Tronox is pleased to announce it has completed its acquisition Cristal. Tronox is now one of the world’s leading producers of high-quality titanium products and zircon with the most diverse global footprint. We believe this combination is not just bright, it’s brilliant – for our employees, customers and shareholders.
The Company’s purpose is producing and trading chemicals, in particular titanium white pigment and its by-products; producing, processing and trading raw materials, whether or not for our own use; importing and exporting raw materials and finished products; producing, processing and trading ores in general, especially rutile, kyanite, ilmenite and zirconite, including surveying, mining, extracting and processing, importing and exporting; holding equity interest in other companies, whether or not related to our objectives, and activities related to fulfilling our objectives.
The brief description below shows the production process for the Company’s main product, the Titanium Dioxide pigment:
- Cristal produces Titanium Dioxide pigment using the sulfate process.
- Firstly, ilmenite or ilmenite enriched slag is crushed.
- Ground ore is then mixed with concentrated sulfuric acid and forwarded to a reactor in which sulfating reactions obtain sulfate mass, which once diluted in water, provides a titanyl sulfate solution, together with sulfates of several other elements found in the ore.
- The sulfate solution contains a high percentage of Ferric Sulfate, which is converted to Ferrous Sulfate by a reduction process using iron filings, which subsequently facilitates its removal from the process.
- After chemical reduction, impurities, including unreacted ore, are separated in a sedimentation process known as liquor clarification, and two process flows are generated: insoluble slurry, which goes through sedimentation and is then sent to filters to recover its liquid fraction as solids are neutralized and taken to deposit; and the low solid-content fraction which is taken from the clarifier to be filtered and forwarded for hydrolysis.
- The hydrolysis reaction occurs when filtered liquor is boiled and diluted in water, after adding a small amount of Titanium Hydroxide (primary seeding) obtained due to chemical imbalance when filtered liquor is mixed with a Sodium Hydroxide solution.
- The hydrolysis reaction’s end-product has a solid phase consisting of Titanium Hydroxide and mother liquor (diluted sulfuric acid), which contains Ferrous Sulfate and various impurities. Pulp is separated and washed in suitable filters. The remaining impurities are eliminated by using sulfuric acid and adding aluminum powder for their reduction.
- All Titanium oxide obtained from Titanium sulfur solution hydrolysis furnishes basic anatase crystals. To obtain rutile, pulp is seeded with basic rutile crystals. Basic rutile crystals for seeding are obtained when a hydrochloric solution of Titanium is hydrolyzed.
- Titanium Hydroxide pulp has to be calcinated at high temperatures in a kiln to remove adhered water which is chemically bonded; sulfuric acid residues are used to develop the required characteristics in the crystals. Even before calcination, various chemicals may be added to the slurry in order to influence crystal formation during calcination. The end-product of this stage is Titanium Dioxide – TiO2.
- In the final stage of production, the calcinated product is crushed and the surface is treated when various metal oxides are precipitated successively in an aqueous environment over the surface of particles formed by TiO2 crystals. The action of each precipitated oxide is very specific since they determine the pigment’s final properties, which the later must possess to meet the requirements of the specific application. After treatment, the product is washed with water to remove salts formed in the previous stage and then dried to remove moisture. Finally, the product now referred to as pigment is treated with organic ingredients and micronized to obtain a fine, homogeneous and highly dispersible product.