File:The quicksilver resources of California (1903) (14597052998).jpg

Identifier: quicksilverresou00forsrich (find matches)
Title: The quicksilver resources of California
Year: 1903 (1900s)
Authors: Forstner, William California State Mining Bureau
Subjects: Mercury mines and mining Mines and mineral resources Mercury ores
Publisher: Sacramento, Calif. : W.W. Shannon, supt. of State printing
Contributing Library: University of California Libraries
Digitizing Sponsor: Kahle/Austin Foundation and Omidyar Network

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
reduced to pounds and feet gives for i pound of ore, 1.46 cubic
feet of air. In most cases the ores carry sufficient iron sul-
phides to make the addition of some quicklime very advisable,
which will absorb the freed sulphur, according to the equation,
4 HgS + 4CaO = 4Hg+3CaS + CaO, SO₃. The sulphur freed
from the reduction of the iron sulphides to ferrous sulphide
(FeS₂= FeS+S) will also be absorbed by the quicklime. The
preceding indicates that the practice of filling the retorts
almost completely with ore is wrong; a charge of about 150
pounds of ore, filling about one third of the retort, is the most
preferable. The retorts must be kept at a relatively low heat,
not exceeding that required for the volatilization of the mer-
cury, from 375° to 400° C. ( = 750° Fahr.). The distillation
of cinnabar (HgS4+2O = Hg+SO₂) takes place at about 360° C.
(Crookes and Röhrig, above cited, page 505.)

204 QUICKSILVER RESOURCES OF CALIFORNIA.

The charge generaly remains twelve hours in the retort,
but at the Helen mine, Mr. Rocca has found that with his
Text Appearing After Image:
highly pyritiferous and rich ore he obtained better results by
leaving the charge twenty-four hours in the retort and keeping
the heat at its lowest limit.

METALLURGY. 205

The Ch retorts are generally 18 inches wide and 12 inche
shigh in the center, giving them an area of i square foot, and
from 7 to 9 feet long. Their charge capacity is consequently
larger. Their cost is also much higher—$200 apiece, against
$25 for a pipe retort.
The opinions of quicksilver operators differ very much on
the relative merits of pipe retorts and q retorts, both having
their adherents; but for soot furnaces those of the q retorts
are probably in the majority.
Mr. C. Fitzgerald has applied the principle of heating the
ore without bringing it into direct contact with the products
of combustion of the fuel to a continuous retort furnace. (See
Fig. 67.) This furnace consists of an inclined, arched channel
of firebrick (angle 35°) with a tile floor. It has a charging
hopper at the upper end and a discharge chamber with door at

Note About Images