PROCESS FOR THE PRODUCTION OF METAL FLUORIDE MATERIALS WITH SUBMICRON STRUCTURES
A process for the production of metal fluorides comprising maintaining a low concentration of the by-products of the reaction between a non-fluorinated metal compound and hydrofluoric acid, so as to produce, by this reaction, sub-micron particle sizes of metal fluoride of high purity.
1 . A method for producing a metal fluoride with submicron particle sizes, high surface area, high purity, and high chemical reactivity, said method comprising:
introducing a quantity of hydrofluoric acid in a reaction zone; and
adding a quantity of non-fluorinated metal halide, a portion at a time over a period, to said hydrofluoric acid to cause a reaction between said non-fluorinated metal halide and said hydrofluoric acid, wherein said adding is at a rate so as to maintain in a particular range, a mole ratio in said reaction zone of a hydrogen halide by-product of said reaction to said hydrofluoric acid.
2 . The method of claim 1 wherein said maintained ratio in said reaction zone is at least about 3 moles of hydrofluoric acid to 1 mole of hydrogen halide.
3 . The method of claim 1 wherein said maintained ratio in said reaction zone is at least about 10 moles of hydrofluoric acid to 1 mole of hydrogen halide.
4 . The method of claim 1 wherein said maintained ratio in said reaction zone is at least about 20 moles of hydrofluoric acid to 1 mole of hydrogen halide.
5 . The method of claim 1 wherein said addition maintains a reactants mole ratio of 1 mole of said non-fluorinated metal halide to at least about 10 moles of said hydrofluoric acid in said reaction zone.
6 . The method of claim 1 wherein said reactants mole ratio in said reaction zone is 1 mole of said metal halide to at least about 20 moles of said hydrofluoric acid.
7 . The method of claim 1 wherein said reactant mole ratio in said reaction zone is 1 mole of said metal halide to at least about 30 moles of said hydrofluoric acid.
8 . The method of claim 1 further comprising:
maintaining a temperature in said reaction zone in the range of about 0-19° C.
9 . The method of claim 1 further comprising:
maintaining a temperature in said reaction zone in the range of about 5-19° C.
10 . The method of claim 1 further comprising: maintaining a temperature in said reaction zone in the range of about 15-19° C.
11 . The method of claim 1 further comprising:
agitating said mixture during said addition, said agitating aiding said maintenance of said mole ratio range.
12 . The method of claim 1 further comprising:
evacuating said hydrogen halide from said vessel, said evacuation aiding said maintenance of said mole ratio range.
13 . The method of claim 1 further comprising:
allowing the contents of said reaction vessel to stand for a period of about 1-3 days after said adding is completed and where said temperature in the range of about 0-19° C. is maintained for said standing period.
14 . The method of claim 13 further comprising:
drying said metal fluoride compound by heating said metal fluoride to a temperature in the range of about between 80-150° C. for a period sufficient to allow said metal fluoride to reach a constant weight at or below atmospheric pressure.
15 . The method of claim 1 wherein a metal of said metal halide is selected from the list of metals consisting of:
Gallium, Indium, Tin and Lead, Groups IVB, VB, VIB, VIIB, VII and IB.
16 . The method of claim 1 wherein a metal of said metal halide is selected from the list consisting of:
Iron, Nickel, Cobalt, Chromium, Molybdenum, Titanium, Zirconium, Tin, and Zinc.
17 . The method of claim 1 wherein a halogen of said metal halide is selected from the list consisting of:
Chlorine, Bromine and Iodine, or mixtures thereof.
18 . The method of claim 1 wherein said non-fluorinated metal halide and said hydrofluoric acid are anhydrous.
19 . The method of claim 1 wherein the addition period is at least 8 hours.
20 . A method for producing a metal fluoride with submicron particle sizes, high surface area and high chemical reactivity, said method comprising:
introducing a quantity of hydrofluoric acid into a reaction zone; and
adding a quantity of non-fluorinated metal halide, a portion at a time over a period, to said hydrofluoric acid to cause a reaction between said non-fluorinated metal halide and said hydrofluoric acid; wherein said adding is at a rate so as to maintain the mole ratio of a hydrogen halide by-product to said hydrofluoric acid in a particular range; wherein a reactant mole ratio in said reaction vessel is 1 mole of said metal halide to at least about 3 moles of said hydrofluoric acid;
maintaining a temperature in said reaction vessel in the range of about 0-19° C.;
evacuating said hydrogen halide from said vessel, said evacuation aiding said maintaining of the mole ratio;
allowing the contents of said reaction vessel to stand for a period of about 1-3 days after said adding is completed and wherein said temperature in the range of about 0-19° C. is maintained for said standing period; and
drying said metal fluoride compound by heating said metal fluoride to a temperature in the range of about 80-150° C. for a period sufficient to allow said metal fluoride to reach a constant weight at or below atmospheric pressure.
21 . The method of claim 20 wherein said maintained ratio is at least about 3 moles of hydrofluoric acid to 1 mole of hydrogen halide in the reaction zone.
22 . The method of claim 20 wherein said maintained ratio is at least about 10 moles of hydrofluoric acid to 1 mole of hydrogen halide in the reaction zone.
23 . The method of claim 20 wherein said maintained ratio is at least about 20 moles of hydrofluoric acid to 1 mole of hydrogen halide in the reaction zone.
24 . A method for producing a ferric fluoride with submicron particle sizes, high surface area and high chemical reactivity, said method comprising:
introducing a quantity of hydrofluoric acid into a vessel; and
adding a quantity of ferric trichloride, a portion at a time over a period, to said hydrofluoric acid to cause a reaction between said ferric trichloride and said hydrofluoric acid; wherein said adding is at a rate so as to maintain the mole ratio of a hydrogen chloride by-product of said reaction to said hydrofluoric acid in a particular range; wherein a reactant mole ratio in said reaction vessel is 1 mole of said ferric trichloride to at least about 3 moles of said hydrofluoric acid;
maintaining a temperature in said reaction vessel in the range of about 0-19° C.;
evacuating said hydrogen chloride from said vessel, said evacuation aiding said maintaining of the mole ratio;
allowing the contents of said reaction vessel to stand for a period of about 1-3 days after said adding is completed and wherein said temperature in the range of about 0-19° C. is maintained for said standing period; and
drying said metal fluoride compound by heating said metal fluoride to a temperature in the range of about 80-150° C. for a period sufficient to allow said metal fluoride to reach a constant weight at or below atmospheric pressure.