INVESTIGATION OF THE PHYSICO-CHEMICAL FEATURES AND THERMODYNAMIC PATTERNS OF THE AGGLOMERATION PROCESS OF PHOSPHATE RAW MATERIALS USING PETROLEUM COKE

Abstract

The article presents the results of physico-chemical and thermodynamic studies of the use of petroleum coke obtained from oil refining waste for use in agglomeration of phosphate raw materials as fuel.Using the method of thin-layer chromatography and IR spectroscopy, groups of organic compounds in the composition of heavy waste used for slow coking of petroleum coke were determined. The obtained results of the analysis of heavy oil waste showed a high content of strong aromatic groups 35.1-54.1%, resin groups 12.0-25.7%, paraffin groups 3.0-41.4%. All these indicators indicate the suitability of heavy oil waste for the production of petroleum coke.The element composition and microstructure of the resulting petroleum coke, which contains C-78.56%, Te-4.05%, Al-12.14%, Si-1.18%, were identified using a scanning electron microscope JSM-6490LV.The results of thermodynamic studies of reactions characteristic of agglomeration firing of a working mixture of phosphorite-phosphate-siliceous shale - neftekox composition are presented, performed using the HSC-5.1 Chemistry software package developed by Outokumpu Research Oy. The results of calculating the Gibbs energy change from the temperature of decarbonization reactions indicate the thermodynamic probability of all studied reactions occurring in the high-temperature region. Moreover, the probability of 5.6 reactions is possible only above 1200K. Thermodynamic modeling of decarbonization of the working systems СаСОз – С – С6Н6 –О2 и СаСО3 – С – С6Н5О – О2 were performed in the temperature range 500-1500 K and pressures 0.1-0.01MPa, typical for the agglomeration process using the Astra-4 software package.The results of graphical dependences of the equilibrium distribution of the main components of calcium and carbon depending on temperature and pressure are of the same type. Moreover, as the pressure decreases, the possibility of formation of CaO and CO2 per 100 K moves to a low-temperature region.