| Abstract [eng] |
The aim of this work is to determine the influence of the peculiarities of AlF3 production process on the chemical and mineral composition of silica gel waste and its properties. It was determined that it is possible to reduce the concentration of fluorine ions to 1.5% by changing the treatment conditions (leaching under static and dynamic conditions or mechanical activation), and by adding alkaline compounds (NH4OH, Ca(OH)2, NaOH, Al2O3). For the first time, it was determined that the compounds containing aluminum and fluorine ions, such as aluminum fluoride, calcium fluoride and/or katoite, are crystallized in the liquid medium which was separated from silica gel by using mechanical treatment or by leaching with alkaline solutions. In this work, fluorine ions removal technology was proposed; it not only allowed reducing the concentration of fluoride ions in silica gel to 1.5%, but also increased the yield of aluminum fluoride. Based on the results of the work, additional equipment was installed, and industrial tests were carried out in the AlF3 production line of Lifosa, JSC. |
