Geological Characteristics and IndustrialApplications of Raw Materials for Cement Productionin the Republic of Yemen

Abstract

Extensive field and laboratory studies were carried out on the currently-used cement raw materials in the quarry sites of six main cement plants located in northwestern, southwestern and southern Yemen. Field studies comprised the determination of the stratigraphy and geologic setting of the rock units containing theseraw materials as well as exploring and evaluating new occurrences. Also, the field work involved the search for promising alternative additives and correctives. Laboratory studies, on the other hand, comprised the use of several techniques and analytical procedures to determine the petrographic, mineral and chemical characteristics of a large number of samples representing both the currently-used and the proposed alternative cement raw materials. The technologic part of this study comprised the preparation of several cement raw mixes having different compositions using both the currently-used raw materials and the proposed alternatives. These raw mixes were burned at 13500C and 14500C. The types and properties of the originated minerals (phases) as well as the physico- mechanical properties of the produced cement clinkers were determined. This permitted in the recognition of the optimum raw mix composition, burning conditions and fuel and water consumption. Geoenvironmental studies were conducted in the raw materials quarry sites and the cement plants to assess and evaluate the negative environmental impacts of the processes of quarrying and cement manufacture. A number of recommendations is outlined concerning: (i) the selection of the most suitable beds of raw materials; (ii) the use of modified quarrying operations in order to optimize the exploitation of the cement raw materials, reduce the proportions of waste and produce cement with larger quantity and better quality; and (iii) avoiding, or at least minimizing, the environmental hazards of the quarrying and manufacture processes.