MANGANESE CHLORIDE 337tion, which is neutral and entirely free from iron salts, yields
crystallized manganous chloride, MnCl 2 -4H 2 O, upon evaporation.
Materials: waste liquor from chlorine generator, 250 cc.
anhydrous sodium carbonate.
Apparatus: 8-inch porcelain dish.
5-inch funnel and filter.
2-liter common bottle,
iron ring and ring stand.
Bunsen burner.Procedure: Boil 250 cc. of waste manganese liquor in an 8-inch
porcelain dish under the hood until the residue becomes pasty.
After a scum begins to form on the surface of the liquid, there is
danger of spattering and the mixture should be stirred with a glass
rod until it becomes semi-solid. Heat the residue to boiling with
750 cc. t5f water; without filtering the solution, take one-tenth of
it, dilute this portion to 1,000 cc. in a 2-liter bottle, and add a solu-
tion of sodium carbonate to it until all the manganese is precipi-
tated as carbonate (test for complete precipitation). Allow the
solid to settle and wash it by decantation at least four times.
Add the solid manganous carbonate to the remaining nine-tenths
of the manganous chloride solution, and boil the mixture in an
8-inch dish until a few drops of the filtered liquid give no red color
when tested with KSCN. Filter the solution and evaporate it
until a crystal scum forms on blowing across the surface. Then
allow the solution to cool slowly and crystallize, leaving it for at
least 12 hours uncovered in a place protected from dust. Collect
the crystals and evaporate the mother liquor to obtain further
crops of crystals until practically all the salt has crystallized.
Spread the light pink crystals on paper towels to dry, and preserve
the product in an 8-ounce, cork-stoppered bottle.
Note. The crystals of manganous chloride are deliquescent
when the temperature is low and the atmosphere charged with
moisture. If the product cannot be obtained satisfactorily by the
above directions, carry out the crystallization and drying in a place
at a slightly elevated temperature, 25° to 30°; or cool the saturated
hot solution rapidly by stirring or shaking, and dry the crystal
meal so obtained by rinsing it with alcohol and then letting the
latter evaporate rapidly.