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Y. Sakata
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File: C:\HSC5\Gibbs\H2SO4”M•ª‰ð.OGI
C
kmol
Temperature
H2SO4
SO2(g)
H2SO4(g)
SO3(g)
O2(g)
°
Fig. 9 Thermal decomposition behavior model of dilute sulfuric acid
body is made of steel plate and water-cooled. The surface of the water cooling jacket
tends to be in a low temperature state, and in particular, the upper part in the raw
material preheating stage is easily affected by the above-mentioned corrosion by
low-concentration sulfuric acid.
Figure 10 shows the configuration of the water-cooled jacket for the cupola furnace
and the photograph of the wear-resistant welding for the water cooling jacket. The
adhered sulfuric acid mainly corroded the upper part of the water cooling jacket (SS
16 mm thickness) and caused water leakage. As a countermeasure, for the part where
the thinning is remarkable, 3 mm overlay was constructed by high Cr wear-resistant
welding. In addition, we started to reduce the amount of attached sulfuric acid as
much as possible to keep the lead components from the lead waste temporarily stored
for a while in a storage yard when we receive them. As a result, problem of corrosion
and leakage of the water cooling jacket in the cupola furnace are cleared.
Fig. 10 Photograph of the
wear-resistant welding for
the water cooling jacket