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How to distinguish between titanium dioxide?
- Nov 16, 2018 -

Titanium dioxide not only provides hiding power, but also an ultraviolet shielding agent. Titanium dioxide for coatings is divided into two types: anatase and rutile. Anatase titanium dioxide and rutile titanium dioxide have different structures and are used in different applications. Anatase titanium dioxide is used for interior wall coatings because it is easy to be pulverized, and rutile is often used for exterior wall coatings because of its resistance to aging.

Its chemical characteristics and physical constants are shown in the table below.

Physical properties anatase type rutile

Crystal system square

Crystal shape cone shape

Relative density .8~3.9 4.2~4.3

Refractive index 2.52 2.71

Mo type hardness 5.5~6 6~7

Dielectric constant 48 114*

The same rutile titanium dioxide, there are two manufacturing methods, different manufacturing methods, quality is different.

Produced by sulfuric acid method: large particle size, red color. The hue is not very white, gray or yellowish, and the color of a batch is different from that of a batch. Therefore, it cannot be used in high-end buildings.

Manufacture by chlorination: fine particle size, blue color. The hue is pure white and very stable.

The product introduction materials provided by the general supplier of titanium dioxide generally include the following contents:

TiO2 % indicates whiteness, hiding power (opacity, coloring strength), and the higher the percentage content, the greater the whiteness and hiding power.

Al2O3 % means dispersion, gloss, weather resistance (treated by dense aluminum), and the higher the percentage content, the greater the dispersion and gloss.

SiO2 % means weather resistance (treated by dense silicon), and the higher the percentage content, the greater the weather resistance.

Organic matter is coated with organic matter and has better dispersibility (wetting).

Color L stands for whiteness and brightness (brightness).

The average particle size determines light scattering and shielding. The smaller the particle size, the more the blue-tone color of the titanium dioxide is.

The oil absorption affects the gloss and dispersibility of the system.

The resistance value indicates the soluble salt content.

Because the price of rutile titanium dioxide is relatively high and the dosage is large, there are many counterfeit products on the market, including the following aspects:

(1) Packaging domestic titanium dioxide into imported titanium dioxide

(2) impregnating the rutile with anatase titanium dioxide or incorporating a portion of anatase titanium dioxide in the rutile type;

(3) Mixing filler materials such as calcium carbonate, lithopone, and barium sulfate in rutile-type titanium dioxide or anatase-type titanium dioxide.

Prevention and identification of counterfeit products:

(1) Imported titanium dioxide usually has its characteristics (such as patterns, fonts, batch numbers, etc.) on its packaging, which can be first identified on its packaging;

(2) For titanium dioxide which is anatase-type impregnated rutile type, it is difficult to distinguish it by general chemical methods, and it can only be identified by X-ray diffraction method.

(3) For the mixing of CaCO3 in titanium dioxide, it can be identified by adding dilute sulfuric acid or dilute hydrochloric acid to titanium dioxide, which will generate bubbles and make the clarified lime water turbid, indicating that the titanium dioxide is mixed. CaCO3;

(4) For the lithopone powder mixed in the titanium dioxide, the smell of rotten eggs will be produced after adding dilute sulfuric acid or dilute hydrochloric acid;

(5) For the incorporation of BaSO4, since it cannot react with an acid, it can generally be identified by X-ray diffraction.

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