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Showing papers on "Aluminium hydroxide published in 1989"


Journal ArticleDOI
TL;DR: In this article, molybdenum/aluminium mixed oxide solids were calcined in air at 500-1000°C and the solid-solid interactions between MoO3 and Al2O3 were investigated using DTA, TG, DTG and XRD techniques.

38 citations


Journal ArticleDOI
TL;DR: In this article, pure finely powdered aluminium hydroxide specimens were treated with solutions containing different proportions of cupric nitrate, followed by drying at 100 ° C and roasting in air at temperatures varying between 500 and 1100° C. The solid-solid interactions between the resulting mixed oxides were investigated using DTA, TG, DTG and X-ray diffraction techniques.

23 citations


Journal ArticleDOI
J. P. Bach1, F. Thevenot1
TL;DR: In this paper, the martensitic transformation of zirconia (tetragonal→ monoclinic) is at the origin of toughening, and the mean grain size of dispersed ZTA particles has been investigated.
Abstract: In zirconia-toughened alumina (ZTA) the martensitic transformation of zirconia (tetragonal→ monoclinic) is at the origin of toughening. If the zirconia particles have a mean grain size less thand’ c, they remain tetragonal; if their size is betweend’ c andd c (d c>d’ c), they are stress-induced transformed into the monoclinic form; if their size is larger thand c, particles are transformed. We prepared ZTA using different precursors and compared their microstructures. The coprecipitation of aluminium and zirconium chlorides gives an hydroxide mixture. Thus the zirconium hydrate is amorphous, and the aluminium hydroxide structure varies with the precipitation temperature and pH values at the end of the neutralization. Alumina is mixed with zirconia obtained by gas-phase reaction. Zirconia is prepared by vaporization of zirconium chloride in an oxygen-hydrogen flame. Alumina powder is impregnated by a zirconium acetate solution. Zirconium acetate is thermally decomposed in a spray-dryer, then by calcination. The cohydrolysis of II Al-butoxide and IV Zr-propoxide was carried out in an alkaline solution. The hydrolysis pH (10 or 12) changes the grain size of the oxide powders. Mechanical property measurements and microstructural analysis allow a comparison of the different composites. The mean grain-size evolution differs according to the preparative route, and may be varied by different elaboration parameters. Fine microstructures were always observed. The mean grain size of dispersed zirconia being very small (neard’ c), we observed a little influence of transformation toughening. We noticed a large increase in rupture strength, while toughness was not noticeably improved.

22 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of aluminium on the polymerization of polysilic acid was studied at pH 7, 8 and 9 in the aluminium concentration range of 0-26 ppm (Al) by spectrophotometry, gel chromatography and 27 Al NMR.

19 citations


Journal ArticleDOI
TL;DR: It is indicated that adequate control of the plasma phosphate can be achieved with low dosage of aluminium hydroxide, and in the medium term is not associated with evidence of bone aluminium toxicity.
Abstract: Sixteen patients treated exclusively by haemodialysis using reverse osmosis water treatment for up to 7 years (mean 49.3 +/- 17 months) were assessed for evidence of bone aluminium accumulation and toxicity. All patients were treated with aluminium hydroxide phosphate binders for the duration of dialysis but the dosage was restricted to a maximum of 2.85 g daily (mean daily dose 2.6 +/- 0.8 g). The mean plasma phosphate over the 12 months prior to the study was 1.68 +/- 0.42 mmol/l and in only three patients was adequate control of the plasma phosphate not achieved. No patient had evidence of fracturing bone disease. Bone aluminium staining was present in only two patients but was seen at the calcification front in only one of these. Three patients had histological evidence of osteomalacia, but in none was aluminium staining present. Mean bone aluminium was moderately high at 36.67 +/- 31 micrograms/g and in only three patients exceeded 40 micrograms/g. This study indicates that adequate control of the plasma phosphate can be achieved with low dosage of aluminium hydroxide, and in the medium term is not associated with evidence of bone aluminium toxicity.

15 citations


Journal ArticleDOI
TL;DR: Routine measurements of serum aluminium levels in patients without renal impairment are not considered necessary following antacid therapy, however, the use of antacids with an aluminium absorption rate as low as possible is recommended.
Abstract: We studied the serum aluminium levels of 30 intensive care patients receiving six daily doses of magaldrate (Riopan®) or aluminium hydroxide (Trigastril®). In both groups we found a significant rise of the serum aluminium concentration (p<0.01) following administration of the antacid solutions. Examination on day 9 and 15 the magaldrate group showed significantly (p<0.05) lower aluminium levels than the aluminium hydroxide group. An increase up to the critical serum aluminium level of 100 ng/ml occurred in none of the patients that all had normal or slightly impaired renal function. Therefore routine measurements of serum aluminium levels in patients without renal impairment are not considered necessary following antacid therapy. However, we recommend the use of antacids with an aluminium absorption rate as low as possible.

11 citations


Journal ArticleDOI
TL;DR: In this paper, the structure of Raney catalysts modified by chromium deposition was investigated by transmission electron microscopy and scanning transmission-empowered X-ray spectrometry.

11 citations


Journal ArticleDOI
TL;DR: In this paper, a review on the hydroxides and oxides of aluminium is given from the viewpoint of their kinds and structures, indicating the particular increase in the intensity of X-ray diffraction peak at the plane (200).
Abstract: The review on the hydroxides and oxides of aluminium is given from the viewpoint of their kinds and structures. Crystalline aluminium hydroxide is composed of five kinds of alumina hydrates due to hydrargillite (and/or gibbsite), bayerite and nordstrandite classified as alumina trihydrate and due to boehmite and diaspore classified as alumina monohydrate. Gelatinous aluminium hydroxide consists of amorphous aluminium hydroxide, pseudoboehmite and intermediate boehmite, indicating the particular increase in the intensity of X-ray diffraction peak at the plane (200) as the orthorhombic structure similar to boehmite. The aluminium hydroxides prepared by various procedures are thermally decomposed to anhydrous aluminas. As it has been reported by many researchers that the thermal transformations of aluminium hydroxides yield anumber of aluminas, such as χ, γ, η, δ, δ1, κ, κ', θ, E, e, ρ and λ, being a transition stage in a process leading ultimately to α-alumina, the thermal decomposition processes are discussed on the basis of the results obtained by the present author. Further the formation of anhydrous aluminas by the thermal decompositions of aluminium salts of inorganic and organic acids such as hydrates of chloride, nitrate and sulphate of aluminium, ammonium alum, formate and acetate of basic aluminium and lactate, citrate and tartrate of aluminium is compared with the thermal transformation processes of aluminium hydroxides to α-alumina. In addition, the preparations of nordstrandite and ρ-alumina are investigated in comparison with the previous results of the author.

9 citations


Journal ArticleDOI
TL;DR: The combination of oral aluminium and citrate should be avoided in patients with poor renal function and the high aluminium concentration was attributed to the concurrent use of an oral citrate solution.
Abstract: 1. A hospitalized patient with renal failure receiving oral aluminium hydroxide was found to have a blood aluminium level of 3124 micrograms/l (116 mumol/l). 2. The extremely high aluminium concentration was attributed to the concurrent use of an oral citrate solution which converted the aluminium to a more soluble and absorbable form. 3. The combination of oral aluminium and citrate should be avoided in patients with poor renal function.

9 citations


Patent
25 Jan 1989
TL;DR: In this article, a method of recovering aluminium from dross and other aluminium oxide containing waste for re-use in fusion electrolysis cells is described, in which the dross is firstly by comminution separated into a coarse fraction which still contains a lot of pure metal, and a fine fraction which mainly contains oxides, a dross dust, with salt-rich residues from a fusion furnace.
Abstract: of EP01677891. A method of recovering aluminium from dross and other aluminium oxide containing waste for re-use in fusion electrolysis cells, in which a) the dross is firstly by comminution separated into a coarse fraction which still contains a lot of pure metal, to be fused in a salt bath, and a fine fraction which mainly contains oxides, a dross dust, b) this dross dust with salt-rich residues from a fusion furnace (2) is washed with hot water in a reaction container (1) to decompose the carbides and nitrides and to dissolve the salts, c) this brime is filtered, a filtrate which runs off in the process being evaporated, the salts crystallised out being fed back to the smelting furnace (2) while a remaining filter residue is disintegrated as a washed out salt-free dross dust in the reaction container by the addition of heated sulphuric acid, d) then this sulphuric dross dust suspension is filtered, a sulphuric filtrate which results is washed until it is free from acid while a remaining filter residue is dried, calcined and then partially fed to the electrolysis cell (8), e) finally the filtrate which has been washed free from acid and in which the aluminium is dissolved as an aluminium sulphate, is neutralised in the reaction container, lye being added slowly, attended by constant agitation, during which aluminium hydroxide is precipitated, magnesium sulphate remaining in solution, whereupon f) the precipitated aluminium hydroxide is filtered out of this solution, dried and calcined and introduced into the electrolysis cell, while filtrate running off as a residual fluid is discharged with the dissolved magnesium sulphate as waste.

4 citations


Journal ArticleDOI
TL;DR: In this article, it has been shown that outerspheric hydroxo-fluoride aluminium complexes are formed under low initial concentrations of fluorine ions, and that the influence of the anode material on the passivating velocity of removal has been investigated, and conditions allowing to stabilize the electrical parameters on the electrode block functioning during a long period of time have been selected.

Patent
19 Sep 1989
TL;DR: A pharmaceutical compsn. comprises ranitidine or one of its salts, alginic acid and a carbonate or bicarbonate as discussed by the authors, and a further antacid may also be present e.g. aluminium hydroxide or magnesium tri silicate.
Abstract: A pharmaceutical compsn. comprises ranitidine or one of its salts, alginic acid or one of its salts and a carbonate or bicarbonate. The (bis)carbonate may be an alkali metal or alkaline earth metal cpd.e.g. NaHCO3, KHCO3, CaCO3 or MgCO3, pref. NaHCO3. A further antacid may also be present e.g. aluminium hydroxide or magnesium tri silicate. The ranitidine is pref. in salt form, esp. the hydrochloride. The alginic acid may be in the form e.g. of sodium or magnesium alginate.

Patent
20 Sep 1989
TL;DR: In this paper, a process for the production of aluminium sulphate, starting from residual slimes of plants for the anodic oxidation of aluminium, according to the reaction is described.
Abstract: Process for the production of aluminium sulphate, starting from the residual slimes of plants for the anodic oxidation of aluminium, according to the reaction: 2Al(OH)₃ + 3H₂SO₄ ----- Al₂ (SO₄)₃ + 6H₂O According to the process slimes (1) undergo a homogenizing treatment (2) which allows them to be subsequently conveyed up to and into the reactor (4). The reaction temperature is kept between 90°C and 160°C, in order to allow the complete conversion of the aluminium hydroxide, and the reaction products are then freed by filtering (7) from any insoluble residues and impurities at a temperature not lower than 40°C. The invention also comprises a special pump for conveying said slimes.

Patent
26 May 1989
TL;DR: In this article, the process for the continuous synthesis of an aqueous aluminium sulphate solution from an aluminium sludge comprises the stages consisting in alternately introducing the aluminum sludge produced during a surface treatment operation of the aluminium, the residual sulphuric acid produced during the removal of a coating during the treatment, and the acid containing aluminium sulfate produced during recovery of the sulphurous acid during treatment into a plurality of reaction vessels, so as to subject these substances to a reaction in the vessels, respectively, while mixing them, stirring them and heating them at a temperature
Abstract: The process according to the present invention for the continuous synthesis of an aqueous aluminium sulphate solution from an aluminium sludge comprises the stages consisting in alternately introducing the aluminium sludge produced during a surface treatment operation of the aluminium, the residual sulphuric acid produced during the removal of a coating during the treatment and the aqueous sulphuric acid solution containing aluminium sulphate produced during the recovery of the sulphuric acid during the treatment into a plurality of reaction vessels, so as to subject these substances to a reaction in the vessels, respectively, while mixing them, stirring them and heating them at a temperature between 80 DEG C and the boiling point of the reaction solution, and, finally, in bringing part of the sulphuric acid solution containing the aluminium sulphate into at least one of the second to last vessels in order to adjust the pH value of the reaction solution in the last vessel to a level between 16 and 25

Patent
13 Nov 1989
TL;DR: In this article, a boehmite-type aluminum hydroxide is represented by the formula A? O(OH)?xSO4?nH2O wherein 0.01 < x < 0.10 and 0. n < 1.
Abstract: Disclosed are (i) a boehmite-type aluminum hydroxide which is represented by the formula A ? O(OH)? xSO4?nH2Owherein 0.01 < x < 0.10 and 0 ? n < 1; and (ii) a process for preparing a boehmite-type aluminum hydroxide represented by the formula A ? O(OH)?xSO4?nH2Owherein 0.01 < x < 0.10 and 0 ? n < 1, the process comprising surface-treating a boehmite-type aluminum hydroxide with sulfuric acid or a sulfate capable of forming sulfuric acid by heating or by hydrolysis, the boehmite-type aluminum hydroxide to be treated being represented by the formula A ? O(OH)?mH2Owherein 0 ? m < 1.

Patent
08 Jul 1989
TL;DR: In this paper, a method of producing amorphous silicic acid and acid solutions of Al salts consists of decomposing the glassy residue of fossel fuel reactors, pref. melt chamber granulate with hot mineral acids.
Abstract: Method of producing amorphous silicic acid and acid solutions of Al salts consists of decomposing the glassy residue of fossel fuel reactors, pref. melt chamber granulate with hot mineral acids. After stirring, the undissolved residue is sepd. washed and dried to be recovered as silicic acid. The acid solns. is treated to recover the aluminium components. The hot acid is pref. 10-37% HCl or H2SO4 and it is used at between 50 deg.C and its boiling point. The acid solution is cooled and/or neutralised and/or alkali adjusted to bring about precipitation of some materials which together with the remaining soln. are further worked. USE/ADVANTAGE - To recover amorphous silicic acid and aluminium hydroxide and alkali aluminates in technically usable quality. The silicic acid is a starting material for producing synthetic zeolite, filler material and at support for catalsyt.

Patent
27 Dec 1989
TL;DR: In this article, the gallium and aluminium are precipitated as amorphous hydrate, and a gallium-rich solution is obtained by introducing slaked lime into the precipitate to remove alumina.
Abstract: The process consists in passing CO2 into the mother liquor remained after separation of aluminium hydroxide by carbonation dissociation treatment complete carbonation dissociation, gallium and aluminium are thus precipitated as amorphous hydrate. Separation of the precipitate removes most part of Na2O. Introducing slaked lime into the precipitate to remove alumina, a gallium-rich solution is produced. On passing CO2 into the solution again, a gallium-rich precipitate is obtained. Dissolving the gallium-rich precipitate with sodium hydroxide liquor and adding sodium sulfide to remove heavy metals, a solution containing 3-9 grams gallium per liter for electrolysis is obtained. This solution is electrolyzed in an electrolytic cell with stainless steel anode and cathode, gallium is deposited on the cathode. By treating with hydrochloric acid, gallium metal with a purity of 99.99-99.999% can be produced.

Journal Article
TL;DR: A randomized, double blind control study of the treatment of acute diarrhea with aluminium hydroxide and cholestyramine in comparison with a control group demonstrated the effectiveness of cholestyle in shortening the hospital stay, and the diarrhea course was better than that of aluminium Hydroxide.
Abstract: A randomized, double blind control study of the treatment of acute diarrhea with aluminium hydroxide and cholestyramine in comparison with a control group demonstrated the effectiveness of cholestyramine in shortening the hospital stay, and the diarrhea course was better than that of aluminium hydroxide However, aluminium hydroxide was superior to intravenous fluid plus early feeding

Patent
03 Jul 1989
TL;DR: In this paper, a composite mica insulating thin-film with excellence in its insulation resistance and in its dielectric breakdown voltage by using as an adhesive a mixture prepared through the process of adding aluminium hydroxide, aluminium silicate, potassium titanate and soft mica dust respectively to a silicone resin in their relevant suitable ratios.
Abstract: PURPOSE:To obtain a composite mica insulating thin-film with excellence in its insulation resistance and in its dielectric breakdown voltage by using as an adhesive a mixture prepared through the process of adding aluminium hydroxide, aluminium silicate, potassium titanate and soft mica dust respectively to a silicone resin in their relevant suitable ratios. CONSTITUTION:As an adhesive for a composite mica insulating thin-film is used a mixture prepared through the process of mixing 100 pts.wt. of a silicone resin, 50 to 200 pts.wt. of aluminium hydroxide, 50 to 200 pts.wt. of aluminium silicate, 2 to 20 pts.wt. of potassium titanate and 2 to 20 pts.wt. of soft mice dust with one another. Of their respective materials, the aluminium hydroxide has the function of preventing the entry of a conductive cracked gas into a mica layer, while the aluminium silicate/together with the aluminium hydroxide, has the property of improving fire resistance. Also both of the potassium titanate and the soft mica dust perform the function of keeping mutual bonding strength of the aluminium hydroxide and the aluminium silicate, both of which form a flaky filler. Thus, a composite mica insulating thin-film can be obtained with excellence in insulation resistance and in dielectric breakdown voltage.

Journal ArticleDOI
TL;DR: In this paper, pure finely powdered aluminium hydroxide specimens were treated with solutions containing different proportions of cupric nitrate, followed by drying at 100 ° C and roasting in air at temperatures varying between 500 and 1100° C.
Abstract: Pure finely powdered aluminium hydroxide specimens were treated with solutions containing different proportions of cupric nitrate, followed by drying at 100 ° C and roasting in air at temperatures varying between 500 and 1100° C. The solid-solid interactions between the resulting mixed oxides were investigated using DTA, TG, DTG and X-ray diffraction techniques. The results obtained revealed that cupric nitrate and aluminium hydroxide decompose readily at 250 and 320° C respectively, to produce CuO and Al 2 O 3 solids. The mixed oxides formed begin to interact at 650° C, yielding CuAl 2 O 4 . The crystallinity of the resulting aluminate increases with increasing firing temperature up to 1000° C, and remains thermally stable up to 1100 ° C in the presence of excess alumina, then partially decomposes to CuAlO 2 , in the case of a stoichiometric mixture of CuO and Al 2 O 3 . When the Al(OH) 3 specimen was roasted in air at 1000° C, it yielded a mixture of κ- and θ-Al 2 O 3 of moderate crystallinity; when fired at 1100° C, a mixture of κ-, θ- and α-Al 2 O 3 phases is produced. However, the presence of CuO (16.3 wt.%) results in the formation of well crystallized α-Al 2 O 3 (corrundum) at a temperature of about 1000° C. The transformation of different aluminas into α-Al 2 O 3 was found to be accompanied by an exothermic peak in the DTA curve at 975° C.

Patent
24 May 1989
TL;DR: In the process for preparing aluminium fluoride trihydrate by reaction of aluminium hydroxide with hexafluorosilicic acid, from 2 to 3% of aluminium remains in the silica obtained as by-product and as a result reduce the yield of aluminium fluorides.
Abstract: In the process for preparing aluminium fluoride trihydrate by reaction of aluminium hydroxide with hexafluorosilicic acid, from 2 to 3% of aluminium (as Al based on dry SiO2) remain in the silica obtained as by-product and as a result reduce the yield of aluminium fluoride trihydrate. The yield of the aluminium fluoride trihydrate preparation process can, in respect of the expensive aluminium component, be increased by treating the silica, after brief washing with mother liquor from the aluminium fluoride trihydrate crystallisation, with the whole of the hexafluorosilicic acid, heated to from 60 to 100@C, required for the subsequent reaction with stirring and filtering off, combining the mother liquor washing filtrate with the reaction solution containing the aluminium fluoride in a metastable state and from which the aluminium fluoride trihydrate is crystallised, and rapidly reacting the hexafluorosilicic acid filtrate, preferably heated to from 80 to 95@C, together with the filter cake wash water with the aluminium hydroxide.

Journal ArticleDOI
TL;DR: In this article, the surface acidity of aluminas prepared by precipitation from sodium aluminate solutions and nitric acid with and without surfactant was determined by IR spectroscopy.
Abstract: Surface acidity of aluminas prepared by precipitation from sodium aluminate solutions and nitric acid with and without surfactant were determined by IR spectroscopy. It was found that the amounts of aprotic acidic sites increase with increasing pH of precipitation and with increasing concentration of surfactant used in the course of precipitation and washing of the precipitate.


Patent
27 Jun 1989
TL;DR: In this paper, a method for obtaining the aluminium oxide with allowing additions consists in boiling a low-water aluminium hydroxide and then mixing it with an aqueous solution of a metal oxide.
Abstract: A method for obtaining the aluminium oxide with allowing additions consists in boiling a low-water aluminium hydroxide and then mixing it with an aqueous solution of a metal oxide. The sediment is extracted from the obtained mass and is dried at a temperature of 150-300°C. The dried sediment is desaggregated sediment is calcinated.