A great deal of experimentation has been carried out by the Wet Process Cement Manufacturers in connection with additives which make possible the production of a pumpable slurry at reduced moisture contents.
The viscosity or pumpability of a slurry at a definite moisture content and fineness seems to depend on two basic phenomena. One is the physical structure of the raw material itself, which on fine grinding may or may not be excessively hydrophilic (water adsorptive).
The second basic phenomenon affecting the hydrophilic tendencies of the raw material is the presence of certain soluble salts, especially gypsum and small amounts of alkaline carbonates or oxides.
Various soaps, and phosphates can be used to produce a pumpable slurry of low moisture content when using hydrophilic raw materials as well as can other proprietary materials such as certain long chain carbon compounds.
For recovering the CO2 laden stack gas we use watersealed rotary compressors. For compressor protection the incoming gas from the dust chamber is passed through a simple water scrubbing device to remove the major portion of the dust. From the pump the gas is dewatered and forced into the raw mill thru the feed screw.
The factor limiting production at the laramie Plant is the amount of heat the kiln will stand in the burning zone. Before using CO2 in the slurry, as well as now, the B.T.U. input to the kiln was held at a maximum with reference to lining and shell temperature.