Geometallurgical characterisation of Mn ores

Abstract

This article details two geometallurgical case studies using classification schemes developed for Mn fine and lump ores. For the first, the relative abundance of 15 material types was compared to chemistry by size fraction. Positive correlations were evident between the proportion of aluminosilicate-bearing ore groups and Al 2 O 3 content, the ratio of Mn oxide/ Fe oxide ore groups and the Mn/Fe content, the proportion of cryptomelane-bearing groups and the K 2 O and BaO contents, and the ratio of hard to moderately hard + friable particles and the K 2 O + Ba + Na content. For the second, agreement was observed between the types of predominant material types in the two different ores and their mass distributions, major and trace element chemistries. Different material types had clear variances in their envelope and apparent particle densities. These two case studies support the expanded use of particle-based ore classification schemes for the characterisation of Mn ores to better predict their downstream processing performance.

Phase Distribution During Slag Formation in Mn Ferroalloy Production

“…Assmang is a Wessels-type ore, which contains both braunite-I and braunite-II minerals (MnOÁ3Mn 2 O 3 ÁSiO 2 ), bixbyite ((Mn,Fe) 2 O 3 ), hematite (Fe 2 O 3 ) and carbonates ((Mg,Ca)CO 3 ), whereas Comilog is mineralogically dominated by pyrolusite (MnO 2 ), nsutite (Mn 4þ 1Àx Mn 2þ 2À2x OH ð Þ 2x ) and cryptomelane (KMn 8 O 16 ) and exhibits a relatively high level of microporosity. [29] The ores were ground and sieved into particle size fractions of 9.5 to 16 mm. The ores were chemically analyzed by SINTEF Norlab using X-ray fluorescence, while the oxygen amount connected to Mn-oxides was obtained by titration for ore, whereas Eltra (combustion-IR) was used to determine the amount of carbon, which was recalculated to CO 2 in the carbonate minerals.…”

Prereduction Behavior of Manganese Ores With Solid Carbon and in CO/CO2 Gas Atmosphere

“…This is mainly because manganese ores used by industry in the production of FeMn alloys have different origins and therefore differ in mineralogy, chemical and physical properties. Typically, metallurgical grade ores contain more than 35 pct Mn and literature [8][9][10][11][12][13][14] covers properties of ores with Comilog, CVRD, Groote Eylandt, Wessels and Mamatwan type ores as examples. Several studies [10,11,[15][16][17][18][19][20][21][22] have been conducted on the prereduction of manganese ores by either CO gas or solid carbon.…”

“…Comilog exhibit high level of microporosity and is mainly composed of pyrolusite (b-MnO 2 ), nsutite ((Mn 4+ ) (1Àx) (Mn 2+ )O (2À2x) (OH) 2x (x = 0.06 to 0.07)) and cryptomelane (K(Mn 4+ 7 ,Mn 3+ )O 16 ) minerals. UMK and Nchwaning contains both braunite-I ((Mn 2+ ,Mn 3+ )6(SiO 4 )O 8 ) and braunite-II (Ca(Mn 3+ ,Fe 3+ )6(SiO 4 )O 8 ) minerals, Nchwaning contains more bixbyite ((Mn 3+ ,Fe 3+ ) 2 O 3 ) and hematite (Fe 2 O 3 ) and less carbonate minerals compared to UMK ore. [12] Characterization of ores and products of prereduction was for porosity and chemical compositions. Techniques used for characterization include pycnometry, X-ray fluorescence (XRF), permanganometric titration, thermogravimetric and combustion-IR methods.…”