Abstract: A method is provided of preparing high-purity mixtures of zirconia and another metal oxide substantially free of sodium oxide impurity. Trioxydizirconium ion and a salt of another metal in an aqueous solution are added to a highly basic solution, resulting in the homogeneous precipitation of the combined hydroxides or hydrous oxides. The precipitate is recovered, washed with the water and then with an organic solvent, and then dried, most preferably employing an azeotropic distillation procedure. The resulting material is then calcined to provide a mixture of zirconia with the other metal oxide. In a preferred embodiment, the zirconia mixtures are in the form of fine powders which can be sintered to form a product having greater than 99% of its theoretical density.

Abstract: A process for preparing titanium dioxide in the form of spherical particles having the particle size distribution indicated by dw/dn.ltoreq.2, by hydrolysis of strongly acid solutions of Ti(IV), wherein the molar ratio SO.sub.4.sup.= /Ti(IV) is at least 1.5, and in the presence of cationic polyelectrolytes having a molecular weight higher than 1 million and a ionicity of at least 3 milliequivalents per gram.

Abstract: A fine powder of stabilized zirconia a process for its preparation and application of the powder in ceramic compositions to obtain good mechanical, thermomechanical and electrical properties.A zirconia hydrate sol having a pH between 0.5 and 5 and containing elementary acicular crystals having dimensions of from about 10 to 500 .ANG. which are agglomerated into submicron aggregates of from abuot 100 to 5000 .ANG. in diameter is mixed with a solution of a stabilizing agent, preferably yttrium; the suspension is dried; the dried suspension is calcined at a temperature of from about 700.degree. C. to 1,300.degree. C. for preferably from about 30 minutes to 24 hours; and if needed, the powder obtained is milled.

Abstract: Disclosed herein is a high-dispersion sol of monoclinic zirconia supermicrocrystals which is translucent and contains monoclinic zirconia supermicrocrystals of uniform size and a rodlike shape or ellipsoidal shape having a diameter or width smaller than 100 .ANG., at a concentration higher than 0.1 mol/liter. The sol is produced by preparing a clear or sherbetlike mixture of water and zirconyl chloride or an aqueous solution of a zirconium salt of hydroxide and hydrochloric acid, subjecting the mixture or the aqueous solution to hydrothermal treatment in a sealed container at more than 130.degree. C. for more than 24 hours, to give a white pasty product, diluting the pasty product with water so that the concentration decreases below 1 mol/liter as zirconium, adjusting the pH to 3 to 7, and finally concentrating the diluted product.

Abstract: A process for the production of coarse scrubbing aggregates of TiO.sub.2 particles by vapor phase oxidation of titanium tetrachloride. The particle aggregates of sizes above 0.15 mm are separated from the TiO.sub.2 fines by wet screening on a moving screen, calcined and returned to the process. In a preferred embodiment of the process, the titanium dioxide prior to calcination is admixed with 0.01 to 0.3% by weight alkaline hydroxides (related to anhydrous TiO.sub.2), hard particle aggregates of sizes between 0.2 to 2.0 mm being generated that are returned to the hot reaction mixture and used for the prevention of deposit formation on the surfaces of the heat exchanger.The process can be carried through in such a way that the quantities of coarse scrubbing TiO.sub.2 aggregates per unit of time consumed by abrasion and newly formed by sintering are equal, their percentages in recycling TiO.sub.2 thus remaining constant which simplifies the TiO.sub.2 production process.

Abstract: A titanium dioxide compositon suitable for incorporation into ceramic frit, and process for preparation thereof. A clarified titanium sulfate liquor is hydrolyzed and precipitated to yield relatively large and uniform-sized hydrolysate particles which are easily separated from the acidic liquor by filtration.

Abstract: A process for preparing a zirconia-alumina base composite ultra-fine powder is described, including the steps of: mixing an aluminum salt or an alumina hydrate with an aqueous zirconium oxychloride solution, with or without metal salt acting as a stabilizer; mixing urea or a substance capable of generating ammonia by hydrolysis with the resulting mixture; and allowing the mixture to react at a temperature of 140.degree. to 300.degree. C. and a pressure of 4 to 150 kg/cm.sup.2 in a high-temperature and -pressure vessel. The reaction product is further dried, calcined and crushed to obtain an ultra-fine powder.

Abstract: A process for the production of high-purity zirconia from dissociated zircon or other zirconiferous material is disclosed. The process includes leaching of the zirconiferous material with concentrated sulphuric acid and continuously removing the water formed during leaching to maintain the concentration of sulphuric acid at a substantially constant level.

Abstract: Substantially spherical mono-sized particles of zirconia can be prepared by the forced hydrolysis of an aqueous solution of zirconyl chloride. A zirconyl chloride solution having a molarity up to about 0.4 is heated for at least 72 hours at a temperature of at least 95.degree. C. to generate suspended particles of hydrated zirconium oxide, which are recovered and calcined to provide the mono-sized zirconia powders. In preferred embodiments, mono-sized powders of a mixture of zirconia with one or more of its stabilizing metal oxides is prepared by precipitating the metal in the form of its hydroxide onto pre-formed zirconium-containing particles.

Abstract: A process for removing one or more contaminants of the formula TiCl.sub.3 OR, in which R is an alkyl or aryl group, from a liquid phase comprising TiCl.sub.4, characterized in that the contaminants are reacted with an organic acid halide ##STR1## in which R' is an aryl or alkyl group, to precipitate an addition complex of the formula ##STR2## in which n is a number of from 0.3 to 3.0, and the addition complex is separated from the liquid phase.

Abstract: The present invention relates to a low temperature method of preparing a compound of the formula:ABO.sub.3whereinA=Ba, Sr, Ca and Pb; andB=Ti, Zr and Hf,by(a) reacting a B-alkoxide, with a predetermined amount of aqueous A-hydroxide,(b) heating the reaction mixture to an initial temperature of 100.degree. C.-250.degree. C. at 1-40 atmospheres of pressure;(c) cooling the reaction mixture and thereafter, heating it to a subsequent temperature of approximately 40.degree. C. to 60.degree. C.;(d) dialyzing the cooled reaction product and recovering the tenate.

Abstract: A sealing composition suitable for sealing alumina packages for integrated circuits at a temperature below about 450.degree. C. for a short time of about 10 minutes. The composition is a mixture of 50-80 wt % vitreous solder glass powder of PbO-B.sub.2 O.sub.3 system having a deformation point of 350.degree. C. or less, 1-35 wt % zinc material powder and 1-35 wt % zircon powder. The zircon powder is of a synthetic zircon artificially prepared to eliminate radioactive impurities such as uranium and/or thorium.

Abstract: A method of manufacturing fine powder of BaZrO.sub.3 is described, in which a zirconium compound is first hydrolyzed. The hydrolyzed zirconium compound is then reacted with a water-soluble barium compound in a strongly alkaline solution having a pH not lower than 13.6.

Abstract: A method is disclosed for the recovery of iron, aluminum and titanium from coal ash. The method comprises magnetically extracting magnetite from the ash, leaching the ash with a solution of a mineral acid, precipitating and removing titanium and iron hydroxides from the leach solution by adding thereto a solution of a strong base, and precipitating and removing aluminum hydroxide by contacting the remaining solution with carbon dioxide or aluminum hydroxide seeding.

Abstract: Titanium is extracted from perovskite ores or concentrates by reaction of e perovskite ores or concentrates with sulfuric acid to form a sulfated residue, dissolving the sulfated residue in water or dilute acid, removing the precipitated calcium sulfate, and recovering the titanium in an aqueous solution.

Abstract: A method of recovering titanium from perovskite by leaching with a strong sulfuric acid solution is disclosed. The leaching produces a sulfate solution containing titanium and a calcium sulfate residue when the time and temperature of leaching are controlled as a function of the grind size of the perovskite and concentration of the sulfuric acid. The titanium-containing solution and the calcium sulfate residue are then separated. The titanium in the leach solution is precipitated by heating, as a mixture of titanium sulfates, which are then redissolved in water or dilute acid solution. Titanium dioxide may then be prepared by hydrolysis of the titanium in the resulting aqueous solution.

Abstract: A method of purifying uraniferous aqueous solutions containing impurities, particularly at least one of the elements zirconium and/or hafnium, and also containing at least one of the anions SO.sub.4.sup.=, NO.sub.3.sup.-, Cl.sup.- or F.sup.- acting as complexing agents for the uranium and impurities, by precipitation of said impurities by means of an alkaline agent, characterized in that the following stages are carried out for the purpose of selectively and quantitatively separating the impurities from the uranium:(a) said uraniferous solution is brought to a temperature of at least 40.degree. C.,(b) the content of complexing agent is adjusted to bring the molar ratio: [complexing agent]/[soluble U+Zr and/or Hf] to at least 3,(c) the pH of said solution is adjusted between 2.2 and 4.3 by introducing an alkaline agent.

Abstract: A process is provided for recovering fluorine from dilute hydrofluoric acid solutions, such as waste scrubber solution obtained in the treatment of phosphates. The dilute solution is used to react with oxidic titanium material to solubilize the contained titanium and subsequently form, in the presence of potassium ions, crystals of K.sub.2 TiF.sub.6 which are commercially useful as a grain-refining agent in the manufacture of aluminum alloys.

Abstract: Titanium metal values may be recovered from a metal-bearing source containing titanium and iron by subjecting the source to an oxidation treatment and a reductive roast. After having crushed the source to a desired particle size, the reduced source is then leached by treatment with a halogen-containing compound to form soluble halides, following which the soluble titanium halide is precipitated as titanium dioxide by treatment with an iron oxide such as ferric oxide and recovered. The amount of titanium dioxide which is recovered may be optimized by utilizing a reductant such as hydrogen or carbon monoxide in an amount in the range of from about 1.5 to about 4.5 times the stoichiometric amount required to reduce the iron oxide to metallic oxide during the reductive roast.

Abstract: The instant invention relates to a process for the preparation of titanium dioxide from an ore comprising titanium oxides which comprises the steps of fluorinating said ore to convert the titanium oxides to titanium fluorides; and, contacting said titanium fluorides with an alkaline material at conditions whereby said titanium fluorides are converted to titanium dioxide. The ore may be an ilmenite ore and the fluorination may be carried out by contacting said ilmenite ore with a fluosilicate salt as sodium fluosilicate.

Abstract: Zirconium is selectively precipitated from aqueous solutions containing zirconium and uranium by treatment with a precipitant consisting of tartaric acid or a tartrate.

Abstract: The process relates to the separation of the molybdenum and/or tungsten, titanium, vanadium, niobium or tantalum present in the form of organometallic compounds in residual effluents.It is applicable, in particular, to the effluents originating from the epoxidation of olefins by hydroperoxides.The process involves treating the effluent with from 1 to 10% by weight of water, at between 150.degree. and 220.degree. C. under pressure, to render the metals listed above insoluble, without forming a distinct aqueous phase. The solid phase containing more than 95% of the metals is separated by filtration. After treatment, the effluents can be used without disadvantage, for example as a fuel, and the metals can be recovered from the solid phase.

Abstract: A process is provided for the manufacture of titanium compounds and particularly titanium dioxide wherein excess titaniferous bearing material is reacted with dilute sulfuric acid having a concentration of between about 25% and about 60% by weight at a temperature below about 140.degree. C. Thereafter, the titanium sulphate may be recovered or processed to provide titanium dioxide hydrate accompanied by recycling the spent acid for reaction with the titaniferous bearing material charged to the process. The titanium hydrate may be calcined to provide titanium dioxide pigment.

Abstract: A process is provided for the manufacture of titanium dioxide pigment wherein excess ilmenite ore is reacted with dilute sulfuric acid having a concentration of between about 25% and about 60% by weight in the presence of an iron reductant, and in preferably at least two stages wherein the first stage is maintained at a temperature up to about 140.degree. C. and the second stage is conducted at a lower temperature (than the first stage) which is below about 100.degree. C. to provide a salt solution of titanium and iron. Thereafter, the titanium is hydrolyzed to provide titanium dioxide hydrate accompanied by recycling the spent acid from the hydrolysis for reaction with the ilmenite ore charged to the process. The titanium hydrate is calcined to provide titanium dioxide pigment.

Abstract: A process is provided for the manufacture of titanium compounds and particularly titanium dioxide wherein excess titaniferous bearing material is reacted with dilute sulfuric acid having a concentration of between about 25% and about 60% by weight at a temperature below about 140.degree. C., and in the presence of a reducing agent which affects the reduction of ferric iron to ferrous iron. Thereafter, the titanium sulfate may be recovered or further processed to provide titanium dioxide hydrate accompanied by recycling the spent acid for reaction with the titaniferous bearing material charged to the process. The titanium hydrate may be calcined to provide titanium dioxide.

Abstract: A process is provided for the manufacture of titanium dioxide pigment wherein excess ilmenite ore is reacted with dilute sulfuric acid having a concentration of between about 25% and about 60% by weight and in preferably at least two stages wherein the first stage is maintained at a temperature up to about 140.degree. C. and the second stage is conducted at a lower temperature (than the first stage) which is below about 100.degree. C. to provide a salt solution of titanium and iron. Thereafter, the titanium is hydrolyzed to provide titanium dioxide hydrate accompanied by recycling the spent acid from the hydrolysis for reaction with the ilmenite ore charged to the process. The titanium hydrate is calcined to provide titanium dioxide pigment.

Abstract: A process is provided for the manufacture of a stable titanyl sulfate solution by diluting a reaction mixture containing iron sulfate and titanyl sulfate with a material selected from water, a titanyl sulfate solution, and mixtures thereof. The titanyl sulfate solution may be recovered or processed to provide titanium dioxide hydrate which may be calcined to provide titanium dioxide pigment.

Abstract: A process for beneficiating ilmenite ore using electrolytic reduction. The ilmenite ore is admixed with an acidic solution to form a mixture. The mixture is electrolytically reduced to convert at least a portion of any ferric iron that is present to ferrous iron. The acidic solution dissolves the ferrous iron in the ilmenite ore and yields beneficiated ilmenite having a relatively high titanium dioxide content.

Abstract: A method of crystallizing zirconium or hafnium oxychloride to remove metallic impurities and phosphorus by maintaining the normality of the mother liquor in which the zirconium or hafnium tetrachloride is dissolved.

Abstract: A method for economically producing high purity zirconium oxide by dissolving calcium zirconate in hydrochloric acid and adjusting the fluorine content of the solution and then mixing this solution with sulfuric acid and heating the mixed solution to a temperature of more than about 80.degree. C. for at least 10 minutes. The resulting suspension is diluted with water and allowed to stand and the precipitate is then filtered, washed and mixed with ammonium carbonate. Carbon dioxide is then passed into the solution, the resulting precipitate is filtered, washed, dried and finally calcined. The zirconium oxide obtained is of sufficiently high purity to be used in the manufacture of electro-ceramics.

Abstract: In a process for recovering titanium metal values from a titanium bearing source which also contains iron, the source is subjected to a reductive roast followed by a leach of the reduced source with hydrogen chloride. The suppression of the dissolution of titanium during the leaching step of the process will be effected by the addition of a phosphoric acid to the leaching solution.

Abstract: Titanium metal values may be recovered from iron and titanium bearing sources such as an ilmenite ore by subjecting the source to a reductive roast after having crushed the source to a desired particle size. The reduced source is then leached by treatment with a halogen-containing compound to form soluble titanium halides and iron halides. Thereafter, the soluble titanium halide is precipitated as titanium dioxide by treatment with an iron oxide such as ferric oxide. The desired titanium dioxide or rutile may be recovered without an appreciable loss by effecting the leach step of the process in such a manner so that the solution potential is not greater than about +150 millivolts.

Abstract: Iron metal values and titanium metal values may be recovered from iron and titanium bearing sources such as ilmenite by subjecting the source to a reductive roast followed by leaching of the reduced source with a halogen-containing compound. Thereafter, the iron halide is crystallized and separated from the soluble titanium halides. One portion of the iron halides is subjected to a reducing step to form metallic iron while a second portion is oxidized, the iron oxides being used to precipitate the titanium as titanium dioxide. The titanium dioxide may then be separated and recovered while the liquid portion is recycled to the leaching zone.

Abstract: Iron metal values and titanium metal values may be recovered from iron and titanium bearing sources such as an ilmenite ore by subjecting the source to a reductive roast after crushing the source to a desired particle size. The reduced source is then leached by treatment with a halogen-containing compound to form soluble titanium halides and iron halides. Thereafter the soluble titanium halide is precipitated by treatment with iron oxides such as ferric oxide and after separation from the soluble iron halides is recovered as titanium dioxide. The soluble iron halides are then crystallized by reducing the temperature of the solution and one portion of the crystals are subjected to a reduction step to form metallic iron. The other portion of the iron halide crystals is oxidized to form ferric oxide which is used to precipitate the titanium compound.

Abstract: Titanium metal values are recovered from a titanium bearing source such as an ilmenite ore by subjecting the source to a reductive roast and leaching the reduced source with a halogen-containing compound. Following this the soluble metal halides are separated from gangue and the pregnant leach liquor if treated with an iron oxide such as ferric oxide to precipitate titanium dioxide. The nucleation of the titanium dioxide may be improved by using a large excess of ferric oxide in the precipitation step. The improvement will thus result in an increased yield of the desired titanium dioxide.

Abstract: Titanium metal values may be recovered from titanium and iron bearing sources such as an ilmenite ore by subjecting the source to an oxidation treatment and a reductive roast after having crushed the source to a desired particle size. The reduced source is then leached by treatment with a halogen-containing compound to form soluble titanium halides and iron halides. Thereafter the soluble titanium halide is precipitated as titanium dioxide by treatment with an iron oxide such as ferric oxide and recovered. The amount of titanium dioxide which is recovered is determined by the amount of reductant utilized in the reductive roast.

Abstract: An improved process is described for producing titanium dioxide from ilmenite-type ore. The ore is digested with aqueous hydrogen fluoride, the resulting liquid mixture treated with a water-soluble oxidizing agent, and the ferric iron impurities, in the resulting digestion solution, at a pH between about 1.0 and 6.0, are extracted out with a mono-or dialkyl, or mono- or di-(alkylphenyl) orthophosphoric acid, such as di-(2-ethylhexyl) orthophosphoric acid. The remaining solution is treated with ammonium hydroxide to precipitate hydrated titanium dioxide which is then calcined to form pigmentary titanium dioxide. Alkali metal and ammonium salts of the organophosphoric acid are also useful in the process.

Abstract: Process for the recovery of H.sub.2 SO.sub.4 from dilute sulfuric acid solutions containing combined acid sulfates by heating these solutions in the presence of excess ammonium sulfate to a temperature from between about 100.degree. and 160.degree. C. until a concentration of free H.sub.2 SO.sub.4 between 50 and 59% by weight is obtained to precipitate the combined acid sulfates.

Abstract: In the recovery of chromium from a residue containing chromate and vanadate, by oxidative decomposition of a chromium and vanadium-containing ore in the presence of an alkali at temperatures of about 600 to 1200.degree. C., and leaching such residue with water, the improvement which comprises adding titanium dioxide to the residue and heating, whereby upon leaching the chromium enters the water while the vanadium is substantially left in the residue.

Abstract: Titanium dioxide of improved properties for use as a pigment is obtained by a process in which a non-concentrated acid solution containing not more than 200 grams of TiO.sub.2 per liter of solution is partially hydrolyzed and filtered; and additional acid solution slowly added with heating to hydrolyze the remaining TiO.sub.2 and give a product which, on calcining has a color index of about 1500.

Abstract: Titanium metal values may be recovered from a metal bearing source by subjecting the source to an oxidation step. The oxidized source is then divided, one portion being set to a reductive roast followed by leaching with hydrochloric acid. Thereafter, the remaining portion of the oxidized source is brought into contact with the leached solution whereby titanium dioxide is precipitated. The precipitated titanium dioxide is separated and recovered while the soluble metal values are treated for recovery thereof with a concurrent formation of hydrogen chloride, the latter being recycled back to the leaching zone.

Abstract: The red mud by-product of the Bayer process by which aluminum oxide is reed from bauxite as an aluminate, is digested with concentrated sulfuric acid or with sulfur trioxide gas to produce sulfates that can be leached out to the resulting mass with water. The solution is then heated at a pH of 1 to precipitate titanium oxide hydrate by hydrolysis. The remaining sulfates of the solution are then obtained in solid form by evaporation, or by precipitation with acetone, and the solid is then roasted to convert the aluminum and iron to the oxide. After leaching out the sodium sulfate with water, the aluminum and iron oxide are separated by the Bayer process, which works in this case even though x-ray diffusion patterns show that the aluminum oxide is mainly .alpha.Al.sub.2 O.sub.3.

Abstract: Titanium metal values may be recovered from a titanium bearing source by subjecting the titanium bearing source to a reductive roast followed by leaching the reduced source with a hydrogen chloride source. Thereafter the leached titanium bearing source is precipitated by contact with a metal oxide such as ferric oxide in which the metal is present in a highly oxidized state. The precipitated titanium dioxide is separated and recovered while the spent liquor is treated to form hydrogen chloride which may be recycled to the leaching zone with a simultaneous formation of the metal oxide for recycle to the precipitation zone.

Abstract: An improved process is described for recovering TiO.sub.2, useful as a white pigment, from ilmenite-type ores, including the steps of digesting the ore with aqueous hydrofluroic acid, separating out iron impurities from the resulting solution, precipitating hydrated titanium dioxide from the iron-free solution with ammonium hydroxide, and calcining the precipitate to obtain pigmentary TiO.sub.2, wherein the improvement comprises subjecting aqueous solutions of by-product ammonium fluoride, formed in the process, to electrodialytic water-splitting to form an aqueous solution of ammonium hydroxide and an aqueous solution of hydrogen fluoride and recycling said aqueous ammonium hydroxide to the precipitation step and said aqueous hydrogen fluoride to the digestion step.

Abstract: Titanium metal values may be recovered from a titanium bearing source by roasting said source in a reducing atmosphere, leaching the source with aqueous hydrogen chloride at an elevated temperature, cooling and saturating the leached solution with gaseous hydrogen chloride to precipitate hydrated ferrous chloride, separating the precipitated ferrous chloride from the soluble titanium chloride, raising the temperature of the solution to precipitate the titanium, separating and recovering the crystallized titanium compound.

Abstract: Hydrolysis of a titanyl sulphate solution is carried out according to the autonucleation method of gradually adding the solution to a body of water at a substantially constant rate over 10-20 minutes, in such a way as to obtain an ionic concentration after one minute of feeding of from 75 to 105 g/l, the concentration of sulphuric acid in the final hydrolysis solution being regulated to a value of from 310 to 330 g/l by adding water from the commencement of clouding of the hydrolysis solution up to the end of hydrolysis.

Abstract: Production of titanium dioxide which is characterized by recovery of reusable H.sub.2 SO.sub.4, highly pure Fe oxide and hydroxide and fractional recovery of Mn, V and Cr, etc., from FeSO.sub.4. nH.sub.2 O and waste acid of 20 - 40% H.sub.2 SO.sub.4 containing abundant heavy metallic ions, which are by-produced in the production of TiO.sub.2 by dissolution of Ti raw materials such as ilmenite, steel production slag, such as electric furnace slag, convertor slag with H.sub.2 SO.sub.4.

Abstract: Metal powders, metal oxide powders, and mixtures thereof of controlled particle size are provided by reacting an aqueous solution containing dissolved metal values with excess urea. Upon heating, urea reacts with water from the solution leaving a molten urea solution containing the metal values. The molten urea solution is heated to above about 180.degree. C. whereupon metal values precipitate homogeneously as a powder. The powder is reduced to metal or calcined to form oxide particles. One or more metal oxides in a mixture can be selectively reduced to produce metal particles or a mixture of metal and metal oxide particles.

Abstract: Titanium sulphate solutions obtained in the sulphate process from titaniferous materials are hydrolized by contacting at 88.degree.-98.degree. C water with a first titanium sulphate solution having a TiO.sub.2 titer of 230-260 g/l and an acid factor of 1.75-1.85, adding at 88.degree.-98.degree. C to the mixture a second titanium sulphate solution having a TiO.sub.2 titer of 230-260 g/l and an acid factor of 2.1-2.4 and heating the resulting mixture at boiling point. A volumetric ratio of from 3:100 to 12:100 is maintained between the first and the second solution.

Abstract: It is known to prepare highly active catalyst components for a Ziegler polymerization catalyst by reduction of titanium tetrachloride with an aluminum alkyl. An improvement in the preparation of such catalysts which leads to production of highly sterospecific as well as highly active catalyst components consists of including in the preparation the step of washing the reaction mixture which contains the desired TiCl.sub.3 composition with an aliphatic hydrocarbon at temperatures above 40.degree.C and separating the washed solids from the wash liquid at a temperature above 40.degree.C. A heat treatment above 80.degree.C precedes, accompanies, or follows the washing and separation step. The washing step may be carried out in a single or in multiple stages.