Manganese and iron symbiotic ores are compound minerals with iron and manganese oxides as the main body, with homogeneous features and fine-grained embedded characteristics, which are difficult to be effectively separated by traditional beneficiation process. This paper will systematically analyze the six major separation technologies and their synergistic application strategies.
1. Gravity sorting technology
Based on the difference in specific gravity of minerals, jigger has significant effect on the processing of coarse-grained (+0.5mm) materials, and the grade of manganese concentrate can be increased by 8-12%. Typical application cases show that the combined flow of trapezoidal jigger and spiral classifier can make the removal rate of siliceous chalcopyrite reach more than 65%. However, it should be noted that the fine-grained (-0.074mm) material sorting efficiency plummeted, need to cooperate with the cyclone for classification pretreatment.
2. Magneto-electric cooperative sorting technology
For the weak magnetic hematite component, high gradient magnetic separator (field strength 1.2-1.5T) can realize the recovery rate of iron component more than 85%. The innovative magnetization roasting process (reduction temperature 750-850℃) can significantly enhance the magnetic properties of manganese minerals, and together with wet magnetic separation, the manganese recovery rate can be increased to more than 78%. The latest research shows that pulse magnetic separation technology can increase the sorting efficiency by 12% for the material of micro-fine particle size (-0.038mm).
3. Flotation sorting technology
New chelating collector (such as hydroxamic acid) with adjusting agent (water glass + sodium carbonate) can increase the recovery rate of fine-grained manganese minerals to 65% level. Industrialized applications show that inflatable flotation machine (KYF-50 type) in the slurry concentration of 30-35%, pH8-9 conditions, the concentrate grade up to 42% Mn. However, it should be noted that the cost of chemicals accounted for 35-45% of the total cost of sorting.
4. Chemical leaching separation technology
Sulfuric acid reduction leaching method (concentration 15-20%) in 85-90 ℃ conditions, manganese leaching rate of up to 92% or more. Although bioleaching technology has the advantage of environmental protection (energy saving 40%), but there are bottlenecks such as long leaching cycle (15-20 days) and poor adaptability of bacterial strains in industrialized application. Currently focus on the development of microwave-assisted leaching technology, which can shorten the reaction time to 1/3 of the traditional process.
Roasting - magnetic separation joint process for complex embedded ore processing effect is remarkable, a plant application examples show that the neutral roasting (650 ℃) after magnetic separation, iron ore concentrate grade from 52% to 68%. Fire enrichment process in the electric furnace (1500-1600 ℃) can achieve manganese slag enrichment degree of 55-60%, but there is a high energy consumption (ton of ore power consumption of 380-420kWh) of the problem.
The preferred process should follow the principle of “pre-tailing - stage sorting - depth purification”, and it is recommended to adopt the three-stage joint flow of re-election - magnetic separation - flotation, with XRT intelligent sorting equipment for pre-selection, which can reduce the subsequent processing capacity by more than 30%.
Currently, the development trend of FeMn symbiotic ore sorting technology focuses on: (1) composite force field sorting equipment development; (2) microbial-chemical synergistic leaching system; (3) big data-driven process parameter optimization.
