EXPERIMENTAL INVESTIGATION OF THE AG-TL-BI-SB-S SYSTEM

Polymetallic ore deposits of low temperature origin often contain thal lium as a minor element. By means of modern analytical methods numerou s new Tl minerals are described, but their coexistence and equilibria are not investigated yet. The equilibria at 200 degrees C of the quasi -quaternary system Ag2S-Tl2S-Sb2S3-Bi2S3 and the corresponding subsyst ems were studied. The system Ag2S-Tl2S-Sb2S3-Bi2S3 contains only one q uasiquaternary phase, AgTlSbBiS4, which is connected by tie-lines with all quasiternary phases in the system (Ag4Sb3BiS8 and Ag3Tl3Sb2S6) an d with most quasibinary phases: SbBiS3, weissbergite (TlSbS2), TIBiS2, pyrargyrite (Ag3SbS3), miargyrite (AgSbS2) and matildite (AgBiS2). Th is phase diagram makes it possible to investigate all important natura lly occurring parageneses of Ag and Tl sulphosalts containing Sb and B i.