Influence of triboactivation conditions on the synthesis in natural phosphate-ammonium sulphate system

Summary

No data is available in the literature about the effects of mechano-chemical activation on the processes of chemical interaction in the Tunisia phosphorite-ammonium sulphate mixture. The purpose of this paper is to study the chemical and thermal reactions in mixtures of Tunisia phosphorite and ammonium sulphate in a mass ratio of 1:1, triboactivated in a planetary mill using different mill balls for a period of 10 h. Using chemical, thermal, X-ray powder diffraction and infrared spectroscopy to analyse the activation products, and analysing the changes occurring during the TG-DTA-DTG measurements, allowed to determine the chemical transformations in the system and to assess the degree of transformation of non-soluble forms of phosphorus from the natural phosphate into soluble. Data from the studies have registered the changes in the solids resulting form preliminary mechano-chemical activation of samples. The additional endo- and exothermic effects resulting from thermal decomposition in the temperature range of up to 1373 K are proof of the changes during the TG-DTA-DTG studies and of new interactions occurring in the system. The results from the thermal and spectroscopic methods show that triboactivation using different mill balls and modes of operation produce new compounds in the form of ortho-, pyro- and tripolyphosphates, soluble in the soil solution. The data obtained are part of the complex studies on the way to optimize the composition and conditions of triboactivation and subsequent thermal treatment aimed to produce high-efficiency slow-acting fertilizer products.