From Sludge to Stucco: A Study of the Potential Utilization of Lime Softening Residuals as a Raw Material in the Manufacture of Portland Cement in Miami-Dade County.

A study of lime residuals from the Preston / Hialeah plants in Miami-Dade was performed to evaluate the use of lime sludge as a cement feed material. The results indicate that this material is suitable as a partial replacement for quarried limestone and the additional iron in the sludge may be of some benefit to the cement manufacturing process. The quantity of solids expected to be available is 175 dry tons per day. While this constitutes less than 10 percent of the production of one of the local cement producers, its use would extend the useful life of their quarries by a similar amount.Although the material is apparently suitable for cement manufacturing, there are several issues to be fully resolved prior to implementation of this alternative as a means of disposal. These include transportation from the current lagoon site to a cement kiln, environmental concerns, and integration of the material into the plant process stream and cost effectiveness of the operation compared to using quarried rock.