Sulphuric Acid Leaching Of Polymetallic Nodules Using Paper As A Reductant

Abstract

Sulphuric acid leaching of manganese nodule for extraction of Cu, Ni, Co and Mn in presence of a novel cellulosic reductant, waste newspaper, has been reported. The various parameters chosen for the study were: time, temperature, H(2)SO(4) concentration and amount of paper. To quantify the linear and interaction coefficients a 23 full factorial design of experiments was followed. The regression equations were determined and the adequacy of these equations was tested by Fischer's test. The linear coefficients for time, acid concentration and amount of paper were found to be significant for extraction of Cu, Ni, Co and Mn. While acid concentration and amount of paper showed positive interactions for Cu, Ni and Co extractions it had negative significance for Mn dissolution. Under the conditions for >97% extraction of metal values iron extraction was similar to 40%. In order to reduce the iron contamination by discarding iron as jarosite effect of addition of ammonium sulphate during leaching was also studied. Iron extraction could be brought down to 14% from similar to 40% with the addition of 30g/L (NH(4))(2)SO(4) without affecting the recoveries of other metals.