Hexafluorokieselsure Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
RAUCHENDE FARBLOSE FLüSSIGKEIT MIT STECHENDEM GERUCH.
ARBEITSPLATZGRENZWERTE
TLV: (as F) 2.5 mg/m?(als TWA); Krebskategorie A4 (nicht klassifizierbar als krebserzeugend für den Menschen); BEI vorhanden; (ACGIH 2005).
MAK nicht festgelegt (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den K?rper durch Inhalation des Aerosols und durch Verschlucken.
INHALATIONSGEFAHREN
Nur ungenügende Angaben vorhanden über die Geschwindigkeit, mit der eine gesundheitssch?dliche Konzentration in der Luft beim Verdampfen bei 20°C erreicht wird.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz ver?tzt die Augen, die Haut und die Atemwege. ?tzend beim Verschlucken. Inhalation des Dampfes kann zu Lungen?dem führen (s.Anm.). Die Auswirkungen treten u.U. verz?gert ein. ?rztliche Beobachtung notwendig. (s.Anm.)
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
M?glich sind Auswirkungen auf Knochen und Z?hne mit nachfolgender Fluorose.
LECKAGE
Pers?nliche Schutzausrüstung: Vollschutzanzug mit umgebungsluftunabh?ngigem Atemschutzger?t. Ausgelaufene Flüssigkeit m?glichst in abdichtbaren Eisenbeh?ltern sammeln. Reste mit Sand oder inertem Absorptionsmittel aufnehmen und an einen sicheren Ort bringen. NICHT in die Umwelt gelangen lassen.
R-S?tze Betriebsanweisung:
R34:Verursacht Ver?tzungen.
S-S?tze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn m?glich, dieses Etikett vorzeigen).
S27:Beschmutzte, getr?nkte Kleidung sofort ausziehen.
Beschreibung
Hexafluorosilicic acid is a kind of inorganic acid. It is majorly used for the fluoridation of water in United State to minimize the incidence of dental caries and dental fluorosis. For chemical synthesis, it is majorly used for the manufacturing of aluminum fluoride and cryolite as well as many kinds of hexafluorosilicate salts. It can also be used for the production of silicon and silicon dioxide. It can also be used as an electrolyte in the Betts electrolytic process for refining lead. It is also a specialized reagent in organic synthesis for cleaving Si–O bonds of silyl ethers.
Chemische Eigenschaften
Fluosilicic acid,H2SiF6, also known as hydrofluorosilicic acid,is a colorless liquid that is soluble in water. It is highly corrosive and toxic,attacking glass and stoneware. Fluosilicic acid is used in water fluoridation, electroplating, and in manufacturing enamels and cement.
Physikalische Eigenschaften
d 1.220 g cm?3 for a 25% aq solution.
Verwenden
Hexafluorosilicic acid is commonly used as a source of fluoride. It is converted to a variety of useful hexafluorosilicate salts. It is also used as an electrolyte in the Betts electrolytic process for refining lead. It is an important organic reagent for cleaving Si-O bonds of silyl ethers. Further, it is used as wood a preservation agent and also used in surface modification of calcium carbonate.
Allgemeine Beschreibung
A colorless fuming liquid with a penetrating pungent odor. Corrosive to metals and tissue. Both the fumes and very short contact with the liquid can cause severe and painful burns. Used in water fluoridation, in hardening cement and ceramics, as a wood preservative.
Air & Water Reaktionen
Fumes in air. Soluble in water with release of heat and corrosive fumes.
Reaktivit?t anzeigen
Hexafluorosilicic acid can react with strong acids (such as sulfuric acid) to release fumes of toxic hydrogen fluoride. Attacks glass and materials containing silica. Reacts exothermically with chemical bases (examples: amines, amides, inorganic hydroxides). Reacts with active metals, including iron and aluminum to dissolve the metal and liberate hydrogen and/or toxic gases. Can initiate polymerization in certain alkenes. Reacts with cyanide salts and compounds to release gaseous hydrogen cyanide. Flammable and/or toxic gases are also often generated by reactions with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and weak or strong reducing agents. Additional gas-generating reactions may occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and carbonates. Can catalyze (increase the rate of) chemical reactions. Decomposes when heated to the boiling point to produce very toxic and corrosive hydrogen fluoride gas.
Hazard
Extremely corrosive by skin contact and
inhalation.
Health Hazard
Inhalation of vapor produces severe corrosive effect on mucous membrane. Ingestion causes severe burns of mouth and stomach. Contact with liquid or vapor causes severe burns of eyes and skin.
Brandgefahr
Special Hazards of Combustion Products: Irritating fumes of hydrogen fluoride may form in fire.
Industrielle Verwendung
Hydrofluorosilicic acid (H
2SiF
6) is a colorless to light brown liquid. It is also manufactured
from calcium fluoride or other fluoride-containing products. Hydrofluorosilic acid
is a strong depressant for many silicates during flotation of a number of oxidic minerals.
It is used for gangue depression during flotation of tin, columbite and tantalite.
Sicherheitsprofil
Poison by subcutaneous route. A corrosive irritant to sktn, eyes, and mucous membranes. Will react with water or steam to produce toxic and corrosive fumes. When heated to decomposition it emits toxic fumes of F-. See also FLUORIDES.
m?gliche Exposition
A solution of fluorosilicic acid is used
for sterilization in the brewing and bottling industry, elec trolytic refining of lead; electroplating, hardening cement;
removing mold, and others.
Versand/Shipping
UN1778 Fluorosilicic acid, Hazard class: 8;
Labels: 8-Corrosive material.
Inkompatibilit?ten
The aqueous solution is a strong acid.
Reacts with water or steam to produce toxic and corrosive
fumes of hydrogen fluoride. Incompatible, and may react violently with: bases, aliphatic amines; alkanolamines,
alkylene oxides; aromatic amines; amides, ammonia,
ammonium hydroxide; calcium oxide; epichlorohydrin, iso cyanates, oleum, organic anhydrides; sulfuric acid; strong
oxidizers; vinyl acetate; water. Attacks glass, concrete, and
ceramics. The anhydrous form dissociates almost instantly
into silicon tetrafluoride and hydrogen fluoride.
Waste disposal
Add slowly to a large amount
of soda ash in solution. Discharge to sewer with large
volumes of water
Einzelnachweise
Robinson, Tim. "Innovative Processes in Electrometallurgy." Innovative Process Development in Metallurgical Industry. Springer International Publishing, 2016. 385- 392.
Sarawade, Pradip B., et al. "Recovery of high surface area mesoporous silica from waste hexafluorosilicic acid (H 2 SiF 6) of fertilizer industry." Journal of hazardous materials 173.1 (2010): 576-580.
Kauffman, Joel M. "Water fluoridation: a review of recent research and actions." Journal of American Physicians and Surgeons 10.2 (2005): 38.
Krot, V. V., et al. "ChemInform Abstract: Preparation of Amorphous Silicon Dioxide from Hexafluorosilicic Acid." Cheminform 23.48(1992):no-no.
Zorya, L., and V. Krot. "Method of high-purity silica production from hexafluorosilicic acid." Reaction Kinetics & Catalysis Letters 50.1-2(1993):349-354.
Hexafluorokieselsure Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
