Development of an industrial mineralogical framework to evaluate mixtures from reservoir sediments for recovery by the heavy clay industry: Application of the Durance system (France)

Abstract

The use of dam reservoir sediments would contribute to preserving non-renewable resources, offer alternative raw materials for the heavy clay industry, and reduce the silting of dams and the environmental impact of its dispersal following dredging.The aim of this work is to present the structure and application of a mineralogical industrial framework (MIF) in the evaluation of reservoir sediments as a replacement for natural raw materials in the heavy clay industry. The MIF is composed of two ternary plots based on the dominant minerals (quartz, clay minerals (imparting plasticity for shaping and cohesion after drying and firing), feldspars, chlorite and muscovite, and carbonates) and clay mineral assemblages (illite, kaolinite and swelling clay minerals) from 36 industrial mixes.The application of the MIF to reservoir sediments of the Durance system indicates that they fall outside of the industrial domain due to high contents of illite and silicate minerals (upstream Durance) or carbonates (middle Durance and Verdon stream). This conclusion is supported by the technical impossibility of extruding the upstream sediments and the occurrence of cracks on the specimen bars from the carbonate-rich sediments.Finally, we demonstrate that the Durance sediments can be recovered by incorporating some opening agent (quartz sand or calcined clay wastes) and mixing sediments from different sites (upstream and middle course) to adjust the grain-size distribution and lower the carbonate content. The ceramic properties of the mixtures (drying and firing linear shrinkage, water absorption and tensile rupture) match the usual values of the heavy clay industry.