Abstract |
One of the detriments to limestone or dolomite injection is the increase in solid wastes produced since the amount of flyash to be disposed of would be approximately doubled. Moreover, the flyash produced would be of little value in conventional flyash utilization schemes because of the large increases in lime, magnesia and sulfur. Two developments of this study involving concentration to recover lime and melting to yield sulfur derivatives and mineral wool have been linked together to form a preliminary conceptual plan for an Emission Control Minerals Complex (ECMC) to utilize all parts of modified flyash. The ECMC process involves slurrying modified flyash with water followed by carbonation of the slurry to convert unreacted lime and magnesia to their carbonate form, concentration of lime from the carbonated modified flyash by agglomerate flotation for reinjection into the furnace, melting of the concentration rejects for the manufacture of such products as mineral wool, and recovery of the relatively clean and more concentrated sulfur gases evolved from the melt for the manufacture of such products as sulfuric acid. In addition to the ECMC process several other potentially successful utilization methods were tested. It was determined that modified flyash had advantages over lime for acid mine drainage neutralization because of decreased sludge settling and filtering time. (Author) |