The abundance of feldspar, as a silicate mineral, makes it feasible as an alternative source toextract potash (KCl) and alumina (Al2O3). The demand of potash has been projected to increasein the following years for its application in fertilizers, with that, this study investigated the effectsof grinding conditions on the mineralogy and dissolution of feldspathic ore in the recovery ofpotash and alumina.

Feldspar ores were subjected todifferent grinding conditions specifically in termsof milling speed, time, and ball-ore-ratio. Samples were analyzed for mineralogy using Back scattered Electrons Image and Elemental Maps using Scanning Electron Microscope where the different grinding conditions has led the materials to exhibit agglomeration as milling speed and time increases. Grinding conditions also showed that most particles who exhibit agglomeration tend to have angular and elongated particle shape in which all ground samples have particle sizes less than10µm. Quartz has mainly been observed to be associated with the microcline from which K⁺ is being extracted. Intrusive elements such as zircon, tungsten and titanium were observed in some of the samples, these elements are usual impurities in feldspar but do not make as much problem with iron which generally affects its purity and affects its marketability as an industrial mineral.

Regression and ANOVA results also showed that among the three grinding parameters used inthis study, ball-to-ore ratio was the most impactful parameter in the grinding product using bothpercentages of particle sizes less than 2µm and 10µm, respectively. Milling speed, on the otherhand, recorded the least impactful among the three. The regression results also indicated that thegrinding results generated has significantly followed that of the milling experiment model whichwas derived by one of the project partners.

Based on mineralogy, particle sizes and the effect of agglomeration, 3 samples were chosen for acid leaching using 2M HCl at 300rpm in 700C for 6h. The feed was chosen because of its coarseness and particles with intact mineral phases, Sample 1, the only sample who did not exhibited much agglomeration compared to rest of the ground samples and lastly Sample 12 waschosen among the samples who exhibited agglomeration as it contains the greatest number offine particles based on the particle size analysis.

The recovery of the main elements K⁺ and Al³⁺ was consistent to increase with increasing timeand at finer particles. Agglomeration in finer sample was not a considerable factor that affected the dissolution, in fact, the finest sample recorded the highest recoveries which is attributed to itshigh Specific Surface Area (SSA), which allowed the particles to be more reactive than the othersamples selected. Coarser particles with distinct mineral liberation have recorded a lower SSA and recoveries, respectively. Sodium (Na) and Calcium (Ca) were the major impurities in the Pregnant Leach Solution (PLS) which exhibited the same increasing trend with increasing time with the main elements. The results show that while grinding significantly increases the concentration of K⁺ and Al³⁺, the concentrations of the soluble Na and Ca impurities have remained low and incomparable to the recovery of the of main elements.