Potassium tetrafluoroborate Property

Melting point:

530 °C(lit.)

Density 

2.505 g/mL at 25 °C(lit.)

refractive index 

1.3245

storage temp. 

Sealed in dry,Room Temperature

solubility 

slightly soluble in ethanol

form 

Micro-Crystalline Powder

color 

White to light gray

Odor

wh. odorless cryst.

Water Solubility 

4.4 g/L (20 ºC)

Sensitive 

Moisture Sensitive

Merck 

14,7686

Exposure limits

ACGIH: TWA 2.5 mg/m3
NIOSH: IDLH 250 mg/m3; TWA 2.5 mg/m3

Stability:

Stable. May decompose on exposure to water or moisture. Incompatible with metals.

CAS DataBase Reference

14075-53-7(CAS DataBase Reference)

NIST Chemistry Reference

Potassium tetrafluoroborate(14075-53-7)

EPA Substance Registry System

Borate(1-), tetrafluoro-, potassium (14075-53-7)

Safety

Hazard Codes 

Xi,C

Risk Statements 

36/37/38-34

Safety Statements 

37/39-26-45-36/37/39-24/25

RIDADR 

3260

WGK Germany 

1

RTECS 

ED2800000

Hazard Note 

Corrosive/Moisture Sensitive

TSCA 

Yes

HS Code 

28269090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P304+P340IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P405Store locked up.

Potassium tetrafluoroborate Chemical Properties,Usage,Production

Chemical Properties

It appears as white powder or gelatinous crystals. It has hygroscopicity with bitter taste. It is slightly soluble in water and hot ethanol, insoluble in cold ethanol.

Application

• Used as the abrasive material of the thermosetting resin grinding wheel, the raw material of boron alloy, the fluxing agent of heat welding and brazing; it can also be used as the components of low chromic anhydride chrome and lead-tin alloy electrolyte.
• Used as analytical reagents and fluxes, also for the production of boron trifluoride, abrasive materials for the aluminum and magnesium casting, electrochemical engineering and chemical testing.
• Used as the fluxing agent of heat flux and brazing, and the raw material for the production of boron alloy using aluminum and magnesium casting; it acts as the filler in the heavy wheel using resin as abrasive adhesive. In the welding and fusion of silver, gold, stainless steel, it can clean up the dross of light metal. It is a raw material for the manufacture of boron trifluoride and other fluorine salts. Also used in electrochemical processes and reagents.
• Used as fluxing agent; also used for the metallurgical industry and for the preparation of boron trifluoride as well as the raw materials of other fluorine salt.
• Used as the resin finishing agents for textile printing and dyeing, improving agent of metal particle size and refining fluxes and the casting sand granules of the aluminum and magnesium alloy.

Preparative Methods

Fluoroboric acid-potassium hydroxide method:
Hydrofluoric acid and boric acid are sent into the reactor at a ratio of 25: 6.2 (weight ratio); the temperature does not exceed 40 ℃. The reaction continues for 6h. The prepared fluoroboric acid is fed to a neutralization tank and neutralized with a 5 mol/L potassium hydroxide under stirring and cooling (until the methyl orange is discolored). Precipitated potassium fluoroborate crystal is subject to centrifugal separation, washing and drying, obtaining the finished product of potassium fluoroborate. its
4HF + H3BO3 → HBF4 + 3H2O
HBF4 + KOH → KBF4 + H2O
Fluoroboric acid/potassium carbonate neutralization method: under the stirring of the coating container, apply the saturated potassium carbonate solution for neutralizing fluoroboric acid to until the methyl orange is discolored. The precipitated potassium fluoroborate is subject to centrifugal separation, washing and drying, obtaining the finished product of potassium fluoroborate. Its reaction is:
2HBF4 + K2CO3 → 2KBF4 + H2O + CO2 ↑

Chemical Properties

white odourlesss crystalline powder

Uses

Potassium tetrafluoroborate is used as an active filler in the preparation of resin-bonded abrasives. It is also used for extraction, refining and processing of metals in the chemical industry. It finds application as additive in alloying industry and welding agent. Further, it is used in the production of fluxing agents for brazing and soldering.

Uses

Has been proposed as a flux for soldering and brazing; filler in resin-bonded grinding wheels.

Hazard

Toxic by ingestion.

Flammability and Explosibility

Not classified

Safety Profile

Poison by intraperitoneal route. When heated to decomposition it emits very toxic fumes of F, K2O, and BOx. Used in sand casting of aluminum and magnesium, grinding, and in resinoid grindmg wheels. See also FLUORIDES and BORON COMPOUNDS.

Purification Methods

Crystallise it from H2O (solubility% (temperature): 0.3 (3o), 0.45 (20o), 1.4 (40o), 6.27 (100o), and dry it under vacuum. It is a non-hygroscopic salt. A 10% solution is transparent blue at 100o, green at 90o and yellow at 60o. [V.rlander et al. Chem Ber 65 535 1932, Kwasnik in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 223 1963.]