Assessment of Tanzania magnesite’s suitability for the struvite recovery and other industrial applications

Abstract

Magnesite (MgCO₃) is a valuable mineral with wide industrial applications; thus, geochemical familiarity and deposit quality are critical for making the best use of these resources. Tanzania is reported to have magnesite deposits in at least 12 different locations; however, four of these were chosen at random for study. This study aimed to examine the mineralogical and elemental composition of rock samples from Chambogo (KL), Muriatata (AR), Lobolosoiti (MN), and Chikaza (DM) using x-ray fluorescence (XRF) and powder x-ray diffraction (XRD). XRF examination revealed that sample KL, AR, MN, and DM, respectively, contain 45.21%, 46.06%, 43.21%, and 43.21% of magnesium oxide. Besides MgO, all samples contained SiO₂, Fe₂O₃, Al₂O₃, CaO and several trace elements as impurities, with only calcium oxide, iron, arsenic, and chromium identified as impurities of concern. However, XRD analysis indicated magnesite as the major mineral phase in rock samples KL, AR, MN, and DM, with percentage concentrations of 65.2, 68.14, 63.87, and 68, respectively. In all rock samples, strong peaks at 2θ ∼ 33^o, 43^o, 54^o and 55^o, confirmed the crystalline nature of magnesite. Calcination of these samples however, resulted in peak shift and phase change, with main diffraction peaks generated at 2θ ∼ 36.9^o, 42.9^o and 62.3^o, confirming the formation of crystalline MgO. Despite considerable contamination levels of CaO, iron, chromium, and arsenic in the samples, all samples had enough magnesite to be mined for industrial use.