Chemical corrosion of basic refractories by cement kiln materials

The study of basic refractories corrosion by cement kiln materials was carried out with powder tests and coating tests at the typical temperature range of the sintered material in the transition zone and the sintering zone (1200–1450 °C). The tested basic refractories were magnesia-spinel (MSp) and magnesia–zirconia (MZ) refractory bricks. The industry cement kiln materials were rich of sulphur and chlorine. The microstructures of the as-delivered and tested samples were researched by XRD and SEM–EDS techniques. The new phases detected in the samples with MSp (with and without ZrO2) bricks after tests at the temperature of 1200 °C were binary (C12A7 tmp − 1392 °C, CaZrO3: tmp − 2345 °C): and ternary (C2AS: tmp − 1593 °C or C3MS2: tdp − 1573 °C) phases. After tests at the temperature of 1300 °C and higher, ternary phases of C7A3Z (tmp − 1550 °C) and CaZrO3 and quaternary phases Q-C20A13M3S3 or C6A4(M,f)S (tdp − 1380 °C) were detected. The C3A3·CaSO4 phase was formed in the samples after the corrosion tests performed up to the temperature of 1300 °C. The new phases formed in the sample with the MZ bricks were clinker phases (β-C2S, C3A and C2(A,F)/C4AF) and the C7A3Z phase.