24-hour service hotline
0086 18733132385
Send us an email
xrguo@xinhaimining.net
Overview of manganese carbonate ore dressing technology
As a strategic mineral resource, manganese has an irreplaceable role in iron and steel, new energy batteries, chemical industry and other fields. China is the world's largest consumer of manganese, but due to the resource endowment of ‘small, poor, miscellaneous and fine’, the external dependence of domestic manganese ores is as high as 82%, especially high-grade manganese oxide ores are almost completely dependent on imports. Manganese carbonate ore, as the main domestic manganese resource (accounting for 56%), with an average grade of only 12%~13%, is mainly used for manganese electrolysis production, but each ton of manganese electrolysis produces 8~12 tonnes of waste residue, which brings a serious environmental burden. Therefore, upgrading the grade of manganese carbonate ore and reducing the amount of manganese slag at the source through beneficiation technology is the key to guarantee the safety and sustainable development of the industrial chain. In this paper, we systematically sort out the progress of beneficiation technology of manganese carbonate ore and discuss its development direction with examples.
Overview of manganese carbonate ore dressing technology
Ore washing removes clay and slime on the surface of ore through hydraulic or mechanical scrubbing to solve the problem of clogging in the ore crushing system. For example, Xiangtan Manganese Ore adopts the process of ‘vibrating screen water spraying + spiral classification’, and the recovery rate of washed ore reaches 94.3%, and the grade is increased by 2.43%. Although the enrichment effect of washing is limited, it creates favourable conditions for subsequent sorting, especially for ores with high mud content.
Re-election using mineral density difference sorting, applicable to coarse-grained ore. A Russian manganese carbonate ore adopts ‘X-ray pre-sorting + jigger sorting’, and the concentrate grade is increased to 37.8%. However, fine-grained manganese carbonate ore (need to be ground to -200 mesh 90% or more) due to the small density difference, the efficiency of re-election alone is low, often used in conjunction with magnetic separation and flotation, such as ‘washing - re-election - magnetic separation’ joint process.
Manganese carbonate ore is a weakly magnetic mineral (specific magnetisation coefficient 50×10-⁶~125×10-⁶ m³/kg), and strong magnetic separation is its core sorting technology. Through process innovation, Dounan Manganese Mine adopts the combined process of ‘dry permanent magnet + wet high gradient magnetic separation’, and the concentrate grade is increased from 17.5% to 28%, with a recovery rate of over 88%. High gradient magnetic separator has become the mainstream equipment for fine-grained ore sorting due to adjustable magnetic field strength and high sorting efficiency.
Flotation is the key to deal with fine-grained embedded manganese carbonate ore, which is divided into positive flotation (fatty acid type of collector) and reverse flotation (cationic collector). A low-grade ore in Guizhou (Mn 9.17%) was flown by positive flotation with ‘oleic acid + water glass’, obtaining a concentrate with a grade of 16.92% and a recovery rate of 85.13%. Pharmaceutical innovation is the focus of flotation breakthroughs, such as modified hydroxamic acid (NO-8, NO-10) in pH 6~7 when the selectivity is significantly improved, and the combination of inhibitors (water glass + sodium hexametaphosphate) can effectively separate calcite and other calcium-containing chalcopyrite.
X-ray transmission (XRT) and image colour separation technology is gradually applied to manganese carbonate ore pre-selection. A mine in Russia adopts ‘XRT pre-sorting + jigging sorting’, and the concentrate grade is increased to 28.5%, with a waste rate of 40%. Intelligent photoelectric technology can greatly reduce the amount of grinding, reduce energy consumption, is an important direction of the future low-carbon mineral processing.
For ‘poor, fine, miscellaneous’ ores, the advantages of the joint process are significant. A low-grade ore in Guangxi (Mn 7.58%) adopts ‘strong magnetic separation - flotation’ combined process, the concentrate grade reaches 18.82%, recovery rate of 87.72%; Zunyi, a high iron sulphur ore through the combination of ‘strong magnetism - reverse flotation - re-election’, the manganese recovery rate increased to 91.85%. The manganese recovery rate of a high iron sulphur ore in Zunyi was increased to 91.85% through the combination of ‘strong magnetism, reverse flotation and re-election’. The combined process achieves maximum utilisation of resources through multi-stage sorting.
© 2021 Yantai KZ Mining Processing Technology & Equipment Inc.
