4113. Tutty Powder

4113.    Tutty Powder. Impure oxide of zinc. It is a substance which collects in the chimneys of the furnaces in which the ores of zinc are smelted.

4114. To Prepare Pure Sulphate of Zinc

4114.    To Prepare Pure Sulphate of Zinc. Mix 4 ounces laminated or granulated zinc with 3 fluid ounces oil of vitriol, and 1 pint water, in a porcelain capsule, and when gas ceases to be evolved, boil for 10 minutes, filter through muslin, and evaporate to dryness ; next dissolve it in 1 pint water, agitate this solution frequently during 6 hours with 1/4 ounce prepared chalk, and filter it; add to the filtered solution 1 fluid drachm each commercial nitric acid and dilute sulphuric acid; evaporate the mixture until a pellicle forms on the surface, and set it aside to crystallize; dry the crystals on bibulous paper without heat, and preserve them in a bottle. The mother liquor will yield more crystals by further evaporation. This substance is als known as white vitriol.

4115. Cyanide of Zinc

4115.    Cyanide of Zinc. Add a solution of cyanide of potassium to a solution of pure sulphate of zinc; wash and dry the precipitate.

4116. Flowers of Zinc

4116.    Flowers of Zinc. This is obtained by tho rapid combustion of zinc in a deep crucible, placed sideways in a furnace, so that the flowers (oxide of zinc) may be collected as they form.

4117. Oxide of Zinc

4117.    Oxide of Zinc. Place carbonate of zinc in a covered clay crucible, and expose to a very low red heat, until a portion taken from tho centre of the mass ceases to effervesce on being dropped into dilute sulphuric acid. This is the commercial zinc-white. (See No. 2696 (Zinc White (oxide of zinc)).)

4118. Tests for the Solutions of Zinc

4118.   Tests for the Solutions of Zinc. The solutions of zinc are precipitated white by the pure alkalies and carbonate of ammonia, but are completely redissolved by excess of the precipitant. The carbonates of potassa and soda give a permanent white precipitate of carbonate of zinc. Hydrosulphuret of ammonia also gives a white precipitate, and so does sulphuretted hydrogen when the solution is quite neutral. Prussiate of potash gives a gelatinous white, or bluish-white precipitate.

4119. Protoxide of Tin

4119. Protoxide of Tin. Usually termed oxide of tin. Precipitate a solution of protochloride of tin with carbonate of potassa, wash and dry the powder at a heat under 166° Fahr., with as little exposure to the air as possible. It is a white or greyish-white powder, soluble in acids and in the pure fixed alkalies. If it be heated in an atmosphere of carbonic acid it loses its water and changes to a dense black powder, which is anhydrous protoxide. (Cooley.)

4120. Sesquioxide of Tin

4120.    Sesquioxide of Tin. A grey, slimy precipitate, soluble in muriatic acid, and in ammonia, obtained by mixing fresh, moist hydrated peroxide of iron with a solution of the neutral protochloride of tin. (Fuchs).