Recovery of feldspar and potential accessory minerals from granites

The optimization of mineral treatment processes performed by the application of updated techniques can enhance the overall mineral recovery, enabling also the economical exploitation of secondary products, thus incrementing the quantity and quality of the final products obtained and increasing the sustainability of the process. Granite rocks can be found all over the world, and are a primary source for feldspar and quartz; moreover, they can contain in small percentages other accessory minerals, as cassiterite, hubnerite, tantalite, monazite and many others, that can represent a valuable source of metals and REE. This work of thesis aims to develop an efficient treatment process for the beneficiation of granite rocks, focusing on the recovery of quartz, feldspar and eventual accessory minerals present in the raw material. For the analysis, two different case studies will be considered, a leucogranite coming from Ecomin Plant (Minerali Industriali, Italy), and an aplite from Abu Dabbab deposit (Egypt). Each of the two raw materials firstly was characterized by means of macroscopical observation, X-Ray powder diffractometry, X-Ray fluorescence and SEM-EDX analysis, then underwent to a comminution process for the free grain liberation, proceeding with magnetic separation and flotation process. For the recovery of accessory minerals, a gravimetric treatment was adopted. The treatment results were then evaluated using X-Ray powder diffractometry, X-Ray fluorescence, SEM-EDX analysis, Micro-Raman spectroscopy and fusion cone tests: for the Verbania sample, an highly pure quartz-feldspar concentrate was obtained, with low iron and titanium oxides values (TiO2 < 0,05% wt, FeO2 < 0,2 %), together with a biotite concentrate. Instead, for Abu Dabbab sample was obtained an high-density mineral concentrate enriched in cassiterite (SnO2, around 10 % in grade) and hubnerite (MnWO4, around 20 % in grade), together with a quartz-feldspar concentrate with considerable sodium content (NaO>6,5 % wt).