In order to avoid the curing stage in formed coke production, the effects of hardeners, on the tensile strength of the briquettes bonded with resole binders of F/P=2.0 and N/P ratios ranging 0.1-0.5, were studied. The raw briquettes were produced by mixing the resole binders containing these hardeners, with the coke breeze. They were hardened at room temperature for 24 h and also at 200 degrees C for 2 h. The briquettes were also produced from the resole binders of the same NI P but containing no hardener, and cured at 200 degrees C for 2 h. The tensile strengths of the briquettes were measured. H3PO4 resulted in the briquettes having the lowest tensile strength under any conditions investigated. H2SO4 and p-TSA hardeners were found to be unsuitable for the aim of this investigation, because they could not fully harden the briquettes at room temperature. ATP resulted in the briquettes of the highest tensile strength of 52.13 MPa, with the resole binder of N/P=0.1 after 24 h hardening at room temperature but resulted in briquettes of relatively lower tensile strength when the N/P ratio of resoles was increased. By blending ATP and p-TSA it became possible to produce formed coke with sufficient tensile strength by hardening them at room temperature. (C) 2009 Elsevier B.V. All rights reserved.