Investigation of wet ground limestones on porous ceramic body properties

Limestone and clay group minerals are used in the production of ceramic wall tile compositions. Wall tiles must have a 10-20% water absorption depending on the EN 14411 standard. In order to meet this water absorption criterion, calcite and dolomite minerals which are in carbonated structure are used in wall tile body composition. Manufacturers supply these minerals from limestone sources close to the enterprises, which are abundant in nature. The size of raw materials must be reduced to finer sizes (-45 µm) for the production of ceramic bodies. For this reason, it is very important to control the size of the limestone during the grinding process limestone to a very fine size (-45 µm) in aqueous media in order to produce qualified wall tile body composition. In this context, this study aimed to investigate the effects of grinding of limestone samples obtained from the Derenti, Nevruz, and Terzialan regions of Çanakkale province, on ceramic wall tiles based on laboratory and industry-scale experiments/analyses. The limestone samples were firstly ground in a discontinuous mill, and the grinding performances were compared in terms of time-dependent particle size, energy consumption, and capacity. Second, the wall tile bodies were shaped and then fired in an industrial kiln, and finally analyzed in terms of sintering properties and TS EN 14411 standards. The results from this study showed that Bond Work Indexes of Derenti, Nevruz, and Terzialan limestone samples were determined as 12.8, 11.7, and 13.0 kWh/t, respectively. As a result of industrial-based discontinuous grinding studies, the energy consumption for grinding to 0.2% sieve residue for +45 µm increased from 67.4 to 73.4 kW/t and the capacity decreased from 1.34 t/h to 1.23 t/h with the increase of quartz content of limestone samples from 0.8% to 2.1%. The particle size analysis of the samples indicated the d90, d50, and d10 values of the ground samples in industrial-based grinding experiments were 16.97 µm, 1.85 µm, and 0.37 µm, respectively, As a result of the studies carried out within the scope of wall tile body composition development, the shrinkage value decreased from 0.43% to 0.31% with the increase in CaO content from 53.9% to 54.6% and wall tile with TS EN 14411 water absorption standard was obtained by using 13% limestone. In conclusion, the mineral content in limestone showed significant effects on particle size distribution, energy consumption, and capacity in the fine grinding process as well as on sintering properties of wall tile body composition.