The Fargo forum and daily republican., 1906-03-19
'CiLASS-SAND INDUSTRY
OF MISSISSIPPI BASIN

A conservative estimate Of the value
Iof the glass products manufactured il
the United States in 1905 is about $685.
100000 The cost of material used ap-
proximates $I8,oooooo, of which $780,
900, exclusive of freight charges, was
paid for glass sand. Within the hall
century preceding 1000 the value OF
glass products showed an average in
crease in value Of 70 per cent for each
decade, and the growth is still vigor-
Hous. I'm view of the remarkable deyel-
Iopn1ent of an industry so largely de-
pendent for its raw materials upon
mineral deposits, it is interesting to
note that Mr.. E. r Burchard Of the
United States geological survey made
"a brief study last summer, of the prin-
5cipal sand producing areas of the mid
die Mississippi basin and of their rela-
.tions to manufacturing centers in the
same district. Undeveloped sands in
Missouri, Arkansas, Kansas and Wis
sconsill, were examined in connection
with geologic surveying in progress in
those states
In the report which Mr. Burchard will
make of his studies the characteristics
which render a sand suitable or unfit
for making glass will be outlined, He
will give in tabular form data concern
ing the chemical composition and phys
5ical character of several sands which
are at spresent in successful use. SIM
liar data regarding sands of hitherto
unknown or doubtful value will be Civ
en- separately Properties will be. de-
seribed in which the conditions of sue
cessful operation and their limitations
are Illustrated
Glass is a fused mixture of the sill
Gates of alkalies. of alkaline earths, and
the more common metals. Sand is the
most important factor in glass consti-
tuting from Sc TO 65 per cent of the
mass of the original mixture. or from
90 to rs per cent of the finished prod
tuct, after melting has driven off car
bon dioxide, sulphur dioxide, and other
volatile materials. To the sand is due
the absence of color (according to its
purity, the transparency, brilliancy, and
hardness of glass. In other words. the
quality of the glass depends largely
upon the quality Of the sand. For the
finest Hint ware, such as optical and
cut glass, water whiteness' or abso-
lutte transparency, great brillianey, and
uniform density are the qualities de-
sired, and only the purest sand can be
employed in the manufacture of this
ware, since slight impurities, especially
small quantities of iron. tend to de-
sstroy these qualities. For plate and
window glass, which are commonly a
pale green, absolute purity is not SO
essential, but it is desirable that the
sand should carry not more than one
tenth per cent of ferric oxide. Green
and amber glass for bottles, jars, and
rough structural work can be made
from sand relatively high in impurities.
An excess of the chief iinpurity, iron,
lis usually avoided in the qliarries by a
careful selection of the. whitest sand,
although the Whitest sand is not i1lvar-
iably the purest. Iron is sometimes re-
moved by repeated washing, sometimes
by magnetic separators, which are es-
pecially resorted to when the iron is
present in, the form of magnetic, Clay
materials are Objectionable because they
cloud the glass, AS these are usually
very finely divided, washing helps 10
remove them Magnesia, more ant to
be introduced into glass materials
through limestone than through sand,
is troublesome because it renders the
batch less ftisible.
The best preliminary test in exarlin-
ing sand for glass making is made with
a nagnifying glass. The following
points should be observed: The sand
should be nearly white in color; il
should be of medium fineness lpassing
20 to so mesh horizontal sieve) the
grains should be uniform in size and
angular, or, less preferably. they NAV
be rounded. A simple chemical test
may be employed by heating the sand
in a dilute acid. Effervescence indi-
Gates the presence of lime, loss of color
the presence of clay impurities. Iron
in the most minute quantity may be
detected by dissolving sand in hydro
huoric acid and adding potassium fero-
cyanide. which produces blue precipi-
tate if iron is. present Complete quan.
titative analyses as well as a furnace
test should be made as final deternli-
nation Of the character Of a prospective
glass sand. e
The impression has long prevailed
that round-grained sands are at de-
cided disadvantage in comparison with
the sharp, angular variety. Practice
seems to disgree with this idea, at least
in the case Of the Mississippi valley
plants, where only smooth, rounded
sand is used for all ordinary varieties Of
glass and for some fine flint ware. Sand
uniformly finer than one-sixtieth of an
inch is said to burn ont IN the batch
and not to produce as much glass per
unit Of weight as does eoarser sand.
In a mixture Of coarse and fine sand
the finer sand is liable to settle to The
bottom of the batch. thus preventing
an even mixture of the materials and
producing in consequence glass that
|is uneven in texture.
Probably much Of the inlpurity which
finds its way into the batch comes I'M
suspectedly from the limestone. which
constitutes about I8 per cent of The
mass Limestone, therefore, should be
analysed frequently, as it may carry
clay and iron pyrites, as well as car
Donates Of iron and magnesia, ill Of
which are Objectionable. Analyses Of
rarfaff lin cfrtac ,xeed ~. s,s ~ .,,.1