A simple method for the estimation of optimum binder content in baked carbon mixes

A detailed study is presented of the optimum amount of binder in various carbon mixes consisting of calcined petroleum coke of different particle size distributions as filler and coal tar pitch as binder. These fillers were subjected to bulk density measurements prior to wet mixing with various amounts of binder and were then shaped into cylinderical blocks by compression moulding. The blocks obtained were measured for green apparent density before being baked to a temperature of 950° C. The baked blocks were then subjected to apparent density, electrical resistivity and crushing strength measurements. The optimum binder contents for these baked carbon mixes obtained on the basis of maximum apparent density, maximum crushing strength and minimum resistivity, were plotted against the bulk density of the corresponding fillers. The optimum binder content on the basis of apparent baked density and crushing strength is found to be an inverse function of the bulk density of the filler. Thus, knowing the bulk density of the particular filler, it is possible to predict the optimum binder content in the corresponding carbon mix with the product diameters up to 19 mm.