1. 296 to 1.357 g/cm3 is obtained. The reaction solution is subjected to pressure filtration through a plate frame to obtain a cake-like lithopone powder having a water content of not more than 45%. The mixture is calcined in a dry roaster to change the crystal form of the lithopone, and then acid-washed with sulfuric acid at a temperature of 80 °C. Finally, it is washed with water, reinforced with coloring agent, pressure filtration, drying and milling.

Another important application of titanium dioxide is in the production of sunscreen and other skincare products. Titanium dioxide is a key ingredient in many sunscreens due to its ability to reflect and scatter ultraviolet (UV) radiation, providing protection against harmful UV rays. Manufacturers of titanium dioxide for sunscreen products often use special coatings and surface treatments to enhance its UV-blocking properties.

Is titanium dioxide dangerous? Has it been linked to any health issues?

A great number of other brands with fancy names have gone out of the German market, because of some defects in the processes of manufacture. The English exporters, as a rule, offer three or four grades of lithopone, the lowest priced consisting of about 12 per cent zinc sulphide, the best varying between 30 and 32 per cent zinc sulphide. A white pigment of this composition containing more than 32 per cent zinc sulphide does not work well in oil as a paint, although in the oilcloth and shade cloth industries an article containing as high as 45 per cent zinc sulphide has been used apparently with success. Carefully prepared lithopone, containing 30 to 32 per cent sulphide of zinc with not over 1.5 per cent zinc oxide, the balance being barium sulphate, is a white powder almost equal to the best grades of French process zinc oxide in whiteness and holds a medium position in specific gravity between white lead and zinc oxide. Its oil absorption is also fairly well in the middle between the two white pigments mentioned, lead carbonate requiring 9 per cent of oil, zinc oxide on an average 17 per cent and lithopone 13 per cent to form a stiff paste. There is one advantage in the manipulation of lithopone in oil over both white lead and zinc oxide, it is more readily mis-cible than either of these, for some purposes requiring no mill grinding at all, simply thorough mixing with the oil. However, when lithopone has not been furnaced up to the required time, it will require a much greater percentage of oil for grinding and more thinners for spreading than the normal pigment. Pigment of that character is not well adapted for use in the manufacture of paints, as it lacks in body and color resisting properties and does not work well under the brush. In those industries, where the paint can be applied with machinery, as in shade cloth making, etc., it appears to be preferred, because of these very defects. As this sort of lithopone, ground in linseed oil in paste form, is thinned for application to the cloth with benzine only, and on account of its greater tendency to thicken, requires more of this comparatively cheap thinning medium, it is preferred by most of the manufacturers of machine painted shade cloth. Another point considered by them is that it does not require as much coloring matter to tint the white paste to the required standard depth as would be the case if the lithopone were of the standard required for the making of paint or enamels. On the other hand, the lithopone preferred by the shade cloth trade would prove a failure in the manufacture of oil paints and much more so, when used as a pigment in the so-called enamel or varnish paints. Every paint manufacturer knows, or should know, that a pigment containing hygroscopic moisture does not work well with oil and driers in a paint and that with varnish especially it is very susceptible to livering on standing and to becoming puffed to such an extent as to make it unworkable under the brush. While the process of making lithopone is not very difficult or complicated, the success of obtaining a first class product depends to a great extent on the purity of the material used. Foreign substances in these are readily eliminated by careful manipulation, which, however, requires thorough knowledge and great care, as otherwise the result will be a failure, rendering a product of bad color and lack of covering power.

Résumé–Cet article traite de la découverte de lithopone phosphorescent sur des dessins à l'aquarelle, datés entre 1890 et 1905, de l'artiste Américain John La Farge et de l'histoire du lithopone dans l'industrie des pigments à la fin du 19e et au début du 20e siècle. Malgré de nombreuses qualités souhaitables pour une utilisation en tant que blanc dans les aquarelles et les peintures à l'huile, le développement du lithopone comme pigment pour artistes a été compliqué de par sa tendance à noircir lorsqu'il est exposé au soleil. Sa disponibilité et son usage par les artistes demeurent incertains parce que les catalogues des marchands de couleurs n'étaient généralement pas explicites à indiquer si les pigments blancs contenaient du lithopone. De plus, lors d'un examen visuel, le lithopone peut être confondu avec le blanc de plomb et sa phosphorescence de courte durée peut facilement être ignorée par l'observateur non averti. À ce jour, le lithopone phosphorescent a seulement été documenté sur une autre œuvre: une aquarelle de Van Gogh. En plus de l'histoire de la fabrication du lithopone, cet article décrit le mécanisme de sa phosphorescence et son identification à l'aide de la spectroscopie Raman et de la spectrofluorimétrie.

Applications

What is titanium dioxide? Why is it used in food products?

BaSO4 + 4C=BaS + 4CO

lithopone supplier in plastics and masterbatch

Absorption

The year 2016 had shown a strong rebound of China’s TiO2 business in general, according to market intelligence firm CCM. The market situation in 2015 was quite depressed, while in 2016 huge price rises have benefited the financial performance of China’s manufacturers.

Our scientific experts applied for the first time the 2018 EFSA Scientific Committee Guidance on Nanotechnology to the safety assessment of food additives. Titanium dioxide E 171 contains at most 50% of particles in the nano range (i.e. less than 100 nanometres) to which consumers may be exposed.  

The conjugation of vitamin C to the P25TiO₂NPs was confirmed by UV-visible spectroscopy of lyophilized vitaminC@P25TiO₂NPs suspensions. The typical absorbance peak of ascorbic acid at 265 nm was found. However, no further characterization was done because they did not show the expected protective effect against the photo-induced cell damage (Fig. 3).