METHOD OF PRODUCING POWDERS OF RARE-EARTH DIOXO-SULPHIDE COMPOUNDS LnOS AND SOLID SOLUTIONS BASED THEREON Ln'OS-Ln''OS (Ln, Ln', Ln'' = Gd-Lu, Y) Russian patent published in 2015 - IPC C01F17/00 C09K11/84 

FIELD: chemistry.

SUBSTANCE: invention relates to inorganic chemistry. A mixture for producing powder of Ln₂O₂S, Ln₂O₂S-Ln'₂O₂S compounds, where Ln, Ln' = Gd - Lu, Y is prepared by adding sulphuric acid to solutions of rare-earth nitrates and precipitation, co-precipitation, crystallisation and co-crystallisation of the obtained rare-earth sulphates. The mixture is heat treated in air at 600°C for 2-3 hours, ground to particle size smaller than 100 mcm and treated in a hydrogen stream at 500-600°C for 5-7 hours while feeding hydrogen at a rate of 7-8 l/h (standard conditions), and then treated in a H₂S stream at 850-950°C for 7-10 hours for Gd-Lu or 5-7 hours for Y at the same rate of feeding H₂S.

EFFECT: shorter duration of high-temperature heat treatment and reduced amount of hydrogen sulphide when producing oxysulphides of rare-earth elements.

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