G. Kullerud
R. Bret
1967
<p><span>The phase relations in the ternary </span>system<span> </span>Fe<span>-</span>Pb<span>-</span>S<span> were determined by quenching and differential thermal analysis experiments in rigid silica-glass tubes. The solubilities of FeS in galena and in liquid </span>Pb<span> and the extent of solid solution of PbS in pyrite and pyrrhotite at 700° C are too small to be determined by the methods employed and are probably less than 0.1 wt. percent. Less than 1 wt. percent </span>S<span> is soluble in liquid </span>Pb<span> at 700° C. Ternary compounds do not occur in this </span>system<span>. An invariant point involving galena, pyrite, sulfide liquid, liquid sulfur, and vapor occurs at 716° C. The ternary liquid at this temperature contains about 60 wt. percent </span>Pb<span>, 13 wt. percent </span>Fe<span>, and 27 wt. percent </span>S<span>, and is thus situated slightly on the sulfur side of the PbS-FeS2 join. At 719° C tie lines between galena and pyrite are replaced by sulfide liquid-pyrrhotite tie lines in an invariant reaction involving vapor. The sulfide liquid field expands rapidly and intersects the PbS-FeS2 join at 723° C. At 848° C the ternary liquid field intersects the FeS-PbS join. Diagrams are presented to illustrate changes in phase relations from 700° to 1,115° C. The experimental results demonstrate that mixtures of galena (about 70 wt. percent) and pyrite (about 30 wt. percent) can crystallize directly from a liquid at 716° C. Additional components may lower this temperature so that it appears possible that pyrite-galena ores may melt at temperatures below 700° C when exposed to thermal metamorphism.</span></p>
application/pdf
10.2113/gsecongeo.62.3.354
en
Society of Economic Geologists
The Fe-Pb-S system
article