Magnesium and lanthanum present some processing challenges in aqueous systems as their suspensions are unstable and thicken during storage. Some phosphorus-and fluorine-containing systems can be addressed by the use of insoluble compounds. For example, Nb2P4O15 and AlPO4 can be used to address a large part of the Nb-Al-P-O system, which is described below. In principle the method could be adapted to work with suspensions in a non-aqueous solvent. This would extend the range of elements that could be addressed though the milling, dispensing and freeze drying equipment would need to be adapted to process the required liquid safely. ) low profile stirrer holding two precursor slurries for dispensing into a rack of vials (2) for mixing the precursor slurries in the required ratios, which are subsequently dispensed into (3) four sets of sample trays on 3D printed holders containing aliquots of the slurry mixtures; b) Isopress tooling showing an unfilled PET tray supported by a silicone holder. The metal insert ensures the rigidity of the holder and the flatness of the pellet faces. The silicone cover sheet protects the samples and prevents them falling from the PET tray during processing; c) Images of a sample set (4) positioned on refractory batts after calcination, a calcined sample set (5) on an adhesive polymer foam pad surrounded by a PLA frame and filled with epoxy, (6) cross-section of a cured epoxy resin block with embedded calcined sample set with flat surfaces uppermost, ready for placing onto an automated XY-stage (7) inside the X-ray diffractometer; d) Two sample sets, embedded in epoxy loaded onto the XY-stage of the X-ray diffractometer.