Portland cement clinker - made from crude flour contg. zinc cpds. which lower sintering temp., thus saving fuel costs

摘要

The raw material pref. contains 0.1-1%, esp. 0.1-0.3% of a Zn cpd. calculated as ZnC, and obtd. from ZnO, ZnS or other Zn salts. The zinc may also be obtd. from natural prods., e.g. ores, waste, or residues; or from old rubber or old oil contg. zinc. The addn. of Zn lowers the sintering temp. as measured by the amt. of free CaO remaining in the clinker after sintering; and the Zn cpds. produce no noxious gases. The Zn cpds. were found to be just as efficient in reducing the sintering temp., for saving energy, as CaF2; but CaF2 cannot be used because it causes environmental pollution and corrodes the clinker mfg. plant.