Laboratory Testing on the Promotion of Madagascar's Industrial Waste and Natural Materials as Clinker Mineralizers

This study presented laboratory tests on the effects of several mineralizers added to black raw materials, in the manufacture of cement. This manufacturing process is based on crushing quarry limestones with clays and fuels in order to be fired at 1450°C to obtain clinker, the main component of cement. In the case of the Ibity cement industry, the natural materials of Madagascar and the waste from local industries were studied. The main goal of this study was to find the best mineralizer that could reduce the thermal energy expended in the formation of clinker while improving its quality. In order to realize this, four different temperature values were applied namely 1250°C, 1350°C, 1400°C and 1450°C. In addition, it was added 1% and 4% of these mineralizers to the white raw materials used and three different qualities of the raw material, a, b and c were used respectively, as controls. The Lime Saturation Factor (LSF) is the performance indicator that indicates the quality level of these raw materials.

With these evaluation criteria, the characteristics of each of these mineralizers also helped us to detect their efficiencies. The glass used comes from the waste of local industries and it is a material rich in amorphous silica which reacts easily under the effect of temperature. Industrial ash is rich in crystalline silica, which prevents its reactivity. Pozzolan is one of the most accessible materials at the industry but possesses poor thermal conductivity despite the presence of reactive silicas while Sulfogypsum 1033 and 1034 are respectively rich in iron oxide and sulphur trioxide. They are responsible for the melting properties in the reaction of clinker formations.

At only 1350°C, our tests with Sulfogypsum (1033 and 1034) gave us the best results. At the low temperature used in the furnaces, the additions of mineralizers allowed the vintages to surpass the quality in front of the control. They will later be able to optimize the compressive strength of the cement, given the high C3S value observed in the experiments. As for other mineralizers, their reactivity requires other conditions that will be the subject of another study.