Elemental Fluorine Contents 1 Introduction ............................................................................................................... 4 2.1 Technical Application of Fluorine ............................................................................. 5 2.2 Electronic Application of Fluorine ........................................................................... 7 2.3 Fluorine On-Site Plant ............................................................................................ 8 3 Specifications ............................................................................................................ 9 4 Safety ...................................................................................................................... 10 4.1 Maintenance of the F2 system .............................................................................. 12 4.2 First Aid ................................................................................................................ 13 5.1 Chemical Properties ............................................................................................. 14 5.2 Physical Data ....................................................................................................... 15 6 Toxicity .................................................................................................................... 18 7 Shipping and Transport ........................................................................................... 20 8 Environment ............................................................................................................ 22 8.1 Product Stewardship for F2 .................................................................................. 22 8.2 Solvay Way ........................................................................................................... 23 9 Solvay – The Specialists for Fluorides ..................................................................... 24 10 Bibliography .......................................................................................................... 26 Solvay Special Chemicals Elemental Fluorine 3 1 Introduction The element fluorine (chemical symbol: F) In the field of organic fluorine chemistry belongs to the halogen group. The name the development of new products con- “fluorine” derives from the mineral “fluor- tinues. Fluorine containing polymers are spar”. highly valued for their remarkable prop- Fluorine is the most reactive element in erties. The most known examples are the periodic table. This is why fluorine oc- polytetrafluorethylene (PTFE) and polyvi- curs in nature only in chemically bonded nylidene fluoride (PVDF). Fluorinated or- form as fluoride. ganic compounds are also used as: Electrolyte in Lithium ion batteries Fluorspar (CaF2) was added to the metal ores to lower their melting point and thus Solvents make them more fluid (hence the name, Surfactants from the Latin = fluere, “to flow”). Among the halogens, fluorine is the element that Pharmaceuticals occurs most abundantly in nature. Solvay Pesticides owns two fluorspar mines in Namibia and Lubricants Bulgaria to secure the raw material for its fluorine production sites in Europe and Blood substitutes Asia. Insecticides The manufacture of fluorine, together with Starting material for organic synthesis its inorganic and organic compounds has And many more. given remarkable new impulse to fluorine chemistry. Typical areas of application Today the main industrial applications for include metallurgy, aluminum electroly- elemental fluorine are fuel tank fluorination sis, the manufacture and processing of for cars and cleaning of CVD tools during glass, abrasives, electroplating process- the production of semiconductors. es, ceramics, electrical engineering, elec- trochemical elements, energy storage, nuclear technology, flat panel production, photovoltaic production and semiconduc- tor production. Fig. 01: The raw material: fluorspar crystal from the Solvay mine in Okorusu, Namibia. 4 Elemental Fluorine Solvay Special Chemicals 2.1 Technical Application of Fluorine Fluorine is widely used in applications for the direct reaction with organic sub- stances. The reaction between the pure fluorine and the organic substance results in the formation of the thermodynamically more stable end products CF4 and HF: CnH2n + 2 + (3n + 1) F2 -> – E nCF4 + (2n + 2)HF This entails that the aim in all methods of fluorine treatment is to minimize the for- mation of by-products or waste products as far as possible. At the same time it is essential to maximize the yield of the tar- get compound. An optimum reaction is achieved through control of the process parameters: Concentration of reagent blow moulding process (in-line treatment) Reaction temperature so that only the inner walls are treated. Fig. 02: Fluorinated plastics for high performance applications. Reaction time. Off-line fluorination, carried out when blow-moulding is completed, is a discon- In simplified terms, the various processes tinuous process. Fluorination may be con- used may be divided into two categories: fined to the inner walls of the container; Single-phase fluorination alternatively, both inner and outer walls Two-phase fluorination. may be treated. In another process, plas- tic surfaces are treated with elemental flu- In the single-phase method, the sub - orine i.e. in solution with inert solvents or stance to be fluorinated and the fluori- solvent mixtures. nating agent (F2 diluted with an inert gas) are present in one and the same phase. Plastic Processing A number of different variants have been The finishing of plastic surfaces is of great developed for both the gaseous-phase significance in the foil industry. For the and liquid-phase fluorination technique. production processes of gluing, coating, In the case of two-phase fluorination the laminating, painting and printing good ad- compound to be fluorinated and the fluori- hesion is absolutely essential. nating agent are present in different phas- During the nineteen eighties a continuous es. As early as 1954, Rudge filed a patent fluorinating process was developed for application in which the fluorination of pol- the treatment of foils. With this method the yethylene surfaces by means of a fluorine/ surfaces of foils can be activated, on one inert gas mixture was described. A whole or both sides, independent of the size and series of processes specifically designed length of the rolls, in a continuous process for direct fluorination of plastic surfaces from roll to roll. The fluorination of almost have subsequently been developed, some all types of foils consistently results in a of them differing in terms of the steps in- significant increase in surface energy. volved. Foam sheeting can be treated in a continuous fluorination process. Selective fluorination of hollow plastic containers can now be carried out during the actual Solvay Special Chemicals Elemental Fluorine 5 Fluorination of Tanks For this reason the automobile indus - try performs the fluorination process to Polyethylene, the plastic employed for the reduce the permeability of fuel through production of fuel tanks and containers petrol tanks walls. A layer of CF will be for different chemicals, has often the dis- 2 formed. The permeation of fuel through advantage of being relatively permeable to polyethylene fuel-container walls can be the stored vapour. This undesirable prop- dramatically reduced by the chemical erty leads to permeate to the extent of a process of forming a layer which is almost few grams per day from a PE container. impermeable. [CF2]n 100% < 1 % Untreated Tank Fluorinated Tank Fig. 03: Permeation in plastic fuel tanks. inner wall outer wall ~ 10 µm ~ 3 mm Fig. 04: Cross-Section of a container wall with a fluorinated inner layer. 6 Elemental Fluorine Solvay Special Chemicals 2.2 Electronic Application of Fluorine Solvay is producing F2 electronic grade in two plants in Germany and South Korea. This is unique in the world so far and ena- bles the highest possible supply security among all F2 high purity manufactures. As fluorine is the most reactive element, it is obvious that it is a strong oxidizer. This ability is useful for the removal of Silicon- oxide (SiO2) and Siliconnitride (Si3N4). This process is done in a CVD Tool (Chemical Vapour Deposition) and the residues of these compounds are deposited at the chamber walls of these tools. After remov- ing the wafer, the tool has to be cleaned with fluorine containing gases like NF3, SF6, CF4, C2F6 and others. These gases however have global warming potential. An environmental friendly alternative Fig. 05: Chamber cleaning in the semiconduc- tor industry with F mixtures. to these cleaning gases are F2/N2 or Ar, Kr as mixtures are used. The radiation 2 F2/N2/Ar mixtures. Fluorine reacts spon- of these gas mixtures is reflecting the min- taneously already at ambient temperature imum size of the structure. with deposits of silicon and all its com- F2 Nitrogen Mixtures as pounds to generate SiF4, which is gase- ous and can be therefore easily removed Replacement for Other Cleaning from the chamber to be cleaned. In order Gases to have the reaction better controlled fluo- F2 in dilution with nitrogen at 20 % is a rine is diluted with nitrogen. very competitive cleaning gas for cleaning CVD tools. Tests at the Fraunhofer Insti- F /N Mixtures 2 2 tute in Munich have proven the full com- Within the production process of semi- patibility of the F2 mixtures on the AMAT P