The catalytic efficiency of leached Sea nodule residue, generated from reduction roasting ammoniacal leaching process, for oxidative degradation of Congo red under varying experimental was studied. The extent of decolourisation was decreased with increase of pH but increased in presence of H,0,. CR decolourisation occurred in two consecutive steps with first step was faster than the later. Formation of a surface precursor complex between WSNR and CR at a rate limiting step followed by electron transfer from CR to active metal centre of WSNR and release of product(s) was proposed for the decolourisation process