Disposal of hydrogen fluoride

Handling precautions for the gas or anhydrous liquid have been detailed.8 A polythene condenser for disposal of hydrogen fluoride has been described.8,9... 

Routine disposal of hydrogen fluoride may be accomplished by discharging the gas directly into a counterflow caustic (KOH) scrubber. The system should contain an antisuckback device to prevent reverse flow into the cylinder. The scrubber vent should discharge into a well-ventilated area away from personnel and building ventilation air intakes, and be monitored for acid breakthrough. 

Disposal. Moderate amounts of chlorine ttifluoride or other halogen fluorides may be destroyed by burning with a fuel such as natural gas, hydrogen, or propane. The resulting fumes may be vented to water or caustic scmbbers. Alternatively, they can be diluted with an inert gas and scmbbed in a caustic solution. Further information on disposal of halogen fluorides is available (115—118). 

After the reaction is completed the products can be poured into water and ice and the aqueous hydrofluoric acid disposed of down the drain. Care must again be exercised as the mixing of hydrogen fluoride and water generates considerable heat. No hazards or disposal difficulties are incurred with hydrofluoric acid in the usual drain lines as these are made of iron pipe and the hydrogen fluoride is soon absorbed as firm complexes with the iron. It is not detectable at any great distance from the source. For some reactions this simple form of disposal is not satisfactory, for example, in the preparation of an acyl halide or other product which reacts with water. Here distillation of the hydrogen fluoride... 

The traditional catalyst hydrogen fluoride, an extremely corrosive, hazardous and toxic chemical used in the production of linear alkylbenzenes (LAB s), has been successfully replaced by a solid acid catalyst, viz. fluorided silica-alumina catalyst, which does not require special material of construction (of the container), involves lower operating costs and obviates the need for an acid scrubbing system and waste disposal of calcium fluoride. ... 

A basic step in hydrofluoric acid manufacture is the reaction of sulfuric acid with fluorspar (calcium fluoride) to produce hydrogen fluoride and calcium sulfate. Spent alumina is also generated by the defluorination of some hydrofluoric acid alkylation products over alumina. It is disposed of or sent to the alumina supplier for recovery. Other solid residuals from hydrofluoric acid alkylation include any porous materials that may have come in contact with the hydrofluoric acid. 

The crude product contains hydrogen fluoride which is removed by the addition of boric acid to the wash water (H3BO3 -f-4HF — HBF4 + 3H2O). The sodium fluoride disposes of... 

As indicated above, the crude product contains hydrogen fluoride. The sodium fluoride disposes of this by-product by the reaction NaF + HF — NaHF. An alternative procedure is to pour the crude product into water and to separate the product by extraction with pentane. 

Liquid. Wear butyl rubber gloves, self-contained breathing apparatus, eye protection, and laboratory coat. In the fume hood, slowly add the hydrogen fluoride to a plastic pail of cold water (at least a 1 10 dilution of acid to water is suggested). Add excess calcium hydroxide or calcium carbonate. Let the precipitate settle for 24 hours. Wash the resulting solution into the drain. Allow the solid calcium fluoride residue to dry, and package and label for disposal in accordance with local regulations.7... 

Alkylation is accomplished by using either of two catalysts (1) hydrogen fluoride and (2) sulfuric acid. In the alkylation process using liquid hydrogen fluoride (Fig. 1), the acid can be used repeatedly, and there is virtually no acid-disposal problem. The acid/hydrocarbon ratio in the contactor is 2 1 and temperature ranges from 15 to 35°C can be maintained since no refrigeration is necessary. The anhydrous hydrofluoric acid is regenerated by distillation with sufficient pressure to maintain the reactants in the liquid phase. 

Tungsten hexafluoride is an irritating and corrosive gas. In the presence of moisture, hydrogen fluoride may be formed. Special care should be taken to avoid inhalation of the vapors or contact with skin. For disposal of tungsten hexafluoride, it can be diluted with an inert gas and scrubbed in water and a caustic solution. Small amounts of tungsten hexafluoride can be decomposed by passing through columns of soda lime or slaked lime. 

Fluoride, Hydrogen Fluoride, and Fluorine 187 Ammonia 187 Paraquat 191 Sodium Azide 194 PERSONAL CLEANING AND DISPOSAL OF CONTAMINATED CLOTHING 198... 

A building was evacuated due to fumes generated by mixing a solution of nitric acid, hydrogen fluoride, and acetic acid with a solution of ethanol, hydrofluoric acid, and water. Investigators determined that the fumes resulted from a reaction between incompatible materials being mixed for waste disposal by a technician. (ORPS Report SAN—LLNL-LLNL-1997-0037)... 

Excess hydrogen fluoride and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution s waste disposal guidelines. For more information on disposal procedures, see Chapter 7 of this volume. ... 

Nitrogen trifluoride effluents have also been disposed of by introducing the gas stream below the flame of a burner operating on a hydrocarbon fuel. While nitrogen trifluoride is destroyed by this method, both hydrogen fluoride and oxides of nitrogen may be formed that require subsequent downstream scrubbing techniques for their removal. 

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