Journal ArticleDOI
Calcination of Metatitanic Acid to Titanium Dioxide White Pigments
TLDR
In this article, the authors describe mechanisms and kinetics of the reactions, using modern concepts of solid state and surface chemistry and physics, and also describe the effects of these reactions on the quality of the calciner discharge in upgrading and for the customer.Abstract:
In the sulfate process for the production of TiO2 white pigments, gel-like metatitanic acid is calcined in a rotary kiln to microcrystals of the rutile polymorph. This process is monitored by the addition of alkali ions, Al3+, phosphate and rutile nuclei. During the last decade, a scientific understanding has developed how these additives influence the solid-state reactions of the material in the kiln, i.e., crystal growth, transformation of anatase to rutile, incorporation of dopants and aggregation of crystals. This review describes mechanisms and kinetics of the reactions, using modern concepts of solid state and surface chemistry and physics. It also describes the effects of the reactions on the quality of the calciner discharge in upgrading and for the customer, i.e., the grindability to pigment particles, their light-scattering properties and photocatalytic activity. The principles of the additive functions revealed here may be used in process engineering of other powder reactions as well as in particle chemistry and nanotechnology in general.read more
Citations
More filters
Journal ArticleDOI
Characterization of food-grade titanium dioxide: the presence of nanosized particles.
Yu Yang,Kyle Doudrick,Kyle Doudrick,Xiangyu Bi,Kiril Hristovski,Pierre Herckes,Paul Westerhoff,Ralf Kaegi +7 more
TL;DR: Food-gradeTiO2 contains engineered nanomaterials with properties quite different from those of P25, which has previously been used in many ecotoxicity studies, and because food-grade TiO2 is more likely than P25 to enter the environment (i.e., potentially higher exposure levels), there is a need to design environmental fate and toxicity studies comparing food- grade to catalytic TiO 2.
Journal ArticleDOI
UV-stable paper coated with APTES-modified P25 TiO2 nanoparticles
TL;DR: The resultant APTES-modified P25 TiO2 nanoparticle-coated paper samples exhibit much greater stability to UV-illumination than uncoated blank reference paper and little, or no, photo-degradation in terms of brightness and whiteness of the P25-TiO2-nanoparticle-treated paper is observed.
Journal ArticleDOI
Preparation of Rutile Titanium Dioxide White Pigment via Doping and Calcination of Metatitanic Acid Obtained by the NaOH Molten Salt Method
TL;DR: In this article, the properties of the rutile titanium dioxide (TiO(2)) white pigment were improved by adding K(2)O, P(2), O(5), Al( 2)O(3), and Rutile nuclei.
Journal ArticleDOI
Influence of Phosphate, Potassium, Lithium, and Aluminium on the Anatase−Rutile Phase Transformation
TL;DR: In this article, the influence of temperature on anatase−rutile phase transformation and on the crystallites' growth variation was investigated on the laboratory scale with the use of hydrated titanium dioxide containing rutile nuclei from the industrial installation (sulfate process).
Journal ArticleDOI
Production of Rutile TiO2 Pigment from Titanium Slag Obtained by Hydrochloric Acid Leaching of Vanadium-Bearing Titanomagnetite
Longsheng Zhao,Yahui Liu,Lina Wang,Hongxin Zhao,Desheng Chen,Binnian Zhong,Jianchong Wang,Tao Qi +7 more
TL;DR: In this article, an alternative route was proposed for preparing rutile titanium dioxide (TiO2) white pigment, which involves the digestion of titanium slag with sulfuric acid, subsequent hydrolysis of unenriched titanyl sulfate solution with ammonia, low-temperature calcination, and unseeded crystallization, producing a high-quality Rutile TiO2 white pigment.