Re-fin′ing.
The process of freeing metals, liquids, or other substances from impurities or crudities which impair their quality or unfit them for their appropriate uses.
1. Liquids are, in some cases, refined by adding soluble substances which entangle the foreign matters, and sink to the bottom, as with wine and cider.
This is termed
fining. In other cases, the refining is by chemicals which combine with the impurities and form a precipitate.
Sometimes standing a length of time suffices to effect the separation, the supernatant liquid being decanted.
2. Saltpeter is refined by dissolving it in hot water until the water is saturated with salt.
On cooling, the salt is deposited in a comparatively pure state.
3. Vinegar is refined by passing it through a filter to separate the mucilaginous matter.
See rape.
4. Alcoholic spirits and liquids generally are refined by successive distillations.
(See Rectifica-tion; still.) The same process is applicable to mercury, sulphur, and other substances, which may be volatilized at a high temperature and afterward condensed.
In one form of apparatus for refining and ageing liquors air from a blower
C is heated in a coil
H communicating with the pipe
F, which has two branches
c e extending downward through a disk near the bottom of the tubs
A B. The liquor in the tub
B is first heated to the temperature of 90°, and agitated by air passing from the coil
H through the pipes
F c, and rising from beneath the disk
d, the cock
k is closed and
h opened, and cool air forced in through the pipe
F. These processes are continued for the space of about a month, or until the desired result is attained.
The air and alcoholic vapors pass over from
B to
A through the condensing-pipe
I in the water-chamber
D, the air being discharged from
A through an aperture above.
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Liquor-ageing apparatus. |
5. Petroleum is refined by treatment with sulphuric acid and by distillation.
6. The process of cupellation (see cupel) is largely employed for refining silver.
In this, lead, already in combination with or added to the silver, is oxidized by heat and absorbed in a porous cup, taking with it most of the other impurities which are not previously expelled by the heat.
7. Gold is refined by cupellation and by
parting, that is, dissolving in nitric acid.
See parting; gold.
8. Iron is refined in the furnace and by
puddling. See iron; refining-furnace; puddling; Bes-Semer-process.
