Subsolidus phase relations in the system ZnWO₄-ZnMoO₄-MnWO₄-MnMoO₄

Abstract

Summary Subsolidus phase relations in the systems ZnWO 4 -MnWO 4 , ZnWO 4 -ZnMoO 4 , MnMoO 4 -ZnMoO 4 , and MnWO 4 -MnMoO 4 , were investigated by using the quenching technique. A complete series of solid solutions forms in the system ZnWO 4 -MnWO 4 above 840° C, whereas limited solid solubilities were found in the other three. The various limits of solubility are, at 620° C, 4·0 mole % ZnMoO 4 in ZnWO 4 and 4·0 mole % ZnWO 4 in ZnMoO 4 , 13·0 mole % ZnMoO 4 in MnMoO 4 and 12·0 mole % MnMoO 4 in ZnMoO 4 , 9·0 mole % MnMoO 4 in MnWO 4 and 6·0 mole % in MnWO 4 in MnMoO 4 ; and at 1000° C, 15·0 mole % ZnMoO 4 in ZnWO 4 and 15·0 mole % ZnWO 4 in ZnMoO 4 , 36·0 mole % ZnMoO 4 in MnMoO 4 and 29·0 mole % MnMoO 4 in ZnMoO 4 , 15·0 mole % MnMoO 4 in MnWO 4 and 27·0 mole % MnWO 4 in MnMoO 4 . Subsolidus phase relations in the system ZnWO 4 -ZnMoO 4 -MnWO 4 -MnMoO 4 were studied at 900° C. The solubility of molybdenum in the (Zn,Mn)WO 4 series increases from both end members to a maximum of 27·0 mole % at the composition Mn 35 Zn 65 . Both molybdates also have limited ranges of solid solutions, and a three-phase region occupies the central portion of the system defined by three points with compositions of 41 mole % ZnMoO 4 , 26 mole % MnMoO 4 , 33 mole % MnWO 4 ; 57 mole % ZnMoO 4 , 10 mole % MnMoO 4 , 35 mole % MnWO 4 ; and 27 mole % ZnMoO 4 , 34 mole % MnWO 4 , 39 mole % ZnWO 4 .