Beneficiation of low-grade, high-phosphorus manganese ores of Andhra Pradesh, India, by wet high-intensity magnetic separation plus jigging or hydrocyclone classification

Jigging of the -2.8 +0.7-mm size fraction of a friable, low-grade manganese ore sample from Andhra Pradesh increased the Mn content of a concentrate b y 7% to 8%, with nit average recovery of 57%. The jig concentrate was mixed with the unjigged -0.7-mm size fraction and ground to -150 mum. The sample was then subjected to wet high-intensity magnetic separation (WHIMS). The magnetic fraction thus obtained showed an increase in Mn content of 6%, but with an overall recovery of only 50%. The results of hydrocyclone classifi cation of -150-mum ground ore indicated that the method is not capable of u pgrading the manganese content, as both ferromanganese oxides and aluminosi licate gangue minerals constitute the fine size fraction. However, when the nonmagnetic fraction obtained from the WHIMS of-150-mum ore is subjected t o hydrocyclone classification and the underflow obtained is subjected to WH IMS again, an overall recovery of about 50% to 52% is obtained with at leas t a 7% to 8% increase in the Mn content of the product. The phosphorus cont ent in the product is not reduced by either of the two combinations of meth ods. The complex association of phosphorus with all the major phases in the ore has been clearly demonstrated from the linear correlation between the distribution ratios of major constituent phases and phosphorus.