Galena, also known as PbS, was widely used in the production of lead glazes
from the beginning of the 18th century to the second half of the 20th century.
Although the PbO-SiO2 system has been studied for years, the PbS–SiO2 phase
diagram, involved in the formation of a glaze with galena, has not yet been investigated.
Temperature ...»»»»
Galena, also known as PbS, was widely used in the production of lead glazes
from the beginning of the 18th century to the second half of the 20th century.
Although the PbO-SiO2 system has been studied for years, the PbS–SiO2 phase
diagram, involved in the formation of a glaze with galena, has not yet been investigated.
Temperature transformations for the system 75 wt% PbS-25 wt% SiO2 are
investigated in a high-temperature resolved X-ray diffraction experiment with synchrotron
radiation and compared to those of the equivalent system 70 wt% PbO-
30 wt% SiO2. Lanarkite, PbO PbSO4, is the phase predominantly formed as soon
as galena decomposes during the heating. The results show that the system melts
at a temperature higher than the PbO–SiO2 system, but far lower than those
expected for the PbO–PbSO4–PbS system. A historical misfired lead glaze produced
with galena is also studied. The presence of galena, lanarkite, and mattheddleite,
Pb10(SiO4)3.5(SO4)2Cl2, is determined and discussed in terms of the
composition of the galena mineral used and the firing conditions in light of the
high-temperature transformations previously obtained.^^^^