To obtain the acid free, mix one part of ore of tungstein with four
parts of carbonat of potash, and melt the mixture in a crucible, then
powder and pour on twelve parts of boiling water, add nitric acid, and
the tungstic acid precipitates in a concrete form. Afterwards, to insure
the complete oxygenation of the metal, add more nitric acid, and
evaporate to dryness, repeating this operation so long as red fumes of
nitrous gas are produced. To procure tungstic acid perfectly pure, the
fusion of the ore with carbonat of potash must be made in a crucible of
platina, otherwise the earth of the common crucibles will mix with the
products, and adulterate the acid.
TABLE _of the Combinations of Tartarous Acid, with the Salifiable Bases,
in the Order of Affinity._
_Bases._ _Neutral Salts._
Lime Tartarite of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Argill argill.
Oxyd of
zinc zinc.
iron iron.
manganese manganese.
cobalt cobalt.
nickel nickel.
lead lead.
tin tin.
copper copper.
bismuth bismuth.
antimony antimony.
arsenic arsenic.
silver silver.
mercury mercury.
gold gold.
platina platina.
180