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TITANIUM TETRACHLORIDE Both toxic and corrosive, anhydrous titanium tetrachloride is a dangerous product to deal with. Updated advice from manufacturers offers valuable guidance on handling and storing it safely
The Titanium Dioxide Manufacturers Association (TDMA), a sub-group of the European Chemical Industry Council (Cefic), has issued updated safety advice on the storage and handling of anhydrous titanium tetrachloride (TiCl4). This eighth edition, as with its predecessors, represents a contribution by the sector to the Responsible Care commitment.
Five producing companies have contributed to the work: DuPont, Huntsman Pigments, Kronos International, Cristal Global and Tronox Pigments. Some indication of the changing nature of the sector – and therefore the need to keep safety information available – is shown by the fact that the list of manufacturers has changed significantly since the first edition. SCM Chemicals and Thann & Mulhouse became part of Millennium Inorganic Chemicals, which is now Crital; Tronox Pigments is the former Kerr-McGee Pigments business, and Huntsman Pigments is the old Tioxide Europe operation.
TDMA notes that the Safety Advice is not mandatory nor should it be regarded as a detailed design code; it does, though, indicate where mandatory codes exist and provides some explanation of those codes. TDMA notes that not all existing installations may be able to meet the recommendations contained in the Safety Advice and that not all the recommendations will be appropriate to all sites. It is the responsibility of those involved in the supply chain – manufacturer, user, site operator and carrier – to ensure that plant is operated correctly and that handling and storage is carried out safely.
Covered for safety
TDMA’s Safety Advice covers four main areas:
- storage installations
- the loading and unloading of transport containers
- the transport containers themselves, and
- basic health and safety measures, emergency response procedures and chemical and physical properties.
TDMA is at pains to stress that the most significant hazard posed by titanium tetrachloride is its violent reaction with water, which produces a mist of hydrochloric acid with fine particles of titanium dioxide and titanium oxychloride that create a dense, white and highly visible cloud. This hydrolysis reaction can be triggered by atmospheric water vapour, so it is imperative to ensure there is no loss of containment. TDMA says this is particularly important during maintenance activities, especially when joints on pipes or equipment have to be broken.
For transport purposes, titanium tetrachloride is classified as UN 1838, Division 6.1, with a Class 8 subsidiary risk, Packing Group I. Advice on storage installations is extensive, though TDMA recognises that local regulations and requirements may override its guidelines. Similarly, the layout of existing facilities may make it impossible to meet the guidelines. For instance, TDMA says that storage installations should be located away from production areas and preferable in the open air; on the other hand, pipework between storage and processing units should be kept to a minimum and it is good practice to keep the storage area roofed so as to minimise the accumulation of rain water in bunds.
Bunds should be designed with TiCl4 in mind: the lining must be impervious to the product, with a sloping floor and gullies leading to a collection area. Storage tanks should be above ground level to allow adequate access for inspection; installation in deep pits is not recommended. Storage tanks should be at least as large as the maximum foreseen unit of delivery and, if continuity of supply is essential, at least two tanks should be provided so as to allow for inspections and maintenance. On the other hand, there should be no more tanks than is necessary, since each additional tank will require more equipment and pipework and lead to further complexity in operation.
TDMA’s advice on storage tanks includes references to design standards, corrosion allowances, vessel supports, manhole sizing and positioning, sizing of nozzles and connections, and gasket material.
The document also gives detailed instructions on the loading and unloading of cargo tanks and other transport containers. This includes the equipment that should be fitted to the storage tank and the transport container, as well as checklists that describe the loading and unloading processes.
TDMA notes that the provisions governing the construction, inspection, maintenance and operation of transport equipment are to be found in the various applicable transport regulations, but it is useful to have all the elements – including, for instance, the margin on intervals for period examinations – gathered in one place. Similar information is provided for the design and construction of packages.
Safety of life
The Safety Advice highlights the dangers of coming into contact with titanium tetrachloride, which will react with moisture on the skin, in the eyes and in the respiratory tract with potentially fatal and often very damaging consequences. A such, the use of personal protective equipment when handling the product, and certainly during any emergency response, is absolutely vital.
The same effects mean that, in the event of an accident, the safety of personnel in the area is paramount. The Safety Advice instructs responders to take an upwind approach. The generation of fumes is critical in deciding how to deal with a spill and water curtains are recommended for downwind knock-down of fumes. Any containers used to collect spilled product must be acid-resistant and chalk is recommended as a neutraliser.
The full text of the Safety Advice can be found on the Cefic website at www.cefic.org/Documents/IndustrySupport/Transport-and-Logistics/Best%20Practice%20Guidelines%20-%20Product%20Specific%20Guidelines/TiCl4%20Safety%20Advice%208th%20Edition_March%202012.pdf.