show the ability of dietary organic acids to increase aluminium absorption and tissue accumulation and indicate that concurrent intake of aluminium and dietary organic acids is not appropriate.

Cement spraying admixture

Abstract: A method for coating a substrate with a cementitious composition by spraying, comprising the addition to the initial cementitious mix one of a β-naphthalene sulphonate-formaldehyde condensate and a water-soluble poly(alkylene oxide) of molecular weight from 100,000-8,000,000, the other being added at the spraying nozzle, there being additionally added at the nozzle (preferably as a single component with the other nozzle-added material) an accelerator selected from aluminium sulphate, aluminium hydroxide and aluminium hydroxysulphate. In a preferred embodiment, the material added at the nozzle also contains a superplasticiser.

Carbothermal reduction and nitridation of aluminium hydroxide

Abstract: Carbothermal reduction and nitridation of aluminium hydroxide was investigated by weight-loss measurement and X-ray diffraction. Experimental results indicated that aluminium hydroxide was first dehydrated to aluminium oxide and then reduced and nitrided to aluminium nitride. Aluminium oxynitride and Al2O were found to be intermediate products. The reaction rate was found to be increased by increasing the nitrogen flow rate, the molar ratio of C/Al(OH)3, or reaction temperature. The rate was also found to be increased by decreasing the sample size, the grain sizes of carbon or aluminium hydroxide or initial bulk density. Empirical rate expressions of the conversion of Al(OH)3 and carbon, as well as the yield of AIN, were also determined.

Removal of Zn(II) from dilute aqueous solutions and radioactive process wastewater by foam separation

Abstract: Ion, precipitate and adsorbing colloid flotations of zinc(II) from dilute aqueous solutions have been investigated over a wide pH range using the anionic surfactant Aerosol OT or the cationic collector cetyl pyridinium chloride. In case of adsorbing colloid flotation (ACF) iron oxyhydroxide and aluminium hydroxide were used, either separately or together, as coprecipitants. The precipitate flotation curves were compared with the corresponding theoretical one calculated from the data published for Zn(II) hydrolysis. In addition to the effect of pH on the percent removal the effects of collector concentration, ionic strength, bubbling time and metal ion concentration were investigated and the optimum conditions were established. High removals could be achieved especially with ACF. The results obtained are discussed with respect to the chemical state of zinc, the ionization behaviour of the collectors and properties of the coprecipitants. The developed ACF process was applied to the removal of65Zn from radioactive process wastewater.

Process for producing aluminium oxide from aluminium hydroxide

Abstract: A process for producing water-free aluminium oxide from aluminium hydroxide in a circulating fluidised bed comprising a fluidised bed reactor (8), separator (6) and return flow line involves the following steps: the aluminium hydroxide is fed into the gas-side second stage of a two-stage suspension pre-heater (2) operated by the waste gases from the fluidised bed reactor (8) of the circulating fluidised bed and at least partially dewatered; dewatered aluminium hydroxide from the second stage of the suspension pre-heater (2) is fed into the gas-side first stage of a suspension pre-heater (5) operated by the waste gases from the fluidised bed reactor (8) of the circulating fluidised bed, further dewatered and then fed into the circulating fluidised bed which is operated by oxygen-containing fluidisation gas (10) indirectly heated in a subsequent cooling stage by the aluminium oxide produced and by oxygen-containing directly heated secondary gas (11) fed in at a higher level. The temperature in the circulating fluidised bed is set at between 850 and 1000 °C. The aluminium oxide removed from the circulating fluidised bed is mixed for at least two minutes with 10 to 25 wt.% of the partially dewatered aluminium hydroxide yielded by the solid-side first stage of the suspension pre-heater (2) and led past the circulating fluidised bed as a by-pass. The mixed material is then cooled in a multistage suspension cooler (15, 16, 17, 18, 19, 20), heating secondary gas (11), and then in the fluidised bed cooler (23), indirectly heating fluidisation gas (10).

Water resistant mineral acoustic insulation board

Abstract: A mineral insulating body, especially a sound insulating board, consists of granular particles having a bulk porous structure surrounded by a water-tight stable binder framework of alkali silicate glass with inclusions of boehmite. Preferably, the boehmite-containing binder framework is formed from a water glass/aluminium hydroxide suspension and the granular particles consist of expanded glass granules of 0.5-4, preferably 0.5-2 mm size. Also claimed is a process for producing the above mineral insulating body by: (i) mixing a viscous water glass/aluminium hydroxide suspension with porous granular particles in amount to form a bulk porous structure with a binder framework between the granular particles; (ii) introducing the mixture into a mould to form a green body; (iii) optionally pre-drying at 100-200 deg C; and (iv) setting the binder framework by heating at above 350 deg C to form boehmite inclusions in the alkali silicate glass framework.

Fire protection element with layered structure, particularly as insert for fireproof doors and semi-product for use in the element

Abstract: The middle layer (4) consists of an inorganic material, which under temp. influence separates water and remains shape-stable, and is arranged as prefabricated semi-product (5) between the outer layers (2,3) of bound mineral wool. The semi-product is plate-shaped and is strengthened at least on one large surface with an open-pored reinforcement (6,7). The reinforcement is made of glass fleece or glass weave and can be provided on both large surfaces. The semi-product consists of water-sepg. hydroxide, such as aluminium hydroxide and a water-glass, silicon hydrosol or magnesium binder. The hydroxide comprises 50 to 90 wt.% and the binder 10 to 50 wt.%. It has a thickness pref. of 4 to 5 mm.

Preparation of Gelatinous Aluminium Hydroxide from Aqueous Solutions of Aluminium Salts Containing Sulphate Group with Alkali

Abstract: The precipitation of gelatinous aluminium hydroxide from aqueous solutions of aluminium sulphate and ammonium, potassium and sodium slums with sodium hydroxide solution was investigated under different conditions. The resulting precipitates were examined by X-ray diffraction study, infrared spectroscopy and thermal analysis (TG and DTA). It was determined that the composition of the precipitates depends on experimental conditions, in particular the pH value of aqueous solutions: this composition varied in the order of amorphous aluminium hydroxide, pseudoboehmite and bayerite as the pH of aqueous solutions in their formation increased, although the precipitation behavior was influenced by aluminium salts containing sulphate. The results obtained are discussed in comparison with the precipitates from aqueous solutions of chloride or nitrate of aluminium with alkali.

Organic sulfur hydrolyst and its preparation

Abstract: The hydrolyst consists of TiO2 in 4-20 wt% and Gamma-Al2O3. During the prepn, refined aluminium hydroxide and titanium hydroxide are mixed in certainr atio and formed into balls, which are then treated with special washing liquid, activiated and calcined to form the said hydrolyst. The hydrolyst has good hydrolysis on sulphur carbonyl, carbon bisulfide, thioalcohol, thioether, etc. and can further convert hydrogen sulfide into element sulfur for re-use. It has a hydrolysis converting ratio higher than 90% at the condition of air speed 1800 each hr and COS content 5000 mg each cubic meter. It may be widely used for the hydrolysis of organic sulfur in desulfurizers.

Effect of ammonium salts on alumina surface properties

Abstract: Aluminium hydroxides were precipitated from sodium aluminate using ammonium salt solutions. The effect of the kind of ammonium salt used for the aluminium hydroxide precipitation on the surface properties of the related alumina was investigated. It was stated that kind of ammonium salt affects the aluminium hydroxide phase composition as well as the Lewis acid site surface concentration and the concentration of anionic OH − groups; the specific acidity was measured by means of TPD NH 3 and the specific rate of cyclohexene isomerization. DRS spectra of the Mo catalyst supported on investigated aluminas as well as the HDS activity vary with the kind of ammonium salt. The obtained results are explained on the basis of processes both during polycondensation of aquo-ions Al III and during ageing of amorphous hydrogel of aluminium hydroxide. Results are discussed on the basis of the literature.

Raw release papers with pigment strips based on aluminium hydroxides

Abstract: A raw release paper for coating with a silicone release compound, in which a pigment strip containing a binder is formed on the paper, has aluminium hydroxide as the sole pigment or a pigment mixture with aluminium hydroxide as the main component.

Perrhenate ion uptake by aluminium hydroxide gels

Abstract: The adsorption of perrhenate ions onto aluminium hydroxide gels was investigated. These gels were prepared by the sol-gel method in non aqueous solutions using a tertiary amine as template. They were amorphous and presented high specific surface areas. The amount of perrhenate ions adsorbed from aqueous solutions depended on the specific surface area of the gels. Removal of perrhenate ions up to 84% could be achieved without reaching saturation.

Additive for cement spray

Abstract: A method for coating a substrate with a cementitious composition by spraying, comprising the addition to the initial cementitious mix one of a beta -naphthalene sulphonate-formaldehyde condensate and a water-soluble poly(alkylene oxide) of molecular weight from 100,000-8,000,000, the other being added at the spraying nozzle, there being additionally added at the nozzle (preferably as a single component with the other nozzle-added material) an accelerator selected from aluminium sulphate, aluminium hydroxide and aluminium hydroxysulphate. In a preferred embodiment, the material added at the nozzle also contains a superplasticiser.

Method for production of high-molecular-ratio ice spar

Abstract: This invention relates to a method for preparing cryolite with high molecular ratio. It uses hydrofluoric acid, aluminium hydroxide and sodium carbonate to be synthesized continuously in several series-connected synthetic tanks with agitators. The hydrofluoric acid and aluminium hydroxide mud are simultaneously, continuously and uniformly added to the fluoaluminic acid synthesizing tank with agitator at the temp. of 70 deg.C-boiling point according to the demand which their mol ratio is 6F/Al=1.0-1.2, and reacted to obtain fluoaluminic acid, then the fluoaluminic acid and sodium carbonate solution are continuously and uniformly added to its cryolite synthesizing tank according to the mol ratio of that Na/Al is greater than 3 so as to obtain the high molecular ratio cryolite whose mol ratio of WaF and AlF3 is greater than 2.7, tilter property is good and impurity content is low.

Skeletal isomerization of 1-pentene

Abstract: Series of ZSM-5 and Y zeolite catalysts have been prepared. Zeolites were submitted to ion exchange, drying, formation with 50 wt.% of aluminium hydroxide as a binder and then to final thermal treatment. Determination of catalysts activity in 1-pentene isomerization reaction was carried out in the temperature range of 175–325°C. The highest activity in isomerization reaction was attained in the presence of ZSM-5 zeolite catalysts with strong and medium strength acidity.

Process for preparing aluminium oxide

Abstract: FIELD: hydromethallurgy SUBSTANCE: aluminium hydroxide is precipitated from sodium aluminate solution with nitric acid at 33-38 C and pH of 85-89 The hydroxide is slightly dried to humidity of 67-75 wt %, treated with acid to acid module Ma value of 003-001 g-m/g-m AlO, molded into extrudates, dried and calcined at 500-600 C Adsorption capacity is thus enhanced by 2 times EFFECT: improved adsorption capacity of aluminium oxide 1 tbl

Hydrogenating treatment catalyst

Abstract: The present invention discloses preparation process of hydrogenating treatment catalyst. Large-pore aluminium hydroxide as raw material, which is prepared with sodium aluminate and aluminium sulphate and at proper temp. and pH value, is treated through moulding, drying and calcining to obtain gamma-Al2O3 carrier. Before carrying active group VIB and VIII metal, the carrier is soaked with low-density (0.01-0.1 wt%) ammonia water to make the ultimate catalyst have homogeneously distributed metal and raised activity.

Inhibition of corrosion of iron and aluminium

Abstract: It has been shown that in order to inhibit the corrosion of iron and steel an ion must fulfil two conditions. It should form an insoluble ferric compound and it should also form a complex with peroxide ionsformed during the cathodic reduction of oxygen, thereby increasing their oxidising power. It is now shown that aluminium inhibition, in the pH range 4-11, is brought about by theformation of aluminium hydroxide (or a basic salt) and that peroxide ions play no part. The chromate ion is inhibitive at lower pH values and here the peroxide ion may be involved.

Solid inorganic resistance reducing agent

Abstract: There is provided a kind of solid inorganic conducting material for reducing ground-resistance in the field of lightning protection and electrostatic protection Said resistance-reducing agent is comprised of 15%-70% of cement, 10%-60% of graphite and 10%-60% of aluminium hydroxide, and is simple in formula, good in resistance-reducing effect, long service life and free from chlorine ion and sulfuric radical; it is non-toxic, pollutionless and has no corrosive action to steel and iron

Process for the preparation of stabilized red mud

Abstract: The stabilized red mud for a ceramic article is produced by neutralizing the red mud, which is a by-product from the manufacturing process of aluminium hydroxide using bauxite as a raw material. The process comprises mixing and stirring the red mud with water at a same weight ratio; therein introducing phosphoric acid to maintain the pH at 7-9; and then leaving the resultant mixture to be stabilized at a temperature of 70-80 deg. C for 1 hour.

Heat resistant material for heat shield used in gas turbines

Abstract: To produce a heat-resistant protective unit of ceramic fibres, contg. alumina, the fibres are mixed through with aluminium hydroxide in water to give mass to be dried to a residual moisture content of , and the material is compressed so that, after firing, it has a density of 1.0-3.5 g/cm .