A response of a co-precipitated uniform deposit of hydrous zirconia and calcium hydroxide to hydrothermal and subsequent high temperature treatments is described in the paper. A nominal oxide composition of the deposit was 30 mol% CaO and 70 mol% ZrO2. The hydrothermal treatment of the deposit was performed for 4 h at 240°C to obtain crystalline product which was subsequently heated at temperatures ranging from 410°C to 1450°C without soaking. Calcium oxide escape was monitored by ICP-OES over the processes of co-precipitation, washing and hydrothermal treatment of the deposit. X-ray diffraction was used to study the development of phase composition and crystallite size of the product, additionally observed by TEM. The behaviour of the hydrothermally crystallized powder during heat treatment was studied by means of thermogravimetric, differential thermal and evolved gas analyses. Evidences were collected on the calcium segregation in the form of calcium carbonate during the hydrothermal preparation of high content CaO nano-zirconia powder.
Support is acknowledged, coming from the project financed with the means of National Science Centre under the decision No. DEC- $2011 / 03 / B / S T 806286$.
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