[en] The replacement of clayey raw material by industrial wastes is an alternative to reduce mineral exploration and environmental impact. In this study, dregs (inorganic waste rich in calcium carbonate generated by the cellulose pulp production) was added to a kaolinitic clay in the contents of 10, 20, 30, and 40 wt%. The specimens prepared by uniaxial pressing were sintered at 850, 950, and 1050 °C with a holding time of 180 min, and at 850 and 950 °C with a holding time of 300 min, aiming to evaluate the influence of firing cycle on the properties of specimens. Then, physical-mechanical properties were measured, and efflorescence development was evaluated, besides the SEM and XRD analysis of specimens after water immersion. Even though satisfactory physical-mechanical properties were achieved after sintering with 180 min holding time, the presence of unreacted CaCO₃ made necessary the sintering at 950 °C and holding time of 300 min to use up to 20 wt% dregs. (author)