Silicomanganese production utilising low grade manganese nodules leaching residue

N S Randhawa, R K Jana, N N Das
2013 Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy  
Among several under trial processes for extract ion of base metals (Cu, Co and Ni) fro m manganese nodules (MN), the reduction-roast ammoniacal leaching {NH 4 OH/(NH 4 ) 2 CO 3 } process is considered very attractive. After the leaching of base metals fro m roast-reduced MN, a substantial quantity of residue left behind (about 70 wt. %, by mass ) as wastes for disposal or further use. Smelt ing studies showed that leached manganese nodules residue (WMNR) can be successfully utilized as raw
more » ... tilized as raw material for silico manganese production after maintain ing proper metallurgical aspects like thermodynamics, viscosity etc. Literature survey on slag liquidus and viscosity aspects of silico manganese smelt ing has been done. The slag liquidus has been found to be closely associated to slag basicity i.e. (CaO+MgO/SiO 2 ) showing significant increase above 0.7 slag basicity. Charge mix basicity of 0.2 was found to give maximu m Mn and Si recoveries. Increasing or decreasing charge basicty fro m 0.2 resulted in lo wer metallic yield and Mn and Si recoveries. Th is has been exp lained with liquidus calculations of final slags obtained at those charge mix basicities. Addition of CaF 2 during holding time i.e. time given after comp lete melt ing of charge mix was found to be beneficial. The optimu m amount of CaF 2 was 4% of WMNR+Mn ore blend, which gave rise to maximu m Mn and Si recoveries and metallic yield. Further addition of CaF 2 (>4%) produced a high basicity slag (basicity =0.83) having very high liquidus leading to decrease in metallic y ield and Mn and Si recoveries.
doi:10.1179/1743285512y.0000000022 fatcat:bbewyahpjbelhezbl2spt3m4fq