TiO2 Pigment Research Articles

The digestion of New Zealand ilmenite by hydrochloric acid

Ilmenite (FeTiO3) is an important source of titanium, for which the main application is TiO2 pigment. One route to the production of TiO2 from ilmenite may be the digestion of both the Fe and Ti components in hydrochloric acid and the subsequent direct hydrolysis of the Ti. The process requires that the Ti be solubilized. A kinetic study is performed of the leaching of New Zealand (Barrytown) placer ilmenite (ground to a 10μm median particle diameter) by hydrochloric acid in a stirred reactor. Around 90% extraction of both Fe and Ti is achieved with a 32% w/w HCl concentration, with a 2:1 w/w ratio of HCl to FeTiO3 over the temperature range 60 to 90°C. The shrinking sphere model is a good representation of the kinetics if particle size distribution is accounted for. The reaction rate is estimated to be 4th order in HCl concentration. The temperature rise due to an exothermic reaction is calculated to be c. 41°C. Undesirable, in situ hydrolysis of Ti during digestion can be limited by control of temperature, reaction time and acid concentration. The data and models presented may facilitate the preliminary design of an industrial process to digest ilmenite to dissolve and retain Ti in solution.

Performance Evaluation of Aro-Ndizuogu Local Clay in Alkyd Paint Production

The potentials of Aro-Ndizuogu clay as an extender in gloss paint have been investigated. The physical properties of the local clay investigated: refractive index (1.54), pH (7.10), oil absorption (32g/100g clay), and specific gravity (2.13) compared favourably with that of conventional extenders. Gloss paints were prepared using the local clay (as an extender), xylene as solvent, and alkyd resin as binder. Paint samples prepared using TiO2 pigment was used for comparison. Results obtained from the analysis of the paint samples showed that TiO2 formulated alkyd paint samples exhibited the highest specific gravity (1.42) while the alkyd paint containing 50 % local clay, the least (1.30). While TiO2 formulated paint samples did not show any settling tendency, paint samples containing 50 and 60 % local clay had poor settling tendencies. The resistance of dry paint films was generally good in 20 % Na2CO3, distilled water, and 20 % NaCl. However, all the prepared paint samples failed NH3, and H2SO4 resistance tests. The present study has shown that Aro-Ndizuogu clay exhibited similar performance properties in the prepared alkyd paint samples like TiO2 prepared paint, and should find utilization in the surface coatings industry.

Gas emission monitoring of pre-heat furnace of metatitanic acid pastes

Due to the gradual convergence of national environmental legislation with European Union requirements it is necessary to conduct environmental monitoring of gas emissions of pre-heat furnace of metatitanic acid pastes. Critically analyzing the current system of clearing, it is established that technology isn’t provide the use of exhaust gas heat. As a result is an irreversible loss of 27,8 MW of heat and thermal pollution of the atmosphere; degree of purification of harmful components doesn’t exceed 55 %, which doesn’t meet modern requirements, then – a significant excess of maximum permissible concentrations of pollutants; insufficient level of dust collection, which causes loss of pigment TiO2. Overall, the current technology is ineffective and has no prospects for intensification.In the article the technological feasibility and economic viability of recycling waste and reducing energy consumption is proved. The concept of two-stage wet cleaning is proposed. Its implementation provides high separation efficiency of TiO2 particles, neutralization of harmful gas components and partial recycling of exhaust gas heat.

Valorisation of a by-product from the TiO2 pigment industry for its application in advanced oxidation processes

The aim of this study was to find a recycling use for waste material (WTiO2) that results from the extraction process of TiO2 from ilmenite in the pigment industry. In view of its high TiO2 content, the photocatalytic activity of this material was tested in the degradation of humic and fulvic acid substances (HFAs) and showed low levels of photoactivity, as was the case for the commercial photocatalyst Aeroxide TiO2 P25 (P25). However, due to its high Fe3+ content, an important application was observed for WTiO2 as an HFA coagulant and catalyst in Fenton and photo-Fenton processes. A two-stage process of coagulation and photo-Fenton treatment was subsequently designed and conducted at laboratory and small pilot scale. High percentages (above 95%) were obtained in total organic carbon (TOC) removal.

Management and Valorisation of Wastes and Co-products from the TiO2 Pigment Industry

This work analyses and evaluates potential applications for several inorganic wastes and intermediate materials, called co-products, generated in the TiO2 pigment production industry through the sulphate method. For this purpose, a physical–chemical characterisation of the input materials (ilmenite and slag), wastes (sludge and red gypsum), and co-products (two ferrous sulphates, mono and hepta-hydrated) was carried out. In addition, because the TiO2 pigment production activity is a Naturally Occurring Radioactive Material industry, a radiological characterisation was also undertaken. The main objective was to gain basic information for the application (actual or potential) of these co-products and wastes in fields such as agriculture, construction, and civil engineering. For each specific application of these wastes and co-products, additional studies were carried out to evaluate their appropriateness with respect to technical properties and their health and environmental impact. The results obtained in this work have revealed several lines of research with potential commercial applications.

Influence of MWCTs and nanometal oxide/MWCTs hybrids on the thermal conduction of their acrylic-based nanocomposites

In this study, acrylic-based nanocomposites containing different contents of multi-walled carbon nanotubes (MWCNTs) and metal oxide nanoparticles (i.e., TiO2, CuO and Fe2O3) were fabricated by solvent mixing method. The thermal conductivity of these samples was evaluated. The results indicated that the thermal conductivity of all fabricated samples was significantly improved even at small loading of MWCNTs. It was found that the thermal conductivity was enhanced by increase in MWCNTs content up to 5 wt%. Similarly, the metal oxide nanoparticles caused up to 75 % increment in thermal conductivity at 1.5 wt% of their loading in acrylic film. Contrary to expectations, the thermal conductivity of acrylic film was more increased by nanometal oxides (i.e., TiO2, CuO and Fe2O3) than MWCNTs. The effect of hybridizing of nanometal oxide particles (1.5 wt%) and MWCNTs (1.5 wt%) on thermal conduction was investigated as well. It was found that hybridizing improved thermal conductivities by about 85, 94 and 97 % for Fe2O3, TiO2 and CuO, respectively. Finally, the effects of TiO2 pigment and CaCO3 extender on the thermal conductivity of acrylic polymer and nano-TiO2 acrylic composites were studied. It was found that TiO2 could increase considerably thermal conduction of its acrylic films and acrylic nanocomposites.

Rapid determination of Ti in TiO2 by ICP OES

An improved, precise and accurate method for the quantitation of Ti by ICP OES in TiO2 pigments and related materials is proposed.

Markers of oxidative damage of nucleic acids and proteins among workers exposed to TiO2 (nano) particles

ObjectiveThe use of nanotechnology is growing enormously and occupational physicians have an increasing interest in evaluating potential hazards and finding biomarkers of effect in workers exposed to nanoparticles.MethodsA study was...

A quick assessment of the photocatalytic activity of TiO2 pigments — From lab to conservation studio!

Titanium dioxide is the most abundantly used white pigment of the 20th century. The pigment is still in use, both in the production of contemporary art and for the conservation of older artwork as a retouching pigment. Unfortunately, next to its positive characteristics, the pigment has one major potential drawback: its photocatalytic activity that can cause degradation of artworks in which it is used. In this paper, we report on a new method to test the photocatalytic activity of different quality grades of titanium dioxide white pigments. This can be done quantitatively in a chemical lab or qualitatively in a quick and easy way, in a museum or artists' studio, with limited use of lab equipment. The photocatalytic degradation of an organic dye, acid blue 9, in an aqueous solution containing titanium dioxide, is followed over time by means of UV–Vis spectrophotometry. Dye solutions containing pigments with high photocatalytic activity lose their color within several hours of UVA exposure. On the other hand, dye solutions containing UV-stable titanium dioxide do not degrade within 24h of UVA exposure. Insight in the photocatalytic activity of titanium white pigments, which can be obtained with this novel test, is of great importance for preventive conservation of modern art.

Preparation of rutile titanium dioxide pigment from low-grade titanium slag pretreated by the NaOH molten salt method

Low-grade titanium slag with a high accumulation of Mg, Al, Si, and the refractory structure of spinel, was sodiumized-oxidized to make it usable in the sulfate process for TiO2 pigment production. In the sodiumized-oxidized process, the Ti3O5 and Mg2SiO4 transform into Na2TiO3 and Na2MgSiO4, respectively. From combined ICP-OES with XRD refinement of the molten NaOH intermediate, the ideal stoichiometric ratio of NaOH to slag was calculated to be 0.9:1. After acidolysis of the intermediate, the obtained TiOSO4 solution, with Mg2+ and Al3+ impurities, was hydrolyzed to prepare metatitanic acid (H2TiO3) with a suitable particle size D(0.5) of 1.0–1.5 μm. The particle size D(0.5) of the hydrolyzed H2TiO3 decreased, while the concentration of Mg2+ and Al3+ increased. Finally, under optimal doping and calcination conditions, the rutile content of the prepared sample was 97.0%, and the achromic abilities of TCS and SCX were 1937 and 1.54, respectively.

USGS shows US TiO2 pigment output fell by 1.6% last year

USGS shows US TiO2 pigment output fell by 1.6% last year

Investigation of the mechanical properties of a photocatalytic pseudo‐paint

ABSTRACTPhotocatalytic oxidative paints (e.g., a paint containing nano‐TiO2) are used to break down volatile organic compounds to CO2 by photooxidation reactions. In this research, a photocatalytic oxidative pseudo‐paint was made with acrylic–styrene copolymer latex, TiO2 pigment, calcium carbonate extender, and TiO2 nanoparticles as a photocatalyst. To investigate the effects of the pigment, extender, and nanoparticles on the mechanical properties of the samples and their relationship to their photocatalytic activity, different contents of the particles were dispersed in the paint formulation. The tensile strengths (TSs) of the samples were measured as the mechanical properties. The samples were characterized by scanning electron microscopy analysis. We found that up to 3% nano‐TiO2 enhanced the mechanical properties of the pigmented resin, whereas beyond this, TS decreased. In samples containing 3% nanoparticles, the incorporation of 15% TiO2 pigment caused optimized mechanical properties, and beyond that, TS decreased because of particle agglomeration. In the absence of nanoparticles, the samples showed improvements in the mechanical properties with up to a 40% loading of pigment. The results reveal that the samples containing nano‐TiO2 and pigment showed the same trend for the mechanical and photocatalytic properties before the critical pigment volume concentration (CPVC). However, when the extender was incorporated or TiO2 particles were loaded beyond CPVC, the mechanical and photocatalytic properties correlation was compromised, and they were not directly correlated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42885.

Manufacture of Ceramic Bodies by Using a Mud Waste from the TiO<sub>2</sub> Pigment Industry

The main objective of this paper is focused in the use of waste generated by the TiO2 pigment industry, ilmenite mud (MUD), on the production of ceramic bodies. These ceramic bodies were produced from mixtures of a commercial red stoneware mixture (RSM) with different concentrations of mud (3, 5, 7, 10, 30 and 50 wt%). The samples were sintered to simulate a fast-firing process. The sintering behaviour of the fired samples was evaluated according to ISO rules by linear shrinkage, water absorption and porosity measurements. Both green powder and fired samples were characterised by means of X-ray diffraction (XRD), differential scanning calorimetry (DSC/TG), field emission scanning electron microscopy (FESEM) and bending strength measurements. Moreover, the activity concentrations of radionuclides were measured by high-resolution low-background gamma spectrometry, because this mud is a NORM (Naturally Occurring Radioactive Material) waste. Finally, the TCLP leaching test (Toxicity Characteristic Leaching Procedure, USEPA) was performed to assess the risks of use tiles from an environmental perspective. The results demonstrated that MUD can be successfully valorisated in the manufacture of red stoneware ceramic bodies with similar, or even better technological properties than commercial materials used currently.

Optical properties and radiation stability of TiO2 powders modified by Al2O3, ZrO2, SiO2, TiO2, ZnO, and MgO nanoparticles

The high-temperature modification of micron-sized grains of titanium dioxide with nanoparticles of Al2O3, ZrO2, SiO2, TiO2, ZnO, and MgO was performed. The influence of these types of nanoparticles on the diffuse reflectance spectra of modified pigments in the range of 350–2000 nm and their changes after irradiation by 30 keV electrons were investigated. It was determined that the modification does not lead to significant changes in the diffuse reflection spectra of the TiO2 pigments. The type of oxide nanoparticles, the size of the ionic radii and the valence of the cations do not noticeably influence the radiation stability of the modified pigment, as determined by the intensity of the absorption bands in the visible and near infrared regions of the spectrum. The determining factor in the increase of the radiation stability of the modified pigments is the specific surface area of the nanopowders.

Modification of TiO2 surface for improved light fastness

Rutile TiO2 dioxide particles were modified with P2O5 treatment for improving its UV light fastness and the characteristics are studied using different techniques. The investigation aimed at improving the light fastness of the TiO2 particles by surface modification with P2O5 and optimizing its content for best performance. The coating of different inorganic oxides such as SiO2, Al2O3, P2O5, etc. were confirmed by atomic absorption spectroscopy. Microscopic evaluation was employed to evaluate the surface morphology of modified TiO2. The specific surface area was estimated using BET method. Effect of the surface modification with oxides on electrokinetic properties and zeta potential is appraised. Changes in the pigmentary properties on UV exposure are determined as a measure of light fastness. The light fastness of the modified samples is superior to commercial TiO2 pigments. The dispersion and pigmentary characteristics of the P2O5 modified samples have approached the commercial rutile TiO2 pigment standards. The reducing strength values indicate good dispersion characteristics of the P2O5 modified samples. The light fastness of TiO2 particles can be improved considerably on imparting the coating of P2O5 along with Al2O3.

Recovery of titanium dioxide and other pigments from waste paint by pyrolysis

In this work, a model paint containing several types of inorganic pigments was pyrolyzed in a microwave-heated unit. The goal of the pyrolysis process was to recover and recycle the inorganic components in the paint, most importantly titanium dioxide (TiO2). The solid residue remaining after pyrolysis was further heat treated in air to remove most of the char in the TiO2-containing product. The recovered TiO2-containing product was used in two types of paint formulation as a replacement for virgin pigments. The properties of the paints containing recycled TiO2 pigment and extenders were evaluated and compared with a standard paint formulation containing only virgin TiO2 pigment and virgin extenders. A reduction in paint whiteness was observed but the opacity, gloss, and durability were nearly equivalent to that of the standard paint. Another consequence of using recycled pigments was that the recycled mix of TiO2 pigments and extenders was harder to disperse in the paint than the mix based on virgin materials, thus giving the painted surface a somewhat rough texture. The recycled material has shown promising results as a pigment/extender but further work is needed to optimize the recycled product to meet whiteness and dispersion requirements for incorporation in paint formulations on an industrial scale.

ICIS sees a 5% decline in US TiO2 pigment prices for 3Q 2015

ICIS sees a 5% decline in US TiO2 pigment prices for 3Q 2015

France, Germany & UK: Huntsman – TiO2 pigments

Roof maintenance practices often involve the application of biocide products to fight against moss, lichens and algae. The main component of these products is benzalkonium chloride, a mixture of alkyl benzyl dimethyl ammonium chlorides with mainly C12 and C14 alkyl chain lengths, which is toxic for the aquatic environment. This paper describes, on the basis of an in-situ pilot scale study, the evolution of roof runoff contamination over a one year period following the biocide treatment of roof frames. Results show a major contamination of roof runoff immediately after treatment (from 5 to 30 mg/L), followed by an exponential decrease. 175–375 mm of cumulated rainfall is needed before the runoff concentrations become less than EC50 values for fish (280 μg/l). The residual concentration in the runoff water remains above 4 μg/L even after 640 mm of rainfall. The level of benzalkonium ions leaching depends on the roofing material, with lower concentrations and total mass leached from ceramic tiles than from concrete tiles, and on the state of the tile (new or worn out). Mass balance calculations indicate that a large part of the mass of benzalkonium compounds applied to the tiles is lost, probably due to biodegradation processes.

Alumina Surface Treated TiO2 - From Process to Application

Titanium dioxide (TiO2) has found widespread use. Typically it is used in another matrix to impart certain properties. For example, it is widely used as a white pigment for paints and polymers. The aim of this research work was to achieve improvements in the sense of processability as well as the dispersion performance of alumina surface treated pigmentary TiO2in polymer matrix. Wet chemical method was used to modify the surface of the TiO2 pigment. Surface treatment included precipitation of hydrous oxides of aluminium on the surface of TiO2 particles. During controlled surface treatment, agglomeration has been avoided, which has been proved to improve applicative properties of TiO2 particles. In addition to that, organic additives were applied to enhance performance attributes of the pigmentary TiO2. The effectiveness of surface treatment was determined using scanning-transmission (STEM) and transmission (TEM) electron microscopy. Quantitative evaluation of quality and dispersion of the pigments has been performed using Filter pressure test. Lower pressure generated during filter pressure test when particles were well dispersed in a polymer matrix. Surface treatment also affected pigment processibility; i.e. filterability and settling, which is of high importance for process planning.

Effect of particle size on the diffuse reflection coefficient of titanium dioxide powder

In the present work a model of light scattering is shown which explains the result about effect of particle size on the diffuse reflection coefficient of initial titanium dioxide powders. The diffuse reflection coefficient depending on particle size for TiO2 pigment varies on the curve with maximum. The experimental results and the model can be used for technology development of manufacturing pigment for light-reflecting temperature-control coatings of spacecraft