An effective additive based on synthetic fluorite and graphitized carbon from aluminum production waste for the synthesis of clinker compounds

The article contains the results of laboratory studies performed to evaluate the effectiveness of introducing a complex additive based on synthetic fluorite and graphitized carbon obtained from aluminum production waste into raw meal for the production of Portland cement clinker. The studies were performed by thermogravimetry, high-temperature radiography, and X-ray phase analysis. The results of the conversion of sodium fluoroaluminates, which are part of the waste, into synthetic fluorite by treating the waste with milk of lime are presented. It has been established that the extraction of fluorine from waste into synthetic fluorite is 100%. The residual sodium content in the additive after treatment with lime whitewash is reduced by 90–98% and is due to the presence of alkali contained in the filtrate in the cake.
Thermogravimetric studies have shown that the introduction of a mineralizing agent intensifies the sintering of raw meal. Thus, at the same temperatures, the degree of decarbonization of CaCO3 in a sample with a complex additive is 15—60% higher than that without a mineralizer. The temperature of liquid phase formation during sintering of raw meal with fluorocarbon-containing additive decreased by approximately 25 °C. The combined action of a fluorine-containing mineralizing agent and a burn-able additive reduced the energy consumption for limestone decarbonization by about 23.5%.
According to the data of high-temperature X-ray analysis, the temperature dependencies of the intensity of the analytical lines of the main clinker compounds during sintering of a regular raw meal and that with a fluorocarbon-containing additive were plotted in the range of 700—1200 °C. The results obtained confirmed the effectiveness of the complex additive. The analytical lines characterizing the synthesis of the main clinker phases in raw meal with an additive are characterized by a greater intensity at the same temperatures

Author: B.P. Kulikov, N.V. Vasyunina, I.V. Dubova, A.S. Samoilo, R.O. Balanev, I.K. Ivanova, Ya.S. Sysoeva

Section: Waste utilization

Keywords: fluorocarbon­containing mineralizer, combustible additive, sodium fluoroaluminates, lime milk, caustification, thermogravimetry, limestone decarbonizing, clinker chemical species synthesis