Batch Rotary Kiln Calcination of YBaCuO Precursor Powders

Precursor powders of Y₁Ba₂Cu₃O_6+x (123) derived from spray roasting were calcined in a batch rotary kiln. The optimum conditions were 15 min in air at temperatures between 920° and 940°C for 1.5 vol% solid loading. Pure 123 was formed in a single calcination step from homogeneous, micrometer‐sized precursor material containing Y₂O₃, CuO, and BaCO₃. Rotation speed did not affect the product quality, but longer calcination times are needed at higher loadings. Product agglomeration increased with increasing loading and decreasing rotation speed. In nitrogen, 123 decomposed so that a pure product could not be obtained. The BaCO₃ decomposition is the rate‐limiting step in the calcination. The presence of Ba(NO₃)₂ in the precursor led to formation of intermediate phases.