The thermal decomposition of the rare-earth sulphates

Recoveries of Valuable Metals from Spent Nickel Metal Hydride Vehicle Batteries via Sulfation, Selective Roasting, and Water Leaching

“…As seen in Fig. 1, the physically and chemically bonded water removal is completed around 286°C, which agrees with previous work for materials of similar composition [31,46,47]. Initial decomposition temperatures measured by TGA normally vary depending on the characteristics of the solids (particle size, shape, quantity), the sample holder, the heating rate and the composition of the gas phase [35].…”

Solution‐Processed HafSOx and ZircSOx Inorganic Thin‐Film Dielectrics and Nanolaminates

“…As noted below, this behavior extends to thin films, making this formula particularly interesting for applications where enhanced levels of chemical and thermal stability are desired. Because the sulfate La 2 O 2 SO 4 is known to be thermally stable (decomposition T > 1300°C), [26,27] La was added to the mother HafSOx solution in an effort to modify dehydration properties and thermal-decomposition temperatures. To explore this mixed-metal system, a solution containing 23 % La (total metal) was prepared, and precipitation was induced by heating; from chemical analysis, however, only 3 % La was found in the product.…”

Isopiestic determination of the osmotic coefficients of Lu2(SO4)3(aq) and H2SO4(aq) at the temperatureT= 298.15 K, and review and revision of the thermodynamic properties of Lu2(SO4)3(aq) and Lu2(SO4)3·8H2O(cr)a

“…(8,9) This treatment converts the rare earth nitrate samples to rare earth chlorides, which can easily be converted to R 2 (SO 4 ) 3 (s) by the method just described. (8) This furnace temperature of T = 773 K was chosen for the rare-earth sulfate analyses because it is well above the minimum temperatures required for complete dehydration of the R 2 (SO 4 ) 3 (s), (428 to 588) K, (10,11) and it is well below the minimum temperatures for decomposition of R 2 (SO 4 ) 3 (s) to form R 2 O 2 SO 4 (s), (1113 to 1219) K. (11)(12)(13) However, we decided to vary the furnace temperature over the range of T=(723 to 823) K during the dehydration analysis of a new Lu 2 (SO 4 ) 3 (aq) stock solution to observe whether the sample masses showed any dependence on furnace temperature. No significant variation of the mass of Lu 2 (SO 4 ) 3 (s) with furnace temperature was found, which confirms that dehydration was complete at these temperatures, but a different problem was identified.…”