The variety of zinced iron commonly known by the name of ‘galvanised iron’ is prepared by immersing the sheets of metal, previously scoured and cleaned with dilute hydrochloric acid, in a bath of melted zinc covered with powdered sal ammoniac, and moving them about until they are sufficiently coated.
ZINCOG′RAPHY. An art closely resembling lithography, in which plates of zinc are substituted for slabs of stone.
ZIR′CON. See Gems.
ZIRCONIUM. Zr. Syn. The oxide of this metal, a white pulverulent earth, discovered in the mineral gargon or zircon of Ceylon, by
Klaproth, in 1789. It has since been found in the hyacinth.
Prep. The stone is calcined and thrown into cold water, and then powdered in an agate mortar; the powder is mixed with 9 parts of pure hydrate of potassium, and the mixture projected, by spoonfuls, into a red-hot crucible, care being taken that each portion is fused before another is added; after fusion, with an increased heat, for an hour and a half, the whole is allowed to cool; the calcined mass is next powdered, and boiled in water; the insoluble portion is then dissolved in hydrochloric acid, and the solution heated, that the silicic acid may fall down, after which the zirconia is precipitated with hydrate of potassium; or, the zirconia may be precipitated with carbonate of sodium, and the carbonic acid expelled by heat.
From this, metallic zirconium is obtained by heating in a glass tube, with a spirit lamp, a mixture of potassium and the double fluoride of zirconium and potassium, carefully dried; the product is washed with water, and digested for some time in dilute hydrochloric acid.
Prop., &c. A black powder; it acquires a feeble metallic lustre under the burnisher, and takes fire when heated in the air. It has not been thoroughly examined.
Oxide of zirconium, or zirconia, ZrO2, has neither taste nor odour, is insoluble in water, and forms salts with the acids. It is distinguished from all the other earths, except thorina, by being precipitated when any of the neutral salts of zirconium are boiled with a saturated solution of sulphate of potassium. The salts of zirconium are distinguished from those of aluminium and glucinium by being precipitated by all the pure alkalies, and by being insoluble when they are added in excess. The precipitated hydrate and carbonate are readily soluble in acids.