We have investigated the impact of the addition to the kaolin, by mechanochemical treatment of bonding agents such as the potassium phosphate compounds (potassium dihydrogen phosphate KH2PO4, potassium monohydrogen phosphate K2HPO4 and potassium phosphate K3PO4) on the structural, thermal and mechanical properties of the kaolin products. The fresh and sintered samples were characterized by using several techniques: X-ray diffraction (XRD), infrared spectroscopy (IR), thermal techniques (DTA/TGA and dilatometry) and the Brazilian test. The addition of the bonding agent by mechanochemical treatment minimized defects after a sintering process. This resulted in reducing the sintering temperatures. (C) 2014 Elsevier B.V. All rights reserved.