Metallized salts
AssigneeCrysus (Lancashire) Limited
InventorDenis Tither
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Abstract
A process and apparatus for producing certain metal salts in very fine particulate form. The process comprises cooling a solution of metal salt until the solution freezes and thereafter evaporating the solvent under very low pressure. The process is particularly applicable to salts of tungsten and nickel from which sub-micron particles of tungsten and nickel can be produced.
Claims7
A process for producing particles of ammonium paratungstate and characterized in that under X-ray analysis no diffracted lines are observed, which process comprises the steps of placing a solution of ammonium paratungstate in a chamber, closing the chamber, reducing the pressure within the chamber below atmospheric pressure, freezing the solution by the combined effect of admitting to the chamber a liquid refrigerant which is inert to said ammonium paratungstate whereby the liquid refrigerant evaporates, the amount of liquid refrigerant admitted to the chamber being not sufficient to raise the pressure in the chamber to atmospheric pressure and circulating a cold fluid through heat exchange means in said chamber, and thereafter evaporating the solvent from the frozen solution.
Dependencies are inferred from the claim text.