THE EFFECTS OF SULFURIZING AGENT ON THE FORMATION OF CALCIUM LANTHANUM SULFIDE

For calcium lanthanum sulphide (CLS) formation, the effect of the sulp hurizing agent is studied. CS2 and sulphur are used as sulphurizing ag ents to sulphurize the lanthanum and calcium carbonate precursors whic h are formed by a coprecipitated method. With CS2 as a sulphurizing ag ent, the intermediate product formed is LaS2 whereas when sulphur is e mployed, the La2O2S was the intermediate product. If LaS2 is formed fi rst, it is not difficult to complete the sulphurizing reaction for CLS at a low temperature (700-degrees-C) for a short soaking time (3 h). However, if the La2O2S is formed first, the phase formation reaction o f CLS should be completed at a high temperature (800-1050-degrees-C) f or a long soaking time in order to dissociate the La-O bond.