Disintegration on heating of a Brazilian manganese lump ore

Abstract

This pioneering study characterized the chemical, physical and mineralogical aspects of the Urucum Standard manganese ore typology, and evaluated some of its metallurgical characteristics, such as the main mineral heat decompositions, and the particle disintegration at room temperature and under continuous heating. A one-ton sample of ore was received, homogenized and quartered. Representative samples were collected and characterized with the aid of techniques, such as ICP-AES, XRD, SEM-EDS, BET and OM. Representative samples with particle sizes between 9.5 mm and 15.9 mm were separated to perform tumbling tests at room temperature, and thermogravimetry tests for both air and nitrogen constant flow at different temperatures. After each heating cycle, the mechanical strength of the ore was evaluated by means of screening and tumbling procedures. The Urucum Standard typology was classified as an oxidized anhydrous ore, with a high manganese content (~47%). This typology is mainly composed of cryptomelane and pyrolusite; however there is a significant amount of hematite. The Urucum Standard particles presented low susceptibility to disintegration at room temperature, but as temperature increased, susceptibility increased. No significant differences were observed between the tests done with the air or nitrogen injections.

Method to Quantify the Effect of Temperature and Rotational Speed on the Decrepitation of South African Manganese Ores in a Rotary Kiln

“…Heat decomposition cryptomelane and pyrolusite to Mn2O3 ,according to Faria this may contribute to the decrepitation phenomenon [7]. This is because according to Faria cryptomelane and pyrolusite have their volumes respectively 5.4 % and 0.6 % higher than Mn2O3 [7]. This means that the decomposition will cause a reduction in volume for these phases, and this induces stress in specific regions of the particles leading to formation of cracks.…”

“…In terms of the rotary kiln operation, one of the unknown parameters is the potential for decrepitation of the manganese ore. Decrepitation is the breakage or disintegration of particles upon heating, resulting in the production of fine particles that cause efficiency losses and reduces the gas permeability of the particle bed in the SAF [2]. Consequently, the process gas will trapped beneath the burden of raw material which may cause an eruption or an explosion [7]. Furthermore, insufficient reduction can occur due to the process gas containing CO being channeled unevenly across the burden.…”

A geometallurgical comparison between lump ore and pellets of manganese ore

“…The mixtures of these ores, which come from various mines or even from different mining fronts in the same mine, are usually defined in ferroalloy plants exclusively according to their chemical and granulometric characteristics (Faria, 2011;Olsen et al, 2007;Tangstad et al, 2004;Faria et al, 2013a).…”

“…The ore extracted from this mine mainly comprises oxides like cryptomelane, in the biggest proportion, and others like magnetite and pyrolusite. Hydroxides, like n-sutite and gibbsite also occur (Faria, 2011;Faria et al, 2013a).…”

STUDY OF PROPERTIES OF Mn ORE FINES AND POSSIBILITIES THEIR UTILIZATION IN THE PRODUCTION OF FeSiMn

“…With the continuous decrease of resources with good quality manganese ores and increasing prices of manganese ores with Mn tot content of about 50 %, the companies start to use low grade carbonate and hydrate manganese ores with manganese content of about 30 %, ores with a higher content of SiO 2 and undersized fractions of Mn ores [4]. A number of studies, which are focused on processing of the Mn ores by hydrometallurgical or pyrometallurgical methods, currently deals with the study of enrichment and processing of low grade manganese ores [5,6]. There is a study of enrichment and processing of low grade manganese ores, where iron was removed by magnetic separation.…”