pa1778data.pdf

U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 104)
providing a return on the company's investment. Yet, even though
the briquettes contained approximately 21 percent manganese, the
inability of company metallurgists to discover a method by which
to separate the manganese from the 12 percent alkali contained
within them prohibited the productive reuse of the briguettes.
As a result, then, of the negative cost-benefit character of the
gas cleaning plant, ferromanganese operations at the Isabella
Furnaces and Clairton Works were shut down while the Duquesne
Works became the company*s principal producer of ferromanganese
within Allegheny County. Consequently, the expansion of
ferromanganese production at Duquesne must be seen as an effort
by the corporation to cut its losses. 4
Beginning with the start-up of rebuilt blast furnace number
three in 1953, plant officials embarked on a program designed to
upgrade the facilities related to the production of cold blast
air by installing a turbo-blower designed and manufactured by the
Ingersoll-Rand Corporation. Adhering to the more traditional
positive cost-benefit rationale for changes to the system, the
turbo-blower replaced three of the old steam engines and was
capable of delivering 90,000 cfra of air at 30 psi to the hot
blast stoves associated with blast furnace number three while
using 50 percent less steam. Moreover, the turbo-blower's
accompanying surface condenser allowed it to recycle the
condensate of the spent steam to the boiler feed water system
without pre-treatment. The production and delivery of cold blast
air to blast furnaces number one, two and four were modernized
with the addition of another 90,000 cfm Ingersoll-Rand turbo-
blower in 1954 and a 125,000 cfm Ingersoll-Rand turbo-blower,
with spilt wind capabilities in 1955. 5
County wide governmental measures to improve the quality of
river water combined with improved technology for reclaiming
suspended particulate in the waste water from the gas scrubbers
and Theisen gas washers to provide plant managers with the
incentive to add a clarifier/thickener to the gas cleaning system
in 1957. Slurry from the gas scrubbers and Theisen washers were
taken by pipeline to the bottom of a 90'-0" diameter x 12'-0"
high clarifier manufactured by the Dorr-Oliver Company. The
waste water was admitted to the top of the clarifier through its
centerwell where a dosage of anionic polymers was fed into it for
the purpose of aiding the flocculation of fine entrained
particles. Slurry water spilled over the centerwell to the
bottom of the clarifier and rose, at a rate of 2900 gpm, upwards
while the suspended solids within the slurry dropped to its
bottom. The treated water overflowed the side of the clarifier
at a constant rate into a launderer, which was an approximately
2'-0" wide x 3'-0" deep ring encircling its outside diameter. A
connecting sewer line, located at the bottom of the launderer.