Pigmentary titanium dioxide and its preparation
(57) Abstract:The invention relates to pigment rutelinae titanium dioxide, the method of its production and can be used in the production of paints, plastics and laminated plates on a paper basis. The invention consists in the pigment comprising particles of titanium dioxide with the besieged them cerium oxide in an amount of 0.01-1 wt.% and dense amorphous silica in an amount of 1-8 wt.% from the amount of titanium dioxide. The pigment may be optionally coated with aluminum hydroxide in the amount of 2-4 wt.% from the amount of titanium dioxide. A method of obtaining a pigment is added to the water slurry of particles rutlege titanium dioxide water soluble compound of cerium in an amount of 0.01-1 wt.% in terms of cerium oxide on the quantity of titanium dioxide, which when reacted with acid or alkali besieging cerium oxide, then add a water-soluble silicate in the amount of 1-6 wt.% and mineral acid to precipitate at least at pH 8 dense amorphous silica, the slurry is continuously stirred and maintain the temperature of 60-100oC during the whole deposition process. In addition to the sludge add water dissolve the military strength, superior resistance to photochemical decomposition. 2 C. and 13 C.p. f-crystals, 1 table. The invention relates to pigmentary titanium dioxide and the way it was received.Pigmentary titanium dioxide, in particular rutelinae titanium dioxide, is used in many products requiring a high degree of strength. For example, rutelinae titanium dioxide is widely used in paints, plastics and laminated plastics on a paper basis. However, in cases where such products are exposed to ultraviolet radiation, decomposition and discoloration of the pigment is accelerated. Thus, there is a need for improved titanium-dioxide pigment with a high resistance, resulting in increased service life of articles containing this pigment.The closest analogue of the invention is U.S. patent N 4450012, which discloses pigments coated with rutile a mixed phase comprising retelny pigment mixed phase having a first coating of oxide or gidrirovannoe metal oxide selected from tetravalent titanium, zirconium, tin and mixtures thereof, and a final coating of oxide or gidrirovannoe aluminum oxide. Also disclosed pic is new or titanium dioxide, zirconium, tin or mixtures thereof on calcined and crushed retelny pigment mixed in the aqueous phase of the suspension, the subsequent deposition of the final layer of oxide or gidrirovannoe aluminum oxide on the already coated with the pigment, washing and drying twice covered rutlege pigment.The present invention meets the above described requirements and eliminates the disadvantages of the known prior art by creating a pigmentary titanium dioxide having improved strength, i.e., improved resistance to photochemical decomposition. Durable pigment titanium dioxide consists of particles rutile titanium dioxide precipitated with them cerium oxide and dense (thick) amorphous silicon dioxide. The cerium oxide is preferably present on the particles of titanium dioxide in an amount of from 0.01 to 1 wt. from titanium dioxide and dense amorphous silica is preferably present in an amount of from 1 to 8 wt. from titanium dioxide.Particles of titanium dioxide with the besieged them cerium oxide and thick amorphous silicon dioxide is also preferably include an external coating of precipitated water (hydrated) oxide of aluminum. The latter is preferably part of the NT is obtained by formation of a water slurry of particles rutile titanium dioxide with the addition thereto of a water soluble compound of cerium, which when interacting with acid or alkali besieging the cerium oxide particles of titanium dioxide. Acid or alkali is added to the slurry to cause the precipitation of cerium oxide on the particles of titanium dioxide. Then the slurry was added water-soluble silicate and a mineral acid, in order to obtain particles of titanium dioxide precipitate dense amorphous silica. Optionally, the order of deposition may be changed, i.e., first precipitated thick amorphous silicon dioxide, and then the oxide of cerium.The preferred deposition coating of an aqueous aluminum oxide particles of titanium dioxide with the besieged them cerium oxide and thick amorphous silicon dioxide is carried out by adding to the slurry is acidic or alkaline aluminum compounds which, in contact with acid or alkali besieging particles aqueous alumina. Alkali or acid is added to the slurry, either simultaneously or after the addition of aluminum compounds.Thus, the main objective of the invention is to provide an improved high strength pigment dioxide and develop the way it was received.Other and additional objectives of the invention, and Yeghia preferred variant of the invention, given in the following description.Durable pigment titanium dioxide includes particles rutile titanium dioxide precipitated with them cerium oxide and thick amorphous silicon dioxide. In addition, the particles preferably include an external coating of an aqueous aluminum oxide to increase the dispersion ability and optical properties of the pigment.The cerium oxide is preferably present on the particles of titanium dioxide in an amount of from 0.01 to 1 wt. from TiO2dense amorphous silica is preferably present in the particles in an amount of from 1 to 8 wt. from TiO2and the external coating of an aqueous aluminum oxide (in those cases when it is incorporated into particles) deposited on them in quantity (in terms of aluminum oxide) from 2 to 4 wt. from titanium dioxide.Particles rutile titanium dioxide preferably receive a "chloride" way, i.e. by oxidation in the vapor phase of titanium tetrachloride, sodium hydroxide and sodium hexametaphosphate, followed by the addition of titanium dioxide. Optionally, the suspension (slurry) is subjected to wet grinding using a sand mill, followed by screening of small solid particles and residue sand.PEFC is acid or alkali besieging the cerium oxide particles of titanium dioxide. Examples of acidic compounds of cerium, which can be used in the process are cerium salts of mineral acids, in particular sulfate or nitrate of cerium. Used acidic compound of cerium causes the precipitation of cerium oxide due to interaction with the alkali, in particular the alkali metal hydroxide. Another option may be used alkali metal salts of cerium, in particular ammonium sulfate or nitrate of cerium, which interact with acid, for example sulphuric, for deposition of CeO2. In a preferred embodiment, the water soluble compound of cerium is a cerium nitrate and reactive with him alkali is an aqueous solution of sodium hydroxide. The connection of the cerium is introduced into the aqueous suspension in an amount (in terms of oxide of cerium) from 0.01 to 1 wt. from fine particles of TiO2in suspension, more preferably in the range of 0.02 to 0.05 wt. from titanium dioxide. Acid or alkali is added to the suspension in an amount sufficient to interact with the compound of cerium and subsequent deposition of cerium oxide particles.After the deposition of cerium oxide is completed, the particles of titanium dioxide are coated with a dense silica, which before the AI from a solution of water-soluble silicate while maintaining the pH of the slurry is more than 8, preferably in the range from 9 to 11. The deposition of a thick silicon dioxide reach by adding to the suspension a water-soluble silicate and the simultaneous or sequential addition of mineral acid. Preferably an aqueous solution of water-soluble silicate is added to the slurry, together with a solution of mineral acid while maintaining the pH of the slurry in the range of 9-10,5, resulting in the particles deposited dense amorphous silica. An aqueous solution of water-soluble silicate is preferably a solution of sodium silicate and mineral acid preferably is a solution of sulfuric acid. Water-soluble silicate is added to the suspension in the amount (in terms of silica) from 1 to 8 wt. from the content of the particles of titanium dioxide in the slurry, more preferably in the range from 1 to 6 wt. from titanium dioxide. Mineral acid is added in sufficient quantity to maintain the pH in the above range of values.During the deposition of the oxide of cerium and dense amorphous silica particles of titanium dioxide aqueous suspension is continuously stirred in the temperature range from 60 to 100oC, preferably at 70
FIELD: mining industry.
SUBSTANCE: perovskite concentrate, which can be used for manufacture of pigment titanium dioxide for paints, paper, enamels, and plastics, is processed as follows. 1 kg of concentrate is treated under atmosphere conditions with concentrated HCl at 90-100оС for 10 to 20 h to solubilize 75-85% of titanium, radioactive, and other acid-soluble components. Concentration of HCl is then lowered by diluting it with 1-5% HCl solution until TiO2 concentration 50-100 g/L. Thermohydrolysis of solution at 100-105оС accompanied by distilling away HCl leads to residual HCl concentration 20-100 g/L. Distilled HCl is sent to processing of perovskite concentrate. Titanium-containing precipitate is separated from mother liquor, washed first with 15-37% HCl solution and then with water to pH 3. Washed precipitate is treated with aluminum acid phosphate with pH 2-4. Aluminum acid phosphate uptake (on conversion to Al2O3) constitutes 0.5 to 5.0% content of TiO2. Treated precipitate is separated and calcined at 850-870оС to give pigment titanium dioxide. From mother liquor (after separation of Ti-containing precipitate), radioactive components are isolated by 4-6-step extraction with tributyl phosphate. Organic phase-to-water phase ratio is (1.5-2.0):1. Degree of titanium recovery is at least 98%, whiteness at least 96.5 conv. units, brightening power 1650-1800 conv. units, spreading capacity 38.0-40.0 g/m2, oil capacity 25-27 g/100 g pigment. Yield of pigment TiO2 is 95.7-98.0%. Amount of radioactive precipitate does not exceed 0.06 kg.
EFFECT: optimized perovskite concentrate processing parameters.
12 cl, 4 ex
FIELD: paint and varnish industry.
SUBSTANCE: invention proposes a flowing pigment mixture comprising titanium dioxide of universal sort or sort used in internal works with the concentration 40-100 vol.%, a thickening agent, dispersing agent and, optionally, water. The volume content of dry TiO2 is 15%, not less. As a thickening agent the mixture can comprise at least one hydrophobically modified ethyleneoxide-urethane polymer or at least one hydrophobically modified alkali-soluble emulsion, or at least one hydrophobically modified hydroxyalkylcellulose. As a dispersing agent the indicated mixture can comprise, for example, copolymers of maleic acid and diisobutylene, or butyl methacrylate and methacrylic acid, or acrylic acid and hydroxypropyl acrylate. Mixture can comprise additionally one or more additive taken among the following series: froth breaker, surface-active substance, coalescent agent, base, biocide, mildewcide agent, combined disperser, polymeric binding agent, a polymer with cellular latex particles. Proposed mixtures are stable and don't require a stirring. Invention can be used in preparing universal dyes and dyes for internal finishing.
EFFECT: improved preparing method, improved and valuable properties of mixtures.
20 cl, 13 tbl, 8 ex
FIELD: composite materials.
SUBSTANCE: invention concerns powderlike composite filler suitable for elastomer materials intended for manufacturing articles operated under elevated wear or dry friction conditions. Filler particles contain at least one core made from ceramic material (metal carbide) and exterior layer made from polytetrafluoroethylene, volume fraction of cores in filler particles ranging from 1 to 10%. Powderlike composite is prepared by activating metal carbide particles in mechanochemical activator at mechanical power supply intensity between 1 and 5 kW/kg and dose 30 to 1000 kJ/kg in a medium selected from: air, nitrogen, argon, vacuum between 10-2 and 1 atm until particles with average size not larger than 15 μm are obtained, after which polytetrafluoroethylene is added to mechanochemical activator and metal carbide particles are modified at mechanical power supply intensity between 0.05 and 0.5 kW/kg and dose 3 to 100 kJ/kg in a medium selected from: air, nitrogen, argon, vacuum between 10-2 and 1 atm.
EFFECT: addition of powderlike composite filler to rubber compound results in reduction in friction coefficient under dry friction conditions and significant reduction in summary friction pair wear under hydroabrasive wear conditions.
4 cl, 2 dwg, 3 tbl
FIELD: composite materials.
SUBSTANCE: invention relates to a process of manufacturing composite powder filler for elastomer compositions designed for fabrication of articles operated under increased wear and dry friction conditions. Process resides in that titanium carbide particles are activated in a mechanochemical activator with mechanical energy supply intensity 1 to 5 kW/kg and dose 100 to 1000 kJ/kg in a medium selected from a series: air, nitrogen, argon, and vacuum at pressure from 10-2 to 1 atm until particles with average size not larger than 15 μm are obtained, after which high-pressure polyethylene is added to activator and titanium carbide particles are modified at mechanical energy supply intensity 0,05 to 0.5 kW/kg and dose 3 to 100 kJ/kg in a medium selected from a series: air, nitrogen, argon, and vacuum at pressure from 10-2 to 1 atm.
EFFECT: lowered coefficient of friction under dry friction conditions and reduced summary rate of wear of friction pair under hydroabrasive wear conditions.
FIELD: chemical industry; public health; medicine; production of the titanium dioxide composition.
SUBSTANCE: the invention is pertaining to production of the titanium dioxide composition. The invention may be used in production of the sun-protective products providing the effective protection against UV-radiation and including titanium dioxide. The composition of the titanium dioxide contains at least one nonionic surface-active substance having the value of HLB(hydrophilic -lipophilic balance) within the interval from 7 up to 18, and the hydrophobic particles of the titanium dioxide, where the average length of the primary, particles is within the interval from 50 to 90 nanometers, the average width of the primary particles is within the range from 5 to 20 nanometers, and the average-volumetric diameter of the secondary particles makes less than 45 nanometers. The hydrophobic particles of the titanium dioxide have the absorption factor at 524 nanometers (Е524) - less than 2.0 l/g/cm, the absorption factor at 450 nanometers (Е450) - less than 3.0 l/g/cm, the absorption factor at 360 nanometers (Е360) - more than 3 l/g/cm, the absorption factor at 308 nanometers (Е308) - more than 30 l/g/cm, the maximum factor of the absorption (Еmax) - more than 45 l/g/cm and λ(max) - within the interval from 260 to 290 nanometers. The invention allows to improve the transparency of the sun-protective products containing the titanium dioxide.
EFFECT: the invention ensures the increased transparency of the sun-protective products containing the titanium dioxide.
24 cl, 4 ex
FIELD: varnish-and-paint industry.
SUBSTANCE: process of producing titanium dioxide pigment according to chloride technology comprises oxidation of titanium tetrachloride with oxygen or oxygen-containing gas in plasmachemical reactor followed by cooling of reaction products in tempering chamber and subsequent multistep fine grinding of intermediate product, titanium dioxide, by way of affection with supersonic gas flow at 100-500°C and ratio of gas mass intake to titanium dioxide mass intake = 0.2. In the first step of titanium dioxide fine grinding, treatment of titanium dioxide is performed with a dry gas supplemented by vapor of organic or organosilicon modifier having in its molecule at least one of the following functional groups: -OH, -NH2, NH, SH at mass intake of modifier representing 0.1-2.0% of the mass intake of titanium dioxide.
EFFECT: improved quality of titanium dioxide pigment and simplified process of production thereof.
1 dwg, 1 tbl
FIELD: methods and plants for increase of volume density of aerated powders.
SUBSTANCE: proposed method of compacting the powder containing oxide or phosphate of metal consists in placing the powder in container and increasing the pressure in its area above atmospheric pressure sufficient for compacting the powder before diffusion of considerable part of gas into powder. Powder containing oxide or phosphate of metal is placed in container and its volume density is increased. Then, concentrated suspension of pigment which is titanium dioxide is prepared. Specification gives description of plant proposed for increase of volume density of powder containing oxide or phosphate of metal and plant for increase of volume density of aerated loose pigment which is just titanium dioxide.
EFFECT: increased volume density of aerated powder; improved consistency; facilitated dispersion in latex paints.
22 cl, 6 dwg, 3 tbl, 8 ex
SUBSTANCE: invention can be applied in production of rutile-structured pigment based on titanium dioxide. The method of obtaining the base for pigment rutile titanium dioxide involves obtaining of source solution containing a titanium compound, addition of effective quantity of a salt catalyst to that solution, preferable addition of a chemical control agent to the solution, solution evaporation for obtaining dry amorphous intermediary product containing a mixture of titanium compounds, and baking of the intermediary product at the temperature under 500°C. Another variant of the method of obtaining the base for pigment rutile titanium dioxide uses eutectic mix of two or more NaCl, KCl and LiCl salts as the salt catalyst, melting temperature of the salt catalyst being lower than baking temperature.
EFFECT: reduction of rutile crystallisation temperature.
42 cl, 12 ex, 19 dwg
SUBSTANCE: invention can be used in lacquer-paint industry, in production of plastics, paper and other branches. Method of superficial procession of pigment titanium dioxide includes dechlorisation of titanium dioxide, wet milling and hydro-classification of titanium dioxide suspension, superficial procession of titanium dioxide, filtration, washing of titanium dioxide paste, its procession with organic compound, drying and microgrinding. Dechlorisation process is carried out at temperature of 50-60°C by combined dispersion of titanium dioxide in water and reduction of admixture chlorine in TiO2 with sodium hypophosphite in the amount twice exceeding content of chlorine in titanium dioxide, with further neutralisation of suspension with solution of sodium silicate to pH 6.5-7.0 and filtration. Suspension stabilisation before hydro-classification is carried out with solution of sodium silicate to pH of suspension 9.0-9.5 at temperature of 50-60°C. Superficial procession of fine fraction of suspension TiO2 is carried out at temperature of 60-70°C with compounds of titanium and aluminium using 1.0% weight TiO2 from solution of titanium tetrachloride, 2.5% weight Al2O3 from solution of sodium aluminate and 1.2-1.5% weight Al2O3 from solution of aluminium chloride. Processed suspension is filtered; paste is repulped in water to remove water-soluble substances; suspension is filtered. Prior to drying TiO2 paste is processed with organic compounds in The form of alkyl dioxyethylene in amount of 0.3-0.6% weight to TiO2, dried and microground.
EFFECT: increased indices of titanium dioxide, such as output of fine fraction of suspension TiO2 on hydro-classification, reduction of content of water-soluble substances in pigment, improvement of dispersibility in organic binders and gloss in akril paint and an increase in atmosphere-resistance.
2 cl, 5 ex, 3 tbl
SUBSTANCE: modification of titanium dioxide by metal oxides involves titanium dioxide treatment in water suspension by solutions of magnesium, or aluminium, or nickel formiates obtained by reaction of aqueous formic acid solution with the indicated metals or their carbonates or hydroxides. Formic acid quantity is stechiometric or exceeds stechiometric quantity by 20-100%. Further the suspension is dried in dispersion dryer with heating of titanium dioxide with applied salts at 200-700°C for 1-60 minutes.
EFFECT: reduced temperature of titanium dioxide modification without surface contamination with hardly removable anions, or anatase form transmutation into rutile form.
2 cl, 9 ex