Sunday, 16 October 2011

Titanium Dioxide - TiO2 - Food Grade - > 99 %

Chemical formula: TiO2

Synonyms: titanium (IV) oxide, titania, Anatase

Amount: 200 g (note that larger quantities can be made available on request)

Appearance and odour: white, fine powder without appreciable odour.

Grade: 99 or more % Anatase, Food Grade (see assay below)

Packaging: professional wide necked, white HDPE bottle with blue conical seal cap and tamper ring. Labelled. Bottle and cap are UN approved and reusable.

Description and uses: titanium dioxide is titanium’s most widely used compound. It’s now by far the most important stable and non-toxic pure white pigment in use, finding high volume applications in paint, paper, plastics, rubber, paper, food and many other industry sectors. This grade on sale is a Food Grade product.

From a chemist’s perspective it’s a gateway compound to most other titanium compounds and even to the elemental metal itself (see below).

Commercial titanium dioxide is highly insoluble in water and most acids and only dissolves in acids like hydrofluoric (HF) or concentrated sulphuric acid (H2SO4). In the latter it dissolves quite well near boiling point, given some patience. Dissolution is quicker in molten sodium bisulphate or in mixtures of concentrated sulphuric acid and ammonium sulphate because in both cases higher temperatures can be reached (compared to concentrated sulphuric acid). It dissolves in all these solvents forming titanyl sulphate (TiOSO4). Strong dilution of these solutions causes this salt to hydrolyse and titanium (IV) hydroxide (Ti(OH)4) to precipitate. Freshly precipitated Ti(OH)4 is remarkably soluble in weaker acids (like HCl) but ages quickly, reverting back to the much less soluble oxide from.

Solutions of TiOSO4 can be reduced to Ti3+ (+III) bearing solutions by reduction with aluminium or zinc. The Ti3+ ion is coloured a wonderful deep blue, as only D-block ions can show. It’s very susceptible to oxidation by air oxygen, which oxidises it back to Ti (+IV). With hydrogen peroxide, Ti (+III) is first oxidised to Ti (+IV), then a Ti (+IV) peroxo complex forms. This complex has a deep orange-red colour and can be used for both qualitative (visual) and quantitative (photometry) analysis of titanium bearing materials.

Commercial titanium metal is produced by reduction of TiCl4 with magnesium metal in the so-called Kroll Process. But lower grade titanium metal can also be produced by means of heat boosted aluminothermic reduction of TiO2 with aluminium powder.

The basic reaction 3 TiO2 + 4 Al === > 3 Ti + 2 Al2O3 however doesn’t yield enough reaction heat to obtain the reaction products in the molten state and obtain good separation between the metal and the slag (alumina by-product). To overcome this, a so-called heat booster system is added to the mix. The booster comprises of extra aluminium and a stoichiometric amount of an oxidiser like potassium chlorate, sodium nitrate or even calcium sulphate. Both the basic reduction reaction and the booster reaction then run simultaneously, generating the heat required to allow liquid Ti metal to form. Search Google for ‘backyard titanium metal’ and click on the #1 listed web page for more information or contact me.

Dispatch: depending on time of receipt of your order, your item will be dispatched either same day or next day at the latest.

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CAS: 13463-67-7

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