Kronos International Inc. | Date: 2016-10-28
The invention relates to a matting agent comprising agglomerates of pigment particles, to a method for the preparation of such matting agents, and to coating formulations containing the matting agents disclosed herein. The present invention further relates to pigmented mat surfaces, and to the use of agglomerates of pigment particles for matting pigmented coatings.
Kronos International Inc. | Date: 2015-07-09
A method for recovering hydrochloric acid from concentrated metal chloride solutions displaying an iron chloride content of more than 50% by weight where the Fe^(3+)/Fe^(2+ )ratio is at least 0.2 by a) spray granulation of the metal chloride solution at temperatures of 150 C. to 300 C. where at least part of the iron chloride is converted into iron oxide by hydrolysis, and pellets and HCl-containing gas are produced; b) pyrohydrolysis of the pellets in a reactor at temperatures of more than 550 C. in which context HCl-containing gas is produced; and c) recovery of hydrochloric acid from the HCl-containing gases produced.
Kronos International Inc. | Date: 2014-08-01
The invention relates to a method for the surface treatment of inorganic pigment particles with agglomerates of fine primary particles or single crystals of inorganic compounds, particularly of oxides or sulphates. The method is characterized in that the inorganic compounds are first precipitated from an aqueous solution under suitable pH conditions in a separate vessel in the form of fluffily structured agglomerates and/or single crystals. The precipitation product is subsequently added to an aqueous suspension of inorganic pigment particles. The method is particularly suitable for the surface treatment of titanium dioxide particles, in order to achieve high hiding power or high opacity when used in emulsion paints or laminates.
Kronos International Inc. | Date: 2014-12-09
The invention relates to a method for manufacturing composite particles, particularly composite particles based on titanium dioxide and carbonate, with the help of combined mixing, homogenization and precipitation in a pipeline mixer based on the rotor-stator principle. The method is based on an aqueous suspension of a particulate base component (e.g. titanium dioxide), which is preferably produced in an intermediate vessel equipped with a high-speed agitator. At least one of the required precursor substances and/or a pH-controlling component for precipitating calcium carbonate, for example, is metered into the pipeline mixer, and the calcium carbonate is precipitated. The method can be operated as a continuous process or as a batch process and permits shorter production times. The composite particles produced display homogeneous dispersion of the precipitated particles and the particulate base component.
Kronos International Inc. | Date: 2014-12-08
The invention relates to composite pigment particles containing calcium phosphate, their manufacture and their use in coatings, plastics and laminates. The composite pigment particles contain titanium dioxide pigment particles and precipitated calcium phosphate. In one embodiment, the composite pigment particles additionally contain an inorganic and/or organic filler as an extender, preferably selected from the group comprising Ca, CaMg and Mg carbonates, natural and synthetic silicon dioxide and oxides. The composite pigment particles are manufactured in a combined process of dispersion and precipitation. Depending upon the combination selected, use of composite titanium dioxide pigment particles of the invention can provide improved optical properties such as tinting strength or permits pigment savings with little to no loss of optical properties. In particular, the composite pigment particles of the invention can be used to replace part or all of the titanium dioxide contained in the users system.
Kronos International Inc. | Date: 2014-11-19
The invention relates to a method for coating the surface of inorganic solid particles in an aqueous suspension. The untreated particles, particularly TiO_(2 )base material, are made into an aqueous suspension and subsequently disagglomerated. According to the invention, a disagglomerated suspension of untreated particles is fed (recirculated) from an intermediate vessel (vessel) in a cyclic process. The intermediate vessel contains a high-speed agitator preferably having a minimum peripheral speed of 15 m/s or a specific agitator capacity P/V of at least 30 W/m3. A pipeline mixer (e.g. inline disperser) based on the rotor/stator principle is furthermore installed in the circuit. The water-soluble precursor compounds of the coating substances, and equally any necessary pH-controlling substances, are metered into the pipeline mixer. This leads to surface coatings with greater smoothness (low specific surface area according to BET), improved density (low sulphuric-acid solubility), and less coating substance precipitated separately (improved gloss).
Kronos International Inc. | Date: 2015-12-03
The invention relates to a method for the further processing of iron sulfate heptahydrate into iron sulfate monohydrate. An aqueous solution or suspension of iron sulfate heptahydrate is formed and heated in a pressure vessel to a temperature above its boiling temperature at atmospheric pressure and where solid iron sulfate monohydrate and a solution are formed. The solid iron sulfate monohydrate is separated from the solution and fed into a pressure vessel at a temperature above the boiling temperature of the solution at the pressure in the pressure vessel, which is lower than the pressure during separation.
Kronos International Inc. | Date: 2016-03-10
The invention relates to the manufacture of composite pigments containing aluminum hydroxide, and their use for improving the pigment light-scattering efficiency in coatings, plastics, paper and laminates. The composite pigment particles contain pigment particles such as titanium dioxide and precipitated aluminum hydroxide and are manufactured by in-situ precipitation of aluminum hydroxide in an aqueous pigment particle suspension. Use of the composite pigment particles according to the invention, based on titanium dioxide, permits savings on pigment with little or no loss of optical properties. Alternatively, if the pigment content remains unchanged, it is also possible to achieve better optical properties.
Kronos International Inc. | Date: 2015-08-06
A method for manufacturing a photocatalyst, based on titanium dioxide containing carbon or metal, in a pulsation reactor, where a raw material mixture, consisting of nanoparticulate titanium oxyhydrate and an aqueous solution or suspension, containing at least one organic, carbon-containing compound or metal ions, is fed into the pulsating hot-gas stream of the pulsation reactor and the titanium dioxide particles containing carbon or metal are formed. The hot-gas stream has a temperature of 450 C. following addition of the material and contains an excess of oxygen. In contrast to the known manufacturing methods, the method according to the invention allows reproducibly good product qualities to be achieved.
Kronos International Inc. | Date: 2015-08-05
The invention relates to a method for coating the surface of inorganic particles in an aqueous phase, particularly of titanium dioxide pigment particles, with a dense skin of silicon dioxide and at least one further inorganic compound, particularly with aluminium oxide, where the coating largely consists of separate layers. Titanium dioxide pigment particles, treated with SiO_(2 )and Al_(2)O_(3 )according to the invention, are characterised by improved tinting strength, reduced acid solubility and an isoelectric point shifted towards higher pH values.