Abstract: This invention relates to a method of treating titania slag to increase the leachability of impurities from the slag consisting of the steps of sizing the titania slag to a particle size from 75 to 850 &mgr;m; oxidizing the sized slag particles at a temperature from about 700° C. to below about 900° C. causing the iron present in the slag to concentrate at the exposed surfaces of the slag particles and/or causing an anatase phase to stabilize in the slag, causing a major portion of the iron in the Fe(II) state to convert to the Fe(III) state, and causing the titanium in the Ti(III) state to be converted to the Ti(IV) state; and reducing the oxidized slag in a reducing atmosphere from about 700° C. to about 950° C. to convert a major portion of the iron in the Fe(III) state to the Fe(II) state. The invention also relates to a method of beneficiating titania slag to increase the TiO2 content thereof wherein the above treated slag is leached with acid.

Abstract: A method of recovering zirconium values from an ore containing zircon, baddeleyite, and uranium is disclosed. The method includes fusing the ore with soda ash and contacting the resulting fused ore with sulfuric acid, which generates an acid leach liquor that contains zirconium and uranium values and solids that comprise baddeleyite and silica. Baddeleyite is recovered by contacting it with sulfuric acid to convert baddeleyite to zirconium sulfate, which can be dissolved in the acid leach liquor. The method also includes separating zirconium from uranium by solvent extraction followed by precipitation.

Abstract: A method for the production of titanium metal from titanium-bearing ore. The method comprises leaching said ore or a concentrate thereof with an aqueous solution of a hydrogen halide; separating solids from the leach solution, to provide a leachate solution. The leachate solution may be subjected to extraction with an immiscible organic phase to selectively remove iron values to provide high purity iron products. Titanium may be separated from raffinate as TiO2 or solvent extract and thermal stripping. TiO2 may also be separated in the initial leach solution. Preferably, the titanium halide is titanium tetrachloride.

Abstract: A process for upgrading of titaniferous material containing silica, including pretreating the titaniferous material by alkaline leaching to precipitate the silica as an aluminosilicate which is amenable to further leaching. Subsequently, the pretreated titaniferous material is leached under acid conditions, causing the silica to enter solution under conditions such that the silica is not hydrolysed or precipitated as a silicate.

Abstract: A method for the production of titanium metal from titanium-bearing ore. The method comprises leaching said ore or a concentrate thereof with an aqueous solution of a hydrogen halide; separating solids from the leach solution, to provide a leachate solution. The leachate solution may be subjected to extraction with an immiscible organic phase. Titanium halide is separated from the organic phase by stripping. Preferably, the titanium halide is titanium tetrachloride.

Abstract: An industrially realistic process for upgrading of titaniferous materials is disclosed. The process comprises the following steps: (i) a pretreatment which has the effect of rendering silica amenable to leaching under the particular conditions of a subsequent leach, and (ii) an aqueous leach in the presence of an acid, the conditions of which are chosen such that silica which enters solution is not hydrolysed or precipitated as a silicate. The pretreatment step (i) may comprise alkaline leaching, roasting or smelting. The leaching step (ii) may be conducted at low solids densities.

Abstract: Disclosed and claimed are efficient methods for leaching minerals from ores using an acidic solution such as sulfuric acid. Additional factors which can improve mineral recovery include the use of an alkali metal halide, grinding the ore, addition of a carbon source, and/or, adjustment of the temperature at which the process is carried out. Minerals such as titanium, iron, nickel, cobalt, silver and gold may be recovered by the methods of the present invention.

Abstract: A method for processing alumina-bearing ores such as bauxite to recover iron, aluminum, silicon and titanium metal values therefrom the method comprising the steps of adding the alumina-bearing ores to a digester containing an acid to provide a mixture of acid and alumina-bearing ores and heating the mixture to dissolve soluble compounds of at least one of iron, aluminum, silicon and titanium to provide a digest containing dissolved salts of the soluble compounds and to provide a gas component. Thereafter, the digest is treated with water to dissolve water soluble salts therein to provide a slurry comprised of a liquid containing water and the dissolved soluble salts and a solid component comprised of silica. The solid component is separated from the liquid and the pH of the liquid is adjusted to form an aluminate and an iron-containing precipitate.

Abstract: A process for the extraction of alumina, iron oxide and titanium dioxide from bauxite ore and clays, and other ore bodies and feedstocks. The process starts by sulfuric acid leaching of the feedstocks in pressure autoclaves at about 200° C. and appropriate pressure. A leach liquor of sulfate salts of aluminum, iron and titanium is obtained. Any iron values are converted to a ferrous state. A recycled potassium sulfate helps produce double aluminum alkali sulfate crystals in the reduced leach liquor. The crystals are removed at about 20°-60° C. with the help of SO2 gases that reduce the ferric. Such double salt is hydrolyzed into a basic aluminum alkali precipitated sulfate salt. This is then dried and calcined at about 950° C. Any alkali sulfate is washed out and recycled. The remainder is alumina. The ferrous sulfate is crystallized out at about 10° C. It is dried and calcined at about 450° C. to produce an iron oxide mixed with other sulfate salts that can be washed out and recycled.

Abstract: The invention provides a process for the production of titanium tetrachloride (TiCl4) by the chlorination of titanium values in a titanium-containing starting material. The process includes exposing the starting material to a chlorinating agent and contacting the starting material with an inert liquid while the starting material is exposed to the chlorinating agent. The inert liquid is at a temperature of 200-350° C. and is at a pressure of 5-100 atmospheres (1 atmosphere=101.325 kN/m2). This causes the starting material to react with the chlorinating agent to form TiCl4. The invention also extends to TiCl4 whenever made in accordance with the method.

Abstract: A process for the production of titanium concentrates from anatase ores with high utilization of the iron contents of the raw ore involving the steps of calcining mechanically treated ore in the presence of an alkali metal carbonate followed by dilute leachings in both alkaline and acid media. No reducing agents are employed during calcination, avoiding the iron contents of the ore to be solubilized in the leaching steps. The final concentrate, which is rich in titanium and iron and has a low content of impurities, can be used as a raw material for the production of titanium slag.

Abstract: The present invention relates to an improved process for the preparation of high grade synthetic rutile from ilmenite with pig iron as a by-product. The process comprises subjecting ilmenite to reduction with coal, cooling and removing unreacted coal to obtain a product having 80-95% metallization, smelting the metallized ilmenite mixed with less than 10% carbon (w/w) in a transferred arc plasma using arc current, under flow of inert gas for a fixed time. The metal is then separated as pig iron and TiO2 as slag, the slag ground followed by oxidation at high temperature in the presence of an oxidizing gas, the oxidized product being leached with dilute HCl followed by filtration, washing and drying to obtain synthetic rutile.

Abstract: The present invention is a process for controlling, at an aim point, the passivation of aluminum chloride in the chlorinator discharge stream in a process for making titanium tetrachloride.

Abstract: A method for processing red mud to recover iron, aluminum, silicon and titanium metal values therefrom the method comprising the steps of adding the red mud to a digester containing an acid to provide a mixture of acid and red mud and heating the mixture to dissolve soluble compounds of at least one of iron, aluminum, silicon and titanium to provide a digest containing dissolved salts of the soluble compounds and to provide a gas component. Thereafter, the digest is treated with water to dissolve water soluble salts therein to provide a slurry comprised of a liquid containing water and the dissolved soluble salts and a solid component comprised of silica. The solid component is separated from the liquid and the pH of the liquid is adjusted to form an aluminate and an iron-containing precipitate.

Abstract: A process for production of titanium oxide comprises digesting an ilmenite ore in which at least 92% by weight of the iron which is present is in the ferrous form, if necessary adding a reducing agent and subsequently precipitating hydrous titanium oxide. When a reducing agent is added the amount used is equivalent to less than 4.0% by weight metallic iron calculated with respect to ilmenite ore. The process enables an increased throughput on a pigment plant and less co-product in the form of iron compounds is produced.

Abstract: A non-polluting liquid-phase process and a supporting system of apparatus for producing titanium dioxide from titanium ore or slag provide a more economical sulfate process for preparing anatase. The ore or slag is reacted with hot sulfuric acid. The reaction product is filtered and washed before being combined with acid water, in which the solids are partially dissolved. The resulting suspension is filtered, and the filtrate hydrolyzed to convert titanium values therein to titanium dioxide hydrate, which is calcined to produce anatase pigment.

Abstract: A process for reacting a zirconia-based material comprises reacting, in a reaction step, plasma dissociated zircon with aqueous hydrogen fluoride to produce a soluble fluoro zirconic acid compound.

Abstract: A method for recovering titanium and vanadium compounds, such as alkoxides, from a liquid hydrocarbon mixture by hydrolyzing the mixture with a base or acid wash having a sufficiently different density so that two liquid phases form, and separating the two liquid phases.

Abstract: Titanium oxide, comprising lamina shaped titanium oxide particles having a thickness of 10-30 nm and a width of 0.5 to 1 .mu.m, may be prepared by exfoliating a layered titanic acid powder having a formula H.sub.x Ti.sub.2-x/4 O.sub.4.nH.sub.2 O, where x=0.60-0.75, to form a titania sol; followed by drying and heating, to obtain a titanium oxide. The layered titanic acid powder may be prepared by contacting cesium titanate having an orthorhombic layered structure with an aqueous acid solution.

Abstract: A method is disclosed including: (a) sizing a titania slag to a particle size range of from 75 microns to 850 microns; (b) oxidizing the sized titania slag by contacting the sized titania slag with an oxygen containing gas at a temperature of at least about 950.degree. C. for a period of at least about 20 minutes such that a substantial portion of the iron oxide is converted to a ferric state, such that the reduced titanium oxides are converted to a tetravalent state, and such that at least a major portion of the glassy silicate phase is decomposed; (c) reducing the oxidized titania slag in a reducing atmosphere at a temperature of at least about 700.degree. C. for a period of at least about 30 minutes such that the ferric state iron oxide is converted to a ferrous state; (d) leaching the reduced titania slag with mineral acid at a temperature of at least 125.degree. C.

Abstract: A process for facilitating removal of one or more impurities from titaniferous material containing the impurities in a form which is highly soluble in acid. The material is in turn leached with a sulphuric acid solution and with a hydrochloric acid solution in either order. To enhance the susceptibility of the impurities to removal, the hydrochloric acid leach is augmented by one or more of the following: (i) addition of an effective amount of an added chloride salt; (ii) pre-treatment of the titaniferous material with a solution of an effective amount of a carbonate salt, preferably an alkali metal or alkaline earth metal carbonate; and/or (iii) pre-treatment of the titaniferous material with a solution of an effective amount of a hydroxide, preferably an alkali metal or alkaline earth metal hydroxide.

Abstract: A process for treating dissociated zircon comprises reacting dissociated zircon with gaseous hydrogen fluoride at an elevated reaction temperature. The reaction temperature is controlled to obtain at least one desired zirconium-based compound and at least one desired silicon-based compound.

Abstract: A process for producing a conductive, fluorine-doped titanium dioxide product which is doped throughout, said process comprising the steps of: (a) reacting the precursors in a system to form fluorine-doped TiO.sub.2, said precursors consisting essentially of a titanium alkoxide and a fluorine source; (b) reducing the fluorine-doped titanium dioxide product at a temperature sufficient to form said conductive, fluorine-doped titanium dioxide product; and (c) recovering the reduced product.

Abstract: A titanium oxide hydrolysate slurry prepared by the sulfate process is treated with either an alkali metal hydroxide or an alkali metal carbonate to solubilize the sulfur bound to the titanium at a temperature of from 60.degree. C. to 120.degree. C. and the slurry is treated with an organic acid to remove the alkali metal compounds present. This process produces titanium oxide hydrolysate of high purity.

Abstract: Zirconium containing less than about 400 ppm aluminum/zirconium is produced by precipitating zirconium sulfate from an aqueous stream containing from 0.5 M to 2 M zirconium oxychloride and contaminated with from 1000 to 3000 ppm aluminum/zirconium and having an acidity of greater than 1.5 N total acid per M zirconium. Ammonium hydroxide having a concentration of at least 14% by weight is added to the zirconium-containing solution to adjust the acidity to between 0.6 and 1.2 N total acid/M zirconium. Because the acidity adjustment results in the premature and undesired precipitation of zirconium hydroxide and aluminum hydroxide, the solution is maintained at a temperature of 60.degree. C. or more for 15 minutes to 60 minutes to dissolve at least some of the zirconium hydroxide without permitting the undissolved zirconium hydroxide to dehydrate to the extent that a gelatinous zirconium oxide precipitate forms. Ammonium sulfate or sulfuric acid is then added to the acid adjusted solution to provide a 0.6 to 0.

Abstract: A process for the preparation of very pure titanium dioxide by reacting titanium tetrahalides with sulphuric acid, hydrolysis the titanyl sulphate solution obtained and calcining the hydrolysate is disclosed wherein the reaction between titanium tetrahalide and aqueous 20-40% by weight strength sulphuric acid is performed in such a way that crystallisation of titanyl sulphate does not take place, the hydrogen halide is separated, the solution is optionally concentrated and filtered and then the ratio by weight of sulphuric acid to titanium dioxide is adjusted to between 1.7 and 2.0 and the titanium dioxide concentration is adjusted to between 250 and 300 g/l, the solution is hydrolyzed and the resulting titanium oxide hydrate is filtered off and calcined to give Futile or anatase.

Abstract: The production of titanium dioxide by the sulphate process generates waste substances such as the wash filtrates, which are formed in the washing of titanium dioxide hydrate, and waste gases which contain sulphur dioxide. In this improved process the wash filtrate is used to remove the sulphur dioxide from the waste gas while the sulphuric acid content of the wash filtrate is raised and the sulphuric acid-containing process solution thus obtained is used within the scope of the titanium dioxide production process. The waste gas and the wash filtrate are passed countercurrently through a series of several washing steps and are contacted with each other by introducing the wash liquid into the waste gas in a finely divided form in scrub towers. The sulphuric acid content of the washing fluid is stepwise changed from washing stage to washing stage. The sulphur dioxide content of the waste gas is reduced to values that may be discharged into the ambient atmosphere.

Abstract: Hydrolyzing finely divided, solid Group IVB metal chlorides by gradually introducing the finely divided solids into the mixing zone of a high intensity mixer operating on an aqueous solution produces solid Group IVB metal oxy salts such as ZrOCl.sub.2.8H.sub.2 O.

Abstract: Disclosed is a process for treating waste sulfuric acid generated from a process for producing titanium dioxide pigment by treating titanium slag with sulfuric acid. The waste acid is treated in a first step with a calcium-containing material to produce a gypsum suspension which is filtered and from which a filtrate is recovered. The filtrate is treated in a second step with a calcium-containing substance and clarification solids from the treatment of the titanium slag with sulfuric acid. A precipitate is produced in this second step which is subsequently filtered. The precipitate is suitable for disposal in a landfill.

Abstract: A process of treating metal chloride wastes produced by chlorination of titanium ore comprises the steps of:(a) leaching said metal chloride wastes in a hydrochloric acid (HCl)-containing solution to obtain a solution containing solids and dissolved metals,(b) separating said dissolved metals from said solids present in the solution obtained in step (a) to obtain a liquid and a residue,(c) selectively precipitating the metals as their hydroxides by adding a neutralizing agent to the liquid obtained in step (b),(d) separating the precipitate of metal hydroxides obtained in step (c) from the liquid to obtain a residue, and(e) dewatering the residue obtained in step (d).

Abstract: A process for the preparation of titanium dioxide by the sulphate process in which titanium raw materials are decomposed with sulphuric acid, the resulting titanyl sulphate is hydrolyzed, the waste acid is separated from the hydrolyzate and evaporated to a concentration of 60 to 70%, sulphuric acid is separated from the solid metal sulphates, and the sulphuric acid which has been concentrated by evaporation is used again for the decomposition of the titanium raw material, the improvement wherein the 60 to 70% sulphuric acid is concentrated to 70 to 80% H.sub.2 SO.sub.4 in a further evaporation stage and the concentration of a part of this sulphuric acid is raised to a concentration of 98 to 99% H.sub.2 SO.sub.4 by the absorption of SO.sub.3 and then used together with the remainder of the above-mentioned 70 to 80% sulphuric acid for the decomposition of titanium raw materials.

Abstract: The iron content of the TiO.sub.2 -containing precursor is subjected to a direct reduction to effect a metallization of at least 90%. The reduced product is separated into magnetic and nonmagnetic fractions by magnetic separation. To oxidize the metallic iron, the magnetic fraction is subjected to an oxidation in an acid medium with agitation at a pH value below 2, under a pressure of 12 to 24 bars, and at a temperature from 150.degree. to 210.degree. C. with a supply of an oxygen-containing gas that contains at least 90% oxygen. When the suspension has been pressure-relieved, the hematite which has been formed is separated from the TiO.sub.2 concentrate.

Abstract: There is provided a method of producing titanium oxides which comprises: admixing an aqueous solution of titanium tetrachloride with sulfuric acid in a molar ratio of sulfuric acid to titanium tetrachloride of at least 0.5 adding an alklai to the resultant solution to produce titanium hydroxide; and drying and calcining the titanium hydroxide. A further method is provided which comprises: adding a solution of an alkali to an aqueous solution of titanium tetrachloride having a concentration of not more than 2.5 moles/l at temperatures of not less than 50.degree. C., thereby to substantially thermally hydrolyze the titanium tetrachloride and to produce titanium hydroxide; and drying and calcining the titanium hydroxide.

Abstract: In the production of TiO.sub.2 pigments by the steps of digesting titanium-containing raw materials with sulfuric acid, hydrolyzing the titanyl sulfate obtained, separating the waste acid from the hydrolyzate, bleaching the hydrolyzate and calcining the hydrolyzate after addition of rutilizing nuclei and standardizing chemicals to form TiO.sub.2 pigments, and recovering sulfuric acid from the waste acid, the improvement which comprises employing as the rutilizing nuclei nuclei produced from part of the bleached and then washed hydrolyzate, which nuclei are added to the remainder of the bleached and washed hydrolyzate before calcination.

Abstract: Process for purifying TiO.sub.2 ore consisting essentially of subjecting the ore to two or more leaching treatments, said leaching treatments alternating between use of an aqueous solution of a mineral acid and an aqueous solution of an alkali metal compound selected from the group consisting essentially of alkali metal carbonates, hydroxides or mixtures thereof.

Abstract: Titanium slag and ilmenite are subjected to a parallel treatment with sulphuric acid obtained by mixing different proportions of sulphuric acid having concentrations of about 98.5% by weight and about 85% by weight, respectively. The reaction mixtures have a temperature slightly below a predetermined starting temperature and the reactions are started by adding small quantities of superheated steam having a temperature above the predetermined starting temperature. The thus obtained solutions are separated from the respective treatment residues and combined. The combined solutions are further processed for obtaining titanium dioxide. The mother liquor constitutes sulphuric acid of a concentration in the range of about 23% by weight and containing metal sulphates. This mother liquor is concentrated to a sulphuric acid concentration of approximately 85% by weight and recycled.

Abstract: Synthetic rutile is prepared from titaniferous slags containing alkaline-earth metal impurities, such as magnesium oxide, by a method comprising contacting the slag with chlorine at a temperature of at least about 800.degree. C., and then leaching the chlorine-treated slag with hydrochloric acid at a temperature of at least about 140.degree. C.

Abstract: The method of the invention is advantageously applicable to realize a multistage chemical process during which liquid clarifiers suitable for the purification of water and sewage, furthermore, fine-disperse pulverulent solid products utilizable as pait pigments and fillers may be recovered. Each final product of the multistage chemical processes is a useful material, so the whole technology is waste free.

Abstract: Process for purifying TiO.sub.2 ore consisting essentially of subjecting the ore to two or more leaching treatments, said leaching treatments alternating between use of an aqueous solution of a mineral acid and an aqueous solution of an alkali metal compound selected from the group consisting essentially of alkali metal carbonates, hydroxides or mixtures thereof.

Abstract: A process for the preparation of an improved quality TiO.sub.2 pigment by hydrolysis of titanyl sulphate, isolation of the hydrolysis product form the waste acid produced during the hydrolysis, washing of the hydrolysis product and calcination of the hydrolysis product to form the TiO.sub.2 pigment, wherein the hydrolysis of the titanyl sulphate is carried out using separately produced hydrolysis nuclei which have been produced by a reaction of titanium salts with alkaline reagents, and in which waste acid and/or wash liquid containing waste acid is added after at least 50% of the total duration of the hydrolysis process.

Abstract: High-grade titanium dioxide is produced by(a) reacting ilmenite or titanium-containing slag with sulfuric acid,(b) dissolving the material from (a) with water or dilute sulfuric acid,(c) separating insolubles from (b) to obtain a black solution containing titanyl sulfate and foreign metal salts,extracting titanyl sulfate from the black liquor with sulfuric acid and an organic medium containing an organophosphorus compound, separating the foreign metal salts in an aqueous extract phase, recovering titanyl sulfate from the organic extract phase, andhydrolyzing the titanyl sulfate to titanium oxide hydrate.

Abstract: A synthetic rutile is prepared from a titaniferous slag, typically containing at least about 1.0 weight percent magnesium oxide and at least some portion of its titanium values as Ti.sub.2 O.sub.3, by a method comprising contacting the slag with chlorine gas at a temperature between about 400.degree. C.-800.degree. C., such that the magnesium oxide and chlorine gas react to form magnesium chloride, and then removing the magnesium chloride from the slag, typically by washing the slag with water. In one embodiment, the synthetic rutile can be further upgraded by subjecting it to either a caustic or acid leaching treatment.

Abstract: A process for the production of TiO.sub.2 pigments by the sulfate process by digestion of titanium-containing raw materials with sulfuric acid, hydrolysis of the titanyl sulfate formed, purification of the hydrolyzate and calcination of the hydrolyzate in rotary kilns, wherein the calcination conditions are regulated through adjustment of the SO.sub.2 content of the waste gases issuing from the rotary kilns used for calcination.

Abstract: A process for preparing nodular 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 for a time and temperature sufficient to form nodular-shaped solids. After removing the acid by filtration and washing the solid residue, the residue is calcined to provide a nodular titanium dioxide pigment.

Abstract: The invention concerns processes for the preparation of zirconium compositions which on calcination form zirconia. The zirconium compositions are prepared by the addition of an ammonia source to an aqueous zirconium sulfate solution to give a solution pH in the range of from 0.1 to 2.5 and preferably 1.0 to 2.0. The zirconium composition precipitated from solution appears crystalline, is readily collected by filtration and has low levels of metallic impurities. Therefore, the process of the invention may be used to advantage in the purification zirconium compounds.The invention also includes the zirconium compositions and processes for the purification of zirconium compounds including zirconia.

Abstract: A process for production of useful materials including a product of similar composition to nepheline involves contacting a slurry of red mud with sulphur dioxide to dissolve components of the red mud that are soluble in sulphurous acid, removing residual undissolved solids by filtration, and recovering a filtrate containing soda, alumina and silica values, removing free water from the filtrate to produce a crystallized residue, and calcining the crystallized residue.

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 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: Process for the preparation of alkali metal fluotitanates by fluorination of a titanium ore, reaction with an alkali metal compound, precipitation and separation of the formed alkali metal fluotitanates, wherein the titanium ore is mixed with a hydrofluosilicate solution, the resulting suspension is evaporated at a temperature of 90.degree.-110.degree. C., the residue is subsequently taken up in water or in a mineral acid and the residue solution is neutralized with an alkali metal compound.

Abstract: The beneficiation or upgrading of an iron-containing titaniferous ore to a synthetic rutile by subjecting the ore to reduction followed by acid leaching of the reduced ore is improved by forming a mixture of the ore and an aqueous sulfuric acid solution, adding a reducing agent to this mixture and then subjecting this mixture containing the reducing agent to reduction at elevated temperatures. The resulting reduced ore, which is characterized by an increase in the ferrous iron content thereof and an increase in its specific surface area, exhibits an enhanced response to subsequent acid leaching to provide a synthetic rutile of improved purity.