Abstract: A process for preparing pigmentary titanium dioxide by grinding and mixing a titanium-bearing material, such as sorelslag, with an alkali metal compound such as sodium hydroxide, and roasting the mixture. The roasted material is ground followed by washing and filtering. Thereafter, the solid residue is digested with hydrochloric acid. After removing the acid by filtration and washing the solid residue, the residue is calcined to provide a titanium dioxide pigment.

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: In the preparation of titanium dioxide comprising autothermically digestion a titanium-containing raw material with sulphuric acid to form a solid relatively easily soluble digestion cake containing titanyl sulphate, extracting metal sulphates from this cake by water or dilute sulphuric acid, separating the undissolved residues and, optionally after crystallization of iron sulphate heptahydrate, hydrolyzing the titanyl sulphate to produce titanium oxide hydrate, and calcining the titanium oxide hydrate to titanium dioxide, the improvement which comprises adding to the raw material a metal sulphate and effecting the autothermic decomposition with sulphuric acid of about 80 to 88% concentration. Advantageously the acid is obtained by mixing dilute acid with concentrated sulphuric acid or oleum, some of the dilute acid and metal sulphate coming from a by-product filter cake produced in the course of the process.

Abstract: Spent catalysts removed from a catalytic hydrogenation process for hydrocarbon feedstocks, and containing carbon undesired metals contaminants deposits, are rejuvenated for reuse. Following solvent washing to remove process oils, the catalyst is treated either with chemicals which form sulfate or oxysulfate compounds with the metals contaminants, or with acids which remove the metal contaminants, such as 5-50 W % sulfuric acid in aqueous solution and 0-10 W % ammonium ion solutions to substantially remove the metals deposits. The acid treating occurs within the temperature range of 60.degree.-250.degree. F. for 5-120 minutes at substantially atmospheric pressure, after which the rejuvenated catalyst containing carbon deposits can be effectively reused in the catalytic hydrogenation process.

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 process for preparing high quality titanium dioxide which exhibits excellent reflectance and tint strength when incorporated into a coating formulation. The process involves the preparation of a seed solution wherein one of the seed curing factors of time, temperature and amount of alkaline neutralizing agent are varied to establish maximum reflectance and tint strength values obtained by the final product. The process can be repeated to analyze one or both of the other factors. The process can be used to prepare titanium dioxide in the anatase or rutile form and on a batch or continuous basis.

Abstract: A process for purifying an acid aqueous solution containing heavy metals by adding sulfide ions to said acid aqueous solution at a first pH lower than 3.4, precipitating a first heavy metal, adding sulfide ions again to said first precipitate containing acid aqueous solution, after adjusting to a pH of higher than 4, to precipitate a second heavy metal, and then removing the resultant first and second precipitates from the acid aqueous solution.

Abstract: Spent catalysts removed from a catalytic hydrogenation process for hydrocarbon feedstocks, and containing undesired metals contaminants deposits, are regenerated. Following solvent washing to remove process oils, the catalyst is treated either with chemicals which form sulfate or oxysulfate compounds with the metals contaminants, or with acids which remove the metal contaminants, such as 5-50 W % sulfuric acid in aqueous solution and 0-10 W % ammonium ion solutions to substantially remove the metals deposits. The acid treating occurs within the temperature range of 60.degree.-250.degree. F. for 5-120 minutes at substantially atmospheric pressure. Carbon deposits are removed from the treated catalyst by carbon burnoff at 800.degree.-900.degree. F. temperature, using 1-6 V % oxygen in an inert gas mixture, after which the regenerated catalyst can be effectively reused in the catalytic process.

Abstract: A process for producing titanium tetrachloride in which iron-titanium ore is leached in hydrochloric acid to produce a solid phase comprising upgraded titanium-containing material, and a spent liquid phase. Dissolved metal chlorides in the spent liquid phase are regenerated to produce hydrochloric acid in an acid regeneration zone. The titanium-containing material is chlorinated to produce a product stream containing titanium tetrachloride and entrained solids, including metal chloride. The entrained solids are recovered from the product stream and the metal chloride portion thereof is recycled to the acid regeneration zone.

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: An improved process for the recovery of substantially anhydrous zirconium tetrafluoride from an aqueous solution of hydrofluoric acid and zirconium fluoride is disclosed wherein the aqueous solution of hydrofluoric acid and zirconium fluoride is sprayed, preferably continuously, into a fluidized bed furnace having a bed comprising zirconium fluoride granules.

Abstract: A process for removing catalyst residues from poly-1-butene which is disclosed which comprises contacting an organic phase containing the poly-1-butene dissolved in an inert hydrocarbon solvent with an aqueous solution of an alpha-hydroxysulfonic acid and then separating the poly-1-butene-containing phase from the aqueous phase.

Abstract: The instant invention relates to a process for the preparation of titanium metal from an ore comprising titanium oxides which process comprises the steps of fluorinating the ore to convert the titanium oxides to titanium fluorides and then reducing the titanium fluorides to the metal. Such reduction may be carried out by contacting the titanium fluorides as a molten salt mixture with a molten alloy of zinc and aluminum at conditions whereby titanium is converted into a titanium-zinc alloy and the aluminum is converted into fluorides of aluminum. The titanium zinc alloy is separated from the fluorides of aluminum and the zinc is distilled from the alloy to leave behind titanium sponge. The ore may be an ilmenite ore and the fluorination may be carried out by contacting said ilmenite ore with a fluosilicate salt such as sodium fluosilicate.

Abstract: Zircon, ZrSiO.sub.4, is retrieved from zircon sand comprised of ZrSiO.sub.4 crystals and contaminants including SiO.sub.2 and iron by comminuting an aqueous slurry of the sand with iron means exposing the contaminants, admixing the resulting comminuted sand slurry with concentrated nitric and hydrochloric acids producing ferric chloride in solution thereby removing its iron component, admixing the resulting suspension with a flocculating agent agglomerating the suspended particles, admixing the resulting agglomerated mass with concentrated hydrofluoric acid to dissolve its SiO.sub.2 component, recovering the resulting ZrSiO.sub.4, washing it with water and drying.

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: Pure alumina (Al.sub.2 O.sub.3) is recovered from alunite (Al.sub.2 (SO.sub.4).sub.3.K.sub.2 SO.sub.4.4 Al (OH).sub.3) which is found mixed with various impurities by first calcinating the alunite in the presence of a chloride to produce impure Al.sub.2 O.sub.3 and other biproducts, and the impure Al.sub.2 O.sub.3 is then contacted with concentrated HCl to produce, after concentration and crystallization, crystals of AlCl.sub.3.6H.sub.2 O. These crystals are then calcinated to yield highly concentrated HCl and pure alumina.

Abstract: The invention relates to the sulfuric digestion of titaniferous slags and more specifically to a method to decrease the reduced titanium concentration in the resulting sulfate liquor. The process uses lignin products to assist in the oxidation of the Ti.sup.+3 content of the slag.

Abstract: An improved process for beneficiating titaniferous material whereby formation of fines during leaching of the titaniferous material is minimized. The titaniferous material and mineral acid reactants each are heated to an elevated temperature prior to admixing in the leaching operation. The heated reactants then are admixed in a leaching zone and further heated to a leaching temperature of from about 110.degree. C. to about 150.degree. C. The preheating causes at least a portion of the acid-soluble titanium values in the titaniferous material to be hydrolyzed upon dissolution and to form an acid-insoluble precipitate. At least a portion of the precipitate is caused to deposit upon the titaniferous material such that fines or slime formation in the leach liquor is minimized. The leaching is continued for a sufficient time to dissolve most of the acid-soluble impurities contained in the titaniferous material. The solid residue remaining in the leaching zone is recovered as the beneficiated product.

Abstract: In the process wherein a titanium-containing material is subjected to react with sulphuric acid to form a solid reaction mass from which the titanium values are recovered in solution by digestion with water or dilute sulphuric acid leaving behind a reaction residue and the reaction residue is thereafter treated to recover at least part of the titanium contained therein, the improvement wherein the treatment of the reaction residue is effected by contacting with sulphuric acid of a concentration greater than 86% a mixture by weight comprising about 5 to 95% of the reaction residue and 95 to 5% of a slag having a TiO.sub.2 content 60% by weight and a Ti(III) content of about 5 to 40% by weight, and thereafter eventually adding water, steam or dilute sulphuric acid to the mass to start the reaction.

Abstract: Significant enhancement of titanium dioxide recovery from a titaniferous ore is achieved by improving the efficiency of the comminution of the ore with the use of polyols of the formula:R--C--R'OH).sub.3wherein R is alkyl (C.sub.1 -C.sub.4), or hydroxyalkyl (C.sub.1 -C.sub.4) containing up to 3 hydroxy groups, and wherein R' is alkylene (C.sub.1 -C.sub.4).

Abstract: The present invention relates to methods for preparing a titanium tanning agent from sulphuric-acid titanium-ferriferous solutions and use thereof for leather tanning.The method for preparing a titanium tanning agent from titanium-ferriferous sulphate solutions comprises introduction, into said solution, of an oxidizing agent comprising a sulphuric-acid solution of a peroxy-titanium complex, follows by the addition of ammonium sulphate and sulphuric acid to precipitate a double salt of titanyl and ammonium sulphate in the monohydrate form (NH.sub.4).sub.2 TiO(SO.sub.4).sub.2.H.sub.2 O. The precipitation of this salt is preferably effected prior to its formation in an amount of 75-85% based on TiO.sub.2. The resulting salt is separated and washed; the filtrate and washings are combined and treated with ammonium sulphate to afterprecipitate the salt which is separated and recycled into the starting solution.

Abstract: A process for the production of a hydrolyzable titanyl sulphate solution comprising contacting sulphuric acid of about 86% concentration with a mixture of slag and ilmenite, the ratio of H.sub.2 SO.sub.4 to TiO.sub.2 in the mixture ranging from about 1.7:1 to 2.2:1 and the mol ratio of Ti(III) to Fe(III) in the mixture ranging from about 25:1 to 1.4:1, the slag having a TiO.sub.2 content of >80% and a Ti(III) content of about 22 to 40% calculated as TiO.sub.2, and the ilmenite having a Fe(III) to Fe(II) ratio from about 1:1 to 10:1, and adding water if necessary to bring the concentration of sulphuric acid to from about 86 to 96%.

Abstract: A process for the preparation of a hydrolyzable titanyl sulphate solution comprising adding sulphuric acid having a concentration greater than about 86% to a ternary mixture of two slags and an ilmenite to bring the proportion by weight of H.sub.2 SO.sub.4 to TiO.sub.2 to from about 1.7:1 to 2.2:1 and adding water, dilute sulphuric acid or oleum in amount sufficient to bring the H.sub.2 SO.sub.4 concentration to from about 86 to 96%, thereby to form the titanyl sulphate solution, the first slag having a TiO.sub.2 content greater than about 80% and a Ti(III) content of about 22 to 40%, the second slag having a TiO.sub.2 content of about 60 to 80% and a Ti(III) content of about 5 to 15%, and the ilmenite having a ratio of Fe(III) to Fe(II) of from about 1:1 to 10:1, the slags and ilmenite being present in such proportions that the ternary mixture of raw materials obtained has a molar ratio of Ti(III) to Fe(III).gtoreq.1.4.

Abstract: In a process for producing tantalum concentrates from ores containing tantalum oxides, tantalic acid or its salts together with rutile type titanium dioxide in mixed crystals, the ores are treated in a sulfuric acid of a concentration not lower than 50% by weight with heating at a temperature from 200.degree. C. to the boiling point of said sulfuric acid, and then the above-treated products are treated with a reducing agent in an aqueous solution of sulfuric acid of a concentration lower than 50% by weight to dissolve the titanium component to thereby obtain tantalum concentrates as solid products.

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 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 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 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: Process of extracting titanium values from titaniferous bearing material by circulating a reaction mixture containing titanium values in an agitation column located within a reaction vessel in a direction countercurrent to the flow of the reaction mixture in the annular space located between the agitation column and the inner reaction vessel wall, said circulation being done in a manner to maintain the titaniferous bearing material in a continuous turbulent suspension flow in the agitation column and discharging the reaction mixture from the reaction vessel and recovering the extracted titanium values.

Abstract: Titanium metal values may be 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 such as hydrochloric acid. The soluble titanium halide is then extracted from the leach liquor by utilizing an organophosphoric acid such as mono-2-ethylhexylphosphoric acid. The extracted titanium may then be stripped from the loaded organic acid solution by treating the solution with a mixture of hydrogen peroxide and an inorganic acid. Thereafter the desired titanium metal value may be recovered from the acid solution by any means known in the art such as hydrolysis.

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 titaniferous ore concentrate or slag is fed, together with sulfuric acid, into a heated pelletizer wherein the sulfation reaction occurs simultaneously with pellet formation.

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: Rutile, which has been obtained by precipitation from a hydrogen chloride solution will contain a relatively large amount of residual chlorine containing compounds such as the various forms of titanium chloride. These residual chlorine containing compounds may be removed in an economical way by treating the rutile with hydrogen peroxide in an acidic solution at relatively low temperatures to substantially reduce the chloride content of the product.

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: A process for recovery of zirconium from pickling solutions which have been used to treat products formed of zirconium or zirconium-based alloys, the invention particularly provides for separating zirconium from the acids contained in such solutions. The present process comprises passing the used or spent pickling solutions which contain from 1 to 50 g/l of dissolved zirconium through a column of an anionic ion-exchange resin by means of which the zirconium ions are separated from fluoride and nitrate ions originally present in the pickling solutions. Approximately 90% of the zirconium contained in such solutions can be recovered according to the invention, it being further possible to recycle residual fluoride and nitrate ions which remain in the used pickling solutions.

Abstract: An improved process for the production of synthetic rutile from ore containing titanium and iron, such as ilmenite ore, by a multi-step procedure employing controlled reduction, controlled oxidation and acid leaching. More specifically, the ilmenite ore first is reduced thermally such that substantially all of the iron (III) present has been converted to iron (II) and some metallic iron. The reduced ore then is oxidized with an oxidizing gas substantially free of elemental oxygen to convert the metallic iron to iron (II) without the substantial formation of iron (III). The oxidized ore then is leached to remove the iron (II) and calcined to produce synthetic rutile. The synthetic rutile so produced contains in excess of 92 percent titanium dioxide and less than 2 percent iron (III), by weight. Often, the synthetic rutile contains less than 1 percent total iron by weight.

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: The process basically consists of the removal of the impurities contained in titanium minerals, in which titanium is present in the form of oxides in complex association with other minerals which cannot be eliminated by the conventional hydro-metallurgical processes.The conditioning of the mineral by pyro-metallurgical treatment followed by magnetic separation, removes a part of the magnetic impurities at the same time that it exposes those impurities to the action of leaching acids and thus makes it possible for them to be removed easily. The alkaline treatment following the acid leaching permits elimination of the phosphorus contained as a harmful impurity, and makes it possible to secure a product within the specifications of the consumer market for use as a raw material mainly for the obtention of pigments and metallic titanium, which are the main forms in which titanium ores enter into consumption.

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: Titanium metal values may be recovered from a titanium bearing source such as an ilmenite ore by subjecting the source to a reductive roast, leaching the reduced source with a halogen-containing compound followed by crystallization of the iron halide impurity which is separated from the soluble titanium halide. The soluble titanium halide is then treated with an iron oxide to form titanium dioxide. The yield of titanium dioxide may be greatly improved by effecting the nucleation of the titanium in a manner which comprises adding the iron oxide to the solution without agitation. Upon completion of the nucleation reaction, the solids are then thoroughly dispersed before removing the solid titanium dioxide.

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: Red mud slurries can be solidified by adding thereto certain fatty substituted quaternary ammonium salts.